Strmec water protection area along the Sava River and Lake Strmec declared in 1971. The ornithological reserve. Its area is 287 ha. It is a unique habitat for many species of birds including several rare. The special value of this field in European terms is the nesting of rare birds - vuge beaches. The area is covered with forest, willows, poplars, alders and dense low vegetation, woven from the backwaters, canals and channels, gravel and sand dunes and marshy meadows.