Use of Groundwater Models to Evaluate Hydraulic Conditions, Predict Flow and Assess Performance of Collector Wells
By
David C. Schafer

Characterizing the hydraulic properties of the aquifer (transmissivity, storage coefficient and boundary conditions) and the river/aquifer interface (leakance) is essential in providing the information needed to evaluate the yield potential of riverbank filtration systems.  Carefully designed and executed pumping tests can provide the data needed to quantify the hydraulic characteristics of the hydrogeologic regime.  Once the relevant hydraulic parameters have been determined, they can support calculation of system yield estimates by careful application of analytical equations and/or groundwater flow models.  As riverbank filtration systems are used yields can decline over time.  Reduction in flow capacity can be not only a result of clogging of the intake structures (wells and galleries), but also a function of clogging of the riverbed whereby the leakance of the riverbed deteriorates.  Careful hydraulic analysis can be applied to assess the causes of such reductions in pumping system capacity.  This information is vital in guiding rehabilitation activities and decisions on future pumping system expansion.