The Peel Region is part of a climatic transition along the west coast of Western Australia from north to south towards cooler temperature and more consistent rainfall. With a coastal plain bordered inland by the Darling Scarp, the Peel Region is situated amongst the highest rainfall areas of South Western Australia.

The Peel's natural river systems have important inherent ecological values with twenty-three rivers, streams and creeks. Three major rivers, the Murray, Serpentine, and Harvey, drain the Peel-Harvey Catchment and discharge into the Peel-Harvey Estuarine System.

The Peel Region's climate, hydrology and watery landscapes also provide it with an extensive wetland system that is of international and national significance, supporting a unique flora and fauna diversity with inherent values that are increasingly under pressure from population settlement, recreational and economic activity.

Lane Poole Reserve was declared in 1984 to protect the conservation and recreation values of the northern jarrah forest and the Murray River and covers 55,000 hectares within the Darling Range, centred on the Murray River. Serpentine National Park, covering 4,367 hectares, is another significant biodiversity asset within the catchment. It forms part of the Darling Range Regional Park in the Perth Metropolitan Planning region and, in common with parts of Lane Poole Reserve, is an important recreational area.

The Peel Inlet and Harvey Estuary comprise a shallow basin of approximately 130 square kilometres and, combined, are almost two and half times the size of the Swan River estuary. The Peel-Yalgorup system is listed as a 'Wetlands of International Importance' under the Ramsar Convention an international intergovernmental treaty that aims to halt the worldwide loss of wetlands and to conserve those that remain through sustainable use and management.