Ulendeltaet is an undisturbed freshwater delta on Lake Ulen, which includes stretches of a meandering river, marshes, islands, oxbow lakes and pools. Spruce and birch forests line the riverbank and vast, well-developed willow scrubs are important breeding areas for different passerines such as the yellow wagtail Motacilla flava thunbergi, the willow warbler Phylloscopus trochilus and the brambling Fringilla montifringilla. The delta and the lake harbour large numbers of brown trout Salmo trutta, Arctic char Salvelinus alpines, burbot Lota lota and common minnow Phoxinus phoxinus. The area also has a stable population of beaver Castor fiber and moose Alces alces. The area functions as a sediment trap and is important for nutrient fixing as well as flood reduction. The Site is mainly used for fishing and moose hunting, but also for canoe trips and bird watching. A National Park Centre is located near the Site.