Barrage Oued El Hajar. 02/02/12; Nabeul; 254 ha; 36°50'N 011°02'E. One of the most recent and biggest freshwater dams in a series recently constructed in Tunisia for agricultural purposes (mainly cereal farming upstream, animal rearing on hillsides, and vegetable and tobacco cultivation downstream). It contributes to flood control during long rainy seasons. The site is an important "migratory bottleneck" for migrating birds which pass across the Mediterranian Sea, and is also a nesting and wintering ground for several waterbirds, among which are endangered and vulnerable species like Oxyura leucocephala and Marmaronetta angustirostris. In spring, it provides a resting place for several species (not only waterbirds) which migrate to Africa in winter. It harbours more than 1% of the population of several important waterbird species including Arythya nyroca, Oxyura leucocephala and Phoenicopterus roseus. A major threat is the use of fertilizers in agricultural activities carried out around the site, which may in the long run lead to eutrophication. Ramsar Site no. 2013. Most recent RIS information: 2011.