| 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 Lowland Catchment
Research. 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.
Keywords: water quality, nitrate, ammonium, phosphorus, pH, alkalinity, nutrients, major elements, trace elements, rainfall, river, Pang, Lambourn, LOCAR |