Aquatic Surveys:
Aquatic macrophyte surveys
These surveys are used to assess the status of rivers, lakes, ponds, estuaries and foreshore in terms of the higher plant life (macrophytes) they support. Because plants are not mobile, they must endure the full range of prevailing environmental conditions and can therefore act as good long-term indicators of those conditions. There are several standard methodologies for this type of assessment, including those listed below. On smaller or more critical sites however, a greater degree of detail may be required and in these cases we are able to advise on the optimum sampling and analytical strategy for the job in hand. Aquatic macrophyte surveys are commonly used as input to flood management schemes, development projects and environmental impact assessments. They can also be used for the long-term monitoring of water bodies and as context to fish and invertebrate surveys.
British River Classifications is a tool devised for the assessment of river reaches based upon the higher plant life occupying their channel and banks. The method was originally devised in the 1980's as a means of relating plant assemblages to the predominant geological and trophic conditions to be found nationally. Since then it has become the standard reference for river typing in the UK.
Mean Trophic Rank (MTR) surveys are used to assess river quality. The method entails the identification and mapping of a broad range of river plants, plus the calculation of their physical coverage of a measured section of river. These results are used to derive a score which can be compared with future surveys, so that river quality can be monitored through time.
The River Habitat Survey methodology is widely used by the UK Environment Agency and by consultants, to assess the physical habitats of river reaches in terms of their vegetational, hydraulic and geomorphological structure. The survey is carried out over 500m reaches to record floodplain, channel and land use attributes; with spot checks made at 50 metre intervals to record more detailed information on substrates and vegetation, plus the dimensions and types of channels and banks.
River Corridor Surveys (RCS) are used as part of the project appraisal process for riparian or in-channel developments. RCS is map-based and records the vegetational and geomorphological status of 500 metre channel reaches before and after development works have been undertaken. In this way, valued habitats can be identified and protected before work commences; while the effects of any mitigation or enhancement measures that have been put in place, possibly as part of the development, can be monitored and directly compared with pre-development status. As with general habitat surveys, target notes can be added to record flora and fauna in as much detail as is required.
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