STABILITY OF TIDAL CHANNELS DEPENDENT ON RIVER IMPROVEMENT

Abstract

Many authors have dealt with the migration of sand in front of the German coast of the North Sea. Especially the movement of sand-banks and deep channels in the Weser-estuary was subject matter of several investigations with different results. Thorough investigations of selected cross-sections point out, that the movement goes on in some regions. The important shipping channel however has obtained a certain stability during the last 3o - 4o years, because the migration of sand occurs otherwise than in former days. This phenomenon coincides with the extensive and decisive river improvement measures in the inner part of the Weser-estuary. Current measurements in the investigation area demonstrate, that concentrated tidal currents in the deep channels guarantee a sufficient clearance for shipping purpose. It seems to be sure, that for the present no essential shifting of the main channel calls for important measures in the field of shipping, dredging and building of sea-marks.