But after several seasons of heavy rainfall the waters have remained for years beyond their low-water level.
At low water it can be reached from Duhnen by carriage.
The level of the lake is subject to seasonal fluctuations, reaching a maximum in midsummer and a minimum in February, as well as to alternating cycles of years of high and low water.
The harbours are connected with the town by an embankment and railway built across a shallow, dry at low water save for a narrow channel.
The latter discolours the sand and so one finds, round the coast and towards the upper margin of the zone between highand low-water marks, an under layer of black sand formed in this way.
