Nutrient water quality of the Wye catchment, UK: exploring patterns and fluxes using the Environment Agency data archives

Abstract

Water quality data, collected by the Environment Agency in England and Wales over 10 years (1991 2000) were used to examine the spatial distribution of nutrient pollution risk and for assessing broad-scale spatial and temporal variability in nutrient fluxes across the Wye catchment. Nutrient water quality across the upper and middle Wye catchment, and along the main River Wye, is generally very good. However, the main areas of concern lie in the small tributaries in the south and east of the catchment, which have lower dilution capacity and high agricultural and effluent inputs, and where mean Total Reactive Phosphorus (TRP) in some cases exceed 1mg-P l -1 . Indeed, mass load calculations have demonstrated that the lowland south and east portion of the catchment contributes more than 85% of the whole-catchment TRP and more than 78% of nitrate (NO 3 ) loads. Ratios of NO 3 :Ca concentrations were used to fingerprint different water-types across the catchment, linked to weathering and agricultural activity. The Wye catchment has been subject to two major sets of perturbations during the study period: (i) climatic fluctuations, with a drought during 1995-6, followed by a subsequent drought-break in 1997/8, and extreme high river flows in the autumn/winter of 2000/2001, and (ii) introduction of tertiary P-treatment at major sewage treatment works in the catchment. The implications of these perturbations for the nutrient water quality of the Wye catchment are discussed. Recommendations are made for more targeted monitoring to directly assess diffuse source nutrient contributions.

Lowland river water quality: a new UK data resource for process and environmental management analysis

“…Such data complement long-standing environmental monitoring as part of the management of both riverine and lacustrine water bodies by regulatory agencies such as the Environment Agency of England and Wales, and the Scottish Environmental Protection Agency (Robson and Neal, 1997a,b;Jarvie et al, 2003a). Both types of data are vital for addressing issues such as sewage effluent and agricultural runoff of pollutants to water courses and their environmental consequences and making the information freely available for research and management purposes is of critical importance (Tromp-van Meerfield et al, 2008;Schofield et al, 2009).…”

Impact of phosphorus control measures on in-river phosphorus retention associated with point source pollution

“…An investigation of the quality of the data revealed that on several occasions TRP concentrations were much higher than T P concentrations. This is likely to be due to analytical problems (see Neal et al, 2000;Jarvie et al, 2003). The relative uncertainty of the observed TRP concentration was about 20%.…”

Appraising riparian management effects on benthic macroinvertebrates in the Wye River system

“…The rural catchment (4136 km 2 ) and invertebrate communities of the River Wye have been comprehensively described elsewhere (Edwards and Brooker, 1982;Ormerod and Edwards, 1987;Jarvie et al, 2003;Clews and Ormerod, 2009). In the middle and upper reaches, pastoral agriculture is the dominant land-use, with rough grazing and plantation forestry also present.…”