Field Survey Guidance Manual:
2003 Version
River Habitat Survey in Britain and Ireland
CONTENTS
Glossary of acronyms
Icons used as prompts for surveyors
Acknowledgements
PART ONE – INTRODUCTION AND GENERAL GUIDANCE
Preamble
Scope of the manual
Health and safety
Access and permissions
Preparatory work
The survey form
General site and surveyor information
Spot-checks
Sweep-up information
Channel dimensions, influences and special features
Suitable conditions and season
Quality control
Contact for enquiries
References
PART TWO – THE HEALTH AND SAFETY FORM, SPOT-CHECK KEY AND 2003 RHS FORM
Site health and safety assessment
RHS spot-check key
RHS field survey forms
PART THREE – DEFINITIONS AND DETAILED GUIDANCE
PART FOUR – PHOTOGRAPH GALLERY
PART FIVE – TECHNICAL APPENDICES
Appendix 1 Health & Safety Guidance
General guidelines
Risk assessment for River Habitat Survey
Appendix 1.1 – Risk assessment form
The site health and safety form
Personal safety
Life jackets
Weil’s disease
Lyme disease
Appendix 1.2 – Site health and safety assessment form
Appendix 2 Lone Working Guidance
Risk assessment
Safe system for lone working
Appendix 3 Diseased Alder Leaflet
Appendix 4 Main differences between the 1997 and 2003 RHS survey forms
River Habitat Survey Manual: 2003 version
1
1.1
1.2
1.2
1.2
1.3
1.3
1.3
1.3
1.6
1.6
1.6
1.7
1.7
1.8
2
2.2
2.3
2.5
3
4
5
5.1
5.1
5.1
5.2
5.3
5.3
5.3
5.3
5.3
5.4
5.5
5.5
5.6
5.7
5.13
GLOSSARY OF ACRONYMS USED IN THE TEXT
CFMP Catchment Flood Management Plan
GQA General Quality Assessment
EA Environment Agency
EHSNI Environment and Heritage Service, Northern Ireland
EU European Union
H&S Health and Safety
NGR National Grid Reference
OS Ordnance Survey
GPS Global Positioning System
PPE Personal Protection Equipment
RBMP River Basin Management Plan
RHS River Habitat Survey
RQO River Quality Objective
SEPA Scottish Environment Protection Agency
SERCON System for Evaluating Rivers for Conservation
SNH Scottish Natural Heritage
SNIFFER Scotland and Northern Ireland Forum for Environmental Research
UK United Kingdom
ICONS USED TO PROMPT SURVEYORS
Rare feature
Photograph in photo gallery
Reminder of survey approach
Video to be used in training
Health and safety issue
ACKNOWLEDGEMENTS
The Forestry Commission for permission to publish Appendix 3, and Centre for Ecology and Hydrology,
River Eden Trust, Angela Walker and Richard Collingridge for all providing photographs for inclusion
within the manual.
River Habitat Survey Manual: 2003 version
PART ONE – INTRODUCTION AND GENERAL GUIDANCE
Preamble
1.1 River Habitat Survey (RHS) is a method designed to characterise and assess, in broad terms, the physical
structure of freshwater streams and rivers. The field survey element does not require specialist
geomorphological or botanical expertise, but recognition of vegetation types and an understanding of
basic geomorphological principles and processes are needed.
1.2 RHS is carried out along a standard 500m length of river channel. Observations are made at ten equally
spaced spot-checks along the channel, whilst information on valley form and land-use in the river
corridor provides additional context.
1.3 The underlying need for any observational method such as RHS is confidence in the survey data. This
means consistent recording of features by competent, well-trained, and accredited surveyors as well as
checks on subsequent data-entry onto the computer database.
1.4 The field survey has been designed, tested and improved as a result of extensive use on rivers in the UK
since 1994. The 2003 version represents the first major overhaul of the form design, revision of some
component elements, and updating of the guidance manual, since 1997. The major differences
between the 1997 and 2003 versions are summarised in Appendix 4.
1.5 Improvements in the contents and design of the form and the supporting guidance have been
necessary to remedy weaknesses in the consistency of recording.
1.6 The 2003 version addresses a number of these weaknesses by:
• providing more comprehensive definitions and guidance;
• including a greatly expanded photographic section;
• using a more user-friendly ‘icon’ system that highlights difficult features, health and safety issues
and rare features, all of which need particular attention;
• introducing more stringent requirements for recording grid references and photographic
information;
• introducing a mandatory health and safety risk assessment component;
• including a logical cross-check list to help minimise the chances of incomplete recording.
1.7 The importance of consistent recording, and also completing all elements of the survey form, is
paramount. Incomplete forms, and those with inadequate details of site location or photographic
evidence, will not be acceptable, and not entered onto the RHS database. There is an underlying
principle that any unusual feature, or any aspect which a surveyor is uncertain about, should be
recorded as a special note and a photograph taken to provide supporting evidence whenever possible.
1.8 Surveyor accreditation is needed for data to be entered onto the RHS database. This means surveyors
attending a training course using the 2003 version, and passing an accreditation test.
1.9 The RHS database contains field observations, map-derived information and photographs from more
than 4600 RHS baseline survey sites visited in 1994-96 and over 12,000 subsequent surveys. The 1994-
96 baseline network comprised a geographically representative cross-section of streams and rivers,
selected on a stratified random basis, with the 10km grid squares of the Ordnance Survey as a sampling
framework.
1.10 An overview of the physical condition of streams and rivers in the UK and Isle of Man was published in
19981
, using the baseline data.
1.11 Since then, surveys have been used for a number of purposes, including: determining the catchment
characteristics of several rivers in the UK; identifying the attributes of known top quality ‘benchmark’
sites; investigating possible species–habitat relationships; and providing input to environmental impact
assessment2
. An educational CD-ROM has also been produced, using a simplified version of the RHS
database3
.
1.12 RHS has also been tested in other European countries such as Finland, France, Austria, Portugal
(Madeira), Italy and Slovenia with a view to adapting the survey for local conditions. Cross-comparison
between RHS and other methods for surveying river hydromorphology in Europe has also been carried
out4
, with a view to producing standard guidance on techniques for assessing the physical
characteristics of watercourses5
.
1.13 The European Water Framework Directive has had a major influence in the development of RHS.
Indeed, the prototype of the survey was developed in anticipation of the requirements of such a
Directive as long ago as 1992.
1.1 River Habitat Survey Manual: 2003 version
1.14 The uses and sampling strategy for RHS depend on the purpose of gathering the survey information.
Given its primary objective of context-setting, RHS can be used in general surveillance as well as sitespecific
surveys6
. What it cannot do, and never was intended to do, is to provide the level of detail
needed for specialised survey work for specific plant and animal groups. Nevertheless, RHS can provide
a consistent framework within which aquatic macro-invertebrate, macrophyte, fish and
geomorphological surveys can be set.
1.15 Although RHS conforms with the basic requirements for the draft guidance standard on assessing the
hydromorphological characteristics of rivers5
, additional information on floodplain features and
hydrology is also required for full compliance.
1.16 RHS also helps to provide information on river structure, vegetation character and land-use required for
SERCON (System for Evaluating Rivers for Conservation), an assessment system that has scoring systems
for several attributes in relation to determining the nature conservation value of rivers7
.
Scope of the manual
1.17 Guidance is provided on the fieldwork survey element of the core RHS method only. It does not cover
map-based information gathering or additional modules such as the one being developed for gathering
specialist geomorphological information. Details on this module, and the links with other surveys, can
be obtained from the RHS team at the Environment Agency in Warrington (see 1.61).
1.18 The manual does not detail how to undertake preparatory work prior to a survey, gaining landowner
permission, or how to link RHS to other surveys that may be carried out in tandem with RHS. All these
aspects need to be planned and agreed between the commissioning organisation and the surveyor well
before fieldwork is carried out.
1.19 The core method described is a UK one and is designed specifically for conditions in Great Britain and
Ireland. Development of European versions of RHS is continuing. Further details can be obtained from
the RHS team at Warrington.
1.20 The contents of the guidance are linked to the sequence of questions on the 2003 Survey form and are
largely self-explanatory. Special icons are used to highlight issues requiring particular attention, such
as when health and safety issues may be of special significance, features that are particularly rare in the
UK, and where photos or videos help to illustrate features.
1.21 Essential equipment for undertaking RHS field surveys includes: survey forms in a waterproof document
holder; laminated spot-check key; ranging-pole; range-finder; digital or a slide transparency camera;
global positioning system for recording locational data and a mobile telephone (or other means of
communication) in case of emergency. If the planned means of communication is by mobile phone, it
is important to check that there is an adequate signal in the area being surveyed.
Health and safety
1.22 It is imperative that all surveys are conducted in conditions which are safe for surveyors (Appendix 1).
A health and safety assessment is an integral part of the survey and the form must be completed
before embarking on the survey, and attached with the completed survey forms.
1.23 The Environment Agency Lone Working Guidance (Appendix 2) must be followed and surveyors must
never put themselves in a position in which they are not in control. This applies to all surveyors working
for, or commissioned by the Environment Agency (EA), Scottish Environment Protection Agency (SEPA)
Environment and Heritage Service, Northern Ireland (EHSNI) and Scottish Natural Heritage (SNH).
1.24 In areas of high risk, it is strongly recommended that a team of two undertakes a survey.
1.25 Not starting, or abandoning a survey when the risk is too high should be the principle that applies
throughout.
Access and permissions
1.26 Whenever practicable, permission from landowners and occupiers should be obtained before surveys
are carried out. This is not always feasible or possible, so if challenged RHS surveyors should be polite,
courteous and provide an explanation of what they are doing and why, and on whose authority. In
some instances, this may mean having to return to do the survey if the landowner requires further
clarification as to the purpose of the work. Identification must be carried by surveyors at all times.
Surveyors should comply with disinfection requests from landowners.
1.2River Habitat Survey Manual: 2003 version
1.27 Surveyors can offer to provide information to landowners if they are interested in receiving it.
Preparatory work
1.28 Experience suggests that some RHS surveyors, no matter how experienced, can still overlook channel
modifications. It is therefore recommended that some preparatory briefing is undertaken before visiting
the site. For example, looking at the river planform and river name on a map will provide clues as to
whether the watercourse has undergone historical channel management. Documentation of past flood
defence works is also a source of invaluable information. Such information will help provide context for
site characterisation, but should NOT over-ride field observations.
The survey form
1.29 The RHS survey form is four pages long and is accompanied by a separate two-page spot-check key.
The health and safety form is integral to the survey and should not be detached. It is recommended
that a clipboard or “Weather-writer” is used, and a waterproof laminated version of the spot-check key
taken into the field at all times.
1.30 Surveyors are required to record the presence, absence, and in some cases the number or extent, of
specific features. Four basic types of records are made:
- counting the number of certain features within the whole 500m site (riffles, pools, unvegetated
and vegetated point bars, and artificial features);
- ticking boxes () to indicate whether a feature is absent, present or extensive;
- entering a two-letter acronym for features in the spot-check section;
- taking measurements of the channel such as height, width and depth.
1.31 Where there is a choice of features to be scored, but only a single entry is allowed, boxes on the survey
form are either ‘shadowed’ (❏) or have emboldened edges ( ).
General site and surveyor information
1.32 Information about the surveyor, general site characteristics and details about when and how the survey
has been undertaken are entered in Section A on Page 1. For most accurate recording, it is best to
survey from both the river and the bank, but the overriding importance of health and safety issues will
determine precisely how the survey is undertaken.
1.33 Section B requires information on the general valley shape and valley-floor to be recorded.
1.34 Most of the information in both Sections A and B of the form can be completed on arrival at a site, or
at the end of the survey, as appropriate.
1.35 The actual number (including zero) of riffles, pools, unvegetated and vegetated point bars is recorded
in Section C. This is best done by keeping a cumulative record of the number of these individual
features when walking between spot-checks, and then tallying them up on completion of the survey.
1.36 Section D on page 1 requires the number of different types and extent of artificial structures to be
recorded. As with counting riffles (Section C), a cumulative record is made during the survey and a tally
made on completion of the survey. Again, zero must be recorded if none are present.
Spot-checks
1.37 Spot-checks are designed to record predominant channel, bank and river corridor features at 10
locations spaced evenly along the 500m RHS site. Data for spot-checks are entered on page 2 of
the form.
1.38 Spot-checks should be located at regular (approximately 50m) intervals along the site. To do this
consistently each surveyor should calibrate their stride length beforehand to identify how many
of their paces represent 50m. Rangefinders can be used for calibration too. It is best to use small
strides – this tends to allow features between spot-checks to be observed and noted more comfortably.
Adjustments may be needed, especially in difficult terrain because it may not always be possible to
access the channel at precisely every 50m. Make a note on the form when this happens.
1.39 At each spot-check information relating to the channel, banks and adjacent land is recorded. This
includes: predominant channel substrate and flow-type; habitat features; modifications to the channel and
banks; channel vegetation types; vegetation structure of the banks and banktop; and land-use. Physical
1.3 River Habitat Survey Manual: 2003 version
features (Section E) are assessed using a 1m wide “transect” across the channel, while all other elements
in Sections F and G are assessed within a 10m wide transect across the river (Figure 1).
1.40 In Sections E and F, spot-check entries are abbreviations. Each entry must use the relevant unique twoletter
abbreviation (e.g. BO = boulder; RI = reinforced bank). All abbreviations are listed as prompts on
the form and are detailed in the spot-check key. Most are easily learnt by surveyors, but having a
laminated copy of the spot-check key in the field allows double-checking in cases of doubt.
1.41 For boxes in Sections E and F with emboldened borders, only a single entry is allowed. This is for
recording the predominant feature only, even though there may be more than one present. Do not
spend long deliberating over which option is the predominant one. Initial reaction is the quickest, and
usually the best, method.
1.42 In boxes without emboldened borders more than one entry is allowed; for example, bank modification
may include both resectioning [RS] and reinforcement [RI].
1.43 Section G provides a list of channel vegetation types; those present are recorded as either a ‘’ provided
they cover at least 1% of the channel area, or as an ‘E’ if more than one third of the channel area within
the 10m wide transect is covered. Records have to be made for each spot-check, including ‘none’ or
‘not visible’. The end column also has to be completed to provide an overview of the presence and
extent of each vegetation type throughout the site as a whole.
1.44 The primary reason for recording at spot-checks is to bring greater consistency of data collection. Each
spot-check column should be completed in sequence. In most instances each spot-check should take
no more than two minutes to complete, particularly since all emboldened boxes and most of the others
too, will have just a single entry. For rivers with complex structure, spot-check recording may take a
little longer – conversely, uniform watercourses will take less time.
1.45 It is essential that all boxes in Sections E and F (and at least one in Section G) are completed
at each spot-check before moving to the next one. It is not possible to complete an acceptable
RHS survey if any of the boxes in Sections E and F do not have entries. Figure 2 shows a
completed spot-check section of the RHS form.
1.4River Habitat Survey Manual: 2003 version
SPOT-CHECK
WETTED
CHANNEL
AREA
CHANNEL VEGETATION
TYPES
BANKFACE VEGETATION
STRUCTURE
LAND-USE
WITHIN 5m
VEGETATION STRUCTURE
WITHIN 1m
PHYSICAL ATTRIBUTES
BANK TOP
RIGHT BANK
LEFT BANK
FLOW
1m
1m
5m
10m
Figure 1 Diagram showing dimensions for spot-checks
INSERT Figure 2 as scanned page (will be a scanned copy of a completed page 2 of 2 of 4)
Figure 2 Example of a completed page 2 of the 2003 RHS form
1.5 River Habitat Survey Manual: 2003 version
Sweep-up information
1.46 Page 3 of the form is designed for recording general information by means of a ‘sweep-up’ checklist.
This is usually best done when walking back along the RHS site following completion of the spot-checks.
The sweep-up represents an assessment of the extent of features over the whole 500m length, and will
include those features not occurring at the spot-checks. Since the sample length is 500m and the
ten-spot-checks are 50m apart, it is important to include the remaining 50m of the sample length
in the sweep-up assessment. This means walking an extra 50m beyond the tenth spot-check and
taking a GPS reading.
1.47 Features in the sweep-up are recorded by entering a ‘’ for those present in at least 1% of the site and
‘E’ for those extending more than 33% along the site. This type of recording is used in Sections H and
I to provide information on land-use and bank profiles. Some features may be important, even if they
do not extend 1% along an RHS site. Such features include underwater tree roots, and all such
categories are marked with an asterisk (*) to highlight they are special cases, and can be recorded as
present even if they do not occur along >1% of the site.
1.48 Information on trees (Section J) is recorded in a tick box format, with categories for the distribution
pattern of trees along each bank, and whether associated features such as ‘underwater tree roots’ or
‘large woody debris’ are absent, present or extensive along the channel as a whole.
1.49 The extent (absence, presence or extensive occurrence) of specific channel features is recorded in
Section K. The check-list represents a range of flow-types and river channel features that are readily
identified in the field. An assessment of their presence, absence and overall extent enables a broad
picture of river character to be established. The five features marked by an *asterisk (e.g. *free fall flow)
can be recorded as ‘present’ even if they do not occur along at least 1% of the site.
Channel dimensions, influences and special features
1.50 Page 4 of the form contains Section L – channel dimensions. These are measured at one location
within the 500m. Ideally, that location should be in a straight or uniform reach (i.e. not on a sharp
bend), with clearly defined banks and preferably across a riffle. If riffles are not present in the site, a
uniform location with clearly defined banks should be used. Channel dimensions do not have to be
measured at a spot-check.
1.51 Guidance on how to measure the channel is included in the spot-check key. Where it is safe to do so,
the bankfull width, wetted water width and water depth should be recorded, preferably using the
ranging pole. A rangefinder will be needed for estimating the width of larger rivers, and these
instruments should be calibrated regularly.
1.52 Page 4 also establishes the absence, presence () or extensive occurrence (E) of the following: ‘features
of special interest’ (Section M); ‘notable nuisance plants’ (Section O); and alders, including diseased
trees (Section Q). Features marked by an *asterisk (e.g. *leafy debris) can be recorded as ‘present’ even
if they do not occupy at least 1% of the site.
1.53 Section N requires surveyors to record whether or not the channel is choked with vegetation. This is
important since RHS might be carried out at times when plant growth in rivers is at its greatest.
1.54 Section P contains text prompts to assist surveyors in describing the overall characteristics of the site,
as well as providing a space for noting other relevant observations. Additional relevant observations are
encouraged and these should be included on a separate sheet, provided that the mid-site grid reference
is clearly marked on it.
1.55 Section R contains seven cross-check prompts to ensure that all parts of the survey form have been
completed correctly.
Suitable conditions and season
1.56 RHS should never be carried out during flood (spate) flows because there are major safety risks
involved. High water levels and turbidity will also obscure many of the features RHS is designed to
record and give a false impression of flow-types compared with those expected under dry-weather
conditions. If a prolonged period of heavy rain occurs, a survey should be delayed until both water
level and clarity, return to acceptable levels.
1.57 In some lowland UK rivers abundant growth by emergent and bankside vegetation in summer will
obscure some channel features. Surveys during this period should be avoided: May and June are
1.6River Habitat Survey Manual: 2003 version
considered the most suitable months. Upland rivers with little or no emergent vegetation are suitable
for surveying over a much longer season.
1.58 If, for special reasons, surveys have to be carried out during non-optimal months, interpretation of the
results will need to take full account of seasonal aquatic and bankside vegetation growth.
1.59 Likewise, in countries with different climatic conditions from the UK, surveys should be ideally carried
out when aquatic vegetation growth is evident, but not excessive, and water levels are not high.
Quality control
1.60 Each RHS form must be checked for completeness. A simple set of questions is included as a checklist
in Section R of the form. These should be used to check the completion of relevant components of the
form, and the boxes on the right of the form should be ticked after checks have been made. An extra
two minutes for quality control at the end of each survey is invaluable, because incomplete forms will
be returned, and a re-survey may be needed.
1.61 It is important that completed RHS forms are legible, the pages stapled together with a site reference
clearly marked on all pages. If an extra sheet is used for additional observations, make sure this is
similarly marked and firmly attached.
1.62 Of equal importance is the need to clearly label all photographs, and ensure they match the
references given on page 1 of the form.
1.7 River Habitat Survey Manual: 2003 version
Contact for enquiries
1.63 Queries and further information on this manual should be addressed to:
The RHS Team,
Environment Agency,
Richard Fairclough House,
Knutsford Road,
Warrington,
Cheshire WA4 1HG
Tel: 01925 653999
Fax: 01925 415961
E-mail: rhs@environment-agency.gov.uk
General Enquiry: 0845 9333111
References
1 P.J. Raven, N.T.H. Holmes, F.H. Dawson, P.J.A. Fox, M. Everard, I.R. Fozzard and K.J. Rouen (1998).
River Habitat Quality – the physical character of rivers and streams in the UK and the Isle of Man.
Environment Agency, Bristol.
2 Special Issue: The Application of Classification and assessment Methods to River Management in
the UK (1998). Aquatic Conservation: Marine and Freshwater Ecosystems 8(4), 383-644.
3 D. Hawley, P. J. Raven, K. L. Anstey, S. Crisp, D. Freeman, J. Cullis (2002). Riverside Explorer: an
educational application of River Habitat Survey information. Aquatic Conservation: Marine and
Freshwater Ecosystems 12 (4), 457-469.
4 P. J. Raven, N. T. H. Holmes, P. Charrier, F. H. Dawson, M. Naura and P. J. Boon (2002). Towards
a harmonized approach for hydromorphological assessment of rivers in Europe: a qualitative
comparison of three survey methods. Aquatic Conservation: Marine and Freshwater Ecosystems
12(4), 405-424.
5 BSI 03/300309 DC. (2003). Draft British Standard BS EN 14614 Water Quality - Guidance Standard
for Assessing the Hydromorphological Features of Rivers. British Standards Institute.
6 P.J. Raven, P. J. Boon, F. H. Dawson and A. J. D. Ferguson (1998). Towards an integrated approach
to classifying and evaluating rivers in the UK. Aquatic Conservation: Marine and Freshwater
Ecosystems 8(4), 383-394.
7 P.J. Boon, N.T.H. Holmes, P.S. Maitland and I.R. Fozzard (2002). Developing a new version of
SERCON (System for Evaluating Rivers for Conservation). Aquatic Conservation: Marine and
Freshwater Ecosystems 12(4), 439-455.
8 C.E. Wentworth (1922). A scale of grade and class terms for clastic sediments. Journal of Ecology
30, 377-392. (Referenced in Section E: Physical attributes – channel substrates.)
1.8River Habitat Survey Manual: 2003 version
PART TWO
• Site Health and Safety Assessment
• Spot-check Key (2003 Version)
• River Habitat Survey Forms (2003 Version)
2.1 River Habitat Survey Manual: 2003 version
2.2River Habitat Survey Manual: 2003 version
RIVER HABITAT SURVEY 2003 VERSION: SITE HEALTH AND SAFETY ASSESSMENT
IF THERE ARE ANY HIGH RISKS OR MORE THAN THREE MODERATE RISKS
DO NOT CONTINUE WITH THE SURVEY.
Site Number
1
:
1 Leave blank if new site. 2 Optional
Grid References/Co-ordinates: Spot 1
2
: End of site
2
:Mid-site:
Accredited Surveyor Code:Surveyor Name:
Weather Conditions:
Flow Conditions:
Site details: (enter comments or circle if applicable and give details)
Risk Level
(Low/Mod/High)
Access and Parking:
(entry & exit)
Conditions: comment on ground stability, footing, exposure/remoteness
Obstacles/Hazards: fencing, stiles, dense vegetation, steep bank
Occupied/Unoccupied: people, livestock, animals
Activities/Land-use: agriculture, woodland, residential, industrial, construction, recreational
Risk if lone-working
Lyme Disease
1. Dress appropriately with skin covered up.
2. Regularly inspect for ticks when in the field.
3. Check for, and remove, any ticks as soon as possible after leaving the site.
4. Seek medical attention if bitten by a tick.
Site Ref: River Name: Date:
Weil’s Disease (Leptospirosis)
Instructions to card holders
1.
2.
3.
4.
5.
6.
As infection may enter through breaks in the skin, ensure that any cut, scratch or abrasion is
thoroughly cleansed and covered with a waterproof plaster.
Avoid rubbing your eyes, nose and mouth during work.
Clean protective clothing, footwear and equipment etc. after use
After work, and particularly before taking food or drink, wash hands thoroughly.
Report all accidents and/or injuries, however slight.
Keep your card with you at all times.
2.3 River Habitat Survey Manual: 2003 version
PHYSICAL ATTRIBUTES (SECTION E)
RIVER HABITAT SURVEY 2003 VERSION: SPOT-CHECK KEY Page 1 of 2
Predominant bank
material
NV = not visible
BE = bedrock
BO = boulder
CO = cobble
GS = gravel/sand
EA = earth (crumbly)
PE = peat
CL = sticky clay
CC = concrete
SP = sheet piling
WP = wood piling
GA = gabion
BR = brick/laid stone
RR = rip-rap
TD = tipped debris
FA = fabric
BI = bio-engineering
materials
Bank modifications
NK = not known
NO = none
RS = resectioned (reprofiled)
RI = reinforced
PC = poached
PC(B) = poached (bare)
BM = artificial berm
EM = embanked
Marginal and bank
features
NV = not visible (e.g. far
bank)
NO = none
EC = eroding cliff (EC if
sandy substrate)
SC = stable cliff (SC if
sandy substrate)
PB
VP
= unvegetated point bar
= vegetated point bar
VS
SB = unvegetated side bar
= vegetated side bar
NB = natural berm
Predominant substrate
NV = not visible
BE = bedrock
BO = boulder
CO = cobble
GP = gravel/pebble
(G or P if
predominant)
SA = sand
SI = silt
PE = peat
Channel modifications
NK = not known
NO = none
CV = culverted
RS = resectioned
RI = reinforced
DA = dam/weir/sluice
FO = ford (man-made)
Channel features
NV = not visible
NO = none
EB = exposed bedrock
RO = exposed boulders
MB = unvegetated midchannel
bar
VB = vegetated midchannel
bar
MI = mature island
TR = Trash (urban debris)
VR = vegetated rock
FLOW-TYPES DESCRIPTION
FF: Free fall clearly separates from back-wall of vertical feature ~ associated with waterfalls
CH: Chute low curving fall in contact with substrate ~ often associated with cascades
BW: Broken standing waves white-water tumbling waves must be present ~ mostly associated with rapids
UW: Unbroken standing waves upstream facing wavelets which are not broken ~ mostly associated with riffles
CF: Chaotic flow a chaotic mixture of three or more of the four fast flow-types with no predominant
one obvious
RP: Rippled no waves, but general flow direction is downstream with disturbed rippled surface ~
mostly associated with runs
UP: Upwelling heaving water as upwellings break the surface ~ associated with boils.
SM: Smooth perceptible downstream movement is smooth (no eddies) ~ mostly
associated with glides
DR: No flow (dry) dry river bed
Coarse sand
Gravel
Pebble
SA GP CO
Cobble (to size of A4 page)
Scale
BANKS CHANNEL
NB: assessed by intermediate axis
NP: No perceptible flow no net downstream flow ~associated with pools, ponded reaches and marginal
deadwater
CL = clay
EA = earth
AR = artificial
Predominant flow-type
FF = free fall
CH = chute
NV = not visible
UWB = broken standing
CF = chaotic flow
RP = rippled
UP = upwelling
SM = smooth
NP = no perceptible flow
DR = no flow (dry)
waves (white water)
UW = unbroken standing
waves
2.4River Habitat Survey Manual: 2003 version
TL = Tilled land
IL = Irrigated land
PG = Parkland or gardens
NV = Not visible
BL = Broadleaf/mixed woodland (semi-natural)
BP = Broadleaf/mixed plantation
CW = Coniferous woodland (semi-natural)
CP = Coniferous plantation
SH = Scrub & shrubs
OR = Orchard
WL = Wetland (e.g. bog, marsh, fen)
MH = Moorland/heath
LAND-USE WITHIN 5m OF BANKTOP (SECTION F) & 50m (SECTION H)
BANKTOP AND BANKFACE VEGETATION STRUCTURE To be assessed within a 10m wide transect (SECTION F)
bare earth/rock etc.
predominantly one type (no scrub or trees)
two or three vegetation types
four or more types
Channel dimensions guidance (Section L)
Select location on
uniform section.
If riffle is present,
measure there. If not,
measure at straightest
and shallowest point.
Banktop = first major
break in slope above which
cultivation or development
is possible.
Bankfull = point where
river first spills on to floodplain.
Banks are determined by looking downstreamLEFT RIGHT
EMERGENCY HOTLINE 0800 80 70 60
24 hour free emergency telephone line for reporting all environmental incidents relating to air, land and water.
bare B
U
S
C
bryophytes
short/creeping
herbs or grasses
tall herbs/
grasses
scrub or shrubs
saplings and
trees
vegetation types
uniform
simple
complex
CHANNEL MODIFICATION INDICATORS
One or more of the following may be indicative of resectioning:
1. Uniform bank profile
2. Straightened planform
3. Bankfull width/bankfull height ratio <4:1
4. Uniform/low energy flow-types
5. No trees/uniformly-aged trees along bank
6. Intensive/urban land-use
AW = Artificial open water
OW = Natural open water
RP = Rough unimproved
grassland/pasture
IG = Improved/semi-improved grassland
TH = Tall herb/rank vegetation
RD = Rock, scree or sand dunes
SU = Suburban/urban development
RIVER HABITAT SURVEY: SPOT-CHECK KEY Page 2 of 2
Cross-section of channel showing definitions
used to define where spot-check recording
and channel dimensions measured
Break in slope
Bankfull width
Bank slope too steep
for cultivation
Water
width
Bankfull
height
Banktop
and
Bankfull
height
Banktop
height
Water depth
Bankface vegetation
structure
Vegetation structure
within 1m of banktop
Land-use within
5m and 50m
2.5 River Habitat Survey Manual: 2003 version
RIVER HABITAT SURVEY 2003 Version Page 1 of 4
A FIELD SURVEY DETAILS
B PREDOMINANT VALLEY FORM (within the horizon limit) (tick one box only)
Distinct flat valley bottom?
shallow vee
deep vee
gorge
C NUMBER OF RIFFLES, POOLS AND POINT BARS (enter total number in boxes)
Riffle(s)
Pool(s)
Unvegetated point bar(s)
Vegetated point bar(s)
Natural terraces? No Yes
(tick one box only)
Is water impounded by weir/dam? No Yes, <33% of site >33% of site
If
none,
tick
box
Is channel obviously realigned? No Yes, <33% of site >33% of site
Is channel obviously over-deepened? No Yes, <33% of site >33% of site
Weirs/sluices
Culverts
Bridges
Other - state
Fords
Major Intermediate Minor Major Intermediate Minor
U-shape valley
asymmetrical valley
concave/bowl
no obvious valley sides
D ARTIFICIAL FEATURES (indicate total number of occurrences of each category within the 500m site)
No Yes
Deflectors/
groynes/croys
Outfalls/
intakes
When options shown with ‘shadow boxes’, tick one box only
LEFT banks determined by facing downstream RIGHT
Site Number:
leave blank if new site
Site Reference:
Spot-check 1 Grid Ref:
Spot-check 6 Grid Ref:
River name:
Reach Reference:
Date / /20 Time:
Surveyor name:
Accredited Surveyor code:
End of site Grid Ref:
ArtificialIs the site part of a river or an artificial channel? River
No YesAre adverse conditions affecting survey?
Is bed of river visible?
If yes, state ........................................................................................
Is health and safety assessment form attached?
Number of photographs taken:
partiallybarely or not entirely+
NoYes
Photo references:
Site surveyed from: left bank right bank channel
2.6River Habitat Survey Manual: 2003 version
G CHANNEL VEGETATION TYPES (to be assessed over a 10m wide transect: use E ( > 33% area), (present) or NV (not visible)
Page 2 of 4
Spot-check 1 is at: upstream end of site (tick one box)downstream end
Material NV, BE, BO, CO, GS, EA, PE, CL, CC, SP, WP, GA, BR, RR, TD, FA, BI
Bank modification(s) NK, NO, RS, RI, PC(B), BM, EM
Marginal & bank feature(s) NV, NO, EC, SC, PB, VP, SB, VS, NB
Channel substrate NV, BE, BO, CO, GP, SA, SI, CL, PE, EA, AR
Flow-type NV, FF, CH, BW, UW, CF, RP, UP, SM, NP, DR
Channel modification(s) NK, NO, CV, RS, RI, DA, FO
Channel feature(s) NV, NO, EB, RO, VR, MB, VB, MI, TR
Material NV, BE, BO, CO, GS, EA, PE, CL, CC, SP, WP, GA, BR, RR, TD, FA, BI
Bank modification(s) NK, NO, RS, RI, PC(B), BM, EM
Marginal & bank feature(s) NV, NO, EC, SC, PB, VP, SB, VS, NB
LAND-USE WITHIN 5m OF LEFT BANKTOP
LAND-USE WITHIN 5m OF RIGHT BANKTOP
Submerged fine-leaved
Submerged linear-leaved
B/U/S/C/NV
B/U/S/C/NV
B/U/S/C/NV
B/U/S/C/NV
For braided rivers only: number of sub-channels
When boxes ‘borderedbordered’, only one entry allowed
RIVER HABITAT SURVEY: TEN SPOT-CHECKS Page 2 of 4
E PHYSICAL ATTRIBUTES (to be assessed across channel within 1m wide transect)
1 GPS 2 3 4 5 6 GPS GPS7 8 9 10
LEFT BANK
CHANNEL
RIGHT BANK
F BANKTOP LAND-USE AND VEGETATION STRUCTURE (to be assessed over a 10m wide transect)
Land-use: choose one from BL, BP, CW, CP, SH, OR, WL, MH, AW, OW, RP, IG, TH, RD, SU, TL, IL, PG, NV
LEFT BANKTOP (structure within 1m)
LEFT BANK-FACE (structure)
RIGHT BANK-FACE (structure)
RIGHT BANKTOP (structure within 1m)
None ( ) or Not Visible (NV)
Liverworts/mosses/lichens
Emergent broad-leaved herbs
Emergent reeds/sedges/rushes/grasses/horsetails
Floating-leaved (rooted)
Free-floating
Amphibious
Submerged broad-leaved
Filamentous algae
Use end column for overall assessment over 500m, including types not occurring in spot-checks (use , E or NV)
Ring EC or SC if composed of sandy substrate
GP- ring either G or P if predominant
Ring EC or SC if composed of sandy substrate
Enterchannelsubstrate(s)notoccurringaspredominantin
spot-checksbutpresentin>1%ofwholesite.
SITE REF.
2.7 River Habitat Survey Manual: 2003 version
None Present E(>33%) None Present E (>33%)
None
Isolated/scattered
Regularly spaced, single
Occasional clumps
Semi-continuous
Continuous
Shading of channel
*Overhanging boughs
*Exposed bankside roots
*Underwater tree roots
Fallen trees
Large woody debris
None Present E (>33%)Left Right
TREES (tick one box per bank) ASSOCIATED FEATURES (tick one box per feature)
EXTENT OF TREES AND ASSOCIATED FEATURES *record even if <1%
EXTENT OF CHANNEL AND BANK FEATURES (tick one box for each feature) *record even if <1%
J
K
BANK PROFILESI
Tall herb/rank vegetation (TH)
Scrub & shrubs (SH)
Moorland/heath (MH)
Orchard (OR)
Coniferous plantation (CP)
Rock, scree or sand dunes (RD)
Broadleaf/mixed woodland (semi-natural) (BL)
L R
Rough/unimproved grassland/pasture (RP)
Improved/semi-improved grassland (IG)
Tilled land (TL)Wetland (e.g. bog, marsh, fen) (WL)
Natural open water (OW)
Suburban/urban development (SU)
Use (present) or E (> 33% banklength)
H LAND-USE WITHIN 50m OF BANKTOP Use (present) or E (> 33% banklength)
RIVER HABITAT SURVEY : 500m SWEEP-UPSITE REF. Page 3 of 4
L R
Coniferous woodland (semi-natural) (CW)
Broadleaf/mixed plantation (BP)
Parkland or gardens (PG)Artificial open water (AW)
Irrigated land (IL)
Natural/unmodified
Vertical/undercut
Vertical with toe
Steep (>45 )
Gentle
Composite
L R RLArtificial/modified
Resectioned (reprofiled)
Reinforced - whole
Reinforced - top only
Reinforced - toe only
Artificial two-stage
Poached bank
Embanked
Natural berm
Not visible (NV)
Exposed bedrock*Free fall flow
Exposed bouldersChute flow
Broken standing waves Vegetated bedrock/boulders
Unvegetated mid-channel bar(s)Unbroken standing waves
Vegetated mid-channel bar(s)Rippled flow
Mature island(s)*Upwelling
Unvegetated side bar(s)Smooth flow
No perceptible flow Vegetated side bar(s)
No flow (dry) Unvegetated point bar(s)
Marginal deadwater Vegetated point bar(s)
*Unvegetated silt deposit(s)Eroding cliff(s)
*Discrete unvegetated sand deposit(s)Stable cliff(s)
*Discrete unvegetated gravel deposit(s)
Set-back embankment
2.8River Habitat Survey Manual: 2003 version
*Debris dam(s)
Have you taken at least two photos that illustrate the general character of the site and additional photos of any weirs/ sluices
and major/intermediate structures across the channel?
Have you completed all ten spot-checks and made entries in all boxes in E & F on page 2?
Have you completed column 11 of section G (and E if appropriate) on page 2?
Have you recorded in section C the number of riffles, pools and point bars (even if 0) on page 1?
Have you given an accurate (alphanumeric) grid reference for spot-checks 1, 6 and end of site (page 1)?
Have you stated whether spot-check 1 is at the upstream or downstream end of the site (top of page 2)?
Have you cross-checked your spot-check and sweep-up responses with the channel modification indicators
given on page 2 of the spot-check key?
*Sink hole(s)
LEFT BANK CHANNEL RIGHT BANK
Banktop height (m) Bankfull width (m) Banktop height (m)
Is banktop height also bankfull Water width (m) Is banktop height also bankfull
height? (Y or N) height? (Y or N)
Embanked height (m) Water depth (m) Embanked height (m)
If trashline lower than banktop, indicate: height above water (m) = width from bank to bank (m) =
Bed material at site is: consolidated unconsolidated (loose) unknown
Location of measurements is: riffle other (state)
RIVER HABITAT SURVEY : DIMENSIONS AND INFLUENCES Page 4 of 4
Major impacts: landfill - tipping - litter - sewage - pollution - drought - abstraction - mill - dam - road - rail - industry - housing
mining - quarrying - overdeepening - afforestation - fisheries management - silting - waterlogging - hydroelectric power
Evidence of recent management: dredging - bank mowing - weed cutting - enhancement - river rehabilitation gravel
extraction - other (please specify)
Animals: otter - mink - water vole - kingfisher - dipper - grey wagtail - sand martin - heron - dragonflies/damselflies
Other significant observations: if necessary use separate sheet to describe overall characteristics and relevant
observations
*Giant hogweed
Q ALDERS (tick appropriate box(es))*Alders? None Present Extensive *Diseased Alders? None Present Extensive
O NOTABLE NUISANCE PLANT SPECIES Use or E (> 33% length) *record even if <1%
P OVERALL CHARACTERISTICS (Circle appropriate words, add others as necessary)
*Japanese knotweed
Is 33% or more of the channel choked with vegetation? No Yes
N CHOKED CHANNEL (tick one box)
M FEATURES OF SPECIAL INTEREST Use or E (> 33% length) *record even if <1%
None
Braided channels
Side channel(s)
*Natural waterfall(s) > 5m high
*Natural waterfall(s) < 5m high
Natural cascade(s)
banktop to 50m
*Himalayan balsam
Q ALDERS (tick one box in each of the two categories ) *record even if <1%
R FIELD SURVEY QUALITY CONTROL ( boxes to confirm checks)
banktop to 50m
L CHANNEL DIMENSIONS (to be measured at one location on a straight uniform section, preferably across a riffle)
*Other (state)..........................
None
bankface bankface
SITE REF.
Very large boulders (>1m)
*Leafy debris
Fringing reed-bank(s)
Quaking bank(s)
Backwater(s)
Floodplain boulder deposits
Water meadow(s)
Fen(s)
Bog(s)
Wet woodland(s)
Marsh(es)
Flush(es)
Natural
open water
Others (state)
PART THREE – DEFINITIONS AND DETAILED GUIDANCE
RHS form page 1: Field Survey Details, Valley Form, Riffles etc. and Artificial Features
SECTION A. FIELD SURVEY DETAILS
Site number
For RHS database entry purposes only. Every site will be given a unique reference number when entered on
the RHS database. Leave blank. For re-surveyed sites, enter original number (if known) followed by (R) to
indicate repeat survey.
Site reference
Surveyors should enter their own unique reference number/name for the site, and replicate it on the left hand
corner on each page of the form. Photos should also contain the same reference number.
Spot-checks 1, 6 and end of site grid reference/co-ordinates
In the UK, using a GPS, it is essential to record a 10 figure NGR (national Ordnance Survey grid reference) for
spot-checks 1 and 6 (the mid-point); a reminder to do so is given in the spot-check columns on page 2 of
the form. The grid reference for spot-check 1 is required to ensure re-surveys start at the same locations as
the original surveys. The grid reference for spot-check 6 is required to calculate distance from source, site
gradient and other map-derived data. It is also essential to record a grid reference for 50m beyond spotcheck
10 (where the site ends). Use 1:10,000 or 1:25,000 scale maps to provide a cross-check for the grid
references and whenever possible annotate the site boundaries on a 1:25,000 scale map.
Alternatively, record latitude and longitude. If there is no GPS signal, or only a poor one, enter an 8-figure
reference from a 1:25,000 scale map.
Reach reference (optional).
Record the reference of the reach (if any). Reaches can be defined as part of a sampling strategy for
Catchment Flood Management Plans (CFMPs), Catchment Abstraction Management Strategies (CAMS),
River Basin Management Plans (RBMPs) or SERCON assessments.
River name
Enter name appearing on River Quality Objective (RQO) map. If not named, or even depicted, on these
maps, use name given on 1:50,000 scale maps, or more detailed scale if available. Use the name appearing
on the map, including Welsh or Gaelic names. Include alternative names if two are given on the map.
Unnamed headwater tributaries should be categorised as such, but refer to the named mainstream
watercourse (e.g. tributary of......Eden). In these cases it is not necessary to enter the words ‘Afon’ or ‘River’.
Date/time
The time of survey, as well as the date, is important because this could be useful regarding significant
observations (e.g. pollution) and in relation to gauged river flow information.
Surveyor name/Accredited surveyor Code
All accredited surveyors have an individual code. Surveyor name and code must be entered on the form to
comply with the RHS accreditation scheme. Names on the survey forms should match those on the surveyor’s
accreditation certificate. Only surveys from accredited surveyors will be entered on the RHS database.
Is the site part of a river or an artificial channel?
Artificial channels are canals, dykes, ditches and drains constructed entirely by human activity. Natural rivers
that have been extensively modified by human activity should be recorded as ‘rivers’ (e.g. navigation course
of the Thames, concrete-lined urban streams). Tick one box only. A1a,b,c,d.
3.1 River Habitat Survey Manual: 2003 version
Are adverse conditions affecting survey?
Surveys should not be carried out in spate conditions. Take full account of the risk assessment carried
out before embarking on a survey. Do not enter the channel if the water is turbid. Beware too that
weather conditions can affect both safety and the accuracy of survey results - examples of conditions
adversely affecting survey include: strong winds and heavy rain (affects flow-type assessment and recording
on the field sheets); overgrown channels (where vegetation may hide some features). Tick one box only.
Is bed of river visible?
A number of factors can affect whether a surveyor can see the bed of the river. Even under low flow
conditions, the bed of wide or very deep rivers will only be partially visible, at best. Dense growth of freefloating
macrophytes or planktonic algae may similarly obscure the bed from view, even when flows are very
low. Use common sense, but as a guide,  the ‘barely or not’ box if 0-33% of the bed visible;  the ‘partially
obscured’ box if 33-95% visible, and  the ‘± entirely’ box if >95% of bed visible. A3a,b.
Is health and safety assessment form attached?
A health and safety assessment must be completed before starting the survey. A separate form must be
filled in (see Appendix 1 for details, and form in Section 2). Tick one box only – if the ‘No’ box is ticked,
reasons for not completing, and attaching, the form should be given. The icon is shown in this manual
to remind surveyors of common health and safety issues.
Photography (general)
A PHOTOGRAPHIC RECORD OF THE SITE IS ESSENTIAL TO AID INTERPRETATION OF DATA, AND AS A
RECORD OF THE SITE FOR FUTURE REFERENCE. At least two photos must be taken, and any others for
clarification purposes. Sufficient photographs should be taken to illustrate the general character of the site.
In more inaccessible sites it may be necessary to seek a vantage point that will provide the most
comprehensive view. It may be necessary to take more than two photographs to effectively illustrate general
character. Avoid taking photos directly into the sun.
Photographs of channel modifications and special features should also be taken. It is essential that all
‘major’ structures are photographed to enable interpretation of potential impacts to be made.
A good quality digital camera is recommended. If this is not possible, take colour transparencies with a film
speed of ASA 200 or 400. The quality of digital photographs required will depend upon their intended use.
For inclusion on the RHS database, a 1024x768-pixel picture with a standard JPEG compression (100-
150kbyte) is required. For inclusion in printed documents, additional photographs at a higher resolution (e.g.
2048x1536 TIFF or JPEG) are recommended. A camera with built-in coding facilities is ideal as this should
ensure photos are accurately assigned to a site, in the field.
If you are unsure about an unusual or unfamiliar feature, take a photograph for reference and make
accompanying notes. Enter the number of photographs taken in the box. Photographs that include, in
the foreground, a chalk-board showing the site reference, will ensure photographs and site survey forms
always correspond. Enter on the form the references used during survey to ensure the correct
photographs are matched with the sites surveyed. It is the responsibility of the surveyor to check that the
photographs and site numbers match.
Site surveyed from
For wide and deep rivers, surveys might only be able to be carried out from one bank only, although for best
results each bank would need to be walked. The same applies for rivers flowing through gorges. For shallow
rivers a survey can be carried out easily from both sides of the channel, or by accessing the watercourse.
Beware of health & safety issues. Insert  in one or more boxes to indicate where site has been surveyed from.
SECTION B. PREDOMINANT VALLEY FORM (within the horizon limit)
Profile diagrams are drawn on the form for guidance. Valley form refers to the shape of whole valley
landform within which the RHS site is situated. It is assessed in the context of the horizon. It is the
predominant valley form viewed by the surveyor when looking from the river to the mid-distant horizon. If
you are unsure about a particular valley form, photograph and make a note or a sketch with an evaluation of
distances. Tick one box only.
3.2River Habitat Survey Manual: 2003 version
Shallow vee
Overall valley side slopes <30˚ from floor to top (horizon). B1a,b, E1Pb.
Deep vee
Overall valley side slopes >30˚ - 80˚ from floor to top (horizon). B2a,b, J1b.
Gorge
Steep (>80˚ to vertical), rocky, valley sides with narrow valley bottom. B3a.
Concave/bowl
Gently curving slopes that do not have a distinct glaciated U-shape. B4a.
Asymmetrical valley
Valley sides are different, shallow on one side and steep on the other. B5a.
U-shape valley
Steep valley sides rising from a flat valley floor that characterises a glacial valley. B6a, C1a.
No valley-sides obvious
No obvious valley sides in near- to mid-horizon. B7a,b, A1a.
Distinct flat valley bottom?
Flat area of valley into which water would spill during floods. If not obvious, record ‘No’. Always tick ‘No’
box if no valley sides obvious. B1a,b, B2a,b, B5a, B6a, B7a,b, B8a,b, M1c.
Natural terraces?
Distinct geomorphological features on a river valley floor forming steps or breaks in slope produced as the
river erodes downwards. Characteristic of moraine-filled glaciated valleys. See Figure B1. B9a,b.
3.3 River Habitat Survey Manual: 2003 version
Deposition
Floodplain
Bankfull
Down-cutting
Erosion
Marked step
Down-cutting
Down-cutting
Floodplain
New floodplain
Erosion
Floodplain
Floodplain
Floodplain
Erosion
Successive deposition
Step indicative
of ‘terrace’
Old floodplain
Bankfull
Natural Berm
New Bankfull
Figure B1 Sequence of natural berm and terrace formation
SECTION C. NUMBER OF RIFFLES, POOLS AND POINT BARS
For analytical purposes, the numbers of riffles, pools, unvegetated and vegetated point bars need to be
recorded. This is best done as a cumulative tally between spot-checks. Always give the actual numbers,
including zero. The tally can be recorded alongside the boxes, or at the top or bottom of page 2, and at the
end of the survey the total number is transferred to the relevant boxes in Section C.
Riffle(s)
Habitat feature characterised by shallow, fast-flowing, water with a distinctly disturbed surface over
unconsolidated gravel-pebble, or cobble, substrate. ‘Unbroken standing waves’ is the predominant flowtype.
Does not include unbroken standing waves associated with bedrock or solid peat/clay substrates.
Riffles recorded in Section C must occupy most of the wetted channel width and be no longer than five times
the river width. Riffles create a distinct ‘bubbling’ sound. C1a,b,c, E5Db.
Continuous ‘unbroken standing wave’ flow-type does not constitute discrete riffles. To be recorded as
discrete individual features, a contrasting flow-type must separate each riffle. As a rough guide, riffles
naturally occur at intervals equivalent to 5-10 times the channel bankfull width.
In well-vegetated streams, aquatic vegetation sometimes creates unbroken standing waves by constricting
or obstructing flow, or cause fine sediment deposition that raises the riverbed. Do not record such examples
as riffles.
Pool(s)
Habitat feature characterised by distinctly deeper parts of the channel that are usually no longer than one to
three times the channel’s bankfull width, and where the hollowed river bed profiles are sustained by
scouring. Typical locations for pools include: the outside of tight meanders, downstream from natural
bedrock outcrops (e.g. downstream from waterfalls or chutes where ‘plunge pools’ are formed), and below
some weirs, where both downward and lateral erosion creates a typical scour pool. Due to their self-scouring
nature, associated flow-types can vary across the pool, and include upwelling, and even no perceptible flow
when there is circulating current. See Figure C1. C2a,b,c, C1b, E5Bb, I1a, M3a, M4a,b.
Deep water impounded upstream of natural (bedrock), or artificial (weir) obstructions does NOT
constitute a pool.
Even where the river bed is visible, pools are difficult to identify with absolute certainty. Do not spend time
agonising over detail, but be consistent in your assessment. If in doubt, take photographs and seek advice
for future surveys.
3.4River Habitat Survey Manual: 2003 version
Unvegetated point bar(s) (PB)
A distinctive depositional feature composed of unconsolidated river bed material. Exposed at low flow,
usually with a shallow slope into the water. Characteristically located on the inside of tight meanders in
actively eroding/depositing rivers. Classified as ‘unvegetated’ if <50% of the surface area has plant cover.
B1b, C1b, C3a,b,c, I1a,b.
Constituent material of point bars is primarily sediment that has been transported from upstream; it is
generally not derived locally. This contrasts with slumped banks recorded in Section I.
Vegetated point bar(s) (VP)
A distinctive depositional feature composed of consolidating river bed material. Exposed at low flow, usually
with a shallow slope into the water. Characteristically located on the inside of distinct meander bends, usually
on rivers that are less active than where ‘unvegetated’ bars are found. Constituent material as for
unvegetated point bars. Classified as ‘vegetated’ if >50% of surface area has plant cover, often showing a
successional sequence from bare shingle to even some scrub. Moss cover on bars is included as part of the
vegetation cover, as this indicates stability. C4a,b,c.
In certain circumstances a sequence from unvegetated to vegetated bars may progress further, so that over
time they may become ‘natural berms’ (see E; Marginal and Bank Features).
3.5 River Habitat Survey Manual: 2003 version
Upwelling flow
Upwelling flow
Bed erosion creates and sustains pool
‘Boil’
‘Boil’
Flow direction
Erosion
creating an
undercut
bank
Bed erosion creates and sustains pool
B
A
Figure C1
A: tight meander bend (cross-section);
B: waterfall or weir (long-section)
Pool character at:
SECTION D.ARTIFICIAL FEATURES
Indicate the number of artificial features in each category (major, intermediate or minor) occurring within the site.
Use the tally system (as in Section C) and add up the total at the end of your survey, and enter the number
in the appropriate box. Insert  in the box to indicate ‘none’ if no artificial features are present.
You should take a photograph of any major or intermediate structure across the channel, with, if
possible, a ranging pole alongside. Take pictures upstream and downstream of the structure if it appears to
be causing a significant change in river character (e.g. a dam). If a structure contains features of interest (e.g.
fish ladder in major weir), make a note in Section P, as well as taking a photograph. Photographs of weirs
should be taken since the height, design and construction material will determine the impact on the river.
If you are unsure about the nature of a structure, take a picture and send it with the form.
Figure D1 shows in plan-form the range of ‘major’, ‘intermediate’ and ‘minor’ artificial features that need to
be recorded.
Weirs and sluices across river channels
Major: any permanent, ±water-tight, fixed (but can be adjustable to control flow), weir/sluice structures.
Typically made of concrete, cemented boulders, wood or metal extending across the entire width of the
channel. Weirs and sluices can be used for controlling water level or water flow, abstracting water or
trapping sediment. (Exclude rubble/loose stone weirs.) D1a,b,c,d.
Intermediate: semi-permeable, fixed, structures controlling water levels; extending across the entire width
of the channel but permeable enough to allow some water to flow through them. Commonly made
from loose rubble, inter-locked boulders and, less commonly, logs. D1e,f.
Minor: small, permeable, and usually temporary structures across the river channel, often made from stones,
cobbles or pebbles by children. They often get dislodged by large spates. D1g.
Composite weirs should be recorded as a single structure. These are a series of weir crests close to each other,
and linked with concrete aprons and/or side-walls so that there is no natural bank material between the weir
crests. D1a,d.
Weirs that have completely collapsed, and only extend partially across the channel (and therefore do not
control water levels upstream), should be recorded as ‘groynes’, and a note made in Section P. ( D6b).
Culverts
Arched, enclosed or piped structures, constructed to carry water under roads, railways and buildings.
Commonly made from concrete, but may be constructed from brick, metal or other building materials.
Culverts either carry the full river flow through a single arch, or through multiple arches.
Do not enter any culverts.
Some culverts may be a kilometre or more long, passing under fields, roads, residential and industrial areas.
In such cases the location of many RHS spot-checks may have to be estimated from maps obtained previously.
Entries for spot-checks in a culvert will normally simply enable ‘CV’ to be recorded as the modification, and
the appropriate land-use noted. All other entries should be ‘NV’ (not visible) or ‘NK’ (not known) as
appropriate unless the culvert is short and a clear view can be gained without entering it, or compromising
the safety of the surveyor. D2a.
3.6River Habitat Survey Manual: 2003 version
Bridges
Major: road or rail bridges of any width, with one or more in-channel supports, OR wide bridges with bank
abutments extending along >25m of bank-length. Banks are often resectioned or reinforced immediately
upstream and downstream of a major bridge. Photographs are essential for interpretation of potential
impacts of the in-channel supports. D3a,b, D5b.
3.7 River Habitat Survey Manual: 2003 version
Major Weirs and Sluices:
permanent and impermeable
impounding structure across
entire river width
Major Deflector:
extends into >20% of
channel width (includes
collapsed weirs)
Intermediate Deflector:
extends into 10-20% of
channel width
Minor Weir:
kiddies weir transient
feature
Culvert:
always recorded
as ‘major’
Intermediate:
bridge abutments, outfalls,
side weirs etc. 10-25m long
Minor Deflector:
extends into <10% of
channel width
Major:
bridge abutments, outfalls,
side weirs etc. >25m long;
ALL bridges with central piers
Minor:
bridge abutments, outfalls,
side weirs etc. <10m long
Fords:
MAJOR: artificial bed and banks
INTERMEDIATE: artificial bed
MINOR: natural bed material
Intermediate Weir:
rubble/loose stone/wood
materials semi-permeable
Figure D1 Illustrated definitions of artificial features
Indicates structures
above water level
Intermediate: road or rail bridges without any in-river supports, and with bank abutments occupying 10-
25m of the bank. D3c.
Minor: all road/rail bridges lacking in-river supports, and with bank abutments occupying <10m of the bank.
Also includes all bridges, irrespective of width, with no abutments on the bank, such as viaducts. D3d,e, Na.
Outfalls/intakes
Outfalls and intakes mark points of discharge to, or abstraction from, watercourses. They are classified
according to size, so this means that associated aprons, wing-walls and bank protection measures are
included as part of the structure. Examples include abstraction intakes, sewer discharges, side weirs and
sluices.
Major: permanent structures occupying >25m of bank-length. D4a.
Intermediate: permanent structures occupying 10-25m of bank-length. D4b.
Minor: permanent structures occupying <10m of bank-length. Includes flap valves on feeder streams. D4c.
Do not include agricultural land drainage pipes (typically <150mm diameter).
Fords
Permanent crossing places for vehicles or machinery. Do not record sites where animals, but no vehicles,
cross a river. D5e.
Major: crossing place with banks and bed comprising artificial material which cause significant ponding of
water upstream. Can be rubble infill (farm track) or a road crossing (e.g. tarmac, concrete). D3f, D5a.
Intermediate: shallow crossing with banks made from artificial material, but bed material not so. May cause
slight ponding of water upstream. D5b.
Minor: shallow crossing with no artificial bank or river bed material. Ponding effects will be negligible. D5c,d.
Deflectors/groynes/croys
Artificial structures that are installed part way across the channel to deflect currents away from eroding banks
or help create more in-channel habitat diversity. Most often installed flush with the bank toe to deflect flow
from one side of the channel to the other, but may be also installed in mid-channel. Can be made from a
variety of materials, including rocks, logs, sheeting, gabions, wooden/heather hurdles, posts and wire, and
occasionally wooden stakes.
Major: extends across >20% of channel width. Includes completely collapsed weirs that no longer influence
water levels upstream. D6a,b.
Intermediate: extends across 10-20% of channel width. D6c,d.
Minor: extends across <10% of channel width. D6e.
If it is clear that these structures have been installed for habitat/fishing enhancement, note in Section P. It
is recommended that all deflectors are photographed since their impact/purpose varies greatly
according to their height and material, not just their extension across the channel.
3.8River Habitat Survey Manual: 2003 version
Other
Other structures (e.g. boat moorings, walls, jetties, fishing platforms) should be recorded as follows:
Major: occupying >25m of bank-length.
Intermediate: occupying 10-25m of bank-length D6f
Minor: occupying <10m of bank-length. D6g.
It is important only to record distinct structures as opposed to bank modifications for buildings and
revetments (covered in Section E).
Is channel obviously realigned?
Only record ‘yes’ if you are sure. Common sense is required, but re-aligned channels are typically straight,
and exhibit the same characteristics of resectioned (and often over-deepened) channels. See below. Tick one
box only. D7a,b, Na,b – for comparison see B1b, B5a, B6a, B7a, C4a, D7c.
Is channel obviously over-deepened?
Only record ‘yes’ if you are sure. Channel-deepening is frequently undertaken in tandem with bank
resectioning. Diagnostic signs of over-deepened channels include:
1. uniform (and sometimes evenly stepped) bank profile;
2. no trees/uniformly-aged trees or saplings along banktop;
3. bankfull height often atypically high compared with bankfull width: ratio of width to depth commonly <4:1.
Tick one box only. D7a, D8a, D8b, D8c, E2Aa.
Is water impounded by weir/dam?
If a weir or dam is present, indicate if water in the site is affected partly (<33% of its length) or predominantly
(>33% of its length) by artificial channel impoundment. You will need to include the effects of weirs or dams
located downstream from the site if appropriate. Effects of impoundment include water velocity reductions
(creating ponded water) and increased water depth. Tick one box only. D9a, D1b,c, D5a.
3.9 River Habitat Survey Manual: 2003 version
RHS form page 2: Sections E, F & G - Spot-checks
It is essential to indicate on the form whether spot-check one (1) is at the upstream or downstream
end of the site; tick one box only.
Ten spot-checks must be completed at regular intervals (c50m) along the 500m site.
At each spot-check, stand on the bank and look across the channel and indicate in each box, in each
column, the material, modifications and features present. In shallow rivers, and where safe to do so,
surveyors may choose to enter the channel to improve accuracy of recording bed character and features of
the opposite bank. Risk assessment is vital before entering the channel.
All boxes in sections E and F must be completed (i.e. entries made in ALL boxes in the column
representing an individual spot-check) before moving on to the next spot-check. At least one box in
Section G must also have an entry for each spot-check. Each entry must be made clearly using the
unique abbreviations shown in the spot-check key and described below.
Bank
Permanent side to the river channel. For recording purposes (see Figure E1) the bank starts at the water’s
edge (and excludes marginal depositional features such as bars) and gives way to the ‘banktop’ where the
break of slope allows cultivation or development to take place.
Left and Right banks
‘Left’ and ‘right’ banks are determined by facing downstream.
For physical attributes (E), use a transect 1m wide at each spot-check across the channel. For land-use,
vegetation structure and channel vegetation types (Sections F and G on page 2), use a 10m wide
transect, at the same location (see Figure 1).
Only one entry per box is allowed for recording predominant bank material.
More than one channel or bank feature or modification can be recorded at a spot-check. In these cases,
use a diagonal line to include a further entry in the box.
Only one entry per box is allowed for recording both predominant channel substrate and flow-type.
Only one entry per box is allowed for recording land-use and bank and banktop vegetation structure.
For channel vegetation, occurrences of all types are entered into appropriate boxes.
GPS readings are required at spot-check 1, 6 and 50m beyond spot-check 10.
3.10River Habitat Survey Manual: 2003 version
Figure E1 Cross-section of channel showing definitions
used to define where spot-check recording
and channel dimensions measured
Break in slope
Bankfull width
Bank slope too steep
for cultivation
Water
width
Bankfull
height
Banktop
and
Bankfull
height
Banktop
height
Water depth
Bankface vegetation
structure
Vegetation structure
within 1m of banktop
Land-use within
5m and 50m
Section E: Physical Attributes of Bank and Channel
To be assessed over a 1m wide transect of bank and channel at each spot-check. Refer to spot-check
key and Figure 1.
SECTION E: PHYSICAL ATTRIBUTES - BANK MATERIAL
As boxes are emboldened, only a single entry per box is permissible (i.e. the predominant material
of the whole bankface within the 1m wide spot-check).
Not visible (NV)
Self-explanatory. This entry may need to be used for inaccessible far banks on wide rivers, especially when
the banks are covered in vegetation, and cannot be given close inspection. Should be also used when a spotcheck
is located at a culvert.
Bedrock (BE)
Exposure of solid rock. E1Aa,b, C2b, E5Ab, M3a.
Boulder (BO)
Large rocks >256mm in diameter (larger than head size) that can be loose, embedded or interlocked. When
boulders are imported, record as ‘rip-rap’ material (RR), and reinforced (RI) bank modification. E1Ba,b.
Cobble (CO)
Loose rock material 64-256mm in diameter (half-fist to large head size). Often associated with glacial
deposits. E1Ca,b.
Gravel/sand (GS)
Combined category. Loose material, comprising: coarse gravel, (including pebbles 16-64mm in diameter);
fine gravel (2-16mm in diameter); and sand (<2mm in diameter). Often associated with glacial and fluvial
deposits. E1Da,,b,c, E3Aa.
Earth (EA)
Soil comprising mainly crumbly loam material, but not predominantly composed of clays (see clay - CL).
A jab with a ranging pole will leave no distinct hole, or one with ragged or crumbling edges. E1Ea,b,
I1b.
Peat (PE)
Material formed almost entirely of organic matter derived from decayed vegetation under water-logged
conditions and therefore usually associated with heaths and bogs. Peat is normally dark brown or black.
E1Fa.
Sticky clay (CL)
Distinctive, solid and cohesive soil material. Compared with earth (EA), it is sticky when rubbed between
finger and thumb. A jab from a ranging pole will produce a neat, smooth, conical hole. E1Ga, FV1a,
I1a, I2a.
ARTIFICIAL MATERIALS
When recorded as bank materials, they will also be noted as reinforced (RI) in bank modifications.
3.11 River Habitat Survey Manual: 2003 version
Concrete (CC)
Cemented bankface reinforcement that forms a solid revetment with no gaps or fissures. E1Ha,b, A1c,
E2Cb, E7Cc.
Sheet piling (SP)
Vertical, inter-locking, steel sheets protecting the bankface. Includes corrugated iron. E1Ia.
Wood piling (WP)
Wooden poles, or horizontal/vertical planks protecting the bankface (most often the lower half or toe of the
bank only). E1Ja,b, I6b.
Gabion (GA)
Stones in wire baskets; installed to protect banks from erosion. E1Ka.
Brick/laid stone (BR)
Bank protection that includes any cemented walls, including brick walls, and also regimented, un-cemented,
laid stones characteristic of riverside walls in the Lake District and limestone dales. E1La,b,c.
Rip-rap (RR)
Boulders (normally quarried and ±square and of similar size) purposely tipped or laid along the bankface to
protect it from erosion. Rip-rap is often along the toe of the bank only. Includes un-cemented blockstone
and boulders compacted into the bank with vegetated soil between. E1Ma,b,c,d, I6a.
Tipped debris (TD)
Discarded material from, for example, farming, mineral extraction and building works. Includes: rubble,
metal, wood, old cars and excavated soils and other minerals. Location on the bank may be un-intentional,
or to provide extra bank protection. If providing bank protection, reinforcement (RI) should be recorded in
bank modification.
If in doubt, enter miscellaneous artificial materials here (e.g. tyres) and take a photograph. E1Na,b,c,d.
Fabric (FA)
Synthetic (usually permeable geo-textile) bank protection fabric often used in conjunction with soil back-fill.
Always non-biodegradable, with the prime function of bank support and protection from erosion. Includes
materials such as plastic, and proprietary products such as ‘enkamat’ and ‘nicospan’. E1Oa.
Bio-engineering materials (BI)
Live or dead plants (or non-synthetic materials) used to protect banks from erosion, and often to
create/restore bankside and marginal habitat. Typical materials include live willow stakes and spiles, dead
brushwood faggots, bio-degradable matting and planted reeds. When used in combination with synthetic
fabrics (FA), record whichever has the dominant surface area. E1Pa,b,c,d,e.
SECTION E: PHYSICAL ATTRIBUTES - BANK MODIFICATION(S)
Boxes are NOT emboldened, so more than one entry per box is permissible (e.g. if the bank is
reprofiled with toe reinforcement, enter RS/RI).
Not known (NK)
If you are unsure whether or not a bank has been modified, record NK. You can consult river management
records to assess if the reach has been previously engineered. If so, make additional notes. Enter ‘NK’ for
spot-checks in culverts.
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None (NO)
No obvious modifications visible. See NK above, and guidance below for signs indicative of resectioning. It
may be that subtle changes are missed at a site on the first spot-checks, but later ones show clearer signs of
modification. Under such circumstances, modifying earlier spot-check records is permissible if, on closer
subsequent inspection, signs are evident. To do so, review spot-checks whilst completing the sweep-up on
the return leg of the survey.
Resectioned (reprofiled) bank (RS)
Bank profile modified (but not necessarily reinforced), often to accommodate flood flows, flood defence or
other maintenance machinery. Recent re-profiling will produce a relatively smooth, uniformly angled, bank
slope. If either the top or the bottom of a resectioned bank is reinforced, enter both RS and RI. A1a,
D8a,b,c, E2Aa,b, E3Da, I6b.
NB One or more of the following clues may be indicative of resectioning:
1. uniform (and sometimes evenly stepped) bank profile;
2. no trees/uniformly aged trees/saplings along banktop;
3. bankfull height often atypically high compared with bankfull width - width to height ratio <4:1
not uncommon;
4. intensive agricultural/urban land-use;
5. straightened river channel.
Typically bank re-sectioning is carried out in tandem with channel deepening; the former alone results
primarily in characteristics 1 and 2 above, whilst bank and channel resectioning can also result in
characteristics 3-5.
Figure E2 illustrates a typical flood defence/channel modification sequence.
Reinforced bank (RI)
Whole or part of bank artificially strengthened for bank protection purposes. Examples include concrete,
sheet piling, corrugated iron, wood piling, gabion, brick/laid stone, rip-rap, and if clearly for bank
reinforcement purposes, tipped debris (see Bank Material descriptions above). E1Ha,b, E1Ia, E1Ja,b, E1Ka,
E1La,b,c, E1Ma,b,c,d, E1Oa, E1Pa,b,c,d,e.
Poached bank (PC)
Bank significantly trampled or puddled by livestock. Includes banks heavily trampled as a result of human
activity such as picnic spots, canoe access points and fishing spots dug into the bank.
Add (B) after PC (i.e. PC(B)) if the bank is predominantly bare due to poaching i.e. <50% vegetation cover.
E2Ba,b,c,d, I5b, P1a.
Artificial berm (BM)
Artificial two-stage channel created when either: a) a bank has been excavated laterally at a level above dryweather
water level, but below the banktop; or b) an over-wide channel has artificial ledges constructed to
reduce the low-flow width. This modification creates a distinct stepped or shelf appearance when first
constructed, but may become less evident over time. Mention in Section P if the berm is part of river
rehabilitation works. E1Hb, E2Ca,b,c,d, F18b.
Embanked (EM)
Artificial raising of bank. A variety of materials can be used, including earth, natural stone or walls of concrete
or brick. Only recorded at a spot-check when it forms an integral part of the bank. Do not include
embankments set back from the immediate banktop; these are accounted for in the ‘sweep-up’, Section I.
E2Da,b.
Note on bank modifications: if you are sure, beyond reasonable doubt, that there are no obvious signs
of bank modification, then record ‘NO’ (none); if in doubt, record ‘NK’ (not known). Beware: some
bankfaces will appear ‘natural’ even though they have been resectioned previously. Use the prompts
listed above to help make up your mind whether to record ‘NK’ or ‘NO’. See Figure E2.
3.13 River Habitat Survey Manual: 2003 version
3.14River Habitat Survey Manual: 2003 version
Figure E2 Sequence of channel modifications for flood defence
River unmodified
Trees removed from one bank to allow machine access
Marginal features (bars) removed
Boulders removed
Trapezoidal channel excavated/
bed and both banks resectioned
Note: bankfull height/channel bankfull width ratio >1:4
Note: bankfull height/channel bankfull width ratio <1:4
SECTION E: PHYSICAL ATTRIBUTES – MARGINAL AND BANK FEATURE(S)
Recording relates purely to ‘cliffs’ (bank features), and ‘bars’ (depositional marginal features). See Figure E3 for
location of bar features. Boxes are NOT emboldened, so more than one entry per box is permissible.
Not visible (NV)
Self-explanatory. Use for culverts and if the far bank and margin are obscured by large mid-channel
structures or impenetrable vegetation. Beware overgrown channels in late summer where vegetation
may also mask features.
None (NO)
No obvious features. Record only when there is a clear view of the bank and marginal areas of the spotcheck,
AND no features are present.
Eroding cliff (EC)
Bankface profile is predominantly vertical, near vertical, or undercut, with a minimum height of 0.5m, and
showing a ‘clean’ face (<50% cover of mosses, ferns and other vegetation). The angle of the cliff will depend
on bank substrate; clay or cohesive earth banks are often almost vertical; sandy ones are rarely this steep.
Other clues: turf overhanging cliff, turf in channel, recently fallen trees, leaning or over-hanging fence posts.
If the eroding cliff is composed of sandy soil, sands and/or gravels put a circle around EC . B1b, E1Da,
b,c, E1Ea,b, E3Aa,b.
Stable cliff (SC)
Bankface profile is predominantly vertical, near vertical, or undercut, with a minimum height of 0.5m, and
without obvious signs of recent erosion. Mosses, ferns and other vegetation on the bankface usually cover
>50% of the bankface. Some clay banks may have little or no vegetation, but are nevertheless stable.
E3Ba,b, E5Fa, FV1a.
If the stable cliff is composed of sandy soil, sands or gravels put a circle around SC .
Vertical rock faces should not be recorded as ‘SC’. The purpose of recording ‘cliffs’ is to identify the
instream sources and character of sediments that may be transported downstream, and those riverine
features associated with active erosion.
Unvegetated point bar (PB)
A distinctive depositional feature composed of unconsolidated river bed material. Exposed at low flow,
usually with a shallow slope into the water. Characteristically located on the inside of a distinct meander
bend in actively eroding/depositing rivers. Classified as ‘unvegetated’ if <50% of the surface area has plant
cover. B1b, C1b, C3a,b,c, I1a,b.
Constituent material of point bars is primarily sediment that has been transported from upstream; it is
generally not derived locally. This contrasts with slumped banks recorded in Section I.
Vegetated point bar (VP)
A distinctive depositional feature composed of consolidating river bed material. Exposed at low flow, usually
with a shallow slope into the water. Characteristically located on the inside of distinct meander bends,
usually on reaches of rivers that are less-active than where ‘unvegetated’ bars are found. Constituent
material comprising the bars is as for unvegetated point bars. Classified as ‘vegetated’ if >50% of surface
area has plant cover, often showing a successional sequence from bare shingle to scrub, and may include
mosses. C4a,b,c.
Unvegetated side bar (SB)
A distinctive depositional feature composed of unconsolidated sediment located along the margins of rivers.
Exposed at low flow, usually with a shallow slope into the water. ‘Unvegetated’ when <50% of the total
surface area has plant cover. Found in locations other-than the inside of distinct bends. Material similar to
that described for unvegetated point bars. E3Ca.
3.15 River Habitat Survey Manual: 2003 version
Vegetated side bar (VS)
A distinctive depositional feature composed of consolidating sediment along the margins of rivers. Exposed
at low flow, usually with a shallow slope into the water. Material comprising the bars is as described for
unvegetated point bars. ‘Vegetated’ when >50% of the total surface area has plant cover. May show a
successional sequence from bare shingle, herbs and mosses, to scrub. Found in locations other-than inside
of distinct bends. E3Da.
In certain circumstances the successional sequence from unvegetated bars to vegetated bars may progress
further, so that over time vegetated bars may become ‘natural berms’. Here sediment may stop
accumulating, and erosion may begin. A key difference between a ‘bar’ and a ‘natural berm’ is the former
has a gradual slope into the water; the latter has a distinct steep face.
Bars are depositional features, primarily composed of material transported down the river channel, and
deposited on the river bed. River bed material can be carried long distances (many kilometres), or very short
distances, depending on the size of the material and the energy of the river. A gravel-bed river will usually
have gravel bars; a sand-bed river will have sand bars.
Point or side bars composed of silt are extremely unlikely to occur in UK rivers. Silt is not considered
to be a substrate of distinct ‘bars’; if silt is the predominant substrate in spot-checks, record SI; if
discrete silt deposits are present record these as ‘present’ in Section K, and if large expanses of silt
occur record as ‘extensive’ in Section K. If the silt forms distinct deposits resembling bars, note this in
Section P, as these deposits are often signs of channels recovering from over-widening as a result of
engineering works.
3.16River Habitat Survey Manual: 2003 version
Unvegetated mid-channel bar
Bankfull height
Mid-channel bars Point bars Side bars
Unvegetated side/point bar
Vegetated mid-channel bar
Figure E3 Location of bar features recorded in RHS:
A - planforms
B - cross-sections
Mature island
B
A
Over time, some continuous silt deposits along river margins may become stable, and resemble ‘bars’. When
they become vegetated and have accreted sufficient sediment to be exposed during dry-weather flow, they
should be recorded as ‘natural berms’. If in doubt, take a photograph.
Natural berm (NB)
A relatively rare feature that is transitional between a depositional bar and a terrace on the floodplain (see
Figures E4 & B1). Not to be confused with an artificial berm (see definition and check against river
management records [see Figure I1]). Natural berms can occur in: (i) actively meandering channels; or (ii)
recovering rivers naturally restoring a low-flow
channel width following over-widening. They
can also occur as a transitional feature if channel
straightening downstream results in downcutting
and channel narrowing produces
increased gradient.
To qualify as a natural berm, the profile must have
a marked step, or a composite profile with ridges
representing a series of deposition/incision
events. Natural berms develop through
deposition (or incision) processes and over time
often attract further sediment deposition. If
formed on the inside of a meander they may also
have a point bar features at the water’s edge.
They are usually vegetated, making them
relatively stable and attracting further deposition.
Depending on location and age, the vegetation
may comprise bankside herbs, grasses and reeds,
or a mixture of these with willow and alder
saplings. As ‘mature bank or riparian’ vegetation
becomes established, and the berm becomes
higher in relation to the river bed (either by
channel down-cutting or further deposition on
the berm), old berms then become the new
‘bankface’ and ‘banktop’ (see Figure B1). Natural berms do not develop from bank erosion features such as
slumping/slips. E3Ea,b,c, E3Ed,e.
Natural berms are difficult to determine precisely, and when recorded, should be photographed for
subsequent confirmation.
SECTION E: PHYSICAL ATTRIBUTES - CHANNEL SUBSTRATE
The ranging pole should be used to prod the river bed to determine the predominant channel substrate.
In some cases a thin layer of silt, especially during low flows, can cover coarser substrates; in such instances,
the underlying substrate should be recorded, together with a note that silt is present as an overlying
deposit (in Section P).
Categories of substrate size are determined by the Wentworth scale8
(Wentworth; 1922). The scale is shown
on the spot-check key. When assessing substrate size, do it using the intermediate axis and not the long axis
(see spot-check key and Figure E5). For more details of similar categories used also for bank material, see
Section E, Bank Materials.
Boxes are emboldened, so only a single entry per box (the predominant substrate type) is
permissible.
Not visible (NV)
Use this only if the channel is too deep, or water too turbid, to determine the predominant substrates of the
channel. Health and safety considerations are paramount – follow the guidance in Appendix 1.
3.17 River Habitat Survey Manual: 2003 version
Cross-sections showing formation
of ‘natural berm’ following recovery
from channel over-widening
Figure E4
Widened and deepened
Original channel
Silt accumulates down
one side of channel
Silt stabilizes, becomes vegetated
and exposed at dry-weather flow
– ‘natural berm’
Time
Bedrock (BE)
Underlying solid rock. C2b, E4Aa,b, E5Bb, E7Bb, M3a,b, M5b.
Boulder (BO)
Large rocks >256mm in diameter (larger than head size). E4Ba,b, E7Aa,b, M5a, M6a,b.
Cobble (CO)
Loose material 64-256mm in diameter (half-fist to large head size). B1a, D3a, E4Ca,b, M1a,b, M2a,c.
Gravel/pebble (GP)
A combined category: Coarse gravel is 16-64mm in diameter (includes pebbles that are conker to half-fist
size); fine gravel is 2-16mm in diameter. Where it is obvious that either pebble or gravel dominate, put a
circle round either G P or G P depending on which one is predominant. If, as is usually the case, the
proportions are roughly equal, or it is not possible to determine which is predominant, simply enter GP.
E4Da,b,c, E4Fb.
Sand (SA)
Particle sizes <2mm but >0.06mm in diameter. E4Ea.
Silt (SI)
Very fine material as a deposit exceeding a depth of 10mm. Exclude thin layers of silt covering coarser
substrates. E4Fa,b.
Clay (CL)
Record ‘CL’ if the predominant river bed material comprises sticky cohesive clay material. E4Ga,b.
Peat (PE)
Peat, as a predominant channel substrate, is rare. Record ‘PE’ only if the river bed is formed of organic
matter derived from decayed vegetation under water-logged conditions. Peat is normally dark brown or
black. E4Ha.
3.18River Habitat Survey Manual: 2003 version
Illustration of correct use of the ‘intermediate
axis’ for channel substrate assessments in RHS
Figure E5
Major axis
Intermediate
axis
Earth (EA)
Reserved solely for recording when earth forms the substrate in streams with seasonal flow (e.g.
winterbournes). Such streams often flow through open fields, and have substrates similar to ‘soil’. E4Ia.
Artificial (AR)
Obviously non-natural bed material predominant (e.g. concrete, bricks, tipped waste) D5a,b, E1La, E4Ja,b.
Any channel substrates that cover >1% of the whole river bed within the whole RHS site, but are
not recorded (i.e. were not predominant) in any of the ten spot-checks, should be entered in the
shaded box in the end column.
SECTION E: PHYSICAL ATTRIBUTES - FLOW-TYPE
Recognising flow-types in the field
The nine flow-types used for RHS are largely based on patterns of the surface, velocity, flow direction and the
influence of river bed substrate. Flow-type at a particular location will vary with different volumetric discharges
and river levels, but the definitions used correspond to those occurring during dry-weather conditions.
Relying on photographs (Part Four) for recognition of flow-types is inadequate. Many of the diagnostic
elements for flow-types come from other clues such as movement, sound and position in relation to channel
features. An RHS geomorphology training video has been produced which describes characteristics of
all the flow-types. All RHS surveyors should study the video as part of their overall training.
In all instances, the predominant flow-type (i.e. that normally occupying at least 50% of the wetted
channel) must be recorded and only one entry per spot-check is allowed. Where there are two flow-types
both occupying about 50% of the wetted channel, the faster flow-type should be recorded.
Beware: strong or gusty winds give a false impression of flow (e.g. wind-dragged ripples may suggest
‘rippled’ flow when flow-type is actually either ‘smooth’ or ‘no perceptible’). Windy conditions should be
recorded in Section A as a factor affecting survey conditions.
Boxes are emboldened, so only a single entry per box (the predominant flow-type) is permissible.
Not visible (NV)
This should only be used when the watercourse is in a long culvert and the flow-type cannot be seen.
Free fall (FF)
Where vertically-falling water clearly separates from the ‘back-wall’ of a distinct vertical rock face. Generally
associated with waterfalls. E5Aa,b, M3a, M4a,b.
Chute (CH)
Low, curving flow with substantial water contact ‘hugging’ the substrate. Where multiple chutes occur over
individual boulders or bedrock outcrops, a ‘stepped’ profile is created. Mostly associated with cascades.
D1d, E5Ba,b.
Broken standing waves (BW)
These are the ‘stoppers’ favoured by canoeists and rafters but they may occur on a more localised scale where
water appears to be trying to flow upstream. A white water tumbling wave must be present for the wave
to be described as broken. Mostly associated with rapids, but may occasionally occur within riffles.
B3a, D3e, E1Ba, E5Ca,b.
Unbroken standing waves (UW)
‘Babbling’ water with a disturbed ‘dragon-back’ surface, which has upstream facing wavelets that have not
broken. White water may occur as crest waves, not as breaking waves. Mostly associated with riffles, but
may also occur within a rapid. C1a,b, E5Da,b,c.
3.19 River Habitat Survey Manual: 2003 version
Chaotic flow (CF)
A chaotic mixture of several faster flow-types (e.g. FF, CH, BW and UW) in no organised pattern. This
category should be used only where there are three of these fast flow-types at a spot-check, and where no
one of them is clearly predominant. Not to be used as a ‘catch-all category’. E5Ea.
Rippled (RP)
Water surface with distinct, symmetrical, small ripples that are generally only a centimetre or so high and
moving downstream. Beware: in windy conditions smooth flow can have wind-induced ripples on the
surface. E5Fa,b.
Upwelling (UP)
Upwellings are found where strong upward flow movements disturb the surface, creating an appearance of
bubbling or boiling water (see Figure C1). Upwellings are sometimes also called ‘boils’. They are typically
found on the outside of tight meander bends, behind in-channel structures (e.g. bridge abutments) or below
waterfalls, cascade weirs and sluices. Upwellings also help maintain the depth of pools by their scouring
action, but also produce lateral bank erosion on meander bends. E5Ga.
Smooth (SM)
Laminar flow where water movement does not produce a disturbed surface. If in doubt, put a ranging rod
into the water (or observe shadows on the bed in clear water) and you will artificially produce disturbed
surface movement either side of the rod or shadow. Mostly associated with glides. E5Ha, E7De.
No perceptible flow (NP)
In ponded reaches (such as upstream from natural bedrock controls and weirs), it may be difficult to perceive
any surface water movement. When using the ranging rod test (as in ‘SM’), no surface movement of water
will be seen. If associated with impounded reaches above dams, note in Section D. Marginal deadwater
(Section K) has no perceptible flow, as will stagnant pools in prolonged dry conditions. Also used to record
flow in pools where there is obvious rotational surface flow, but no obvious net downstream movement of
water at the surface. A1a, E1Da, E51a,b.
No flow (DR)
When a channel is dry, either naturally or due to excessive water abstraction in a dry year, record flow as ‘DR’.
In limestone or chalk areas, dry reaches will occur downstream from sinkholes or in headwater winterbournes
that naturally dry annually. Record channel, bank and bed materials as if flow was present, EXCEPT for dry
channels with soil/earth beds – record as ‘EA’. Record channel vegetation according to ‘type’, and provide
notes in Section P. Do not include terrestrial vegetation. E5Ja,b.
In rivers with pools present between long stretches of dry channel, record ‘DR’ in spot-checks where the
channel is dry, and ‘NP’ if spot-checks are located at pools.
SECTION E: PHYSICAL ATTRIBUTES - CHANNEL MODIFICATION(S)
All recording of modifications should be confined to alterations made to the river BED, not the
banks. If you are sure, beyond reasonable doubt, that there are no obvious signs of channel
modification, record ‘NO’ (none); if in doubt, record ‘NK’ (not known).
Boxes are NOT emboldened, so more than one entry per box is permissible.
Not known (NK)
When unsure, record ‘NK’. Seek further information from maps and flood defence records if unsure. For
guidance on identifying individual types of modification, see below.
3.20River Habitat Survey Manual: 2003 version
None (NO)
No obvious modification to the channel bed.
Culverted (CV)
As for ‘Culvert’ described earlier in Section E – ‘Bank Modifications’.
Resectioned (RS)
Obvious over-deepening of the channel bed resulting from lowering of the river bed, affecting both long- and
cross- section profiles, as well as artificially increasing the channel depth relative to its width. See ‘Bank
Resectioned’ described earlier in Section E – ‘Bank Modifications’. In Britain and Ireland channel deepening
on its own is rare, so look for other signs as listed in Section E. A1a,b,c,d, E6a,b,c,d,e,f, I6b.
Reinforced (RI)
Artificial reinforcement of the channel bed with material such as concrete, brick or gabion baskets. Bank
materials (artificial). E1H-M, E1Nd, E1O-P.
Dam/weir/sluice (DA)
Permanent in-channel structures installed to control river flows/levels. The presence of such structures at spotchecks
may be rare, but their presence within an RHS site, and their ‘impounding impacts’, will be noted in
Section D, and described in Section P. D1a,b,c,d,e,f.
Ford (FO)
Permanent, shallow, artificial fording place: can be made from concrete, metalled road surface, rubble infill
or natural consolidated river bed material. (In Section D the ‘category’ of fords occurring within the site will
be noted.) D5a,b,c,d,e.
SECTION E: PHYSICAL ATTRIBUTES - CHANNEL FEATURE(S)
Most channel features recorded by RHS will not be obvious unless the river is flowing at dry-weather
level, or below.
Boxes are NOT emboldened, so more than one entry is permissible (e.g. if unvegetated mid-channel
bar and exposed bedrock present, record ‘MB’/‘EB’).
Not visible (NV)
Self-explanatory. Record ‘NV’ if flows are too high for accurate recording, or if mid-channel obstructions,
including vegetation, obscure parts of the channel from view. Also use for culverts.
None (NO)
No channel features present. ‘NO’ must be entered if no other categories are recorded.
Exposed bedrock (EB)
Bedrock exposure protruding above the water at low flow. E4Aa,b.
Exposed boulders (RO)
Naturally occurring large, (at least ‘head size’) boulders protruding above the water. May be covered with
mosses/liverworts in upland streams. Exposed boulders should only be recorded in spot-checks and in
Section K if they are prominently protruding from the water, and where the predominant channel substrate
3.21 River Habitat Survey Manual: 2003 version
is cobble, boulder or bedrock. In cases where boulder-sized material has been placed in the river for fishery
enhancements, or has collapsed into the channel from boundary walls or rip-rap, this should be recorded as
artificial (‘AR’) when predominant in the spot-check (i.e. material is out of context with the overall river bed
character). Note the presence of failed reinforcement, or imported boulders for other purposes, in Section
P. E7Aa,b, K4a.
Vegetated rock (VR)
Bedrock or groups of boulders protruding from the water that have accumulated fine sediments in crevices
which has allowed higher plant vegetation to become established (e.g. tall herbs, reeds, grasses, shrubs).
Does not include rocks with only mosses or liverworts. E7Ba,b.
Unvegetated mid-channel bar(s) (MB)
A distinctive, in-channel, depositional feature composed of unconsolidated river bed material. Exposed at
low flow, usually with shallow sloping sides into the water. Classified as ‘unvegetated’ if <50% of the total
surface area has plant cover. See Figure E3 for characteristics. E7Ca,b,c.
Vegetated mid-channel bar(s) (VB)
A distinctive in-channel depositional feature composed of consolidating river bed material. Exposed at low
flow, usually with shallow sloping sides into the water. Classified as ‘vegetated’ if >50% of the total surface
area has plant cover. Vegetation may include perennials such as reed canary-grass, shrubs and trees.
Moss-covered substrates are also included as these indicate stability. Surface of bar is lower than the bank
height, so the whole feature is submerged during large floods. E7Da,b,c,d,e.
Mature island(s) (MI)
Permanent in-channel feature with the surface at the same height, or above, the bankfull height. Usually well
vegetated, often with mature scrub and trees. If significant deposits of fresh material surround a
mature island, then both mature island (MI) and unvegetated mid-channel bar (MB) can be present –
if so, record both at the spot-check because this indicates both the presence of a mature feature and active
deposition. See Figure E3. E7Ea,b,c.
Trash [urban debris] (TR)
Rubbish such as bricks, shopping trolleys, piles of flotsam and jetsam etc. E7Fa, E7Cc.
Braided channels
Braided rivers are dynamic and mobile, where the channel is divided into several sub-channels separated by
active mid-channel bars along most (>50%) of the 500m site. In braided rivers, most bars are unvegetated
and the wetted area, at low flows, represents substantially less than 50% of the river bed. Bar surfaces are
typically at lower elevations than the vegetated floodplain margins. Braided rivers must feature at least two
sub-channels and two mid-channel bars along most of the site. Some of the sub-channels may be dry at the
time of the survey. Recording features of braided channels is very difficult to do accurately, and surveys
will take much longer to complete than on a more typical RHS site.
For more details, see Section M, Special Features. M1a,b,c.
When recording spot-checks on braided channels, record the number of sub-channels (wet and dry)
at each spot-check in the grey row dedicated for such records, and then record all channel features of
a spot-check on the channel carrying the major flow at the time of survey.
Marginal and bank features, bank modifications and bankface vegetation structure records are all made from
the outer edges of the two channels abutting the floodplain.
3.22River Habitat Survey Manual: 2003 version
SECTION F: BANKTOP LAND-USE AND VEGETATION STRUCTURE
To be assessed over a 10m length of bank at each spot-check (See Figure 1). Refer to spot-check key
prompts on the form.
The contribution of adjacent land-use and vegetation structure alongside watercourses can contribute
significantly to riparian habitat diversity.
At each spot-check, using the 10m wide transect guidance (Figure 1), surveyors are required, for both
banks, to record:
(i) land-use within 5m of the banktop, using abbreviations in the spot-check key;
(ii) vegetation structure within 1m of the banktop;
(iii) vegetation structure on the bankface, using ‘B’ (bare), ‘U’ (uniform), ‘S’ (simple) or ‘C’
(complex) categories. See below for guidance and Figure F1.
Since floodplain land-use up to 50m from each bank is also recorded in Section H, the combination of
vegetation structure within 1m, land-use within 5m and a general overview of land-use will provide a
collective picture of riparian habitat character.
Banktop
This is defined as the first major break in slope where cultivation or development would be possible. Where
no distinct breaks in slope occur (e.g. streams in vee-shaped valleys), the bankfull height may be estimated
by the winter flood level, often marked by a trashline or ‘notches’ at similar heights above the bed level.
Notches may be seen along lines of exposed bank material that represent where vegetation has been ripped
out by the roots at the level water reaches during times of peak floods.
Illustrated examples of banktop and bankface, as defined for recording vegetation structure and land-use
during RHS are shown in Figures E1 and F1.
A banktop hedgeline (as shown in photo D7a) should be recorded as complex structure (C) in spot-checks
and not included as tree distribution (Section J). A hedgeline with scattered “standard trees” would be
similarly recorded as complex structure in the spot-checks, but with “isolated” or “regularly spaced” trees (as
appropriate) recorded in Section J.
SECTION F: LAND-USE WITHIN 5m OF BANKTOP
Boxes are emboldened, so only a single entry per box (the predominant land-use) is permissible.
Broadleaf/mixed woodland (BL)
Woodland containing predominantly deciduous broadleaved trees. Does not include broadleaf/mixed
plantations. Vegetation below trees (understorey) is usually mixed young trees/shrubs and/or mixed
grasses/herbs. C3b, E7Dd, F1a,b, J6a,b, M2b.
Broadleaf/mixed plantation (BP)
Plantation woodland containing deciduous broadleaved trees such as poplars planted in rows, or in similar
regimented fashion. Include young plantations with just saplings. F2a.
Coniferous woodland (CW)
Native conifers, typically Caledonian forest in Scotland. Excludes all coniferous plantations. F3a.
Coniferous plantation (CP)
Coniferous trees (e.g. sitka spruce, lodgepole pine) planted for commercial forestry. F4a.
Scrub & shrubs (SH)
Scrub (e.g. brambles, gorse, rhododendron) and woody shrubs (e.g. blackthorn and hawthorn). F5a.
3.23 River Habitat Survey Manual: 2003 version
3.24River Habitat Survey Manual: 2003 version
Bankfull width
Symmetrical channel
Figure F1 Examples of different channel shapes affecting
definitions of bankface, banktop and bankfull width.
trashline
trashline height
Bankfull width
4m
Bankfull width
Water
depth
Water depth
Water depth
Gorge
Asymmetrical channel or valley
Bankfull width
Note: in over-deepened artificial channels there will be a trashline – see text.
4m
LEFT BANK
Banktop height
Is banktop height
also bankfull height?
3m
3m
6m
Yes
Trashline height:
RIGHT BANK
Banktop height
Is banktop height
also bankfull height?
3m
Yes
Trashline height:
LEFT BANK
Banktop height
Is banktop height
also bankfull height?
7m
No
Trashline height: 2m
RIGHT BANK
Banktop height
Is banktop height
also bankfull height?
7m
No
Trashline height: 2m
LEFT BANK
Banktop height
Is banktop height
also bankfull height?
6m
No
Trashline height: RIGHT
BANK
Banktop height
Is banktop height
also bankfull height?
1m
Yes
-Trashline height:
2m
1m banktop vegetation structure
5m and 50m land-use
Bankface vegetation structure
For recording vegetation:
0 1 2 3 4 5 6 7 8 9 10
metres
Scale
3.25 River Habitat Survey Manual: 2003 version
Bankfull width
Bankfull
width
Bankfull
width
7m
Deep vee/shallow vee valley
(and rivers with no obvious banktop)
Embanked channel
Channel with set-back embankments
Two-stage channel formed through excavation
To be used only when no obvious banktop evident for both banks. Look for presence of small
‘notches’ at consistent height to indicate level of water during large floods. Use this, or trashlines,
to determine bankfull height, and areas for recording banktop vegetation structure and land-use.
LEFT BANK
Banktop height
Is banktop height
also bankfull height?
-
Trashline
height: 1.5m
RIGHT BANK
Banktop height
Is banktop height
also bankfull height?
-
Trashline
height: 1.5m
LEFT BANK
Banktop height
Is banktop height
also bankfull height?
3m
No
Trashline height: -
1.5m
RIGHT BANK
Banktop height
Is banktop height
also bankfull height?
Trashline height:
3m
No
Embanked
height Embanked height: 1.5m
LEFT BANK
Banktop height
Is banktop height
also bankfull height?
3m
Yes
Trashline height: RIGHT
BANK
Banktop height
Is banktop height
also bankfull height?
Trashline height:
3m
Yes
Embanked
height 1m Embanked height 1m
LEFT BANK
Banktop height
Is banktop height
also bankfull height?
2m
Yes
Trashline height: RIGHT
BANK
Banktop height
Is banktop height
also bankfull height?
Trashline height:
2m
Yes
Bankfull
width
6.5m
trashline
notch
Berm
3m
Water depth
3m
Water depth
Water depth
Water depth
2m
Orchard (OR)
Horticultural crop of fruit trees planted in lines and carefully managed to produce fruit crops. Includes hop
fields and vineyards.
Wetland (WL)
Includes bog, marsh, and fen. Fens typically have groundwater sustaining them as wetlands, with
vegetation, often (but not exclusively) growing over peat, where the water-table is at, or just below, the
surface. Water is derived from both rainfall and drainage of surrounding land. Some fens may have
Sphagnum moss, but typically the vegetation is dominated by tall reeds, wetland herbs, sedges, and rushes.
Bogs have vegetation growing on wet peat; the water source is direct rainfall, or in some cases, over-land
flow during heavy rain events. Sphagnum moss is always present, often with bog cotton (Eriophorum). In
locally drier areas heather (Calluna, Erica) may also be present, but never dominant. F7a,b,c, M15a,
M18a,b, M20a.
Moorland/heath (MH)
Typical moorlands and heaths have heather (Calluna, Erica) present, even if not the dominant vegetation
type. In some upland areas (e.g. Bodmin Moor), or lowland heath areas (e.g. the machair of the Outer
Hebrides), the plant communities may be dominated by acid-tolerant grasses such as purple moor-grass
(Molinia caerulea). Cotton-grass (Eriophorum spp.) may occur in wetter areas, and in more free-draining areas
may merge with heathy scrub with dwarf willow and birch (Salix, Betula) present. B2a,b, E7Dc, E7Ea,
F8a,b, J1b, M16b.
When the bog component within heathland is small, and heather is dominant, record wetland as
‘present’, and moorland/heath as ‘extensive’ in Section H.
Artificial open water (AW)
Off-line artificial lakes, reservoirs, water-filled gravel pits, canals and the full range of amenity, farm and
‘conservation’ ponds. Natural lakes which have been modified by control structures are regarded as artificial.
Includes mill streams, and artificial secondary channels which branch from, or join, the main watercourse.
F9a,b,c.
RHS should not be undertaken on on-line lakes.
Natural open water (OW)
Natural lakes, ponds and pools, including bog pools and old river cut-offs.
Some natural lakes have impounding structures; if these are not clearly visible, record ‘OW’. F10a,b,
M20b,c.
Rough/unimproved grassland/pasture (RP)
Unimproved (i.e. not reseeded or fertilized) upland or lowland grassland. Usually herb-rich, and includes hay
meadows. If ground is seasonally wet, tussocks of ‘coarse’ grass or rushes (e.g. Deschampsia cespitosa, Juncus
effusus), can occur. F11a,b.
Improved/semi-improved grassland (IG)
All agricultural grassland other than ‘RP’. Includes pasture/meadow grassland which has been re-seeded
(typically with Lolium perenne – rye-grass) or artificially fertilised. B7b, F12a.
Tall herb/rank vegetation (TH)
Vegetation at least waist-high, dominated by herbs (not grasses or reeds, but includes bracken – Pteridium).
‘‘Wildlife areas’ where farmers have left the land on the inside of meanders uncultivated to grow ‘wild’ for
conservation reasons are included. F13a,b,c.
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Rock, scree or sand dunes (RD)
Collective category that includes extensive rock outcrops, mountain scree or sand dunes. F14a,b.
Suburban/urban development (SU)
Buildings, metalled roads, tracks, railways. Also includes land-fill sites.
Where un-metalled tracks follow the banktop, the land-use in which they are located should be recorded,
and not ‘SU’. A1c, F15a,b.
Tilled land (TL)
Agricultural land where crops grown on regularly ploughed soil. Includes root and horticultural crops and
allotments. E1Jb, F16a.
Irrigated land (IL)
Agricultural land dependent on irrigation for crop yield. In Britain this includes cress beds. F17a.
Parkland or gardens (PG)
Includes parks, golf courses, public amenity spaces, sports fields and gardens. This includes a wide variety of
land-uses, where grass is mown for recreational purposes. Do not confuse with agricultural land-use of
improved grassland. E1La,b, F18a,b.
Not visible (NV)
Self-explanatory. Only to be used if land-use is genuinely obscured (e.g. top of a gorge, behind a mature
island, or beyond dense stands of tall trees on the far bank).
SECTION F: BANK AND BANKFACE VEGETATION STRUCTURE
To be assessed over a 10m length of each bank (see Figure 1). Separate records are made for the
structure of the vegetation on the face of the bank, and the vegetation structure in the 1m zone
beyond the banktop (see definition above; Figures E1 and F1). Even in intensively farmed arable land,
the 1m banktop vegetation structure may contrast with the land-use within the full width of the 5m
banktop zone (recorded separately, and described above).
When recording bankface vegetation structure, ignore vegetation on bars or berms at the base of
banks.
The category recorded is determined by the complexity of structure produced by different vegetation types.
If the vegetation structure cannot be assessed (i.e. when surveying from the bottom of a gorge), record ‘NV’
for not visible. On wide rivers, binoculars can assist with defining vegetation structure on the far bank.
Since this exercise is a rapid overview, only the predominant structure is to be assessed. Use your initial
assessment - time must not be wasted searching for relatively inconspicuous types of vegetation.
Vegetation structure is based on four categories. Component elements represent vegetation types that
contribute to vertical layering on the bank. Refer to the spot-check key for diagrammatic representation,
and the categories of vegetation types listed below.
Bryophytes Mosses and liverworts. FV1a.
Short/creeping herbs or Below knee height (includes ivy).
grasses A1a, B7a,b, E2Ca, FV2a,b.
Tall herbs or grasses Knee height, and taller; includes bracken and other ferns.
C3a, D1c, D8a, E1Oa, F18a, FV3a,b.
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Scrub or shrubs Brambles, woody (and multi-stemmed) shrubs, thickets.
D1c, F18a, FV4a,b.
Saplings and trees Mature trees and single-stemmed young trees (cf. bushy nature of shrubs).
FV5a,b, G2b.
Boxes are emboldened, so only a single entry per box (the predominant vegetation structure) is
permissible.
Bare (B)
Predominantly bare earth or unvegetated artificial bank material (e.g. concrete, sheet piling, gabion).
Vegetation cover <50% over the 10m bank-length. A1c, E1La,b, E1Ma,b,c, E1Pa, E7Cc, FV6a,b.
Uniform (U)
Predominantly one vegetation type (e.g. grass, nettles, heather), but lacking scrub or trees. B7a,b, C4c,
D6c, E2Ca, F8a, FV1a,b, FV2a,b, FV5b, FV7a,b.
Simple (S)
Predominantly 2-3 vegetation types, often with scrub, and may include trees. Trees with sparse herb
understorey (e.g. coniferous forest extending to the riverbank) to be included in this category. E1Pd,
E7Dd, F18a, FV8a,b, G2b.
Complex (C)
Four or more vegetation types, and scrub and/or trees must be present. FV4b, FV5b, FV9a,b, G2b.
Not visible (NV)
To be used only where the bank is genuinely obscured.
SECTION G: CHANNEL VEGETATION TYPES
To be assessed within a 10m wide transect across the channel at each spot-check (see Figure 1).
Channel vegetation types are recorded in categories that assess the habitat structure they provide at the time
of survey, not their morphological character described in textbooks. The purpose is to provide information
on the range of functional habitats that channel vegetation may be providing for invertebrates and other
animals. This is especially important in rivers with otherwise limited structural diversity.
To be recorded as present (), a channel vegetation type must occupy at least 1% of the channel
area within the 10m wide transect (e.g. 1m2
on a 10m wide river). To be recorded as extensive (E), the
channel vegetation type must occupy at least 33% of the channel area within the 10m wide transect.
Thus, vegetation growth should be obvious, and time should not be wasted looking for isolated plants.
It is essential that at each spot-check at least one box has an entry. Several ‘vegetation type’ entries
will be made for the same spot-check when there is more than a single type present. When the water
is very turbid, enter ‘NV’, and record cover of emergent, floating or amphibious vegetation as
appropriate.
It is important to complete the end-column to assess overall presence of vegetation types occurring
along the 500m as a whole, including those types not recorded at the spot-checks. Use ‘E’ for
vegetation forms covering >33% of the 500m site, or  for those vegetation types occupying at least
1% of the 500m site, but <33% of it.
This end-column is not a summation of the vegetation types recorded in spot-checks – it is possible
that rare forms may be recorded in one or more spot-checks, but not cover >1% of the whole RHS site;
as such they would not be recorded in the end-column.
None/Not visible
If <1% vegetation cover, or none is visible, even though water clarity is good, enter  in this box. When the
bed of the channel is not visible (e.g. when enclosed in a culvert) also enter ‘NV’. Also enter ‘NV’ if the water
is too turbid to determine submerged plant cover, even though entries for emergent, amphibious and
floating forms can be made if present.
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Liverworts/mosses/lichens
Aquatic liverworts (e.g. Scapania), mosses (e.g. Fontinalis) and lichens (e.g. Collema). Includes vegetation that
is submerged, or in the splash zone. G1a,b,c, M6a,b.
Emergent broad-leaved herbs
Broad-leaved plants rooted on the river bed or along the water’s edge. Leaves and flowers grow above water
level e.g. fool’s water-cress (Apium nodiflorum) and water-speedwell (Veronica spp.). G2a,b.
Emergent reeds/sedges/rushes/grasses/horsetails
Narrow-leaved monocotyledons (e.g. reeds, sedges, rushes, grasses and horsetails) rooted below water-level
or along the water’s edge. Examples include branched bur-reed (Sparganium erectum), reedmace (Typha),
common/Norfolk reed (Phragmites australis), sedges (Carex spp.), rushes (Juncus spp.) bulrush (Schoenoplectus
spp.), reed sweet-grass (Glyceria maxima) and water horsetail (Equisetum fluviatile). G3a,b,c.
Floating-leaved (rooted)
Plants rooted on the river bed but with either broad floating leaves such as yellow water-lily (Nuphar lutea)
and broad-leaved pondweed (Potamogeton natans); or linear floating leaves such as those produced by
unbranched bur-reed (Sparganium emersum). . G4a.
Free-floating
Plants floating on, or just under, the water surface, and not rooted to the river bed. Examples include
duckweeds (Lemna spp.), frogbit (Hydrocharis morsus-ranae), hornwort (Ceratophyllum spp.) and water soldier
(Stratiotes aloides). G5a,b,c.
Amphibious
Plants rooted at the edge of the river, or on the bank, but shoots or leaves trail across the water. Examples
include amphibious bistort (Persicaria amphibia), creeping bent-grass (Agrostis stolonifera), floating sweetgrass
(Glyceria fluitans), marsh foxtail (Alopecurus geniculatus), and water forget-me-not (Myosotis scorpioides).
G6a,b.
Submerged broad-leaved
Rooted submerged plants with underwater leaves no more than four times longer than broad. Some part of
the plant, or some leaves, may reach the surface but the majority are submerged. Includes submerged
‘cabbage-like’ leaves of yellow water-lily (Nuphar lutea), perfoliate and several other broad-leaved pondweeds
(Potamogeton perfoliatus, P. lucens, P. alpinus), Canadian pondweed (Elodea canadensis), and starworts
(Callitriche spp.). G7a,b,c.
Submerged linear-leaved
Rooted submerged plants with narrow, unbranched, laminar leaves (blade/strap/belt-shaped) that are either
totally submerged or just have their tips or upper parts floating on the surface. The most typical examples
are unbranched bur-reed (Sparganium emersum) and the underwater leaves of arrowhead (Sagittaria
sagittifolia), bulrush (Schoenoplectus spp.) and flowering rush (Butomus umbellatus). G8a,b.
Submerged fine-leaved
Rooted submerged plants with fine, branched, leaves. Examples include the feathery leaves of water milfoil
(Myriophyllum spp.) and the longer ‘shoe-lace’ appearance of some water-crowfoot species (Ranunculus spp.)
and fennel pondweed (Potamogeton pectinatus). G9a,b,c.
Filamentous algae
Blanketweed (Cladophora), mole pelt (Vaucheria) and other obvious filamentous algal growths (e.g.
Enteromorpha). Do not record diatom films that occur alone, or coating aquatic plants or stones.
G10a,b.
3.29 River Habitat Survey Manual: 2003 version
RHS form page 3: Sweep-up
All sweep-up information is based on the occurrence of features and river characteristics over the
whole 500m site.
It is important to continue another 50m beyond the last spot-check to ensure the whole RHS site
is 500m long.
For the majority of features, record their presence only if they occur along at least 1% of the channel
or bank. Exceptions to this general rule include the presence of specific features such as waterfalls or
overhanging boughs that typically may not extend more than 5m along the channel. All features
that can be recorded as present even if they occur along <1% of the RHS sites are marked with an
asterisk (*) on the form.
It is possible that some features recorded as dominant in a spot-check in Section E (e.g. poached
bank ‘PC’) may not even be recorded as a  in the sweep-up if they do not extend at least 5m along
the bank.
SECTION H: LAND-USE WITHIN 50m OF BANKTOP
Record ‘E’ if a land-use type occurs along > 33% of bank-length, or  when it extends for 1-33% of
the bank-length. Only record land-use occurring within 50m of the banktop. Record left and right
sides of the watercourse separately. Where two parallel land-uses border the river (e.g. along 50% of
one bank there is a 20m grassland strip giving way to arable) - both are recorded as ‘E’. Moreover, if
the other 50% is a parallel pattern of urban and artificial open water, these too are both recorded as
‘E’. Therefore, in exceptional circumstances, more than three ‘E’ categories can be recorded for one
bank.
Use the prompts on the form. For descriptions of land-use categories, see Section F. The following categories
are used:
Broadleaf/mixed woodland (BL)
Broadleaf/mixed plantation (BP)
Coniferous woodland (CW)
Coniferous plantation (CP)
Scrub & shrubs (SH)
Orchard (OR)
Wetland (WL)
Moorland/heath (MH)
Artificial open water (AW)
Natural open water (OW)
Rough/unimproved grassland/pasture (RP)
Improved/semi-improved grassland (IG)
Tall herb/rank vegetation (TH)
Rock, scree or sand dunes (RD)
Suburban/urban development (SU)
Tilled land (TL)
Irrigated land (IL)
Parkland or gardens (PG)
Not visible (NV)
SECTION I: BANK PROFILES
Use ‘E’ (> 33% of bank-length within the site) or ‘’ (present - >1% but <33%) for profiles visible on
both left and right banks.
3.30River Habitat Survey Manual: 2003 version
NATURAL/UNMODIFIED PROFILES.
Record in the ‘left’ and ‘right’ bank columns the profiles (slopes) of unmodified banks. The first two
categories cover vertical banks, including ‘cliffs’ recorded in Section E, and other vertical banks not forming
cliff features such as banks on chalks streams that are vertical, but may be only a few centimetres high. Other
steep banks should be recorded in the third category, and gently sloping banks in the fourth.
All natural bank profiles are recorded here. In cases where there is uncertainty over bank profile,
record them as best as possible in the natural/unmodified categories.
Vertical/undercut
Predominantly vertical banks, which may include eroding and stable cliffs. B1b, C4a, E3Ab, I1a,b.
Vertical with toe
Vertical bank with slumped material at base. E1Ea, I2a,b.
Steep
Bank slope >45˚ angle, but not predominantly vertical. B3a, I3a, I4a.
Gentle
Bank slope <45˚. B1b, B7a, C4a, E3Ec, I4a.
Composite
Banks with complex profile which may be caused by previous slumping or sequences of channel erosion.
I5a,b.
Natural berm
See detailed definition in Section E and Figure E4. A transitional feature that requires a well-trained eye to
confirm its presence. Beware: if artificial two-stage channels have been excavated just above the original
river bed level, these may, over time, appear ‘like a new floodplain’; if so, do not record here. E3Ea,b,c,
d,e – for artificial berm, see E2Ca,b,c,d.
ARTIFICIAL/MODIFIED PROFILES.
The same modifications to banks noted in Section E are also included here, and as for ‘unmodified banks’, all
the different resectioned and reinforced profiles on the left and right banks should be recorded in the
appropriate columns. This is the only place where the occurrences of embankments set back from the bank
are recorded.
All modifications to banks are summarized here.
Resectioned (reprofiled)
Bank profile modified, often to accommodate flood flow, flood defence or other maintenance machinery.
Recent re-profiling will produce a relatively smooth, uniformly angled, bank slope. See Section E; Bank
Modifications. Only record in the sweep-up if not accompanied by whole bank reinforcement. A1a,
D8a,b,c, E2Aa,b, E3Da, I6b.
Reinforced bank
Whole or part of bank artificially strengthened for bank protection purposes. Examples include concrete,
sheet piling, corrugated iron, wood piling, gabion, brick/laid stone, rip-rap and builders’ waste (see
descriptions of above in E: Bank Materials). For sweep-up purposes, bank reinforcements are differentiated
into three categories to indicate their vertical extent: (i) whole bank; (ii) top only; (iii) toe only. When the
whole bank is reinforced, there is no need to record resectioning. A1c, E1Ja,b, E1Ka, E1La,b, E1Oa,
I6a,b,c.
3.31 River Habitat Survey Manual: 2003 version
Artificial two-stage channel
Typically this is where one or both banks have been
excavated laterally into the floodplain to create a
shelf above dry-weather flow (see Figure I1). Also
included are shelves constructed in previously
widened channels to create narrower low-flow
channels. Water spills over the second (normally
dry) stage shelves during high flows. These are
constructed features. E2Ca,b,c,d.
Do not confuse with natural berms (see Natural
berm E3Ea,b,c,d,e).
Poached bank
Bank significantly trampled or puddled by
livestock. Include banks trampled as a result of
human activity such as picnic spots, canoe access
points, and fishing spots dug into the bank.
E2Ba,b,c,d, I5b, P1a.
Embanked
Artificial embankment created to increase the
banktop height. Only recorded here when it forms
an integral part of the bank. Do not include
embankments set back from the immediate
banktop; these are recorded as set-back
embankments (below). E2Da,b.
Set-back embankment
Artificial embankment or earth bund designed to increase flood capacity but set back from the river channel
and forming a distinct floodplain landscape feature. I7a.
SECTION J: EXTENT OF TREES AND ASSOCIATED FEATURES
Due to the importance of trees and
associated features, these warrant individual
attention and are recorded in more detail in
this section.
TREES
Distribution along each bank for the entire
500m length is recorded using five
descriptive categories. These are not meant
to represent an accurate distribution pattern
for individual sites, but to provide an
overview. Recent aerial photographs can
provide an extra check.
For each bank tick one box only for the
nearest distribution ‘match’ based on the
categories in Figure J1. ONE BOX FOR
EACH BANK MUST BE TICKED.
3.32River Habitat Survey Manual: 2003 version
Artificial Berm
(excavated)
Before
After
Figure I1 Artificial two-stage channel –
berm formation through:
A - bank excavation
B - channel infill
A
Before
Widened
After
B
Artificial Berm
(infilled)
Isolated/scattered
J2a,b.
Regularly spaced, single
J3a, F18b.
Occasional clumps
J4a,b,c.
Semi-continuous
J5a.
Continuous
J2a, J6a,b,c.
Figure J1 Illustration of RHS recording of bankside trees
ASSOCIATED FEATURES
These are habitats, or features, associated with trees.
IN EACH CASE, ONE BOX PER FEATURE MUST BE TICKED.
Records are made on their occurrence within, or along, the total 500m length of the site. Record
‘None’ when <1% occurrence (absent, or not present in >5m of channel length); ‘Present’ if 1-33%
occurrence (present in 5-165m of channel length); and ‘E’ when > 33% occurrence (present in >165m
of channel length).
For the three features marked with an asterisk (*), presence can be ticked even if they do not occur in
>1% of the site.
Shading of channel
Extent of direct, overhead, tree canopy shade. Do not include shade from culverts and bridges. J7a,b,
M4a, M6a, M7a.
*Overhanging boughs
Large (forearm-size or larger) tree boughs which arc horizontally over, or dip close to, the water surface.
C2a, E4Bb, I1a, J6b, J7a, J8a,b, J9b.
*Exposed bankside roots
Large (forearm-sized or larger) exposed roots and associated cavities. These can provide a good location for
otter holts. J9a,b.
*Underwater tree roots
Exposed underwater tree or shrub roots. Alder and willow roots are distinctive examples. J10a.
Fallen trees
Uprooted or collapsed tree(s) that are still attached to the bank, either alive or dead. J11a,b,c.
Large woody debris
Whole trees or large trunks and branches swept downstream and lodged in the channel or on the banks.
J12a,b.
SECTION K: EXTENT OF CHANNEL AND BANK FEATURES
This section includes a wide variety of features ranging from flow types to exposed bedrock.
IN EACH CASE, ONE BOX PER FEATURE MUST BE TICKED.
Records are made on their occurrence within, or along, the total 500m length of the site. Record
‘None’ when <1% occurrence; ‘Present’ if 1-33% occurrence; and ‘E’ when > 33% occurrence .
For the five features marked with an asterisk (*), presence can be ticked even if they do not occur
in >1% of the site.
3.33 River Habitat Survey Manual: 2003 version
RHS uses flow-types as a diagnostic guide to channel habitats. Predominant flow-type is determined at the
10 spot-checks (Section E). However, it is also necessary to assess flow-types in the site as a whole. For this
purpose only, you need to record flow-types when they are dominant across most of the channel width and
when they form a distinct feature that is at least 5m long (i.e. >1% of channel length). ‘Free fall’ and
‘upwelling’ flow-types can be recorded as present even if they do not represent a predominant flow type
along at least 5m of the channel length. Do not record these flow-types in Section K if they result
from artificial features such as weirs.
For the definitions of flow-types and channel features, see Section E. The following are recorded (spot-check
abbreviations are included for easy cross-reference).
*Free fall flow (FF) – but only if associated with natural features
Chute flow (CH)
Broken standing waves (BW)
Unbroken standing waves (UW)
Rippled flow (RP)
*Upwelling (UP) - but only if associated with natural features
Smooth flow (SM)
No perceptible flow (NP)
No flow [dry] (DR)
The following other (non-flow-type related) features are recorded.
Marginal deadwater
Margins of the main channel which have no perceptible flow. These are good refuge areas for various
aquatic invertebrates and fish fry. Examples include where the bank has eroded into an embayment, or
remnants of old abandoned channels are still connected to the main channel (also recorded as backwaters in
Section M). Marginal deadwater may also occur downstream of large ‘side’ or ‘point bars’. K1a,b,c,
M12a,b.
Eroding cliff(s)
See Section E, marginal and bank features. Extent is for both banks.
Stable cliff(s)
See Section E, marginal and bank features. Extent is for both banks.
Exposed bedrock
See Section E, channel features.
Exposed boulders
See Section E, channel features.
Vegetated bedrock/boulders
See Section E, channel features.
3.34River Habitat Survey Manual: 2003 version
Unvegetated mid-channel bar(s)
See Section E, channel features.
Vegetated mid-channel bar(s)
See Section E, channel features.
Mature island(s)
See Section E, channel features.
Unvegetated side bar(s)
See Section E, marginal and bank features. Extent is for both banks.
Vegetated side bar(s)
See Section E, marginal and bank features. Extent is for both banks.
Unvegetated point bar(s)
See Section C. Extent is for both banks.
Vegetated point bar(s)
See Section C. Extent is for both banks.
*Unvegetated silt deposit(s)
DO NOT RECORD when silt covers the bed from bank to bank and does not contrast with the
predominant substrate present in the whole site (recorded as ‘SI’ in spot-checks in Section E) – the deposits
must contrast with the predominant river bed substrate(s). Unvegetated silt deposits may be either
underwater or exposed, in the channel or on the margins with a minimum size of 5m2
. Silt deposits are often
formed in response to obstructions (e.g. fallen tree, naturally protruding boulders, or artificial deflector
structures); such deposits would be recorded as ‘present’. Extensive deposits are often associated with rivers
recovering from artificial channel over-widening. If they form discrete ledges, and occur in more than
33% of the site, record as ‘E’. K2a,b,c.
*Discrete unvegetated sand deposit(s)
A discrete unvegetated sand deposit is either underwater or exposed, in the channel or on the margins with
a minimum size of 5m2
. DO NOT RECORD when sand covers the bed from bank to bank (recorded as
‘SA’ in Section E) – the deposits must contrast with the predominant river bed substrate(s). Discrete sand
deposits are often formed in response to obstructions (e.g. fallen tree, naturally protruding boulders or
artificial deflector structures), or in recesses in banks. Discrete sand deposits are recorded because they are
valuable habitats for several invertebrate species. As sand deposits are not considered to be ‘discrete’ if they
are present along more than 33% of a site (sand would be a predominant substrate in Section E), it is not
possible to record extensive discrete sand deposits (‘extensive’ box not on the form). K3a,b.
*Discrete unvegetated gravel deposit(s)
A discrete unvegetated gravel deposit is either underwater or exposed, in the channel or on the margins with
a minimum size of 5m2
. DO NOT RECORD when gravel covers the bed from bank to bank (recorded as
‘GP’ in Section E) – the deposits must contrast with the predominant river bed substrate(s). Found only in
channels with a predominant substrate of cobbles/boulders/bedrock, and located in the lee of large boulders,
structures, fallen trees or other obstacles. Do not record in any other circumstances, and not to be
confused with bars (recorded in Section E). As gravel deposits are not considered to be ‘discrete’ if they are
present along more than 33% of a site (gravel would be a predominant substrate in Section E), it is not
possible to record extensive discrete gravel deposits (‘extensive’ box not on the form). K4a,b.
3.35 River Habitat Survey Manual: 2003 version
RHS form page 4: Dimensions and Influences
SECTION L. CHANNEL DIMENSIONS
Make sure that Health & Safety guidance (Appendix 1) is strictly followed when entering the
channel to take measurements. For large rivers where mid-channel water depth cannot be safely
measured, enter “unknown” in the appropriate box.
Measurement of channel width, water depth and banktop height.
Choose a straight part of the site if possible, preferably with well-defined banks and a riffle. This is the
optimum location for measuring channel and bank dimensions. In many instances channel dimensions will
need to be measured at a location other than at one of the spot-checks.
For guidance on banktop, water width etc., see Figure F1. To ensure consistent recording it is
imperative that surveyors fully comprehend this information before undertaking field measurements.
Both steep and very low gradient sites will not have riffles. In such cases choose a relatively uniform
(and if possible, shallow) cross-section and state on the form the predominant flow-type at the
location where channel dimensions are taken. In some instances, the river bed will be inaccessible and
consequently water depth and river bed consolidation will not be determined. If so, indicate
accordingly on the form.
Rangefinders and ranging poles will improve the accuracy of measurements taken. When a rangefinder is
used to measure width, indicate by adding ‘R’.
Measuring channel dimensions on braided channels can be very complicated due to the
presence of several sub-channels. Water depth should be the average depth of water in the largest
channel (i.e. the one from which flow-type and substrate are recorded in spot-checks), but water width
cannot be measured. Banktop height and bankfull width should be measured using the banks abutting
the floodplain.
Banktop height (m)
Banktop height is the vertical distance from water level, to the first major break in slope above which
cultivation or development is possible. Use the ranging pole to estimate height (m).
Bankfull width (m)
Bankfull width is the horizontal distance across the channel to be measured at the level where the river first
spills out of the channel on to the floodplain.
Where no distinct breaks in slope occur (e.g. streams in vee-shaped valleys or gorges, the bankfull height
should be estimated using clues such as the winter flood level, often marked by a trashline, or ‘notches’
along the bank at similar heights to the trashline. Estimate bankfull width and height at this point: ENTER
MEASUREMENT IN LINE FOUR – and do not enter bankfull width measurements in line one.
Is banktop height also bankfull height?
Bankfull height is the vertical distance from water level on the day, to the point where the river first spills out
of its channel on to the floodplain (if it can). Indicate, using ‘yes’ or ‘no’, whether the bankfull height is
equivalent to the banktop height.
Water width (m)
Water width is the distance across the wetted perimeter of the channel. Use the ranging rod to make crossing
the watercourse in shallow locations safer, and use the rod to help measure the width. When a range-finder
is used to measure channel width, indicate by adding (R) with the width measurement entry. Note on the
form the max-min range of the range-finder used.
Beware: in misty conditions, or where the bank has a non-reflective substrate, accurate range-finder
readings are difficult to get.
If it is impossible to wade safely across the river, and you do not have a range-finder, a reasonably accurate
estimate can be made by sticking a ranging pole on the bank, and walking along the bank until the pole
appears to be the same distance away as the far bank; pace the distance to the pole to estimate the channel
width. Wherever possible, however, use a range-finder for measurements.
3.36River Habitat Survey Manual: 2003 version
Water depth (m)
Water depth is the estimated average depth of the channel (to the nearest 10cm). Where possible, always
try to estimate the actual depth, using the ranging pole; otherwise use “not known”. Common sense should
prevail, but recording the average of three measurements taken across the depth range is good practice.
If access to the channel is considered too risky, estimate the depth if feasible; if in doubt, record ‘NK’ in
the box.
Embanked height (m)
Where embankments are present, record the extra height created by the embanked material. Include setback
embankments where practicable.
Trashline height (m)
The height of the trashline above water level is to be recorded only if lower than the banktop. This may give
an indication of an over-deepened channel with the ‘natural’ bankfull height, indicated by trashline marks.
The width of the channel at the trashline height can be estimated and recorded. As the height of the
trashline is dependent on the previous flood, measurement of this level provides less reliable information than
bankfull and banktop heights and widths.
NOTE: Do not choose a location for channel measurements based on the presence or absence of a trashline.
River bed consolidation
Consolidated river bed material will be normally characterised by luxuriant bryophyte or rooted higher plant
macrophyte growth. Where gravel and cobbles are present, these will be firmly inter-locked with other
substrates, be hard to dislodge, and give a stable ‘feel’ when kicked.
Unconsolidated river bed material will comprise gravel, pebbles, cobbles or boulders which are not
inter-locked and so are easily dislodged or moved when kicked.
In deep rivers where the channel cannot be safely accessed, record as ‘unknown’.
Location of measurements
Tick one of two boxes; if ‘other’ box ticked, enter the predominant flow type present across the channel
where the measurements were taken.
SECTION M. FEATURES OF SPECIAL INTEREST
This is an opportunity to record features of special ecological interest, either in the river channel or adjacent
corridor.
The extent of all these features should be recorded as present () if present along >1-33% of the site,
or ‘E’ if present along >33% of the site. Five of the 21 listed features are marked by an asterisk (*) –
these can be ticked even if they do not occur within at least 1% of the site.
Special features should be recorded as ‘’ or ‘E’ if they are within a 50m corridor either side of the
channel. Where features of special interest are observed beyond this 50m limit, their presence should
be noted in Section P.
None
An entry is required in this box when no entries are made in any other boxes to confirm that no features
of interest were observed.
Braided channels
Braided rivers are dynamic, mobile, rivers where the channel is divided into several sub-channels separated
by active mid-channel bars along most (>50%) of the 500m site. In braided rivers, most bars are unvegetated
and the wetted area, at low flows, represents substantially less than 50% of the river bed. Bar surfaces are
3.37 River Habitat Survey Manual: 2003 version
typically at lower elevations than the vegetated floodplain margins. Braided rivers must feature at least two
sub-channels and two mid-channel bars along most of the site. Some of the sub-channels may be dry at the
time of the survey.
Excludes all river reaches with more than a single channel that are not actively changing the location
of the sub-channels – these include:
(i) where two or more channels have developed naturally and are separated by vegetated midchannel
bars or mature islands;
(ii) man-made by-pass channels, including mill leats;
(iii) secondary feeder channels;
(iv) parallel floodplain drainage systems;
(v) chalk streams with multiple, man-made, channels.
It is recommended that aerial photographs are included to confirm braided rivers. M1a,b,c.
Side channel(s)
To be considered as features of special
interest, side channels must be natural,
and convey only a minor flow compared
with the main channel. They may be dry
in periods of low-flow, and will always
have bed levels higher than in the main
channel (cf. multiple channels associated
with islands). Side channels generally
indicate channel migration across the
floodplain, and are most often associated
with down-cutting of the main channel.
They are always connected to the main
channel at their upstream and
downstream limits (which may be
outside/beyond the site), and convey
flow during moderate to high flows (see
Figure M1). M2a,b,c.
Do not record as special interest features any artificial channels (e.g. mill races, water meadow feeder
channels and multi-channels of chalk rivers) which can be recorded in Section P as appropriate.
*Natural waterfall(s) >5m high
Uninterrupted natural free-fall flow more than 5m high. M3a,b.
*Natural waterfall(s) <5m high
Uninterrupted natural free-fall flow < 5m high. M4a,b.
Natural cascade(s)
Distinct series of ‘stepped’ flow features occurring over boulder substrate or bedrock outcrops. E5Ca,
M5a,b.
Very large boulders (>1m)
Very large, (at least 1m diameter), boulders protruding well above water level. Very large boulders will be
recorded as extensive only if they occur along more than 33% of the channel length. Only naturally
occurring boulders are noted; those introduced for fisheries enhancement purposes, or derived from
collapsed rip-rap, are excluded but can be recorded in Section P. E4Bb, M5a, M6a,b.
3.38River Habitat Survey Manual: 2003 version
Figure M1 Side channels and backwaters
Side-channel Backwater
Small permanent flow
or seasonally dry
No low-flow connection
with main channel
Minor or
intermitent
flow
Main river
flow
*Debris dam(s)
Log jam of large woody debris creating an obstruction across the channel and significantly impeding water
flow. M7a,b.
*Leafy debris
Significant accumulations (at least 2m2
) of twigs
and leaf litter along channel edge. An important
temporary habitat for some insects. M8a,b.
Fringing reed-bank(s)
Fringing reeds such as common/Norfolk reed
(Phragmites australis) which extend at least
half-way up the bank. To be recorded, a
fringing reed-bank must extend at least 10m
along the bank-length. See Figure M2.
M9a,b,c.
Quaking bank(s)
A distinct floating ‘ledge’ or shelf of vegetation
only, equivalent to a ‘quaking’, bog which
extends into the channel. Usually an extension
of adjacent wetland into the channel. Very rare
in Britain and Ireland. See Figure M3.
M10a.
*Sink hole(s)
A feature of some channels in limestone areas. Except during spates, flow in the channel upstream disappears
into the ground through the channel bed, re-appearing further downstream. M11a,b.
Backwater(s)
Redundant river channels that are connected to the main channel only at one point, normally the
downstream end. In contrast to side channels, they do not act as flood-conveyance channels (see Figure M1).
B8a, K1c, M12a,b.
Floodplain boulder deposits
Boulders deposited on the floodplain by the river, typically close to the banktop and downstream of a
constricted section of channel (e.g. gorge or V-shaped valley). Boulders in the channel should be
recorded as boulder substrates or exposed boulders, as appropriate, and not floodplain boulder deposits.
M13a.
Water meadow(s)
Floodplain meadows, primarily associated with chalk streams, and traditionally flooded via constructed feeder
channels. These drainage channels are straight, shallow and parallel. Features include remnant channels
and floodplain grasslands. M14a,b.
3.39 River Habitat Survey Manual: 2003 version
Banktop
Minimum extent up the
bank to qualify as fringing
reed-bank
Figure M2 Fringing reed bank
Quaking overhangs
of floating vegetation
Peat
bog
Figure M3 Quaking bank
A distinct floating ‘ledge,’ which
extends into the channel
Fen(s)
Wetland vegetation, often (but not exclusively) growing over peat, where the water-table is at, or just below,
the surface. Water is derived from both rainfall and drainage of surrounding land. Some fens may have
Sphagnum moss, but typically the vegetation is dominated by tall reeds, wetland herbs, sedges, and rushes.
M15a.
Bog(s)
Vegetation growing on wet peat where the water table is at, or just below, the surface. The water source is
direct rainfall and in some cases, over-land flow occurs during heavy rain events. Sphagnum moss is always
present, often with bog cotton (Eriophorum). In locally drier areas heather (Calluna, Erica) may also be
present, but never dominant. When the heathland component is uncommon, and bog predominates,
record ‘Moorland/heath’ as ‘present’, and record ‘Bog’ as ‘extensive’. M16a,b,c.
Wet woodland(s)
Wet woodland comprises trees such as willow (Salix spp.) and alder (Alnus spp.), usually with an understorey
of wetland herbs, reeds and mosses. Often at the edge of other wetlands, and often referred to as ‘carr’.
M17a,b.
Marsh(es)
Wetland habitat that includes tall grasses and rushes on periodically wet ground (unlike fen or bog that are
permanently wet), or where wetland herbs are an important component of the ground flora (e.g.
meadowsweet – Filipendula ulmaria, marsh orchids – Dactylorhiza spp., kingcup – Caltha palustris, valerians –
Valeriana spp.). F7a, M18a,b.
Flush(es)
A collective term for wet areas near springs where water emerges from the ground or seeps from fissures in
rock faces, or valley slopes. Flushes are fed by groundwater – when surface water predominates a stream is
formed. M19a,b.
Natural open water
Includes abandoned ox-bows, natural lakes, bog-pools and meres.
Only include features that are NOT connected to the river channel except during periods of floods.
M20a,b,c.
Others
It is important to record any other features of ecological interest, such as reedbeds, herb-rich wet grassland
etc. associated with the river and adjacent land.
SECTION N. CHOKED CHANNEL
If 33% or more of the total channel area is choked with vegetation, causing significant impediment to flow,
indicate by putting a  in the ‘Yes’ box. If not,  the ‘No’ box. One of the two boxes must be ticked.
Na,b.
The extent of vegetation will depend to some degree on seasonal influences, but choked channels can
present a barrier to fish migration, or increase flood risk.
3.40River Habitat Survey Manual: 2003 version
SECTION O. NOTABLE NUISANCE PLANT SPECIES
Indicate the absence or presence (including extent) of those alien plant species listed on the form by ticking
appropriate boxes.
Estimate abundance within the site as a whole by using a ‘’ when present along <33% of the bank-length
or ‘E’, when present along >33% of total bank-length. Separate records are made for the bankface, and the
river corridor up to 50m from the banktop. Include plants growing on mid-channel bars in the ‘bankface’
category.
The main introduced nuisance species associated with rivers in Britain and Ireland are:
* giant hogweed (Heracleum mantegazzianum) O1a;
* Himalayan (Indian) balsam (Impatiens glandulifera) O2a;
* Japanese knotweed (Fallopia japponica) O3a.
If you know that other alien species are present, list these in the space provided. A common example in some
upland locations is Rhododendron. O4a.
Species are shown on the form prefixed by an *asterisk, so the presence of a single plant should be
recorded. It is important to report even an isolated occurrence, since control measures may be able to be
taken.
SECTION P. OVERALL CHARACTERISTICS
This section has a prompt check-list to capture important additional information. Circle relevant prompt
words on the form and add others as appropriate.
Major impacts
Any major impacts on the site using the self-explanatory checklist on the form. P1a,b.
Evidence of recent management
A brief descriptive checklist for obvious and recent activities is listed. Briefly describe other activities as
appropriate.
‘Recent’ management is defined by the presence of obvious signs e.g. machinery present, excavated bare
earth, weed/brash cuttings and bank mowing, unvegetated dredge spoil on the bank etc. E2Aa, P2a.
Enhancement works: examples include meander or riffle reinstatement, channel narrowing, bank reprofiling,
reed-planting and tree-planting. Most will be obvious only when recently undertaken. E1Hb,
E1Mb, E2Cc,d, P2b.
Animals
Sightings of mammals, birds, insects and other taxa of interest. Use the checklist and add as appropriate.
Indicate if the presence is indirectly inferred from footprints or faeces (e.g. otter spraints). Records of animals
will not be systematic since they will depend greatly on the interests and expertise of individual surveyors.
Other significant observations
It is important to record your overview of the site to complement information recorded on the form and
photographs. Use a separate sheet if necessary, and make sure it has the mid-site grid reference clearly
marked on it and the sheet is attached to the form.
3.41 River Habitat Survey Manual: 2003 version
SECTION Q. ALDERS
In this section record the presence or absence of alder trees (Alnus glutinosa). Record whether they are present
or absent, and indicate whether they are healthy or affected by Phytophthora root disease. Information on
Phytophthora is needed for a national assessment of the incidence of the disease. Qa,b.
See Appendix 3 for illustrated guidance on how to recognise symptoms. This has been reproduced with
the permission of the Forestry Commission from: Information Note 6 ‘Phytophthora Disease of Alder’ © Crown
Copyright 2000.
One of the three boxes in both categories must by ticked. Record ‘none’ if no alders are present; ‘present’
if alders occur in <33% of bank-length (even if just one tree – hence the *asterisk reminder on the form); and
‘E’ if present along >33% of bank-length, irrespective of whether they are affected by the disease or not.
If no trees are affected by Phytophthora, record ‘None’; ’Present’ if diseased alders occur in <33% of banklength;
and ‘E’ if disease affects alders along >33% of bank-length.
Observations of diseases affecting other trees (e.g. willows [Salix]) can be noted in Section P.
SECTION R. FIELD SURVEY QUALITY CONTROL
However experienced you are with filling in RHS forms, it is easy to make a mistake or send in an
incomplete site record. To avoid this, you should check the form and tick the seven boxes as each one
is checked in the field. This will save you having to rectify omissions later, and possibly save the need
for a re-survey. The prompts ask the surveyor if they have:
• taken at least two photos that illustrate the general character of the site and additional photos of all
weirs and any major/intermediate structures across the channel?
• completed all ten spot-checks and made entries in all boxes in E and F on page 2?
• completed column 11 of section G, and E if appropriate on page 2?
• recorded in section C the number of riffles, pools and point bars (even if 0) on page 1?
• given an accurate (alphanumeric) grid reference for spot-checks 1 and 6, and the end of the site
(page 1)?
• stated whether spot-check 1 is at the upstream or downstream end of the site (top of page 2)?
• cross-checked spot-check and sweep-up responses with the channel modification indicators
given on page 2 of the spot-check key?
3.42River Habitat Survey Manual: 2003 version
PART FOUR – PHOTO GALLERY
River Habitat Survey Manual: 2003 version
4.1
A1a Artificial channel cut through flat fens; site is
not part of a river. Note no obvious valley sides.
A1b Artificial channel – straight cut through flat
landscape; site is not part of a river. Channel
vegetation = choked. See also Nb.
A1d Deepened and resectioned channel; site is
hugely modified, but is still obviously part of a river.
See also D7a.
A3a Turbid and high water levels – bed of river is
not visible.
A3b Dense free-floating macrophytes – bed of river
is not visible.
SECTION A. FIELD SURVEY DETAILS
A1c Concrete channel replacing part of natural
watercourse; site is obviously hugely modified but is
still part of a river.
B1a Shallow vee valley; flat valley bottom absent.
Cobble bed. See also K4b.
B1b Shallow vee valley; narrow flat valley bottom
present. Note bank profiles; vertical undercut on
right, gentle on left; unvegetated point bar and
eroding cliff present.
B2a Deep vee valley; flat valley bottom absent.
Note also moorland/heath land-use.
B2b Deep vee valley with very small flat valley
bottom.
B3a Gorge.
B4a Concave/bowl with a flat valley bottom
evident.
4.2
SECTION B. PREDOMINANT VALLEY FORM
4.3
B5a Asymmetrical valley. Note river abuts steep
side of valley; flat valley bottom present.
B6a U-shape glaciated valley (always with distinct
flat valley bottom). See also C1a.
B7a No valley sides obvious and therefore no flat
valley bottom. See also A1a.
B7b No valley sides obvious and therefore no flat
valley bottom. Note improved agricultural
grassland land-use and slightly embanked left bank.
B8a Obvious flat valley bottom with floodplain
wetlands (including backwater). See also B1b, B2b,
B5a, B6a.
B8b Obvious flat valley bottom, but lacking
floodplain wetlands. See also B1a, B2a, B7a,b, M1c
for flat valley bottom absent.
B9a Natural river terraces.
B9b Natural river terraces. Note embanked floodbank in foreground.
4.4
‘Steps’ between terraces
Terrace step
Embankment
4.5
C1a Riffle with ‘unbroken standing wave’ flow-type.
Note U-shape valley form. See also E5Db.
C1b Riffle at exit of meander pool with
‘unvegetated point bar’ on inside of bend.
C1c Riffle in lowland, low gradient, woodland
stream.
C2a Pool on tight meander bend. Note overhanging
bough on left. See also C1b, I1a.
C2b Pools in bedrock; the lower one is a plunge
pool. See also E5Bb, M3a, M4a,b. C2c Pool feature below a weir.
SECTION C. RIFFLES, POOLS AND POINT BARS
C3a Unvegetated point bar formed from sand. C3b Unvegetated point bar formed from coarse
sand.
C3c Unvegetated point bar formed from
gravel/pebble. See also B1b, C1b I1a,b.
C4a Vegetated point bar formed from sand and silt.
Vertical bank on right, gentle on left.
C4b Vegetated point bar formed from pebbles and
cobbles. Continuous trees on right, absent on left.
C4c Vegetated point bar formed from mixed
pebbles, gravel and silt. Uniform vegetation
structure on both banks.
4.6
4.7
D1a Major weir/sluice – weir; has a fixed level. This
is an example of a composite weir. Note also to
record a minor bridge. Flow-type is ‘chute’. It is
essential to photograph all major structures to aid
interpretation of probable impact.
D1b Major weir/sluice – sluice; settings can be
changed to influence water levels upstream. Water
is impounded upstream.
D1c Major weir/sluice – despite small size, the weir
structure is ‘fixed,’ and does not leak water. Note
scrub and short grass on right, and short grass and
tussocky tall grass on left – both with simple bank
vegetation structure. Water upstream is impounded.
D1d Major weir/sluice – example of a complex weir
structure used for measuring flow. Note also an
intermediate bridge.
D1e Intermediate weir – boulders are not
cemented, and water can leak through the fissures.
D1f Intermediate weir – wooden log construction,
and water can leak through gaps.
SECTION D. ARTIFICIAL FEATURES
D1g Minor weir – a temporary structure; often built
by children from boulders and cobbles.
D2a Culvert – all are recorded as ‘major’ structures.
When channel modification records ‘CV’, and it is
impossible to see the bed and banks clearly, all
other channel characteristics should be recorded as
‘NK’ or ‘NV’.
D3a Major bridge – all bridges with central piers are
classed as ‘major’. Note importance of
photographs to show size of piers, and degree of
associated bed armouring. Classic cobble channel
substrate exposed in foreground. See also D5b.
D3b Major bridge – all bridges with bankside
abutments >25m long.
D3c Intermediate bridge – no central piers, and
with bank-side abutments 10-25m long. Note
broken standing waves.
D3d Minor bridge – farm track bridges <10m wide
are recorded as ‘minor’.
4.8
4.9
D3e Minor bridge – pipelines crossing rivers, if
lacking central piers, are recorded as minor bridges.
See also Na. Note exposed boulders and broken
standing waves.
D3f Minor bridge – bridge lacks in-channel supports
and has bank abutments <10m wide. Note major
ford in fore-ground.
D4a Outfalls and intakes - this is a major water
abstraction point (intake) occupying >25m bank-
length.
D4b An intermediate outfall, 10-25m long.
D4c Minor outfall – example of a flap-valve on a
drainage channel – all such structures occupying
<10m bank-length are recorded as ‘minor’.
D5a Major ford – both the bed and banks are
made of artificial material, and there is obvious
ponding of water upstream. See also D3f.
D5b Intermediate ford – note the bed is composed
of artificial material, but the banks are ‘natural’
gravel. Note major bridge downstream with inchannel
supports.
D5c Minor ford - farm track where bed and banks
are of both composed of natural material, and there
is no significant ponding impact from the ford.
D5d Minor ford - farm track where bed and banks
are of natural material, and there is no ponding
from the ford.
D5e Cattle crossing point - NOT recorded as
‘Ford’, but as poached bank.
D6a Major deflector/groyne/croy – extends across
>20% of the channel width. This example is
composed of mixed materials, including compacted
earth.
D6b This collapsed weir is recorded as a major
deflector as it extends >20% across the channel.
4.10
4.11
D6c Intermediate deflector/groyne/croy – an
example of a boulder deflector extending across 10-
20% of the channel.
D6d Intermediate deflector/groyne/croy – example
of bank, and in-channel, deflectors extending across
10-20% of the channel.
D6e Minor deflector/groyne/croy – extends across
<10% of the channel width (installed to encourage
reed encroachment that now almost obscures the
deflector).
D6f Other artificial features – boat moorings.
These extend 10-25m along the bank, so are
classed as ‘intermediate’.
D6g Other artificial features – fishing platforms.
These extend <10m along the bank, so are classed
as ‘minor’.
D7a An obviously realigned and over-deepened
channel. Note hedge at the top of the bank that
should be recorded as complex banktop vegetation
structure.
D7b An obviously realigned channel.
D7c A channel showing NO obvious signs of
having been re-aligned. See also B1b, B5a, B6a,
B7a, C4a, Na,b.
D8a Over-deepened channel – very obvious telltale
signs are the uniformly sloping, artificially steep,
banks and a channel width/bank depth ratio <4:1
See also E2Aa.
D8b Over-deepened channel – obvious signs
include the slumping of the artificially steep banks
and the channel width/bank depth ratio is <4:1.
D8c Over-deepened channel – less obviously overdeepened,
but with artificially steep, undercutting,
banks and the channel width/bank depth
ratio is <4:1.
D9a Is water impounded by weir/dam? Photo
shows water artificially impounded behind a shallow
weir structure. See also D1b,c, D5a.
4.12
4.13
E1Aa Bedrock bank material. See also C2b, E5Ab,
M3a,b.
E1Ab Bedrock bank material. This is an example of
a vertical rock bankface, but this is NOT recorded as
a stable cliff.
E1Ba Boulder bank material. Note broken standing
waves.
E1Bb Boulder bank material.
E1Ca Cobble bank material. Note continuous trees
on right. E1Cb Cobble bank material.
SECTION E: PREDOMINANT BANK MATERIAL
4.14
E1Da Gravel/sand bank material – example with
fine sand predominant. See also E3Aa.
E1Db Gravel/sand bank material – example with
mixed materials, but gravel/sand predominates.
E1Dc Gravel/sand bank material – example with
mixed materials, but gravel/sand predominates.
Note in Section P use of bank by sand martins.
E1Ea Earth bank material; example of vertical bank
with toe. Also an eroding cliff. See also I1b, I2b.
E1Eb Earth bank material; a ‘jab’ with the ranging
pole will not leave a smooth, well-defined, hole. E1Fa Peat bank material.
4.15
E1Ga Clay bank material: a ‘jab’ with the ranging
pole will leave a smooth, well-defined, hole. This
bank illustrates that a stable clay bank is not always
well vegetated. See also FV1a, I1a, I2a.
E1Ha Concrete bank material. See also A1c, E2Cb,
E7Cc.
E1Hb Concrete bank material. This example
illustrates an artificial berm as habitat creation as
part of a flood defence scheme, and this should be
noted in Section P.
E1Ia Sheet piling bank material.
E1Ja Wood piling bank material – horizontal poles.
See also I6b.
E1Jb Wood piling bank material – vertical poles
below resectioned bank and arable (tilled) land-use
in background.
E1Ka Gabion bank material – boulders/cobbles in
wire baskets. Typical example of use in protection
of the bottom half of a bank.
E1La Brick/laid stone bank material – cemented.
E1Lb Brick/laid stone bank material – cemented
bricks. Note parkland land-use on right.
E1Lc Brick/laid stone bank material – example of
stone wall bank material used in rural areas such as
the Lake District.
E1Ma Rip-rap bank material; placed (but not
cemented), non-regular, blocks. Bank vegetation
structure is recorded as bare.
E1Mb Rip-rap bank material; placed (but not
cemented), square, blocks. Note under-water
‘pipes’ for fish shelter (note in Section P).
4.16
4.17
E1Mc Rip-rap bank material; tipped boulders. E1Md Rip-rap bank material; laid boulders with
earth between. See also I6a.
E1Na Tipped debris – soil.
E1Nb Tipped debris – gravel.
E1Nc Tipped debris – pebbles.
E1Nd Tipped debris – this category includes tyres,
old cars, builders waste, and other materials
considered as ‘waste’. Record also as reinforced (RI).
E1Oa Fabric bank material – non-degradable sheet
(‘nicospan’). Note tall herb bank vegetation above,
so record structure as ‘simple’.
E1Pa Bio-engineering bank materials – biodegradable
matting with vegetation planting.
Record bank vegetation structure as ‘bare’.
E1Pb Bio-engineering bank materials – brushwood.
Note shallow vee valley.
E1Pc Bio-engineering bank materials – woven dead
stakes and twigs.
E1Pd Bio-engineering bank materials – live willow
stakes. Bank vegetation structure is ‘simple’.
E1Pe Bio-engineering bank materials – here biodegradable
hessian has been used in combination
with reed planting and other vegetation.
4.18
4.19
E2Aa Resectioned (reprofiled) bank – tell-tale smooth
(trapezoidal) slope even though undertaken many
years ago; river also over-deepened, with tell-tale
‘step’ in the profile where bed material at the base of
the bank removed. See also A1a, D8a,b,c, E3Da, I6b.
E2Ab Resectioned (reprofiled) bank – tell-tale even
(trapezoidal) slope of newly resectioned bank.
E2Ba Poached bank – due to human trampling.
E2Bb Poached bank – light cattle trampling (not
bare as >50% vegetation cover). Note discrete silt
deposit (bank material is earth, bed is gravel).
E2Bc Poached bank – heavy due to cattle trampling
(recorded as ‘bare’ due to <50% vegetation cover).
See also I5b, P1a.
E2Bd Poached bank – heavy due to human
trampling (recorded as ‘bare’ due to <50%
vegetation cover).
SECTION E: BANK MODIFICATION(S)
E2Ca Artificial Berm – formed by excavating bank
material (here on both sides) to form a two-stage
channel. Both the flat base of the berm, and the
face of the top of the bank, constitute ‘bankface’.
See also E1Hb, F18b.
E2Cb Artificial Berm – formed by infilling wide,
totally artificial, channel (here on both sides) to
form a two-stage channel.
E2Cc Artificial Berm – formed by infilling an overwidened
channel (here on both sides) to form a
distinct two-stage (slightly meandering) channel.
Note in Section P, as part of river rehabilitation works.
E2Cd Artificial Berm – formed during rehabilitation
project by installing shallow shelves (here on both
sides) to create a narrower low-flow channel with
indistinct berms; note in Section P.
E2Da Embanked - note the earth embankment is
placed on top of the natural bank (cf. set-back
embankment, Section I).
E2Db Embanked - note the rock embankment is
placed on top of the natural bank. Top of
embankment represents ‘banktop’.
4.20
4.21
E3Aa Eroding cliff of sand (EC on form is circled).
See also E1Da.
E3Ab Eroding cliff of earth (EC on form NOT
circled). See also B1b, E1Dc,b, E1Ea,b.
E3Ba Stable cliff – no signs of recent erosion, and
ferns and other vegetation well established. See
also E5Fa, FV1a.
E3Bb Stable cliff – example of clay bank that is
stable, but has little or no vegetation.
E3Ca Unvegetated side bar – unconsolidated
sediment bar along one side of a relatively straight
section of river with <50% vegetation cover.
Continuous trees on left.
E3Da Vegetated side bar - consolidating sediment
bar along one side of a relatively straight section of
river with > 50% vegetation cover, and progressing
towards natural berm. Note resectioning on left.
SECTION E: MARGINAL AND BANK FEATURE(S)
4.22
E3Ea Natural berm – depositional feature with a
marked step from the river bed, and to the bank.
E3Ec Natural berm – young example where an overwide
channel has restored its previous low-flow
width through formation of the natural berm. Note
very gentle bank slopes.
E3Eb Natural berm – depositional feature with a
marked step from the river bed, and to the bank.
In the foreground is an extensive silt deposit. The
‘natural berm’ is in the background; note the
vertical face into the gravel-bedded river.
E3Ed Natural berm - this example shows the clear
steep step between the river bed, and the bankface.
E3Ee Natural berm that has evolved to become the
new ‘bankface’ - this example is 100m downstream
of the berm shown in E3Ed, and shows the clear
steep step to the river bed, but a gentle slope to the
bankface.
Natural berm
Silt deposit
E4Ca Cobble channel substrate. See also B1a, D3a,
M1a,b, M2a,c. E4Cb Cobble channel substrate.
E4Ba Boulder channel substrate. See also E7Aa,b,
M5a, M6a,b.
E4Bb Boulder channel substrate. Note overhanging
bough.
E4Ab Bedrock channel substrate. Exposed bedrock
also.
E4Aa Bedrock channel substrate. Exposed bedrock
also. See also C2b, D3e, E5Bb, E7Bb, M3a,b, M5b.
4.23
SECTION E: PREDOMINANT CHANNEL SUBSTRATE
E4Da Gravel/pebble channel substrate (mixed,
neither dominant).
E4Db Gravel/pebble channel substrate (pebble
dominant – P ringed on form).
E4Ea Sand channel substrate.E4Dc Gravel/pebble channel substrate (gravel
dominant – G ringed on form). See also E4Fb.
E4Fa Silt/mud channel substrate
E4Fb BEWARE thin silt over ‘natural’ channel
substrate – this should be recorded as ‘gravel’.
4.24
4.25
E4Ga Clay channel substrate.
E4Gb Clay channel substrate – close-up.
E4Ha Peat channel substrate – photograph on fen
drain following lowering of water level.
E4Ia Earth channel substrate – to be used ONLY
when intermittent streams are dry, and soil forms
the bed.
E4Ja Artificial channel substrate – both bed and
banks artificial. See also D5a,b, E1La. E4Jb Artificial channel substrate – concrete bed.
E5Aa Free fall flow-type - vertically falling water.
See also M3 & M4.
E5Ab Free fall flow-type - vertically falling water on
high waterfall.
E5Ba Chute flow-type – steeply falling water, but
water ‘hugs’ the substrate. See also D1d.
E5Bb Chute flow-type - steeply falling water, but
water ‘hugs’ the substrate. Note plunge pool
below.
E5Ca Broken standing waves flow-type – typical
turbulent white water waves. See also B3c, D3e,
E1Ba, E4Ba.
E5Cb Broken standing waves flow-type - typical
turbulent white water waves.
4.26
SECTION E: PREDOMINANT FLOW-TYPE
E5Da Unbroken standing waves – surface like
‘dragon-back’, but waves not broken. See also
C1a,b.
E5Db Unbroken standing waves - surface like
‘dragon-back’, but waves not broken.
E5Dc Unbroken standing waves - surface like
‘dragon-back’, but most waves not broken.
E5Ea Chaotic flow-type – Rare mix of three of the
four most turbulent flow-types (free fall, chute,
broken standing waves and upwelling) In centre of
photo.
E5Fa Rippled flow-type – surface with small,
symmetrical, ripples. Note uniform bank vegetation
structure.
E5Fb BEWARE – appearance of ‘Rippled flow-type’ –
surface with small ripples, but these are generated
by wind action creating small waves.
4.27
E5Ga Upwelling flow-type – surface with
appearance of ‘boiling’ water.
E5Ha Smooth flow-type – water movement only
obvious when stick or finger put in water; slight
surface movement evident.
E5Ia No perceptible flow – no water movement
obvious; when stick or finger put in water there is
no rippling effect either side. Boulder substrate.
E5Ib No perceptible flow. See also A1a, E1Da.
E5Ja No flow – dry channel; a typical chalk
winterbourne – dry in summer and autumn.
E5Jb No flow – dry channel associated with upland
limestone.
4.28
E6b Resectioned channel – typical signs include
trapezoidal 45 degree banks and no trees.
E6d Resectioned bank – this example shows
straight river with no trees, with channel width <4
times bank height; combination indicates
deepening, resectioning and straightening.
E6f Resectioned channel – this shows a mobile,
gravel-bed, river that has been resectioned, with
tell-tale spoil on the right.
E6a Resectioned channel – typical signs seen here
include deep channel cf. width, steep smoothsloped
banks, and even-aged trees only on top of
bank. See also A1a-c, I6b.
E6c Resectioned channel – even after many
decades, past resectioning obvious due to even
gradient of bank. Note also Himalayan balsam on
near bank.
E6e Resectioned bank – this example shows river
with few trees, very even gradients to the banks,
and with the banktop width <4 times the banktop
height indicating both deepening and resectioning.
4.29
E: CHANNEL MODIFICATIONS
4.30
E7Aa Exposed boulders – these are relatively small
boulders, but many are exposed. See also K4a.
E7Ab Exposed boulders – example with very large
boulders, the majority being exposed.
E7Ba Vegetated rock – example where boulders are
the dominate substrate.
E7Bb Vegetated rock – example where bedrock is
the dominate substrate.
E7Ca Unvegetated mid-channel bar – example in
upland stream.
E7Cb Unvegetated mid-channel bar – very large
example from northern Europe.
SECTION E: CHANNEL FEATURES
Mid-channel bar
E7Cc Unvegetated mid-channel bar – example in
urban stream. Note concrete bank material and
presence of shopping trolleys (urban debris; but not
predominant).
E7Db Vegetated mid-channel bar – small example
composed of consolidated earth, with vegetation
cover >50%. Note simple bank vegetation structure
with shrubs and short herbs and grass.
E7Dd Vegetated mid-channel bar – example with
saplings; note discrete sand deposit adjacent. Note
mixed woodland (semi-natural) land-use on right.
E7Da Vegetated mid-channel bar – small example
composed of gravel and sand, with vegetation
cover >50%.
E7Dc Vegetated mid-channel bar – intermediate
sized example composed of gravel/pebble with
vegetation cover >50%. Note upwelling in
foreground.
E7De Vegetated mid-channel bar – example with
trees; note height of bar is lower than bank height,
therefore NOT a mature island.
4.31
4.32
E7Eb Mature islands – note height of islands is the
same as that of the surrounding land; trees not
present due to grazing.
E7Ea Mature island – height of island probably the same as that of the surrounding land; trees mature, so if in
doubt, record as mature island.
E7Ec Mature island – height of island probably the
same as that of the surrounding land; trees mature, so
if in doubt, record as mature island. If spot-check at
the extreme upstream point of island, vegetated midchannel
bar should be recorded, not mature island.
E7Fa Urban debris. See also E7Cc.
Mature islands
4.33
F1a Broadleaf/mixed woodland (semi-natural) landuse.
See also C3b, E7Dd, J6a,b, M2b.
F1b Broadleaf/mixed woodland (semi-natural) landuse
– an un-metalled path follows the bank; this is
recorded as the same as the adjacent land-use.
F2a Broadleaf/mixed woodland (planted). Even
though trees may be native willows, this is a
plantation.
F3a Coniferous woodland land-use – very rare in
the UK, and primarily in Scotland.
F4a Coniferous plantation – typically even-aged
structure, and little or no vegetation below the trees
(understorey).
F5a Scrub & shrubs land-use on horizon – multibranched,
short, woody vegetation.
SECTION F AND H: LAND-USE WITHIN 5m AND 50M OF BANKTOP
4.34
F7a Wetland land-use – wet marshland.
See also M15a, M18a,b.
F7b Wetland land-use – reedbeds.
F7c Wetland land-use – wet blanket bog.
F8a Moorland/heath land-use – this shows dry
heath dominated by heather and uniform bank
vegetation structure. See also E7Dc, E7Ea, J1b.
F8b Moorland/heath land-use - dominated by
grass, with little heather. See B2a,b, M16b.
F9a Artificial open water land-use – wide range of
types; includes shallow scrapes re-creating lost open
water habitats.
4.35
F9b Artificial open water land-use – wide range of
types; includes all man-made ponds, gravel pits and
amenity lakes (as shown).
F9c Artificial open water land-use – wide range of
types; includes canals.
F10a Natural open water land-use – wide range of
types, including natural lakes and ponds surrounded
by dry land.
F10b Natural open water land-use – old ox-bows,
backwaters, secondary channels and pools in
floodplains. See M2a,b,c, M20b,c.
F11a Rough/unimproved grassland/pasture landuse
– includes rough, usually herb-rich,
tussocky/rushy floodplain grassland.
F11b Rough/unimproved grassland/pasture landuse
– includes herb-rich meadows.
F12a Improved/semi-improved grassland. See also
B7b.
F13a Tall herb/rank vegetation land-use – typically at
least waist high vegetation dominated by tall herbs.
F13b Tall herb/rank vegetation land-use – typically
tall herb vegetation reverting to scrub due to lack of
grazing/mowing.
F13c Tall herb/rank vegetation land-use – tall herb
vegetation includes bracken.
F14a Rock, scree or sand dune land-use – fine scree
on steep slope.
F14b Rock, scree or sand dune land-use – coarse
scree on steep slope. Note multi-channels; these
are not braiding – record as mature islands and
vegetated mid-channel bars, and note as special
feature in Section M.
4.36
4.37
F15a Suburban/urban development land-use - rivers
surrounded by houses or industrial buildings. Note
minor outfall and resectioned bed and banks.
F15b Suburban/urban development land-use includes
rail tracks and roads. See also A1c.
F16a Tilled land-use – includes arable crops or
allotments. See also E1Jb.
F17a Irrigated land-use – rare within UK; cress-beds.
F18a Parkland & gardens land-use – includes
public open space and sports fields. See also E1Lb.
Note uniform bank vegetation structure on left with
tall herbs and grasses; simple bank vegetation on
right.
F18b Parkland & gardens land-use – includes
sports fields. Note river has artificial berm and
floodbank on left. Regularly spaced trees on right.
4.38
FV1a Bryophytes - liverworts on clay bank. FV1b Bryophytes – mosses.
FV2a Short/creeping herbs or grasses - short grazed
grass. See also A1a, B7a,b, E2Ca.
FV2b Short/creeping herbs or grasses.
FV3a Tall herbs or grasses. See also C3a, D1c, D8a,
E1Oa, F18a, G2b. FV3b Tall herbs or grasses.
SECTION F: BANKFACE AND BANKTOP VEGETATION TYPE AND STRUCTURE
4.39
FV4a Scrub or shrubs bank vegetation structure –
bramble on right is included in this category. See
also D1c, F18a.
FV4b Scrub or shrubs.
FV5a Saplings and trees on bank. See also G2b.
FV5b Saplings and trees on left; on right tall herbs
and grass.
FV6a Bare bank on left, uniform on right.
See also A1c, E1La,b, E1Ma,b,c, E1Pa, E3Aa, E7Cc. FV6b Bare bank.
Bramble on banktop and bankface
Uniform
Complex
4.40
FV7a Uniform banktop (bare bankface) predominantly
one vegetation type only. See also
B7a,b, C4c, D1c, D6c, E2Ca, FV1a,b, FV2a,b, FV5b,
FV7b Uniform - predominantly one vegetation type
only along both bankface (reeds) and banktop
(grass).
FV8a Simple – mixed layer of two or three types.
See also E1Pd, E7Db, F18a, G2b. FV8b Simple – mixed layer of two or three types;
note if trees present, structure is not necessarily
‘complex’.
FV9a Complex – shrubs, tall herbs & grasses and
short/creeping herbs & grasses. See also FV4b,
FV5b, F18a, G2b.
FV9b Complex – mixed saplings, scrub and tall
herbs & grasses and short/creeping herbs & grasses.
4.41
SECTION G: CHANNEL VEGETATION TYPES
G1a Liverworts/mosses/lichens – submerged
bryophyte.
G1b Liverworts/mosses/lichens - splash-zone
bryophytes (close-up).
G1c Liverworts/mosses/lichens - splash-zone
bryophytes; include such exposed cover as part of
the channel vegetation. See also M6a,b.
G2a Emergent broad-leaved herbs (brooklime –
Veronica beccabunga).
G3a Emergent reeds/sedges/rushes/grasses/
horsetails (bulrush – Schoenoplectus lacustris).
See also M9c.
G2b Emergent broad-leaved herbs (water-cress –
Nasturtium officinalis agg.). Note also complex
bank vegetation structure (saplings and trees
dominant) on the left, and simple structure
(dominated by tall herbs and shrubs) on the right.
4.42
G3b Emergent reeds/sedges/rushes/grasses/
horsetails (branched bur-reed – Sparganium erectum).
G3c Emergent reeds/sedges/rushes/grasses/
horsetails (water horsetail – Equisetum fluviatile).
G4a Floating-leaved (rooted) (yellow water-lily Nuphar
lutea & unbranched bur-reed - Sparganium
emersum). Note majority of the leaves of the latter
are floating, not submerged, therefore not recorded
as submerged linear-leaved – see G8a.
G5a Free-floating (frogbit - Hydrocharis morsusranae).
See also A3b.
G5b Free-floating (common hornwort Ceratophyllum
demersum).
G5c Free-floating (ivy-leaved duckweed – Lemna
trisulca).
4.43
G6a Amphibious (whorl-grass – Catabrosa
aquatica).
G6b Amphibious (amphibious bistort – Persicaria
amphibia).
G7a Submerged broad-leaved (opposite-leaved
pondweed – Groenlandia densa).
G7b Submerged broad-leaved (submerged
‘cabbage-like’ leaves of yellow water-lily –
Nuphar lutea).
G7c Submerged broad-leaved (bog pondweed –
Potamogeton polygonifolius).
G8a Submerged linear-leaved (unbranched bur-reed
– Sparganium emersum) Note majority of leaves
submerged, therefore not recorded as floatingleaved
– see G4a.
4.44
G8b Submerged linear-leaved – rosettes (common
plantain– Alisma plantago-aquatica).
G9b Submerged fine-leaved (floating club-rush –
Eleogiton fluitans).
G9c Submerged fine-leaved (mare’s-tail – Hippurus
vulgaris).
G10a Filamentous algae – algae smothering the bed
of the river (Vaucheria) mixed with floating-leaved
(rooted) star wort (Callitriche).
G10b Filamentous algae – algae free-floating
(Enteromorpha).
G9a Submerged fine-leaved (water-crowfoot –
Ranunculus sp(p.)).
4.45
I1a Vertical/undercut bank profile – undercut.
Note classic point bar, overhanging bough and pool
present. See also B1b, C4a, E3Ab.
I1b Vertical/undercut bank profile – vertical. Note
also classic point bar and eroding earth cliff opposite.
I2a Vertical plus toe bank profile. See also E1Ea.
I2b Vertical plus toe bank profile. Note bank is
eroding cliff with sandy/gravel soil (EC).
I3a Steep bank profile. See also B1b (right), B3a
(gorge) I4a (left).
I4a Gentle bank profile – on right, steep on left.
See also B1b, B7a, C4a, E3Ec.
SECTION I: BANK PROFILES
4.46
I5a Composite bank profile – slumping earth bank.
I5b Composite bank profile – combination of rock
and earth. Note bank is also poached.
I6a Reinforced bank – toe only; reinforcement is
with large boulders (rip-rap). See also E1Ja,b, E1Ka,
E1Oa.
I6b Reinforced bank – toe only; reinforcement is
wood-piling. Note also bed and banks have been
resectioned, and a series of low weirs installed.
I6c Reinforced bank – record as ‘top only’ on right,
and ‘whole’ on left. See also A1c, E1La,b, E1Mb,c
(all whole banks).
I7a Set back embankment made of earth (on
right).
4.47
J1a No trees on bank – a single small tree is not
counted; requires 1% of bank to be covered by
canopy (5m on each bank). See also C4b, FV2a, FV6a.
J1b No trees on bank. Note moorland/heath landuse.
Note deep vee valley.
J2a Isolated/scattered trees on bank on right;
continuous on left. See also E2Db, FV3a.
J2b Isolated/scattered trees on right.
J3a Regular spaced trees. See also F18b. J4a Occasional clumps of trees on bank (right).
SECTION J: EXTENT OF TREES AND ASSOCIATED FEATURES
4.48
J4b Occasional clumps of trees on bank (right). J5c Occasional clumps of trees on bank (left).
J5a Semi-continuous trees on bank (left). J6a Continuous trees (on right). Broadleaf/mixed
woodland (semi-natural) is land-use in 5m banktop
and 50m corridor zones on right. See also C4b,
E1Ca, E3Ca, E4Cb, FV9a, J2a.
J6b Continuous trees on both banks. J6c Continuous trees on right.
4.49
J7a Shading of channel present. Note also overhanging
boughs. See also M4a, M6a, M7a
J7b Extensive shading of channel.
J8a Overhanging boughs. See also C2a, I1a, J7a, J9b. J8b Overhanging boughs.
J9a Exposed bankside roots - forearm-sized roots
and branches with associated cavities.
J9b Exposed bankside tree roots – on left. Also note
overhanging boughs on right.
4.50
J10a Underwater tree roots– fine roots of willow
(Salix). J11a Fallen trees – note tree still attached to steep
earth bank by roots.
J11b Fallen trees – note tree still attached to
unstable bank. J11c Fallen trees – note still attached to earth bank.
J12a Large woody debris – whole branches and
trunks washed down and lodged in the channel.
J12b Large woody debris – whole branches and
trunks washed down and wedged across the channel.
4.51
K1a Marginal deadwater. Note also a backwater (as
feature located where old cut-off channel enters the
river) and discrete silt deposit as predominant channel
substrate is cobble/pebble. See also M12a,b.
K1b Marginal deadwater – area of no flow in
between extensive shelves with reeds.
K1c Marginal deadwater – area of no perceptible
flow behind a sand bar.
K2a Unvegetated silt deposit – surface has >50%
vegetated cover, but the underwater part of the
deposit has no vegetation. See also E2Bb, K1a.
K2b Unvegetated silt deposit – surface has >50%
vegetated cover, but the underwater part of the
deposit has no vegetation.
K2c Unvegetated silt deposit – surface has >50%
vegetated cover, but the underwater part of the
deposit has no vegetation.
SECTION K: EXTENT OF CHANNEL AND BANK FEATURES
4.52
K3a Discrete unvegetated sand deposit – deposit is
unvegetated and in mid-channel, with sand NOT
the predominant substrate.
K3b Discrete unvegetated sand deposit – deposit is
unvegetated (<50% cover) and on the channel
margin; sand is NOT the predominant channel or
bank substrate.
K3c Discrete unvegetated sand deposit – deposit is
unvegetated (<50% cover) and on the channel
margin; sand is NOT the predominant channel or
bank substrate.
K4a Discrete unvegetated gravel deposit - deposit
is unvegetated (<50% cover) and in mid-channel in
lee of a large boulder; gravel is NOT the
predominant channel substrate.
K4b Discrete unvegetated gravel deposit - deposit is
unvegetated (<50% cover) and on the channel
margin; gravel is NOT the predominant channel or
bank substrate. See also M7b.
4.53
M1a Braided channel – view across a typical example
with several channels and coarse, mobile, sediment.
M1b Braided channel – aerial view of a typical
example with several channels clearly evident.
M1c Braided channel – aerial view of a highly
mobile channel with floodplain absent.
M2a Side-channel – example of a seasonally dry
side channel (upstream).
M2b Side-channel – same channel as M2a in mid-
reach.
M2c Side channel – same channel as M2a,b close
to the downstream confluence with main channel.
Note another, older, side channel on right.
SECTION M. FEATURES OF SPECIAL INTEREST
4.54
M3a Natural waterfall >5m high – example of falls
with plunge pools. See also E5Ab.
M3b Natural waterfall >5m high – example with
vertical ‘free-flow’ flow-type plunging more than 50m.
M4a Natural waterfall <5m high – example of
single fall into a wide pool. Shade extensive
upstream of fall.
M5a Natural cascade – boulder substrate. M5b Natural cascade – bedrock substrate. See also E5Ca.
M4b Natural waterfall <5m high – example of
several falls into a plunge pool.
4.55
M6a Very large boulders. See also E4Bb, M5a. M6b Very large boulders.
M7a Debris dam – woody debris is creating an
obstacle to flow. Channel also shaded.
M7b Debris dam – woody debris is creating an
obstacle to flow, downstream of which is a large
discrete gravel deposit formed from scouring a hole
below the debris dam.
M8a Leafy debris – discrete accumulations of twigs
and/or leaf litter.
M8b Leafy debris – deposit on top of a point bar –
record both.
4.56
M9a Fringing reed-bank – extends >50% up the
bank, and is >10m long. See also D6e, E3Ed. M9b Fringing reed-bank – extends >50% up the
bank, and is >10m long.
M9c Fringing reed-bank – shows primarily inchannel
reed growth, but as extends >50% up the
bank, and is >10m long, recorded as fringing reedbank
and extensive emergent vegetation.
M10a Quaking bank – overhanging reeds forming a
mat over the water; very rare feature, and
impossible to illustrate properly in a photo.
M11a Sink hole – extremely rare feature in the UK.
M11b Dry channel associated with the sink hole
shown in M11a.
4.57
M12a Backwater formed from old redundant
channel arm. Also marginal deadwater. See also
B8a, K1c.
M12b Backwater formed from old redundant
channel arm.
M13a Boulder floodplain deposits – feature rarely
associated with UK rivers.
M14a Water meadow – historic floodplain
management involving flooding in spring.
M14b Water meadow – flooded example.
M15a Fen – rich higher plant community dominated
by great tussock-sedge (Carex paniculata) growing in
areas with very high water-table.
4.58
M16a Bog – bog moss (Sphagnum), over peat, is a
characteristic component of bog vegetation.
M16b Bog – cotton-grass (Eriophorum) is often
associated with wet blanket bogs, with surrounding
slopes grassy moorland/heath.
M16c Bog – Some bogs may have invasion of
heather as they dry; when bog pools, cotton grass
or Sphagnum present, record as bog. M17a Wet woodland – also known as carr; typically
yellow-flag (Iris pseudacorus), sedges (Carex spp.)
and king-cup (Caltha palustris) are present as part of
the under-storey community.
M17b Wet woodland – typically alder (Alnus
glutinosa) and willow/sallow (Salix sp(p.)) are the
dominant trees/shrubs.
M18a Marsh – extensive example of a grazed rushy
wet field. See also F7a.
4.59
M18b Marsh – example of an ungrazed rushy wet
field.
M19a Flush – example is springs rising in open land
to form a small flush.
M19b Flush – example is springs rising in woodland
to form a flush that has an intermittent flow.
M20a Natural open water – example of old
channel now forming a sinuous shallow open water
habitat – where no open water present, record as
wetland. See also B8a.
M20b Natural open water – an old ox-bow
forming a large pond.
M20c Natural open water – a small pond left in an
old meander pool of a redundant channel.
4.60
Na Realigned channel choked with submerged
aquatic vegetation. Note minor bridge. See also
A1b. Do not record ‘channel choked’ when just
free-floating vegetation (see A3b).
Nb Channel choked with emergent reeds. Also
realigned.
O1a Giant hogweed (Heracleum mantegazzianum)
O2a Himalayan (Indian) balsam (Impatiens
glandulifera).
O3a Japanese knotweed (Fallopia japonica).
O4a other nuisance species – a common example
is rhododendron.
SECTIONS N AND O CHOKED CHANNEL AND NOTABLE NUISANCE PLANT SPECIES
4.61
P1a Major impact - extreme effect of trampling.
P1b Major impact – silt run-off to river.
P2a Evidence of recent management – silt
dredging. See E2Aa for bank mowing.
P2b – Evidence of recent management – river
rehabilitation works. See also E1Hb, E1Mb, E2Cc,d.
Qa Alders (Alnus glutinosa) along river bank. Qb Diseased alder (Alnus glutinosa).
SECTIONS P AND Q OVERALL CHARACTERISTICS AND ALDERS
PART FIVE – TECHNICAL APPENDICES
Appendix 1 – Health & Safety Guidance
General guidelines
Being near rivers, streams or any other body of water, either for work or recreation, is potentially hazardous.
When doing an RHS survey, health and safety must always be taken into account.
Safety is an integral, and important, part of the RHS training course with the main hazards/risks being
highlighted. However it is not fully comprehensive and line managers of surveyors are responsible for making
all field staff aware of potential dangers, and the procedures to follow, in case of accidents.
RHS surveyors need to be physically fit and must have adequate personal protective equipment (PPE) i.e.
appropriate footwear and waterproof jacket and trousers. Footwear should have cleated, felt or studded
soles. Waders or wellington boots must be worn when surveying from the channel.
Every effort should be made to minimise risks in the field and the following guidelines should be followed:
• Life jackets should be worn at all times when working in rivers, and in any other situations wherever
there is a risk of drowning. Do not enter a river in spate flow.
• Do not enter the water if the river bed is not visible.
• When entering the channel, take into account the depth, flow and temperature of water, conditions
under foot (e.g. substrate, algae) and entry/exit points. Check for any potential obstructions.
• It is sensible to walk against the flow of the river.
• When in the channel, use a ranging pole or wading stick to check depth and substrate.
• Avoid steep, unstable and overhanging banks, and always have an identified exit route close to
where you are surveying.
• Work in pairs if river channels need to be crossed.
• Never enter a culvert.
• Look out for hazards, especially in urban rivers, e.g. broken glass, sharp metal, decomposing waste
or pollutants.
• Take care to avoid contact with the water, soil or vegetation before eating or drinking during
survey work.
• Wear the right clothes for both the job and the weather conditions.
• When driving, shoes or walking boots should be worn and not waders.
• Carry a basic first-aid kit and hand-wipes.
• Wear a whistle, especially in remote, urban or wooded areas. Do not put it in a rucksack or pocket.
• When there is good reception, carry a mobile telephone.
• Always double-man or use a ‘lone worker’ system i.e. reporting-in and signing-off procedures, linked
to a home base. (NB lone working also includes where two people are working in a remote
location.) Line managers should have systems in place that ensure that the location of surveyors is
known, and should establish an agreed system of emergency action in case a surveyor does not
report back at the end of the day. For more details on lone-working, see Appendix 2.
A risk assessment should be carried out before doing survey work and an RHS health and safety assessment
needs to be completed on-site. If there are problems on site, the surveyor needs to report these to their line
manager, or survey coordinator, at their office. If it is considered unsafe, or there is any doubt, the survey
should not be carried out.
Risk assessment for a River Habitat Survey (see Appendix 1.1)
Surveyors need to decide if there are any risks and to what level they are. Measures are suggested to reduce
the risks and they should be applied. However it is down to the surveyor’s, and their line manager/survey
supervisor’s, personal judgement(s) whether to proceed with the survey. The information in the Appendix
1.1 table should be used as a guide in undertaking risk assessment.
River Habitat Survey Manual: 2003 version5.1
Appendix 1.1 – River Habitat Survey 2003 version: risk assessment
River Habitat Survey Manual: 2003 version 5.2
Task
Element
Arriving
at site
and the
duration
of survey
When
surveying
from
channel
Site Number/Reference: Date:
Risk
Aggressive animals/
people, hostile situation.
Cautionary approach, avoid animals where possible, conflict
resolution/breakaway training, double-man or lone worker
system, mobile phone, personal alarm, whistle
Cautionary approach, test with ranging pole/wading stick,
double-man, wear a lifejacket.
Cautionary approach, double-man, wear a lifejacket, walk in
upstream direction.
Try to find a safe crossing point. Do not climb over, or crawl
under, unless assessed to be safe to do so. If not safe to cross
and no alternative crossing points, abandon the survey.
Bank stability, high/steep
banks.
Falling in, swept-off feet,
losing footing.
Fences
(barbed wire, electric).
Cautionary approach, avoid animals where possible, walk
around the edges of fields.
Livestock.
Double-man or lone worker system, estimated finish time
known to others, assess communications before starting
survey, mobile phone, personal alarm, whistle.
Lone or remote working,
lack of visibility, lack of
local knowledge,
vulnerable position.
Double-man or lone worker system, estimated finish time
known to others, assess communications before starting
survey, personal alarm, whistle.
No communication (out
of mobile range/no
telephone).
Find a safe crossing point.Railway, road.
Appropriate footwear and clothing, watch footing, walk
around outer edges of bogs etc.
Rough terrain,
marsh/bogs.
Wear long sleeves & trousers, regularly check for ticks, inspect
body at end of survey.
Ticks (Lyme disease).
Double-man in such locations, estimated finish time known to
others, assess communications before starting survey, mobile
phone, personal alarm, whistle. If confronted for equipment,
always give it over.
Valuable equipment, high
crime rate location.
Heat: wear suncream, sunglasses, keep head and back of neck
covered, have bottled water, go into shade regularly. Cold:
have insulating layers, wear hat/hood and gloves. Wet: do not
survey in heavy rain, be extra vigilant to conditions underfoot.
Be prepared for all likely conditions.
Weather: dehydration,
heatstroke, hypothermia
or unpredictable.
Double-man, use ranging pole to test depth and ground
before entering channel, wear lifejacket, If water above kneeheight
or you do not feel comfortable, do not survey from channel.
Swept-off feet, losing
footing.
Check bank stability with ranging pole, wear lifejacket,
double-man.
Entry & exit points.
Use ranging pole to check in the channel before entering, and
whilst in, the channel. If hazards found, do not enter channel
or make a safe exit from it.
Hidden hazards under the
water.
Keep open skin covered, wear gloves, have hand wipes and firstaid
kit, wash hands thoroughly, avoid touching face, carry
Leptospirosis Card.
Infection (in particular
Leptospirosis).
Use ranging pole to test depth and ground, move around outer
edges, watch footing.
Use ranging pole to check in channel, watch footing. If not
comfortable do not survey from channel.
Poor visibility/water clarity.
Pools.
Wear gloves, keep open skin covered, have hand wipes and
first-aid kit, wash hands thoroughly before eating/drinking.
Poor water quality,
pollution, sewage
outfall/treatment works.
Use ranging pole to test depth and conditions underfoot before
entering the channel and whilst in it. If not comfortable, do not
survey from channel.
Substrate soft or uneven.
Use ranging pole to check in channel, watch footing. If not
comfortable, do not survey from channel.
Algae, thick weed growth,
woody debris dams.
Risk Level
(low, moderate,
high) Potential Risk Control Measures
Proceed
With Survey
(Yes or No)
Site health and safety form (see Appendix 1.2)
This is now a required component of an RHS Survey and should be submitted along with the other four pages
of the survey form. Surveyors need to assess, and comment on, the general characteristics of the site, and
specifically on such aspects as weather and flow conditions. On the form it is necessary to record if the risks
are low, medium or high. If a single category is recorded as a ‘high’ risk, surveys should not be carried
out; similarly if more than three ‘moderate’ risks are recorded, RHS should not be carried out.
Personal safety
Equipment used in an RHS survey can be highly expensive and the surveyor should also have a mobile phone.
This may attract unwanted attention, particularly in urban areas, and might lead to a hostile situation.
Surveyors need to be able to recognise these types of situations and know how to deal with them
appropriately, minimising risk of personal injury. Some sort of ‘conflict resolution’ training may be required
so that the surveyor is able to evaluate the situation, avoid aggravating it, and know how to breakaway and
escape attack if necessary.
If confronted for survey equipment, always give it over. Equipment, or data, are not as valuable as the
surveyor!
Life jackets
Where there is a risk of drowning a life jacket must be worn.
Surveyors must be trained in how to use, maintain and inspect their life jacket. They also need to know about
the dangers of immersion and hypothermia.
Weil’s disease (Leptospirosis)
This can be a life threatening disease and surveyors need to carry a medical/warning card at all times (for
England and Wales available from the RHS team at Warrington) to alert people to the nature of any potential
illness. The symptoms start as a fever and headache. Treatment with antibiotics is needed straightaway.
Rivers being surveyed for RHS may contain rat urine, which can cause this illness. Therefore waterproof
clothing must be worn when in the channel. Dead rodents at the site should not be touched, with or
without, hand protection. Infection enters through breaks in the skin (i.e. abrasions, cuts, eyes, nose and
mouth). Cuts and/or broken skin must be covered with waterproof plasters and surveyors should not rub
their eyes, nose and mouth.
Surveyors must always wash their hands before drinking, eating or smoking. Clothing and equipment
should be cleaned after use.
Lyme disease
Lyme Disease can lead to serious illness if not treated quickly and properly. It is caught through being bitten
by infected ticks, particularly in areas with sheep and deer. The first symptom is a ring-shaped rash around
the bite followed by the development of flu-like symptoms within 24-48 hours. Treatment with antibiotics
is required and is normally successful. If the disease is not treated, serious complications will develop over 1-
12 weeks.
Whilst doing survey work in areas where tall grasses, reeds, heather (Erica, Calluna), bracken (Pteridium) and
cranberry/blueberry/bilberry (Vaccinium) are abundant, surveyors must keep their skin covered (i.e. trousers
and long sleeves). They also need to regularly inspect their clothing and skin for ticks and thoroughly check
their body at the end of the day.
If ticks are found on the body, use tweezers to remove them. This needs to be done slowly and carefully to
ensure no mouth-parts are left behind below the skin. Following removal, put a dressing over the bite, and
seek medical attention.
River Habitat Survey Manual: 2003 version5.3
Appendix 1.2 – River Habitat Survey 2003 version: site health and safety assessment form
River Habitat Survey Manual: 2003 version 5.4
RIVER HABITAT SURVEY 2003 VERSION: SITE HEALTH AND SAFETY ASSESSMENT
IF THERE ARE ANY HIGH RISKS OR MORE THAN THREE MODERATE RISKS
DO NOT CONTINUE WITH THE SURVEY.
Site Number
1
:
1 Leave blank if new site. 2 Optional
Grid References/Co-ordinates: Spot 1
2
: End of site
2
:Mid-site:
Accredited Surveyor Code:Surveyor Name:
Weather Conditions:
Flow Conditions:
Site details: (enter comments or circle if applicable and give details)
Risk Level
(Low/Mod/High)
Access and Parking:
(entry & exit)
Conditions: comment on ground stability, footing, exposure/remoteness
Obstacles/Hazards: fencing, stiles, dense vegetation, steep bank
Occupied/Unoccupied: people, livestock, animals
Activities/Land-use: agriculture, woodland, residential, industrial, construction, recreational
Risk if lone-working
Lyme Disease
1. Dress appropriately with skin covered up.
2. Regularly inspect for ticks when in the field.
3. Check for, and remove, any ticks as soon as possible after leaving the site.
4. Seek medical attention if bitten by a tick.
Site Ref: River Name: Date:
Weil’s Disease (Leptospirosis)
Instructions to card holders
1.
2.
3.
4.
5.
6.
As infection may enter through breaks in the skin, ensure that any cut, scratch or abrasion is
thoroughly cleansed and covered with a waterproof plaster.
Avoid rubbing your eyes, nose and mouth during work.
Clean protective clothing, footwear and equipment etc. after use
After work, and particularly before taking food or drink, wash hands thoroughly.
Report all accidents and/or injuries, however slight.
Keep your card with you at all times.
Appendix 2 – Lone Working Guidance
This Appendix contains excerpts form the Environment Agency’s Health and Safety Risk Management Manual
and the Lone Worker Code of Practice.
‘Lone working’ is where there is either no visual or audible communication with someone who can effectively
get assistance in the event of an incident.
‘Remote working’ is when there are two people working in an area which is regarded as being isolated from
potential rescuers, either because of the distance from inhabited locations, or because of features which make
the site inaccessible.
Lone or remote working surveyors need to have the same level of safety as those working with others, or in
populated locations, i.e. be in a minimal risk situation.
If it is deemed high risk for a lone surveyor to do a survey, those responsible for the safety of surveyors
need to make an additional person available. Surveyors should not perform RHS alone when there is a
foreseeable chance that doing so might result in an accident, which would require a second person to be
available to summon help.
Those who do work alone, or remotely, should have health and safety training which includes first-aid,
map reading, using safety equipment and conflict resolution/breakaway skills.
Risk assessment
Personnel responsible for the safety of surveyors must carry out a risk assessment for lone and remote
surveyors and reduce risks to an acceptable level. However, surveyors must complete a risk assessment on
site and use their own judgement. If they feel they are vulnerable, they should have assistance.
Surveyors should not put themselves or others at risk.
The risk assessment may be carried out in three phases:
River Habitat Survey Manual: 2003 version5.5
Identify tasks as a lone worker
Action: Line Manager/Supervisor
Carry out ‘desk’ risk assessment
based on knowledge and experience
Action: Line Manager/Supervisor
Carry out on site risk assessment
Action: Lone/remote Worker
Lone or remote surveyors need to evaluate the following key risk criteria:
• the kind of accidents that may occur;
• the type of injuries that might result;
• the need for those injuries to receive immediate treatment;
• the chances of the injured person being able to summon help using telephone/radio equipment.
These should be looked at in addition to the RHS Risk Assessment (Appendix 1.1).
Lone, or remote, surveyors should not do RHS in:
• reduced visibility when there is a risk of falling into deep or fast flowing water or if there are steep banks;
• sites where banks are unstable or slippery;
• urban areas with high crime rates or known problems of physical attacks and muggings;
• sites where a hostile situation might be anticipated.
Lone surveyors should not undertake survey from within the channel if the water is above knee height,
fast flowing, or turbid.
Safe system for lone working
Once risks have been assessed, and hazards identified, then risk control measures can be put in place to
minimise the risks.
When designing a safe system of work, the following areas must be examined:
• work location;
• hazards;
• safety equipment;
• personnel;
• communication.
Personnel responsible for the safety of surveyors need to ensure there is a system in place to enable effective
communication with, and monitoring of, surveyors working alone or remotely. They should know the
surveyor’s location, route, estimated start and finish times and be able to contact them. Similarly,
surveyors should be able to make contact with personnel operating their safety procedures.
Good practice procedures for lone, or remote, surveyors include reporting to their office:
• at the start of a survey;
• periodically during a survey;
• if there are problems or changes to the planned routine;
• at the end of the survey.
There also needs to be a pre-determined course of action in case a surveyor fails to report in at the end of
survey work, or at the agreed times. In such circumstance, good practice requires attempts to be made
to contact the surveyor at 5-10 minute intervals, and record the attempts made. If after an hour there is still
no contact, search and emergency procedures should be initiated.
River Habitat Survey Manual: 2003 version 5.6
River Habitat Survey Manual: 2003 version5.7
1
INTRODUCTION
1. A previously unknown disease of alder was described
in southern Britain in 1993 (Gibbs, 1995). It was shown
to be caused by a fungus resembling Phytophthora
cambivora, an organism which was well-known as a
pathogen of broadleaved trees but which had not
previously been reported from alder. During the next
few years, considerable efforts were directed to
determining the distribution and severity of the disease
within the UK. A research project into the biology and
control of the disease was also instituted (see Gibbs
and Lonsdale, 1996). This information note provides
a current assessment of the situation. A companion
note on the alder species commonly grown in Britain
is in preparation (White and Gibbs, 1998).
CHARACTERISTICS AND
PATTERNS OF OCCURRENCE
OF THE DISEASE
2. From a distance, diseased alders attract attention in
mid to late summer because the leaves are abnormally
small, yellow and sparse (Figure 1). They frequently
fall prematurely, leaving the tree bare. The stem base
of a tree with severe crown symptoms is often marked
with tarry or rusty spots, sometimes occurring up to
two metres from ground level (Figure 2). These spots
indicate that the underlying bark is dead. Over the
next few years the fine twig structure, the bark and
eventually the trunk will break up. However, it is
quite common for narrow strips of bark to remain
alive and to support a limited growth of new shoots
from the trunk and major branches.
ABSTRACT
Phytophthora disease of alder can be found in young woodland plantations and orchard shelterbelts. However, its
greatest impact is on the riparian alders of southern Britain. Survey results for trees alongside rivers over 8 m wide show
that the incidence of the disease has increased every year from 1994 to 1997. The rate of increase in 1997 was less than
that in the year before. Current information is presented on the possible origin of the disease and on approaches to
management and control.
I N F O R M A T I O N N O T E
Phytophthora
Disease of Alder
231 Corstorphine Road
Edinburgh
EH12 7AT
http://www.forestry.gov.uk
I S S U E D B Y F O R E S T R Y P R A C T I C E
B Y J O H N G I B B S A N D D A V I D L O N S D A L E O F F O R E S T R E S E A R C H
J U L Y 1 9 9 8
FCIN6
Figure 1
Affected alder stem showing rather sparse yellow foliage
typical of Phytophthora disease.
Figure 2
Base of alder stem showing the tarry spots commonly
found with Phytophthora disease.
Appendix 3
River Habitat Survey Manual: 2003 version 5.8
3. Phytophthoras infect their hosts mainly by means of
free-swimming spores, which are often dispersed by
flowing water. This form of transmission could
explain the spread of the 'alder Phytophthora'
amongst riparian trees. Indeed, surveys of disease
incidence within 10 m of the water’s edge have shown
a very strong negative effect of distance from water.
However, the disease has also been found in sites
remote from watercourses: in young woodland
plantations for example and in orchard shelterbelts.
4. It has been shown that the free-swimming spores of
the alder Phytophthora are attracted to the fine roots
of young alders. However, it is by no means certain
that fine roots are the main infection sites in nature.
Detailed studies of diseased trees have indicated that
bark-killing often begins at the collar (the base of the
stem) rather than well down the root system. It is
evident that foliar symptoms do not occur until a stem
has been largely girdled, and that, in consequence,
many years can elapse between infection and the
appearance of visible disease in the crown.
5. It has recently been found that trees with severe crown
symptoms may recover in subsequent years, due to the
arrested development of the lesions at the stem base,
followed by the development of sufficient live tissues
to provide an effective link between root system and
crown. Such trees show basal cankers, sometimes in
the absence of tarry spots.
6. Most records of the alder Phytophthora have come
from the common alder Alnus glutinosa, but the
fungus has also been detected in grey alder, A. incana,
and the Italian alder, A. cordata (Figure 3). It has not
been recorded on any other species of tree and
experiments on a number of common riparian trees
have not shown any of them to be susceptible.
2
DISEASE DISTRIBUTION IN
THE UK AND ELSEWHERE IN
EUROPE
7. It has been known for some years that the disease is
present through much of southern Britain (see maps in
Gibbs (1995) and Gibbs and Lonsdale (1996)).
Recently attention has been focused on determining its
distribution further north. In 1996 it was found on
the Till, a tributary of the Tweed in the extreme
north-east of England and on the Spey in north-east
Scotland. Following the description of the disease
from the UK, it has been reported from a number of
other countries, such as Austria, France, Germany,
and Sweden. It has not been found outside Europe.
THE SCALE OF THE DISEASE
IN THE UK
On Rivers
8. The principal information on the scale of the disease
comes from a series of riparian plots established in
1994 on rivers over 8 m wide in southern Britain.
These plots have now been assessed for four successive
years and data from them are contained in Table 1.
Further analysis of the survey data from 1994 to 1996
can be found in Gibbs, Lipscombe and Peace (1998).
Figure 3
Italian alder in the remnant of a woodland-planting
subject to occasional flooding. One tree has recently died
from Phytophthora disease.
River Habitat Survey Manual: 2003 version5.9
3
Table 1 Summary of data from riparian alder
plots surveyed from 1994–1997
Number of trees assessed 1704 1741 1744 1746
Number of trees observed with Phytophthora disease 67 78 97 105
Number of standing dead trees* 21 27 40 44
Percentage of trees observed diseased or dead 5.2 6.0 7.9 8.5
Year
1994 1995 1996 1997
The survey is based on alders (maidens or coppice
stools) that have at least one stem of 7 cm dbh.
Annual fluctuations in the total number of trees
assessed are due to the net effect of recruitment,
through growth into the 7 cm size class, and loss, due
to activities such as felling or events such as flood. The
data show that in 1994 5.2% of the trees were
diseased or dead, although it was recognised that a
small proportion of the dead trees had not been killed
by Phytophthora. This percentage has increased each
year such that by 1997 8.5% of the total was diseased
or dead. By extrapolation from the plot data, it is
possible to produce rough estimates of the total
numbers of trees affected. This procedure gives a
population of 580,000 trees of which 35,000 were
diseased and 15,000 were dead.
9. The biggest increase was between 1995 and 1996
(Table 1), with the increase between 1996 and 1997
being notably smaller. Scrutiny of the individual plot
data for this last year indicates considerable variation,
with some plots showing much increase in disease
while others show little or none at all. A few trees
have definitely recovered from the disease, i.e. there
has been no recent death of bark and the leaves are of
a normal size and colour, although they may remain
sparse. Such trees show the development of new
tissues at the edge of basal stem lesions, as described
above. It remains to be seen whether this remission
from disease is permanent.
10. On average, the disease incidence is highest in southeast
England. However, heavy losses are occurring in
some of the large alder populations that occur along
western rivers - for example, in the Marches (Figure 4).
On Smaller Watercourses
11. Comparative data for rivers over 8 m wide and
smaller watercourses are available only for two parts
of the country. Both show a markedly lower incidence
of disease on the smaller streams. Thus in south-east
England the incidence of disease was 15% of the alder
population on streams below 8 m in width as
compared to 41% on the larger rivers. In the Welsh
borders the equivalent figures were 1% and 19%.
*Between 1994 and 1997 a total of 23 trees which had died of Phytophthora disease were felled or washed away. These figures are not included in the table.
Figure 4
Alders killed by the disease along the River Lugg in Herefordshire.
River Habitat Survey Manual: 2003 version 5.10
4
DISEASE HISTORY AND
ORIGIN
12. From a knowledge of the biology of the causal fungus
and from its wide distribution, it is evident that the
disease has been present in the UK for at least 20
years, probably much longer. The key question is
whether it is caused by a native pathogen, the effects
of which have been exacerbated by particular
environmental circumstances, or whether it is caused
by an entirely new fungus, originating within, say, the
last century.
13. In favour of the first hypothesis can be cited the
evidence, presented above, that the incidence of overt
disease increase can fluctuate and that trees can
recover from the disease. It seems possible that there
was a distinct wave of infection in the mid-1990s and
that this has to a degree subsided. Additional evidence
for this point comes from the presence in many
severely affected riparian alder stands, of substantial
numbers of healthy young saplings of c. 2–3 years of
age (Figure 5). It seems probable that these saplings
are intrinsically susceptible yet they are at present
apparently free from infection.
14. The second hypothesis is supported by increasing
evidence that the causal fungus is of recent genetic
origin. This first became apparent from a study of the
morphological and cultural characteristics of the
fungus (Brasier, Rose and Gibbs, 1995) and has
subsequently been borne out by data from studies on
the molecular biology of a collection of alder
Phytophthora isolates obtained from across its known
range in Britain and mainland Europe.
15. Some evidence can be interpreted in various ways.
From the survey data, a correlation has now been
established between the level of total oxidised nitrates
in a stretch of river and the incidence of Phytophthora
infection in the adjacent riparian alder (Gibbs,
Lipscombe and Peace, 1998). However, much more
research is required before a causal relationship
between these two variables can be inferred. The
sections of river with highest nitrate counts will also
be those most exposed to other types of human
activity, and if we are dealing with a newly evolved
pathogen and this is being gradually disseminated
around the country by one means or another, it could
appear in much-disturbed rivers before more remote
watercourses.
Figure 5
Healthy young growth of alder alongside some small trees that
show severe disease symptoms.
DISEASE MANAGEMENT AND
CONTROL
16. It is not recommended that time and resources should
be spent in attempts to eliminate the fungus from a
site through the felling or winching out of affected
trees. These operations cannot be conducted in a
sufficiently comprehensive way to be effective.
Moreover, at least in riparian sites, additional
infective propagules of the fungus may well be
brought to remaining healthy trees from diseased trees
further upstream.
17. Studies on an approach to disease management
through the coppicing of affected trees were initiated
in summer 1996 when 50 alders, in various stages of
disease, were felled along the Hadley Brook in
Worcestershire. As might be expected, some stools
were either already dead or soon died. However,
vigorous coppice growth occurred from the stumps of
a number of quite severely affected trees and this was
still healthy in September 1997. This observation is
consistent with the view that the fungus may
sometimes die out within tissue that it has colonised,
and that the remaining tissue will remain unaffected
unless or until a new infection is initiated. Coppicing
gives any new growth a chance to develop under
favourable space and light conditions.
River Habitat Survey Manual: 2003 version5.11
5
Disease Resistance
18. Three experiments involving various alder species and
various provenances of A. glutinosa have been
established on ground subject to flooding alongside
rivers on which many diseased trees can be found. No
disease data are available as yet from these experiments.
However, an inoculation experiment conducted on 1year-old
seedlings of twelve A. glutinosa provenances
provided some evidence that western European
provenances were more resistant to the disease than
those from further east. The same experiment
provided evidence that the North American red alder,
A. rubra could be infected by the pathogen but that it
was rather more resistant than A. glutinosa.
PLANTING POLICIES
19. There is a possibility that the fungus can be
disseminated on plants; something that is common
with Phytophthoras affecting ornamental nursery
stock. We only know of two putative occurrences so
far; disease in two young woodland plantations had
the common feature that both had been planted with
alders supplied by the same nursery. The plants had
been imported from Belgium.
20. Those who are concerned about the risk of buying
infected plants, should evaluate potential suppliers
carefully and, if possible, see the growing stock in the
nursery prior to purchase to determine that there are
no apparent health problems.
21. It is quite clear that the planting of alder on sites liable
to flooding by rivers, on the banks of which diseased
alders are known to occur, presents a high risk. While
alder is often the most suitable genus for a variety of
reasons, owners should take account of the threat of
disease, and consider other flood-tolerant species, such
as willow, as replacements or in mixture.
22. Special care should be taken not to introduce the
fungus to remote riparian sites. Here it should be
noted that natural regeneration of alder can often be
achieved through the use of a stockproof enclosure,
and this is often preferable to planting.
REFERENCES
BRASIER, C.M., ROSE, J. AND GIBBS, J.N. (1995).
An unusual Phytophthora associated with widespread
alder mortality in Britain.
Plant Pathology 44, 999–207.
GIBBS, J.N. (1995).
Root disease of alder in Britain.
EPPO Bulletin 25, 661–664.
GIBBS, J.N. AND LONSDALE, D. (1996).
Phytophthora disease of alder: the situation in 1995.
Research Information Note 277, 4 pp.
Forestry Commission, Edinburgh.
GIBBS, J.N., LIPSCOMBE, M.A. AND PEACE, A.J. (1998).
The impact of Phytophthora disease of riparian populations
of common alder (Alnus glutinosa) in southern Britain.
European Journal of Forest Pathology (in press).
WHITE, J. AND GIBBS, J.N. (1998).
Alders in Britain.
Forestry Commission Practice Note (in prep).
ACKNOWLEDGEMENTS
This work described here is funded jointly by the Forestry
Authority and the Environment Agency. Over the years a
number of FCRA staff (notably Martin Lipscombe, Nigel
Rylance and Brian Hanwell) have assisted with the river
surveys. The survey of streams below 8 m in width was
conducted in south-east England by Karen Mantripp and
in the Welsh Borders by staff of the Environment Agency.
Records for the distribution of the ‘alder Phytophthora’ in
northern Britain come from Steve Gregory and Grace
MacAskill and information on its genetic nature from
Clive Brasier. We would like to thank Joan Rose for
assistance with research work.
River Habitat Survey Manual: 2003 version 5.12
6
© CROWN COPYRIGHTISSN 1460-3802
ISBN 0-85538-375-5
Enquiries relating to this publication should be addressed to:
Dr John Gibbs
Forest Research
Alice Holt Lodge
Wrecclesham
Farnham
Surrey
GU10 4LH
Tel: 01420 22255
Fax: 01420 23653
E-mail: j.gibbs@forestry.gov.uk
River Habitat Survey Manual: 2003 version5.13
Appendix 4 Main differences between the 1997 and 2003 RHS survey forms
2003 Form 1997 Form NOTES
- Section A Background map-based information – no longer part of field-survey, so
not on 2003 form.
Field survey details - minor changes of detail only. It is now important to
record grid-references at spot-checks 1, 6 and the end of site for
map-based data gathering and GIS applications.
Predominant valley form – minor changes: e.g. addition of U-shape valley;
presence/absence of floodplain recorded.
Number of riffles, pools and point bars – no change.
Artificial features - moved to front page from back, and types refined.
Physical attributes - 3 additional bank materials: tipped debris (TD)
[includes old category of ‘builders waste, as well as other discarded
materials], fabric (FA), bio-engineering (BI); one additional marginal and
bank feature: natural berm (NB); Flow-type: No water abbreviation
changed from NO to DR to give unique 2-letter abbreviation; Earth (EA)
added as bed material for seasonally dry channels; two additional channel
features: Exposed bedrock (EB) and Vegetated rock (VR); capability to
record numbers of channels at braided sites.
Banktop land-use and vegetation structure – Same method of recording,
but seven new categories of land-use to enable, for example, separation
of ‘natural’ woodlands from plantations, and ‘natural’ open water from
artificial open water.
Channel vegetation types – no change, but clearer guidance on data entry
in column 11.
Land-use within 50m of banktop – same additions of categories as F.
Bank profiles – natural berm added.
Extent of trees and associated features – no change except clearer
guidance, by way of *asterisks, for recording discrete features that may not
extend along 1% of the site, but require recording if present.
Extent of channel and bank features – significant changes. All descriptive
flow types (e.g. rapids, runs) replaced by flow types (e.g. broken standing
waves, rippled); eroding/stable cliffs, vegetated bedrock/boulders,
unvegetated/vegetated point bars and discrete gravel deposits additions to
2003 form. Use of *asterisks for some features, as in J.
Channel dimensions – no significant change, but now requires flow-type
to be noted if measurements not taken at a riffle.
Features of special interest – more categories. Includes: splitting of braided
and side channels; slight changes in terminology (e.g. wet woodland(s) for
carr); new categories <5m high waterfalls, natural cascades, very large
boulders, floodplain boulder deposits, backwaters.
Choked channel – no change in recording.
Notable nuisance plant species – ability to record on the bankface and in
the 50m corridor separately. Use of *asterisks to remind surveyors that just
a single occurrence of an alien species should be recorded.
Overall characteristics – only minor additions in guidance notes.
Alders – no change, but use of *asterisks to remind surveyors that just a
single alder, or a single diseased one, should be recorded.
Field survey quality control – new guidance for checking entries are
completed before leaving the site.
A
B
C
D
E
G
H
I
J
K
L
M
N
O
P
Q
R
F
A
B
C
D
E
G
H
I
J
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F