Abstract
The Kattegat, the Belt Sea and the Baltic are treated as a branch system of one-dimensional canals with homogeneous water. Sea levels and water transports are computed from the hydrodynamical equations including terms of acceleration, wind stress, air pressure, tidal acceleration and friction. Some non-linearities are also included. The computations are made numerically by means of an explicit model, the timestep being 15 minutes. The computations are concentrated to a case, August 1–5, 1964, when there was an international cooperation in exploring the Baltic.