Implementation in MIKE SHE

In MIKE SHE the current level of surface detention storage is continually esti­mated by solving the continuity equation

(24.55)   

where D1 is the detained storage volume at the start of the time step and D2 is the detained storage volume at the end of the time step, q is the overland flow during the time interval, and q_supply is the amount of water being added to overland flow during the time step. Since q is a function of the average detained storage volume, (D1+D2)/2, equation (24.54) is solved iteratively until a solution satisfies both equations.