From the City of Geesthacht to the river mouth at Cuxhaven, the Elbe estuary covers a distance of some 170 km between the territories of Hamburg, Lower Saxony and Schleswig-Holstein. Being a continually changing, dynamic system it is subject to storm floods coming in from the North Sea at almost regular intervals. Providing maritime access to important sea ports like Hamburg, it also bears considerable ecological value with freshwater ecosystems of the river being influenced by saltwater tides coming in from the sea. The preservation of this valuable habitat and harmonization of ecological and economical demands in the area is a joint objective of the Federal Waterways Administration and the neighbouring states of Schleswig-Holstein, Lower Saxony and Hamburg. For this reason an integrated management plan was drawn up by 2012.