Problems of seepage to empty ditch and drain

Analytical solutions for the maximum area of the cross section of a drain ditch and a mole drain are obtained. In the case of seepage to a ditch from an underflooded soil surface, the extreme curve is represented by a semicircle, with a constant value of flow velocity along the curve. Seepage to a system of empty horizontal drains is studied for one of three possible patterns of water tables. At low values of infiltration to a phreatic surface, the drain of a maximum area is nearly circular.