Planet WGSW-24010 User Manual page 150

MTR SURVEY: SUMMARY OF METHODOLOGY
Befor e you go out
Ensure that you have all the equipment you need and are familiar with appropriate health and safety
guidance.
Pr ior to commencing the sur vey
1. Confirm that the site is suitable for a MTR survey. Think again if:
·
the suffixes of confidence for the survey and comparability are C and/or III
·
there has been a recent temporal perturbation (eg spate or weed-cutting)
·
flows are high and/or the water is turbid
·
there is heavy/steady rain and/or windy conditions
·
an alternative method is more appropriate.
2. Select/locate the survey length.
·
Use the sketch/location map if the survey length has been surveyed before.
·
If this is a new site, select the most appropriate survey length, giving consideration to the factors
influencing the MTR.
·
The survey length is 100m long: measure (or pace) out and mark. For its width, see the definition of
the 'channel'.
Exceptions to surveying the full survey-length are:
·
if the river is very wide and/or deep and it is impractical to survey the full width, then a 5m wide
(minimum) strip down one side of the channel may be surveyed instead (downstream length to be on
the discharge side)
·
if an effluent tracks along one bank for at least 500m, then a 5m wide (minimum) strip down that side
of the channel can be surveyed, provided that a full-width survey is undertaken first;
·
if a mature island is located within the survey length when assessing the impact of a discharge, then
only the side on which the discharge enters should be surveyed;
·
if there is a deep or rapid area(s), not exceeding 20% of an otherwise wadeable site, which is
impractical to survey using a boat and a camera/bucket, then this may be left as a 'black hole' (mark
clearly on the map and discount from all plant cover and physical attribute estimates except width).
·
if it is impossible to find two comparable 100m sites near to the discharge being assessed, then 50m
reaches of similar character may be surveyed, provided the river is at least 10m wide.
3. Complete the site and survey details on the standard field recording sheets.
The Sur vey
4. Aim to traverse the channel 4 times in every 10m length of river, either by wading or by boat as
appropriate. In narrow, non-wadeable sites, the survey can be undertaken from the bank.
5. Assess and record all macrophytes present within the survey length, and their individual percentage
cover class (SCV), using the standard field recording sheet.
·
This includes: all macrophytes likely to be submerged for more than 85% of the time; both scoring and
non-scoring plants.
·
Do not record macrophytes overhanging but not rooted in the channel area, nor detached macrophyte
material except for floating species. Include macrophytes on artificial structures only if a similar
structure is present at both sites being compared.
·
Use a glass-bottomed bucket or underwater camera to improve visibility, where appropriate.
R&D Technical Report E38 136