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Estimating groundwater recharge for Great Britain considering the heterogeneous thickness of low permeability superficial drifts

Wang, Lei. 2015 Estimating groundwater recharge for Great Britain considering the heterogeneous thickness of low permeability superficial drifts. [Poster] In: 17th IWA International Conference on Diffuse Pollution and Eutrophication, Berlin, Germany, 13–18 Sept 2015. (Unpublished)

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Abstract/Summary

Groundwater recharge estimates are required for water resource management and the investigation of water related hazards and environmental problems. The hydrological processes of recharge are controlled by spatially and temporally distributed characteristics that are both internal (e.g. topography, soil, and land-cover) and external (climate variables). BGS’ field experiments showed that the thickness of low permeability superficial deposit affects the amount of water and soluble pollutants (such as nitrate) entering the groundwater system. Traditionally, the thickness of superficial drifts on recharge, however, is rarely considered in the recharge estimation. A method was developed in this study to objectively estimate recharge considering the spatial distribution and thickness of low permeability drifts. Based on SLiM method (Wang et al., 2012), recharge in Great Britain was estimated using the information on rainfall intensity, potential evapotranspiration, topography, soil type, crop type, and baseflow index. The drifts were divided into five thickness classes, i.e., 0 – 2m, 2m – 5m, 5m – 10m, 10m – 30m, and >30m. The reduction of recharge for each class was identified based on Monte Carlo simulations. The model was calibrated using the surface water component of observed river flow in 103 river gauging stations in Great Britain. The national daily distributed recharge estimates from 1962 to 2011 were produced. The modelled results have been successfully applied in estimating the nitrate concentration trend in groundwater bodies at the national scale. This national recharge model could be a basis for investigating the impacts of climate changes on groundwater resources. In addition, this method that requires readily available datasets can be easily transferred to other areas. Wang, Lei; Barkwith, Andrew; Jackson, Christopher; Ellis, Michael. 2012 SLiM : an improved soil moisture balance method to simulate runoff and potential groundwater recharge processes using spatio-temporal weather and catchment characteristics. [Lecture] In: 12th UK CARE Annual General Meeting, UK Chinese Association of Resources and Environment, Bristol, UK, 8 Sept 2012.

Item Type: Publication - Conference Item (Poster)
Additional Keywords: GroundwaterBGS, Groundwater, Groundwater resources, Groundwater modelling
Date made live: 22 Dec 2015 12:34 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/512503

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