the environment agency is the navigation authority for the river, which is navigable as far upstream as crowland, and with very shallow draught to west deeping bridge, where further progress is hindered by the derelict lock around the weir. the traditional head of navigation was wharf road in stamford. the management of the lower river has been intimately tied up with the drainage of deeping fen, and the river remains important to the welland and deepings internal drainage board, for whom it provides the final conduit to the sea for pumped water.