Abstract
Water use is expected to increase and climate change scenarios indicate the need for more frequent water abstraction. Abstracting groundwater may have a detrimental effect on soil moisture availability for crop growth and yields. This work presents an elegant and robust method for identifying zones of crop vulnerability to abstraction. Archive groundwater level datasets were used to generate a composite groundwater surface that was subtracted from a digital terrain model. The result was the depth from surface to groundwater and identified areas underlain by shallow groundwater. Knowledge from an expert agronomist was used to define classes of risk in terms of their depth below ground level. Combining information on the permeability of geological drift types further refined the assessment of the risk of crop growth vulnerability. The nature of the mapped output is one that is easy to communicate to the intended farming audience because of the general familiarity of mapped information. Such Geographic Information System (GIS)-based products can play a significant role in the characterisation of catchments under the EU Water Framework Directive especially in the process of public liaison that is fundamental to the setting of priorities for management change. The creation of a baseline allows the impact of future increased water abstraction rates to be modelled and the vulnerability maps are in a format that can be readily understood by the various stakeholders. This methodology can readily be extended to encompass additional data layers and for a range of groundwater vulnerability issues including water resources, ecological impacts, nitrate and phosphorus.
Highlights
The Water Framework Directive (EC, 2000) has radically altered the management of the water environment within the EU
3.1 Overall The overall approach is conceptually elegant: archive groundwater level data sets are used to generate one composite groundwater surface; this surface is subtracted from a digital terrain model (DTM); the resulting figure is the distance from surface to groundwater
Having identified areas underlain by shallow groundwater the designation of risk vulnerability of crop growth being affected by abstraction is further refined by characterising the permeability of the intervening drift type(s)
Summary
The Water Framework Directive (EC, 2000) has radically altered the management of the water environment within the EU. It rationalises water legislation, including five previous Directives, and embodies the concept of integrated river basin management. It sets out environmental objectives for water status based on:. The Water Framework Directive (WFD) approach promotes integrated management at the River Basin level. Because it is a Framework Directive, it provides common approaches and common objectives, principles, definitions and measures. In areas that have historically had an adequate soil water supply, without recourse to irrigation, there is a risk that as water abstraction rates increase and water levels fall, agricultural yields may decrease and organisations with responsibility for water abstraction may find themselves facing claims for compensation
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