Basement hydrogeology and fortification of the Channel Islands: legacies of British and German military engineering
N. S. Robins, E. P. F. Rose, C. S. Cheney, 2012. "Basement hydrogeology and fortification of the Channel Islands: legacies of British and German military engineering", Military Aspects of Hydrogeology, E. P. F. Rose, J. D. Mather
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The islands of Jersey, Guernsey, Alderney and Sark lie close to the Normandy coast of France. They expose a largely Precambrian crystalline basement of metamorphic and igneous rocks – Jersey and Alderney also expose some early Palaeozoic clastic sediments – and all have a thin but widespread Quaternary sedimentary cover. The three largest islands were progressively fortified by the British between the early 13th and mid-19th centuries, and by German forces during occupation in World War II, a legacy illustrated by the castles, forts and numerous German coastal fortifications that still adorn them. A German military geologist based on Jersey from mid-1941 to mid-1944, and a military geological team on Guernsey and Alderney during 1942, generated hydrogeological maps and reports that were then in advance of understanding of crystalline basement aquifers elsewhere in the British Isles. All the major documents have now been found in Germany, the USA and UK, although none survived on the islands themselves. Geological mapping and hydrogeological studies postwar under the auspices of the British Geological Survey were completed without access to German data. However, German and British data together now facilitate an appraisal of the heavily stressed aquifers on these small, hard-rock islands over an unusually long (65 year) timespan.
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This book, generated under the auspices of the Geological Society of London’s History of Geology and Hydrogeological Groups, contains 20 papers from authors in the UK, USA, Germany and Austria. Historically, it gives examples of the influence of groundwater on battlefield tactics and fortress construction; describes how groundwater was developed for water supply and overcome as an obstacle to military engineering and cross-country vehicular movement by both sides in World Wars I and II; and culminates with examples of the application of hydrogeology to site boreholes in recent conflicts, notably in Afghanistan. Examples of current research described include hydrological model development; the impact of variations in soil moisture on explosive threat detection and cross-country vehicle mobility; contamination arising from defence sites and its remediation; privatization of water supplies; and the equitable allocation of resources derived from an international transboundary aquifer.