Model analysis of the climate change impact on the water balance of groundwater intake in the river valley

The results of groundwater intake simulation for Sudogodsky groundwater field under present and forecast climatic conditions for the next 25 years, which reflect the observed changes in meteorological characteristics, are considered. Comparison of the pumped water sources, obtained by simulation, showed that the predicted climate changes will lead to increasing of the reduced groundwater discharge to the river and to decreasing of the induced stream infiltration. Expected climatic changes cause a slight increase in the stream depletion under the influence of groundwater pumping, which will not have negative consequences, as it is compensated by an increase in the transit river flow. The research results reflect the scale of the observed and expected climate changes impact on the pumped water sources for river valley groundwater fields at the center of the European part of Russia.

Analysis of groundwater flow and stream depletion in L-shaped fluvial aquifers

Understanding the head distribution in aquifers is crucial for the evaluation of groundwater resources. This article develops a model for describing flow induced by pumping in an L-shaped fluvial aquifer bounded by impermeable bedrocks and two nearly fully penetrating streams. A similar scenario for numerical studies was reported in Kihm et al. (2007). The water level of the streams is assumed to be linearly varying with distance. The aquifer is divided into two subregions and the continuity conditions of the hydraulic head and flux are imposed at the interface of the subregions. The steady-state solution describing the head distribution for the model without pumping is first developed by the method of separation of variables. The transient solution for the head distribution induced by pumping is then derived based on the steady-state solution as initial condition and the methods of finite Fourier transform and Laplace transform. Moreover, the solution for stream depletion rate (SDR) from each of the two streams is also developed based on the head solution and Darcy's law. Both head and SDR solutions in the real time domain are obtained by a numerical inversion scheme called the Stehfest algorithm. The software MODFLOW is chosen to compare with the proposed head solution for the L-shaped aquifer. The steady-state and transient head distributions within the L-shaped aquifer predicted by the present solution are compared with the numerical simulations and measurement data presented in Kihm et al. (2007).