Skip to main content


Title: Llyn Brianne acid waters project : final report, May 1992
Author: National Rivers Authority Welsh Region
Document Type: Monograph
This report covers Phase II of the Llyn Brianne Acid Waters Project, October 1987 to March 1991. The project is a multidisciplinary investigation into the effects of atmospheric deposition and land management on surface water acidification. At the moderately high altitude of the study area (c.300-500 m) occult deposition was important. Solute concentrations in cloudwater were up to l lx those in bulk precipitation. The cloudwater ions were dominated by sea-salts, though 45% of the sulphate was of non-marine origin, compared to 69% in bulk precipitation. Data on cloudwaters are important in revising estimates of deposition. Soil hydrology is an important influence on stream acidity and aluminium concentrations. Field measurement and hydrochemical modelling showed that flow pathways were dependent on soil type and land use. Forestry may cause a more flashy storm flow response with a more variable contribution to stream flow of groundwaters which are usually well-buffered in comparison to soil waters in surface horizons. Storm run off in a forested catchment was dominated by highly acidic flow along drainage ditches which may have mobilized aluminium from the ditch surfaces.
Publisher: National Rivers Authority
Publication Date: 1992
Publication Place: Cardiff
Subject Keywords: Surface waterWater reservoirsAcidificationAtmospheric depositionLand managementAluminium
Geographic Keywords: WalesLoughor to Taf catchment
Extent: 79
Total file downloads: 276

Download PDF    Display PDF in separate tab