vol_dp_b

Volume depth coefficient for HRU impoundment

The parameters vol_area_co, vol_dp_a and vol_dp_b are coefficients that control how strongly the wetland surface area changes as storage volume changes relative to principal storage. They are used for wetland initialization and to update wetland area for each simulation time step.

vol_dp_a and vol_dp_b are used to infer wetland depth from current storage volume. They are not used independently in a physically transparent way but rather interact through the quadratic. If vol_dp_a is smaller than vol_dp_b, the wetland surface area shrinks more strongly when water volume declines. If vol_dp_a is larger than vol_dp_b, the wetland keeps a larger surface area even at lower storage. vol_area_co is used to convert the wetland depth to wetland area.

The final area is clipped between 0.01 and 1.0, so the effect of extreme values of vol_area_co, vol_dp_a, and vol_dp_b may get hidden by those limits.

The wetland area affects seepage, groundwater exchange, depth/release calculations, and constituent settling.