2.3 Flow-through Stream

Flow-through streams occur when the water table adjacent to the stream is higher on one side of the channel and lower on the opposite side of the channel (Figure 20). Groundwater enters the stream through one section of stream bed and channel bank, and stream water leaves the opposite bed and bank recharging the local groundwater system (Figure 20a). Equipotential lines are parallel to the stream channel (Figure 20b). Under these conditions, the stream stage is connected to the groundwater system and represents the water table elevation.

Cross section and map views of a flow-through stream
Figure 20 – Cross section and map views of a flow-through stream. The black triangle is a stage location and the black number is the stream stage. Equipotential lines and relative head values are shown as blue water table contours. Groundwater flow is in the direction indicated by blue arrows. Aquifer conditions are assumed to be isotropic and homogeneous. Monitoring wells are open only at the bottom. a) Cross section showing groundwater discharging on the left bank and recharging the adjacent groundwater system at the right bank. b) The map view shows equipotential lines are parallel to the stream channel. Groundwater flow lines are perpendicular to the stream channel. The location of the cross section is approximated by the position of the dashed black line (C-D) (Woessner, 2020).

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