Strip-focused phreatic surface flow driven by evaporation: Analytical solution by the Riesenkampf function

Steady free-surface seepage in a homogeneous porous aquifer is studied by a conformal mapping of the inversed hodograph (angle) onto the domain in the Riesenkampf plane (slanted-face half-strip or trapezium). Seepage from the water table is caused by evaporation uniformly distributed with a horizontal coordinate. This distributed sink forms a regional trough on the phreatic surface with groundwater moving from the flanks to the trough center on the regional scale and from the water table to the soil surface locally. The free surfaces, streamlines of marked particles, travel times, and Darcian velocity are presented.