The carried out review of major methods for solution of hydrographic task have shown the non- sufficient adequacy of them for solving of inverse task. The task of inverse hydroinformation modeling is considered and solved. The sphere of application of results of solution of this problem is shown. In the suggested model it is assumed, that hydrograph of the process can be presented in the triangular form. At the same time the temporal dependence of rain torrent at the input of the hydroobject also can be presented in the triangular form and the process of flooding of the area begins after full saturation of the hydroobject’s area soil. It is shown, that calculation of the soil water content using the suggested technique and the presence of information on vegetation cover and the relief’s slope make it possible to predict the flooding if the speed of incoming rain water is known. The information grounding of solution of the problem is described. It is noted that the suggested inverse hydroinformation method envisages the routing, i.e. the condition of the soil in all areas of hydroobject’s zone can be studied.