Currently large-scale studies of water-power potential of minor and mean rivers are being conducted to identify location of prospective hydropower plants and estimate their manufacture and economic efficiency. Because of tight schedule, large study area and large number of criteria involved in choosing prospective hydropower plants, it is necessary to use modern methods and technologies to solve the problem. This paper reviews the methodology that allows performing multi-criteria analysis to find locations on plain rivers suitable for hydropower development. All estimations were performed using geographic information systems (GIS). Traditional way to find location for prospective hydropower plants consists in comparing several variants of location for hydropower development and several marks of normal pond level. Unlike traditional method, developed methodology and GIS-based tools allow analyzing large number of locations and considerably automating calculations.