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| Titel |
The occurrence of groundwater in the Lower Palaeozoic rocks of upland Central Wales |
| VerfasserIn |
C. Neal, A. J. Robson, P. Shand, W. M. Edmunds, A. J. Dixon, D. K. Buckley, S. Hill, M. Harrow, M. Neal, J. Wilkinson, B. Reynolds |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 1, no. 1 ; Nr. 1, no. 1, S.3-18 |
| Datensatznummer |
250000079
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| Publikation (Nr.) |
 copernicus.org/hess-1-3-1997.pdf |
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| Zusammenfassung |
| A series of boreholes of up to 50 m depth, drilled
into Lower Palaeozoic mudstone, shale and greywacke bedrock in the headwater
catchment areas of the River Severn at Plynlimon in Central Wales, shows
an extensive chemically- and hydrologically-active shallow groundwater
fracture flow system. Groundwater chemistry varies in space and time with
lowest water levels and highest alkalinities occurring during the drier
summer months. The groundwaters are enriched in base cations, silica, sulphate
and alkalinity relative to surface waters indicating significant silicate
weathering sources and sulphide oxidation. These sources provide important
contributions to both stream water quality and flow. At one site, the introduction
of a borehole near to the main river opened bedrock fractures which increased
the amount of groundwater entering the river. This had a profound effect
on the river water quality by increasing the pH, alkalinity and calcium
concentrations. As well as pointing to the possibility of the wider availability
of groundwater resources in upland areas, the results highlight (a) the
potential value of groundwater as a acid neutralizing resource, (b) the
importance of weathering processes and flow routing within the groundwater
environment for stream water chemistry, (c) the potential for altering
stream water quality by manipulation of groundwater routing and (d) the
need to include groundwater characteristics in hydrochemical management
models of surface water acidification. |
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