Wilson Inlet catchment

Wilson Inlet (Nullaki) has a catchment area of about 2,250 km2. Nearly half of the catchment (47 per cent) has been cleared, mostly for livestock grazing, plantations, horticulture and residential land uses. Large areas of flat and waterlogged land have been artificially drained to enable agriculture, particularly in the south-east, which forms part of the Albany Drainage District. The clearing and drainage have changed the hydrological pathways (which determine how much and when water flows into the inlet), and increased the concentrations of nutrients in the waterways.

Five rivers enter Wilson Inlet: the Hay and Sleeman rivers and Cuppup Creek on the eastern side of the inlet, and the Denmark and Little rivers on the western side of the inlet. The two largest rivers, the Hay and the Denmark, drain about 88 per cent of the catchment. Scotsdale Brook and Sunny Glen Creek do not directly flow to the inlet but join the Denmark and Hay Rivers respectively, a few kilometres upstream of the inlet. Lake Saide wetlands and many smaller tributaries around the foreshore of the estuary are minor parts of the overall catchment.