Report No SR2713/1

EUTROPHICATION OF UPLAND WATERS

SR2713/1

Apr 1991

SUMMARY

Replies to a questionnaire sent to all River Purification Boards and Scottish Regional Councils were followed up by a series of meetings to gather data on upland waterbodies for which concerns about increasing trophic status have been raised. This information is presented in the context of UK eutrophication case studies and international monitoring programmes. Sampling guidelines and outline catchment management plans are presented.

The following conclusions were reached:

  1. Only a small proportion of Scottish upland lochs appear to be subject to increasing trophic status, but the number of lochs for which eutrophication concerns have been raised in this report is almost certainly an underestimate of the total number.
  2. Action is required now if further deteriorations in the quality of upland lentic waters are to be prevented.
  3. The four major sources of increasing phosphorus loads are forestry, sewage treatment effluent, fish farming and agriculture.
  4. All River Purification Boards and Regional Councils need to measure total phosphorus to a detection limit of 2-3 g/l (or lower) as part of a trophic status monitoring programme.
  5. Whenever water samples are collected from a boat or reservoir valve tower, chlorophyll-a, total phosphorus and Secchi depth should be regarded as the absolute minimum determinands for any trophic status monitoring programme.

Copies of the report are available from FWR, price 12.50, less 20% to FWR Members.