The Leschenault catchment, which drains to the Leschenault Inlet and then the ocean, has an area of approximately 2,020 km2 and includes the catchments of the Wellesley, Brunswick, Ferguson and Preston rivers, as well as the Collie River catchment below Wellington Reservoir.
Artificial drains have been introduced into the flat coastal plain areas to enable agricultural and urban land uses. An irrigation drainage network also supplies water to the catchment from the Stirling, Harvey and Wellington dams. This has led to a complex hydrological network of drains and natural rivers.
