Walpole and Nornalup Inlets

Walpole and Nornalup Inlets Marine Park is a 15,170-hectare marine protected area on the south coast of Western Australia, protecting the remarkable drowned valley estuary systems of the Walpole Inlet, Nornalup Inlet, and Deep River. These sheltered coastal inlets and estuaries are surrounded by the Walpole-Nornalup National Park karri and tingle forests. The marine park protects productive estuarine and coastal marine habitats including seagrass meadows, tidal creeks, and sheltered bay environments. The park is managed by DBCA.

The inlets support significant marine and estuarine wildlife. Black bream, Australian herring, and mulloway are important recreational fish. Dolphins visit the inlets seasonally. Black swans, pelicans, royal spoonbills, herons, and cormorants are resident waterbirds. Sea-run marron and marron breed in the rivers draining into the inlets. Little terns nest on sandbanks. The inlets are significant nursery areas for coastal fish species.

Seagrass meadows (Ruppia and Zostera species) occur in the shallower inlet waters. Mangroves are absent (too cool and southern for mangrove growth). Saltmarsh communities fringe the upper tidal reaches. The inlet shores are backed by the spectacular karri and tingle forests of Walpole-Nornalup National Park, providing a dramatic forest-to-sea landscape.

Walpole and Nornalup Inlets are drowned river valleys (rias) — formerly river valleys flooded by rising sea levels after the last glacial maximum approximately 10,000 years ago. The rivers (Deep River, Frankland River) carved these valleys during lower sea-level periods. The inlet floors are covered in estuarine mud and sand. The surrounding catchments expose Archaean granites and laterite.

Cool temperate Mediterranean climate with high annual rainfall (900–1,200 mm). The sheltered inlets provide calm water for boating even when coastal swell is large. Water temperatures are cool (12–20°C) year-round. Southern Ocean storms affect the outer coasts.

The Walpole-Nornalup inlets lie within Bibbulmun Noongar country. The inlets were important food resources for Noongar people — fish, shellfish, and marine mammals. The timber towns of Walpole and Nornalup developed in the early twentieth century as karri timber was extracted.

Walpole and Nornalup Inlets Marine Park was established to protect the marine and estuarine values of the inlet system, complementing the adjacent Walpole-Nornalup National Park on land. The marine park provides a comprehensive protection framework from forest to sea.

Houseboat and kayak hire on the inlets. Fishing for bream and herring. The Valley of the Giants Tree Top Walk and Ancient Empire boardwalk are in the adjacent national park. Dolphin and waterbird watching. Cruises through the tingle and karri forest-lined inlets.

Walpole township serves as the gateway. Boat ramps and foreshore facilities in Walpole. The Valley of the Giants visitor centre is nearby. Walpole provides accommodation, cafes, and services.

Nutrient enrichment from the catchment (farming and forestry operations) affects inlet water quality. Introduced marine invertebrates may have established in the inlets. The tingle forest catchment's groundwater quality directly affects the inlet's ecological health.