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Recharge through till : developing a methodology for\ud estimating groundwater recharge with examples from two case\ud studies in East Anglia

By R.J. Marks, A.R. Lawrence, A.J. Humpage and R. Hargreaves

Abstract

This report describes the results of a desk study to investigate recharge in an area of\ud discontinuous low permeability till in the Waveney catchment. Within the study area the till is\ud absent in the valley of the River Waveney and also in the lower parts of some of the tributary\ud valleys. The study develops a methodology to identify the main recharge areas and make\ud initial estimates of recharge in such hydrogeologically complex areas. Following earlier work\ud on Chalk recharge through till this combined study area was selected to include both the\ud Chalk and the Crag aquifers. It was thought that the difference between these two aquifers\ud may shed further light on the recharge mechanisms through the overlying till.\ud The main outcomes of the study have been:\ud 1. A recharge estimate methodology is devised based on the effective rainfall, the till\ud thickness, estimates of runoff from the till sheet and delimiting the main recharge\ud areas where the till is thin or absent.\ud 2. The infiltration through thick till (>10 m) is low and as a consequence, runoff from the\ud till sheet is large and is potentially a significant component of recharge at the margins\ud of the till sheet. Estimating the quantity of water that may runoff the till sheet is\ud essential when attempting to assess the amount and distribution of groundwater\ud recharge.\ud 3. An important issue, when considering catchment water balances, is the relative\ud proportion of runoff that infiltrates to groundwater at the margins of the till sheet,\ud compared with that which flows directly into the river. It has not been possible in this\ud study to devise a methodology to split these two components. More catchment scale\ud studies are required to evaluate how catchment characteristics influence the infiltration\ud rates.\ud 4. The time-lag between rain falling at the soil surface and recharge arriving at the water\ud table will be relatively short at the margins of the till sheet where the water table is\ud generally shallow. This has important implications for water quality, as widespread\ud changes in land-use are likely to be observed more rapidly in groundwaters at the edge\ud of the sheet than in areas of extensive Chalk-Crag outcrop

Publisher: British Geological Survey
Year: 2004
OAI identifier: oai:nora.nerc.ac.uk:12635

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  1. (2002). Early and early Middle Pleistocene river, coastal and neotectonic processes, southeast Norfolk, England. doi
  2. (2001). Evaluation of heterogeneity and field-scale groundwater flow regime in a leaky till aquitard.Hydrogeol doi
  3. (1968). Evidence for pre-Cromerian permafrost in East Anglia.
  4. (1999). Fractures and biopores in Weichselian clayey till aquitards at Flakkebjerg,
  5. (1993). Geology of the country around Sudbury (Suffolk); Memoir of the British Geological Survey, sheet 206
  6. (1981). Hydrogeological map of southern East Anglia. British Geological Survey.
  7. (2003). Hydrology, Conceptual and Computational models.
  8. (1974). Late Pleistocene deposits at Wretton, Norfolk: II Devensian deposits. Philosophical transactions of the Royal Society of London. doi
  9. (1996). Mechanisms and rates of recharge through glacial till: Experimental and modelling studies from a Norfolk site. British Geological Survey
  10. (1975). Middle Pleistocene sedimentary sequences in East Anglia (United Kingdom) In: After the Australopithecines: Stratigraphy,
  11. (1985). Palaeosols and the interpretation of the British Quaternary stratigraphy.
  12. (2001). Pre-Anglian fluvial and coastal deposits in Eastern England: lithostratigraphy and palaeoenvironmnets. doi
  13. (1992). Prediction of permeability of fractured tills.
  14. (2002). Recharge through drift: A modelling investigation into recharge pathways through the Lowestoft Till of East Anglia, with special reference to sand lenses and fractures. MSc dissertation Reading University
  15. (2004). Recharge to the Chalk aquifer beneath thick till deposits in East Anglia. British Geological Survey Internal Report,
  16. (1989). Stadial type sections in the British Quaternary. In: Quaternary Type Sections: Imagination or Reality? Eds: doi
  17. (1979). The distribution, variation and origin of PreDevensian Tills in eastern England,
  18. (1985). The Early Anglian Barham Soil of Eastern England. In: Soils and Quaternary Landscape Evolution.

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