The UK Environment Agency has responsibility for the regulation of water resources, whilst also having due regard to the environmental needs of ecosystems. A number of legislative drivers provide a framework for assessment of these environmental needs with the aim of optimizing water use and minimizing potential adverse impact. The impacts of concern occur at a variety of scales, from ecological effects caused by alteration of the hydrogeological regime around small wetland ecosystems, to affecting the reliability of flows in large rivers.
In the study area (East Anglia, UK),
many of these wetland sites are quite close together, such that their ‘areas
of influence’ overlap. Potential mitigation options derived from studies
focused on single sites, and frequently comprising a re-distribution of groundwater
abstraction, may therefore cause detrimental effect at a nearby site. Similarly,
potential solutions attained at a catchment scale may not ‘work’ at
the wetland
scale, or vice versa. There is a clear need for holistic solutions embracing
a variety of scales.
Regional scale groundwater models have been developed as tools to assist water resource management. The models help conceptualise and understand hydrogeological regimes in a quantitative way which has not been previously available in the study area. Particular attention has been paid to model representation and behaviour in the vicinity of these wetland sites.
Careful application of the models has helped in the establishment of reference hydrological regimes and target criteria, related to ecological ‘well-being’ of the sites, against which resource management options may be assessed. The biggest benefit lies in the ‘unified’ nature of the models: the quantitative description of the hydrogeology at regional scale permits consistent calculations and assessment to be undertaken throughout the entire model area, facilitating equitable application of the Environment Agency’s regulatory functions.