Planet WGSW-24010 User Manual page 12

STR Species Trophic Rank. A value assigned to a species on a scale of 1 to 10,
designed to reflect the tolerance of that species to eutrophication. Low
scores indicate tolerance or cosmopolitan distribution (ie no preference).
High scores indicate preference for less enriched conditions or intolerance
of eutrophic conditions.
Survey The collection of data at one site according to the prescribed methodology.
Survey length This is the sample area — the actual river channel area surveyed, between
two fixed points on the bank. The survey length is 100m long for
standard MTR surveys.
Survey season The MTR survey season is mid-June to mid-September inclusive.
TDI The Trophic Diatom Index. A method for assessing the trophic status of
rivers using benthic diatoms.
u/s Upstream.
UWWTD The European Community Urban Waste Water Treatment Directive
(UWWTD, 91/271/EEC).
WWTW Waste water treatment works.
R&D Technical Report E38 ix