Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 8 4 2004 10.5194/hess-8-614-2004 http://www.hydrol-earth-syst-sci.net/8/614/2004/ http://www.hydrol-earth-syst-sci.net/8/614/2004/hess-8-614-2004.html http://www.hydrol-earth-syst-sci.net/8/614/2004/hess-8-614-2004.pdf 614 635 0000-00-00 The water quality of the LOCAR Pang and Lambourn catchments C. Neal H. P. Jarvie A. J. Wade M. Neal R. Wyatt H. Wickham L. Hill N. Hewitt Centre for Ecology and Hydrology, Wallingford, OXON, OX10 8BB, UK Department of Geography, University of Reading, Whiteknights, PO Box 227, Reading, RG6 2AB, UK Email for corresponding author: cn@ceh.ac.uk The water quality of the Pang and Lambourn, tributaries of the River Thames, in south-eastern England, is described in relation to spatial and temporal dimensions. The river waters are supplied mainly from Chalk-fed aquifer sources and are, therefore, of a calcium-bicarbonate type. The major, minor and trace element chemistry of the rivers is controlled by a combination of atmospheric and pollutant inputs from agriculture and sewage sources superimposed on a background water quality signal linked to geological sources. Water quality does not vary greatly over time or space. However, in detail, there are differences in water quality between the Pang and Lambourn and between sites along the Pang and the Lambourn. These differences reflect hydrological processes, water flow pathways and water quality input fluxes. The Pang’s pattern of water quality change is more variable than that of the Lambourn. The flow hydrograph also shows both a cyclical and "uniform pattern" characteristic of aquifer drainage with, superimposed, a series of "flashier" spiked responses characteristic of karstic systems. The Lambourn, in contrast, shows simpler features without the "flashier" responses. The results are discussed in relation to the newly developed UK community programme LOCAR dealing with <b>Lo</b>wland <b>Ca</b>tchment <b>R</b>esearch. A descriptive and box model structure is provided to describe the key features of water quality variations in relation to soil, unsaturated and groundwater flows and storage both away from and close to the river.</p> <p style="line-height: 20px;"><b>Keywords: </b>water quality, nitrate, ammonium, phosphorus, pH, alkalinity, nutrients, major elements, trace elements, rainfall, river, Pang, Lambourn, LOCAR