Reservoir - Groundwater Interaction
Groundwater Seepage and a Single Pool Reservoir
A reservoir seepage model is incorporated with a single pool reservoir model to provide a dynamic simulation of seepage demands on reservoir volume. The surface water reservoir portion of the model comes from the "Single Pool Reservoir Model" from the GoldSim Model Library. This reservoir provides water deliveries to a single water demand input and is constrained by an upper and lower bound on volume capacity. The surface water reservoir model is adapted in this model to represent interaction with groundwater via seepage to and from the reservoir.
The "Seepage" container is the new or example portion of this model. The purpose of the seepage portion of this model is to simulate the interaction between the reservoir pool and groundwater. In this representation it assumed that the aquifer (groundwater storage location/volume) is much larger/greater than the reservoir surface area. As a result, the groundwater surface elevation is assumed to be independent of the reservoir water volume. In other words, groundwater levels are specified using a fixed value or a time series which is external to the simulation. The groundwater level then is not directly impacted by the reservoir water level and by reservoir seepage but it does determine if seepage flow occurs into the reservoir or from the reservoir to the aquifer. The calculated seepage is used in the reservoir water balance (see the "Volume" Reservoir element inflows and outflows in the "Surface_Reservoir" container). Groundwater volumes and groundwater water balances are not tracked in this model.