NONMONOTONIC MOISTURE PROFILE AS A SOLUTION OF RICHARDS EQUATION FOR SOILS WITH CONDUCTIVITY HYSTERESIS

Qualitative analysis of similar moisture profiles advancing in dry soi ls during the constant rate infiltration is proposed. The Richards par tial derivative equation is reduced to the ordinary one, which is easi ly integrated. Using simple kinematic relations nonmonotonic saturatio n-depth profiles travelling both in 1D case and in 2D finger-type flow s are interpreted as a consequence of hysteresis of conductivity depen ding on water content. The estimations made allow the description of f ingering as a result of hysteresis. The mean velocity of hysteretic fi nger-type flow can be higher than velocity of 1D hysteretic flow while the last advances faster than the usual monotonic front without hyste resis. (C) 1998 Elsevier Science Limited. All rights reserved.