Unmanned water vehicles have been routinely used for marine purposes. This technology has emerged only recently for inland waters. It is used for two main purposes: bottom area scanning, in order to create maps of bottoms of rivers and lakes, artificial or natural. This information is needed for water engineering development and rehabilitation projects, and for flood protection planning. The other use is for the determination of flow velocities in rivers and lakes, which is needed for the determination of hydraulic properties of rivers, also necessary for flood protection. For the first purpose, an original vehicle is shortly described (UPP-1E), for the other, a Commercial-Off-The-Shelf solution is presented (RiverSurveyor of SonTek).