Improved Assessment of Baseline Conditions and Change in Wetlands Associated with Groundwater Withdrawal and Diversion

Abstract

Some deficiencies with current approaches for maintaining environmental integrity where ground water is being withdrawn or diverted include: 1) lack of metered withdrawals and monitored water table responses; 2) failure to consider cumulative impacts of multiple withdrawals and diversions; 3) lack of sufficient baseline data and general knowledge of wetland hydroperiods; 4) assumptions that water table responses in wetlands approximate those in uplands; 5) inability to predict aquifer responses to long-term ground-water perturbations, and under heterogeneous and anisotropic conditions; 6) lack of knowledge of short and long-term ecological responses to groundwater perturbations; and 7) limited assessment techniques for detecting ecological degradation due to groundwater perturbations. Alternative approaches for site selection and improved detection of changes in wetland hydroperiod in areas of groundwater withdrawal or diversion include 1) ground-penetrating radar and fracture trace analyses; 2) networks of surveyed elevations; and 3) qualitative and quantitative assessments of ecological indicators. Activities such as proposed groundwater withdrawals which are capable of causing widespread, irreversible environmental damage and social problems should include Environmental Impact Statements during the planning stage.