The most of wet areas is in the Nemunas river lowland, on the right coast of the river. This coast is not protected by dikes. The left coast shore line is in Kaliningrad region and territory is embanked.

In order to control a floodings started to embank the area and built polders in 19 century. Water from the polders taking out by pumps. 1907 was built 36 summer and winter polders. Total area is about 50 thousand hectares. Most intensive land was used from 1970 till 1999 (1. figure). Currently island territory is embanked, built 6 polder systems. Level of groundwater is regulated by the polder’s pumps.

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Polders is divided into the two types: Winter’s polders (or not flooded all the years) and summer’s, which are flooded vegetation period. The type of polders depends on agricultural, production, industry activities.