Flood control in the Vistula river delta (Poland)

This paper presents past and recent water management in the area called the Vistula Delta Fens (Zulawy Fens). This area (56 x 56 km) is located at the outlet of the Vistula River to the Baltic Sea, at the shore of the Gulf of Gdansk. A large part of the area (30%) is located below sea level as potentially submerged depressions. A multitude of rivers, channels, ditches and pumping stations have been constructed here during several centuries. The area is characterized by highly productive alluvial soils, surface water with a high potential for fish-farming and fishery, and attractive tourist areas at the banks of the rivers and channels. Historically, floods have occurred repeatedly as a result of: i - breaks in the dams along of big rivers, e.g. after heavy rains and high water levels (in summer); ii - dam breaks caused by accumulation of ice-cakes in winter or during spring times; iii - dam breaks after storms on the sea with increasing sea water levels at the river outlets (mainly in winter); iv - overflow of water into flat land after heavy rains followed by slow drainage of water from the fields, ditches, channels and pumping stations (in summer); v - overflow of water into depressions and swamps below sea level after interruptions of, or decreases in, the pump operations at the pumping stations. The EU directive on flood control advises that the member countries should: i - produce maps of the areas vulnerable to floods to facilitate communication and planning; ii - develop management plans for flooding events; iii - exchange experience and codes of good practice during flood; iv - facilitate a close cooperation between the scientific society and politicians in the field of flood protection; v - rise the level of knowledge, communication and awareness among local societies living in areas prone to flooding.