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Recharge to the chalk aquifer beneath thick till deposits in\ud East Anglia

By R.J. Marks, A.R. Lawrence, E.J. Whitehead, J.E. Cobbing, W.G. Darling and A.G. Hughes

Abstract

This report describes the results of a project to investigate the Chalk-till groundwater system in East Anglia and to estimate rates of recharge through thick till (boulder clay) deposits. The project has involved drilling two cored boreholes, monitoring groundwater levels, sampling\ud Chalk and till groundwaters and porewaters, and development of a conceptual model of Chalk-till groundwater hydrogeology.\ud The main findings of the report have been:\ud • the till has a significant impact on recharge quantity and distribution. Beneath the interfluves recharge appears to be lower than previously estimated (Klink et al. 1996,\ud Soley and Heathcote 1998), probably <20 mm/a and possibly as low as 5 mm/a. Recharge to the Chalk aquifer is enhanced at the edge of the till sheet because of runoff\ud from the till;\ud • the Chalk groundwater beneath the interfluves is old (probably a minimum of several hundreds of years) and has negligible nitrate concentrations. This groundwater makes\ud only a relatively small contribution to the active circulation system in the valleys, which is normally characterised by modern (post-1960s), high-nitrate waters;\ud • the Chalk-till groundwater system and the spatial distribution of recharge to the Chalk aquifer determine the shape and dimensions of the catchment areas of abstraction boreholes. This in turn controls the proportion of modern water pumped by abstraction boreholes, which has implications for the concentration of nitrate in pumped water. One consequence is that boreholes close to the edge of the till are likely to pump a greater proportion of modern recharge than previously believed, probably with higher nitrate concentrations

Topics: Earth Sciences, Hydrology
Publisher: British Geological Survey
Year: 2004
OAI identifier: oai:nora.nerc.ac.uk:11670

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Citations

  1. (1962). A hydrogeological study of the permeability of the Chalk.
  2. (1987). Assessment of recharge compenents for a Chalk aquifer unit. doi
  3. (1985). Autochthonous bacteria in the chalk and their influence on groundwater quality in East Anglia. doi
  4. (1999). Chlorofluorocarbons. In Environmental Tracers in Subsurface Hydrology (Eds. P Cook and A L Herczeg),
  5. (2001). Evaluation of heterogeneity and field-scale groundwater flow regime in a leaky till aquitard
  6. (1982). Hydraulic conductivity of a glacial till in Alberta.
  7. (1976). Hydrogeologic and hydrochemical properties of fractured tills in the interior plains region.
  8. (1975). Hydrologic characteristics and response of fractured till and clay confining a shallow aquifer.
  9. (1990). Importance of drift deposits in influencing Chalk hydrogeology.
  10. (1996). Mechanisms and rates of recharge through glacial till: Experimental and modelling studies from a Norfolk site. British Geological Survey
  11. (2000). Mechanisms of water storage and flow in the unsaturated zone of the Chalk aquifer. doi
  12. (2001). Methods for determining the in situ hydraulic conductivity of shallow aquitards – an overview. doi
  13. (1952). Pleistocene drift sheets in the Lethbridge region,
  14. (1992). Prediction of permeability of fractured tills.
  15. (1981). Recharge mechanisms and groundwater-flow in the Chalk and drift deposits of southern East Anglia. doi
  16. (1998). Recharge through the drift: a study of contrasting Chalk catchments near Redgrave Fen, doi
  17. (1993). The Chalk as an aquifer. In:
  18. (1969). The influence of joints on the movement of groundwater through glacial till. doi
  19. (1997). The physical properties of major aquifers in England and Wales, British Geological Survey
  20. (1972). The relevance of soil fabric to site investigation practice. doi
  21. (1946). Water supply from underground sources of Cambridge–Ipswich District – General discussion. Geol Surv GB Wartime Pamphlet No 20, Part X,

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