A simplifed approach for the evaluation of groundwater fow in stream–aquifer interaction

Stream–aquifer interaction process plays an important role in modulating food wave propagation in a channel. The most elementary understanding of stream–aquifer interaction can be interpreted by the fux direction between a surface water body and the underlying aquifer. At the time of foods, stream stage rises, and the water gets infltrated into the aquifer, and this process gets reversed at the time when the stream stage gets declined. Therefore, an integrated mechanism between the surface and subsurface fows is particularly important for models, where the response of the system is based on simultaneous interactions between these two major fow domains. In this study, numerical simulation of a food wave has been demon strated considering stream–aquifer interaction. The calibration has been executed on a hypothetical food event accessed by routing a known stage hydrograph for a channel reach having a rectangular cross section which fully penetrates the adjoining aquifer given by Zitta and Wiggert (Water Resour Res 7:1341–1345, 1971). A simplifed mathematical approach, based on Darcy’s law, has been presented here for the solution of groundwater fow equations. The results obtained from the adopted procedure are also compared with the solution proposed by Zitta and Wiggert in 1971. The NSE and RMSE (m3 /s) estimate assessed for the simulated hydrographs using the proposed methodology with respect to the procedure adopted by Zitta and Wiggert (Water Resour Res 7:1341–1345, 1971) is 0.9983 and 0.8544, respectively. Therefore, the use of Simpson’s (3/8)- rule is not suggestible due to its complicated calculation and its sensitivity, and it is better to use the proposed simplifed approach for the evaluation of lateral fow.