Lakes in the Cascade Model of Storage and Drainage Reservoirs

The study area covers a compact, decentric hydrographic system called the Kashubian hydrographic system, which includes the drainage basins of the Słupia, Łupawa, Łeba, Reda, Wda, Wierzyca and Radunia. The Kashubian hydrographic system can be presented in the form of a cascade model of storage-drainage reservoirs—kord. One of the properties of a hydrographic system is its extent. Its horizontal extent is delimited by topographic watersheds, and its vertical extent is delimited at the bottom by the surface of the drainage base and in the roof by the land surface. Since reservoirs of the kord model are inscribed one into another, the upper border of all the reservoirs of the cascade is assumed to be the land surface, and the lower border of particular reservoirs of the cascade is a surface going through the level (elevation) of recipients receiving their waters. In the kord model on all its levels there are water reservoirs; however they differ in terms of origin, development, hydrological features and the role they play in the system. Depending on the type of recipient, drainage and storage can occur with various intensity. As follows from the hydrographic analysis the deepest lakes are situated in local and regional recipients, hence in these types of recipient, drainage and storage have greater intensity. On the other hand, in the transit recipient, transport is dominant.