Deep River is a river located in the Great Southern region of

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to t ...

. The river is under tidal influence for the last of its length. Although generally shallow the Deep River has depths of up to in places. The Deep River is one of the few

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widel ...

rivers in Western Australia although 80% of its discharge occurs in winter and spring. The rivers

water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...

is very good, fresh and low in

nutrient A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excre ...

s. The majority of the catchment of the Deep River is not cleared. The silt and clay content can be high during the winter period. The Deep River begins just west of

Lake Muir Lake Muir is a freshwater lake, with a larger surrounding wetlands area, that is located in the South West region of Western Australia. The lake lies near Muirs Highway, north of Walpole and southeast of Manjimup. Description The lake has a ...

about 50 km from the coast on the edge of the Yilgarn Plateau. Lake Muir may, in flood, overflow into the Deep River catchment. It flows through a valley between granite hills then wanders across the coastal plain finally entering the

Nornalup Inlet Nornalup Inlet ( /ˈnoːnələp ˈɪnlət/ Australian English) is an estuarine body of water on the south coast of the South West of Australia, approximately from Perth. It is approximately in extent, and up to deep. It is fed by the Deep ...

on the western side. The two

tributaries A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drain ...

of the Deep River are the

Weld River The Weld River is a river in the South West region of Western Australia. The river rises below Mount Burnside in the Lake Muir State forest. The river flows in a southerly direction through the Shannon National Park until it flows into the D ...

and Croea Brook. Some features of the river include wide unobstructed pools interspersed with rapids such as Rowell's Pool and two waterfalls, Fernhook Falls and Gladstone Falls. The Deep River flows through forested areas of National Park including the

Walpole-Nornalup National Park Walpole-Nornalup National Park is a national park in the South West region of Western Australia, south of Perth. It is famous for its towering karri and tingle trees. Red tingle trees are unique to the Walpole area. The park is part of the la ...

before discharging into the

. The first recorded name of the river was given in 1841 by the Colonial Secretary, Peter Broun. It had been known as the Frankland River by sealers that operated in the area. The explorer William Nairne Clark named it the West River on his charts but Broun later decided on the current name.

References

{{Rivers of Western Australia Rivers of the Great Southern region