A12. River Habitat Survey

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Figure 1: RHS form

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1. Objectives[edit]

  • Characterise and asses, in broad simple terms, the physical character of freshwater streams and small rivers

2. Method summary[edit]

RHS is carried out along a 500m length of river. Observations on channel features and modifications are made at 10 equally spaced spot-checks, together with an overall “sweep-up” summary for the whole site. Other information such as valley form and land-use in the river corridor is also collected.

The survey starts by completing a Health & Safety form which is attached to the finalised, completed form. Weather conditions, site conditions and flow conditions are recorded prior to starting the survey. The RHS form is 4 pages, which can be completed as a paper form or using the RHS Android mobile App. The first page asks for information about the surveyor, reference information and coordinates. This is also where you are asked to record the valley type, and keep a tally of natural and artificial features including pools, riffles, point bars, weirs, culverts, bridges, outfalls and deflectors. These features should be recorded whenever they are observed across the 500m survey area.

On the second page (Figure 1) you are asked to complete 10 spot checks. Every 50m along the 500m stretch, you stop and record your observations across the cross-section of the channel within that 1m width. Features recorded include bank composition, modifications, bank and channel features, substrate, flow type, land use, vegetation structure and in-stream vegetation coverage.

As well as the 10 spot checks, a sweep-up is completed to include any other features which fall outside of the 10 spot check areas. This might include channel modifications, natural and artificial features (pools and riffles; bridges). Bank types and land use are also recorded, and a degree of presence is recorded. If a bank type or land use is present for more than 33% of the 500m site, then this is recorded as ‘E’ for extensive. If a land use type or bank modification therefore is recorded at more than 3 spot checks, this can be an indication of an extensive modification or feature.

Finally, the last page of the RHS form asks for channel dimensions, which are to be recorded once along the stretch. There is also space to record any other features such as woody debris, non-native invasive species, animals, alders, as well as any other comments.

3. Advantages[edit]

  • Fixed survey length allows standardisation and comparison of results across different sites
  • Great for characterising a reach and setting a baseline
  • Can be surveyed on Android on the RHS App and uploaded straight to the RHS database
  • RHS site data can be directly compared to sites of similar type in the RHS database

4. Limitations[edit]

  • Surveyor bias and subjectivity of some data
  • Fixed survey length does not allow targeted assessment of small scale changes

5. Recommendation for method application[edit]

  • The RHS field manual (2003) provides guidelines for trained, accredited surveys
  • Ensure detailed sweep up and careful observation
  • Undertake surveys in spring if possible
  • Do not survey in high flows as the data will be unreliable

6. Costs[edit]

RRC offer training to become a certified RHS surveyor. This enables the surveyor to carry out RHS surveys for any site or project. This training costs approx. £700 and is validated for three years after which a refresher is due.

7. Data analysis[edit]

A database of previously surveyed sites now contains field observations, map-derived information and photographs from more than 24,000 surveys undertaken since 1994. During 1994-96, a stratified random network of nearly 5000 sites provided baseline information about the physical character from a geographically representative sample of streams and rivers across the UK. A second survey in England and Wales was carried out during 2007 and 2008.

RHS information can be inputted into the RHS database by surveyors, or unloaded directly using the RHS App from a smartphone or tablet. The database analyses the observed data and produces indices values, representative of 4 hydromorphological characteristics, namely, substrate type, vegetation types, flow regime and geomorphological activity. Context analysis can be performed to compare your site with other sites of similar type already in the database. Similarly, RHS could be carried out before and after a restoration project in order to quantify the changes to the river and banks. This shows the comparability of data using this method for monitoring.

River Habitat Survey data have been analysed and used as part of research projects both in the UK and abroad. Research projects have been carried out on urban rivers and RHS data have been used for describing habitats for various species from macro invertebrate to fish, birds and macrophytes.

8. Examples[edit]

In collaboration with various organisations, RHS has been used to help analyse rivers and catchments. For example:

9. More information[edit]

10. References[edit]

  1. Environment Agency, SEPA and Environment and Heritage Service. River Habitat Survey in Britain and Ireland: Field Survey Guidance Manual: 2003 version.
  2. Fox, P.J.A., Naura, M. & Scarlett, P. (1998) An account of the derivation and testing of a standard field method, River Habitat Survey. Aquatic Conservation-Marine and Freshwater Ecosystems, 8, 455-475
  3. Jeffers, J.N.R. (1998) Characterization of river habitats and prediction of habitat features using ordination techniques. Aquatic Conservation: Marine and Freshwater Ecosystems., 8, 529-540.
  4. Naura, M., Clark, M.J., Sear, Atkinson, P.M. Hornby, Kemp, P., England, G., Peirson, G., Bromley, C., Carter, M.G. (2016) Mapping habitat indices across river networks using spatial statistical modelling of River Habitat Survey data. Ecological Indicators. 66, 20-29. Doi: 10.1016/j.ecolind.2016.03.055
  5. Raven, P.J., Fox, P., Everard, M., Holmes, N.T.H. & Dawson, F.H. (1997) River habitat survey: A new system for classifying rivers according to their habitat quality. Freshwater Quality: Defining the Indefinable?, 215-234
  6. Raven, P J, Holmes, N T H, Dawson, F H, Fox, P J A, Everard, M, Fozzard, I, Rouen, K J (1998). River Habitat Quality: the Physical Character of Rivers and Streams in the UK and the Isle of Man. Environment Agency, Bristol
  7. Walker, J. (2005) River Habitat Objectives. Environment Agency, England and Wales.