Ah. Kara et Cm. Khalique, Conservation laws and associated symmetries for some classes of soil watermotion equations, INT J N-L M, 36(7), 2001, pp. 1041-1045
We generate conservation laws of the equations that govern the motion of so
il water and associate these, where possible, with Lie symmetry group gener
ators in two ways. Firstly. we impose the action of any Lie-Backlund symmet
ry generator on the conservation law of the soil water motion equation. Alt
ernatively, we determine the conserved vectors by the direct method and the
n check if the symmetry condition for the various symmetries ton the conser
ved vector) is satisfied. As the equations are of evolution type, no recour
se to a Lagrangian formulation is made. (C) 2001 Elsevier Science Ltd. All
rights reserved.