They affect the distribution of permafrost, support populations of fish, waterfowl and mammals, and provide storage for water, sediment and pollutants. The main driving force is the Mackenzie River that is responsible for introducing large amounts of water, energy and sediment to the delta. The large number of lakes result primarily from the cold conditions that prevent a large and quick accumulation of organic material within the lakes. Flooding of the Mackenzie River, precipitation, and evaporation controls the water levels of these lakes. High elevation lakes are sensitive to changes in these controlling factors and without flooding by the Mackenzie River they dry up rapidly.
Delta lakes are shallow.
Few exceed 3 m in depth, when measured at low water. Depths at high water are much greater, and can be estimated by noting the high water marks on lakeshore willows. The high water marks show up as broad bands encircling the lakes. Water levels in the Mackenzie River and adjoining channels change in various ways. Spring ice jams bring on a rapid increase in levels and flooding in many areas.