The occurrence of groundwater in the Lower Palaeozoic rocks of upland Central Wales
The occurrence of groundwater in the Lower Palaeozoic rocks of upland Central Wales
复制标题
威尔士中部高地下古生代岩石中地下水的出现
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
B. Reynolds
中科院分区：
文献类型：
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作者：
C. Neal;A. Robson;P. Shand;W. Edmunds;A. Dixon;D. Buckley;S. Hill;Martin Harrow;M. Neal;J. Wilkinson;B. Reynolds
在威尔士中部Plynlimon的塞文河源头集水区的下古生界泥岩、页岩和杂砂岩基岩中钻取了一系列深度达50 m的钻孔，显示出广泛的化学和水文活性浅层地下水裂隙流系统。地下水的化学性质在空间和时间上各不相同，在干燥的夏季，水位最低，碱度最高。相对于地表沃茨，地下沃茨富含盐基阳离子、二氧化硅、硫酸盐和碱度，这表明存在重要的硅酸盐风化源和硫化物氧化。这些水源对河流水质和流量都有重要贡献。在一个地点，在主要河流附近钻孔打开了基岩裂缝，增加了进入河流的地下水量。这对河流水质产生了深远的影响，增加了pH值，碱度和钙浓度。除了指出在高地地区更广泛地利用地下水资源的可能性外，结果还强调了（a）地下水作为酸中和资源的潜在价值，（B）地下水环境中风化过程和水流路线对溪流水化学的重要性，（c）操纵地下水流向可能改变溪流水质;（d）需要将地下水特性纳入地表水酸化的水化学管理模型。
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.