Wetlands play an important role in flood control. Wetlands associated with rivers and lakes capture and retain water, reducing the duration and severity of floods. Wetlands intercept surface flow and slow it down, reducing the potential for floods. Loss of floodplains in favour of agricultural lands and settlements has reduced this capacity. Construction of levees and dams on rivers to improve flood control often did not bring the expected effect. The National Nature Reserve Zelienka, dealt with in the paper, can be one example of inter-dune wetlands in the Záhorská nížina Lowland.