The purpose of the work is to consider methods for calculating the forecast of groundwater backwater in the zone of influence of hydraulic structures. The analysis of the analytical dependencies for calculating the forecast of groundwater backwater for various schemes. A numerical model is proposed and a computational program for calculating the groundwater backwater has been developed for a homogeneous geofiltration structure which allows discretely calculating the groundwater backwater from the canal at any time. To simplify the solution of the problem of calculating the backwater of groundwater, a computer program was created in the Python Version 3.8 programming language, which quickly solves this hydrogeological problem. A possible range of geofiltration parameters is proposed. The results of predictive calculations of groundwater backwater are the basis for assessing the zones of possible flooding - the territory within which the groundwater level rises as a result of backwatering by a hydraulic structure.