Flow-through lakes occur when the water table is higher on one side of the lake than the other, creating a gradient for groundwater to enter and leave the lake (Figure 32d and Figure 36). In some settings these lakes have no surface-water outlet or inlet. The lake surface represents the elevation of the local water table.
Figure 36 – Cross section and map view of flow-through lake exchange. Equipotential lines and relative head values are shown in black. Groundwater flow is in the direction indicated by blue arrows. Aquifer conditions are assumed to be isotropic and homogeneous. Monitoring wells are open at the bottom. a) Cross sectional representation showing an upward groundwater gradient at the up-gradient side (left) and a downward gradient as lake water flows into the groundwater system (right). Lake stage is shown as a water level on the vertical rectangle. b) A map view showing equipotential lines and groundwater flow converging at the lake at the up-gradient side and diverging from the lake on the downgradient side (Woessner, 2020).
