Torbay Inlet is an estuarine inlet

Inlet

An inlet is a narrow body of water between islands or leading inland from a larger body of water, often leading to an enclosed body of water, such as a sound, bay, lagoon or marsh. In sea coasts an inlet usually refers to the actual connection between a bay and the ocean and is often called an...

 in the Great Southern region of Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

 situated approximately 40 kilometres (25 mi) East of Denmark

Denmark, Western Australia

Denmark is a town in the Great Southern region of Western Australia, south-south-east of the state capital of Perth. At the 2006 census, Denmark had a population of 2,732.-History:...

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Torbay Inlet is a wave dominated estuary that functions primarily as a result of wave energy. The estuary has been severely modified as most of the natural catchment

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 cover has been cleared.

Covering a total surface area of 3.1 square kilometres (1 sq mi) 2.1 square kilometre (0.810814533044324 sq mi) of this is the central basin with the remainder being composed of saltmarsh and tidal delta. The lagoon is quite shallow and fringed with sedges

Cyperaceae

Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...

 and paperbarks

The inlet outflows into the Southern Ocean

Southern Ocean

The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...

 and is part of the Torbay Inlet and Lake Powell Catchment Area.

Much of the land surrounding the inlet has an elevation of less than 1 metres (3 ft) so that under certain tidal and wind conditions the land is inundated with sea water that floods back up the estuary. As a result, in 1912, a barrage with floodgates was constructed to prevent this, but this proved to be unsuccessful.

A sandbar exists across the mouth of the estuary for most of the year, but it is often breached following significant rain events.

Trekkers on the Bibbulmun Track

Bibbulmun Track

The Bibbulmun Track is a long distance walk trail in Western Australia. It runs from Kalamunda, east of Perth to Albany and is almost 1000 km long...

 use the either the sandbar to cross the inlet or an alternative route using the Lower Denmark Road to go around the inlet.

Catchment

The catchment area is one of the most altered on the South Coast. The inlet drains a large swampland area that includes Lake Powell, Lake Manarup, Five Mile Swamp, Seven Mile Swamp and Marbelup Brook along with a number of man-made agricultural drains.

The area of the catchment is 330 square kilometres (127 sq mi) of which 55% has been cleared and contains 244 kilometres (152 mi) of water ways.

Some swampland in the lower catchment was drained to open land for agriculture

Agriculture

Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...

, Unfortunately this exposed Iron Pyrite in the soil that oxidised in the open air rendering the soil acid

Acid

An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

 and infertile.

Watershed Torbay

Watershed Torbay was a four year project which planned and implemented a restoration plan for the Torbay Catchment. The Torbay catchment Group is the community group

Community Group

Community Group are a British political party in Doncaster, South Yorkshire, founded in 2001. The Community Group has four councillors serving on Doncaster Metropolitan Borough council....

 that formed in 1999 to implement the restoration plan. The activities of the group include establishing and repairing fencing around the waterway, Watsonia

Watsonia (plant)

Watsonia is a genus of plants in the iris family, subfamily Crocoideae, native to South Africa. The genus is named after Sir William Watson, an 18th century British botanist....

 control and Wetland construction for nutrient

Nutrient

A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...

stripping.