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Water quality along a river continuum subject to point and diffuse sources

Neal, Colin; Jarvie, Helen P.; Love, Alison; Neal, Margaret; Wickham, Heather; Harman, Sarah. 2008 Water quality along a river continuum subject to point and diffuse sources. Journal of Hydrology, 350 (3-4). 154-165. 10.1016/j.jhydrol.2007.10.034

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Abstract/Summary

The water quality along the River Kennet, in the Thames basin of southern England, was examined in terms of the influence of point- and diffuse-nutrient inputs. The river is supplied mainly from a Cretaceous Chalk aquifer and hence the waters are of a calcium bicarbonate type. The nitrate largely comes from agricultural sources, with concentrations decreasing downstream due to plant uptake and probable denitrification. In contrast, soluble reactive phosphorus (SRP) is largely associated with sewage inputs and concentrations increase downstream in line with effluents from major towns such as Newbury and Reading. Adjacent to the river in the lower half of the catchment is the Kennet and Avon Canal and the two are in places hydrologically connected. The canal inputs may influence calcium carbonate (calcite) precipitation and increase suspended sediment and particulate phosphorus concentrations in the river. Monitoring upstream and downstream of Marlborough sewage treatment works (STW) showed that SRP concentrations in the effluent were highly variable due to variable efficiency of P stripping and still sufficiently concentrated to dominate downstream river SRP with potential impacts on stream ecology. Biological recovery in this river following P stripping at STWs is complex and controlling those spikes in SRP that are above a threshold of 100 μg l−1 may be a critical requirement. More stringent effluent targets than are currently recommended may be needed (less than 800 μg RP l−1) to achieve good ecological status in this river depending on SRP concentrations upstream.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1016/j.jhydrol.2007.10.034
Programmes: CEH Programmes pre-2009 publications > Water > WA02 Quantifying processes that link water quality and quantity, biota and physical environment
CEH Sections: Acreman
ISSN: 0022-1694
Additional Keywords: AMP4, Canal, Kennet, Phosphate, River, Sewage
NORA Subject Terms: Ecology and Environment
Date made live: 05 May 2009 11:18
URI: http://nora.nerc.ac.uk/id/eprint/5537

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