Gwyneth Howells

Loch fleet: liming to restore a brown trout fishery.

This project has been successful in meeting its objectives in terms of demonstrating that catchment liming techniques can restore acidified waters to conditions suitable for fish populations for relatively long periods. This improvement in conditions has extended to the inlet stream, which provides vital fish spawning and nursery areas, which are difficult to treat effectively be other means in remote locations. The project has also provided an assessment of the effectiveness of differing rates and modes of lime application, which suggest that only quite restricted parts of a catchment require treatment. This not only maximizes the cost-effectiveness of the treatments, but also helps to minimize any side-effects on, for example, moorland vegetation. The biological monitoring programme at Loch Fleet has also provided an assessment of the overall ecological consequences of adding limestone to naturally acidic and calcium-deficient ecosystems.

The Loch Fleet Project, SW Scotland

Loch Fleet is an upland loch in SW Scotland, distant from significant local pollution, and unlikely to be affected by changes during the five-year project. The underlying geology is granitic. The 111 ha catchment is 90% moorland, dominated by heather and flying bent; 10% is planted with conifers. Rainfall is approximately 2200 mm per year, predominantly from W and SW. More than half of rain events are pH>4·7; mean pH is 4·84 (1985). Marine salts are the major solutes. Deposition of acidity is about 0·1 g H + m −2 per year, about twice that of eastern Scotland; deposition of non-seasalt sulphur is 1·6 g S m −2 per year. Soils are shallow and comprise organic peats, peaty gleys, and peaty rankers; base saturation is 3–19%. Soils (pH 2·5 to 4·6) are most acid in the forested area. The loch is more acid (×5) than bulk deposition; additional acidity is mobilised from soils by the predominantly (>90%) superficial drainage. Moorland drainage dominates; that from the forest is more acid, but very variable in quantity and composition. Catchment interventions in 1986 and 1987 are designed to alter the chemistry of drainage waters and the loch, so that the fishery can be restored. In addition to the work reported, extensive soils, sediment and biological investigations are underway.

Rapporteurs' report on discussions at the workshop on excess nitrogen deposition, Leatherhead, September 1987.

This paper reports major points from the discussions which took place during the Workshop on Excess Nitrogen Deposition.

The interaction of forest vegetation and soils with the aquatic environment; effects of catchment liming on lakes

Abstract Evidence that processes within forests and soils, as well as atmospheric deposition, influence the aquatic environment, specifically the phenomenon of acidification, is reviewed and mechanisms suggested for acidification effects. The Loch Fleet Project (Galloway, southwest Scotland) has collated data on atmospheric deposition, soil drainage and runoff chemistry since 1985, with liming of parts of the catchment in 1986 and 1987. Comparison of conditions prior to and following liming of forested and moorland areas can be compared. Both direct observations and modelling of forest acidity transfers demonstrate that forests can acidify soils and surface waters in the absence of acid deposition and forest soil liming is suggested as a possible sylvicultural management practice to counter such acidification.

Organotin-Environmental Fate and Effects

Abstract Edited By M. C. Champ and O. F. Seligman. Published September 1996, Chapman and Hall, London Etc., Price

A review of: “Toxic Impacts On the Aquatic Environment”

195.00, Pages 623isbn Hb 412 582406. Index, List of Acronyms, Tables and Figures.

The Loch Fleet Project: Overview

Abstract Edited By J. F. Tapp, J. R. Wharfe and S. M. Hunt, Royal Society of Chemistry, Isbn 0-85404-781-6. Price

Second International Ocean Pollution Symposium, 4-8 October 1993

49.50, 1996. Pages 295, Index, Figures and Tables.