Planet WGSW-24010 User Manual page 41

Box 3 Conditions when sur veys should not be under taken
1. Do not carry out macrophyte surveys during steady/heavy rain and windy conditions
as the disturbance of the water surface leads to reduced visibility and could affect
operator safety.
2. Surveys should not be undertaken after spates because of dangerous conditions for
wading and the probable loss of plant material and disturbance of habitat caused by
high flows. Do not underestimate the potentially serious effects of flooding, as even
minor flooding will cause temporary changes in the relative composition of species
at a site. It is very important to either avoid surveying after flooding or at least to
reflect the flooding in the suffix of confidence for the survey. It is always best to
survey after a period of low flow as the water is usually clear and macrophytes are
easily visible.
3. Where surveys are undertaken over a number of consecutive years, to gain an overall
picture of the 'typical' trophic status over the period, periods of unusual flow should
be avoided as they will not reflect the 'typical' situation.
4. Try to avoid surveying navigated rivers at holiday periods or peak of summer as high
boat activity leads to increased turbidity and a more dangerous situation for the
surveyors.
5. Do not survey macrophytes immediately after a weed-cutting operation or other
management activity which may adversely affect the macrophyte community.
6. Do not carry out a survey if conditions are atypical for the survey site. Atypical
conditions may relate to large floating masses of filamentous algae, excessive
turbidity, or recent weed-cutting/dredging. If floating masses of algae or high
turbidity are normal for the site then consideration should be given to using an
underwater camera during surveys (see 4.5.3).
3.3.5 Sur vey equipment
The following is a list of equipment required to carry out an MTR survey; it is reproduced as a
checklist in Appendix 7.
· Safety equipment - refer to safety manuals and advice available from your manager or safety
advisor
· Maps - Ordnance Survey 1:50 000
· Location and/or sketch map to enable accurate location of the survey length (if surveyed
before)
· Standard record sheets + sketch map sheet (on waterproof paper if necessary)
· Summary of the MTR methodology and definitions reference sheets (optional) - Appendix
7
· Substrate reference and % cover reference sheets (optional)
· Pencil and pen
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