Gordon Inlet is an estuarine

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

 inlet, located in the Goldfields-Esperance 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...

. The inlet is at the south west corner of the Fitzgerald River National Park

Fitzgerald River National Park

Fitzgerald River National Park is a national park in Western Australia , southeast of Perth, in the Shire of Ravensthorpe and the Shire of Jerramungup....

 and approximately 15 kilometres (9 mi) north west of the town of Bremer Bay

Bremer Bay, Western Australia

Bremer Bay is a coastal town situated on the south coast of Western Australia in the Great Southern region between Albany and Esperance, at the mouth of the Bremer River. Bremer Bay is southeast of the state capital, Perth, and east of Albany. The town has a population of about 240...

.

The estuary is transient and is quite shallow with a high rate of evaporation

Evaporation

Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....

 so that the estuary often dries out almost completely. The water is saline

Saline water

Saline water is a general term for water that contains a significant concentration of dissolved salts . The concentration is usually expressed in parts per million of salt....

 with salinity levels varying from slightly less than seawater

Seawater

Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...

 to over four times as saline.

The Gairdner River

Gairdner River

Gairdner River is a river located in the Great Southern region of Western Australia. There is another Gairdner River in Western Australia, located in the Kimberley region....

 flows into the inlet and discharges an average of 9400000 cubic metres (331,957,862 cu ft) per annum.

The inlet is wave dominated and functions primarily as a result of wave energy. It has a total surface area of 6.4 square kilometres (2 sq mi), the majority of whichis made up of the main basin and the estuary barriers with a small area of salt marsh

Salt marsh

A salt marsh is an environment in the upper coastal intertidal zone between land and salt water or brackish water, it is dominated by dense stands of halophytic plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh...

and intertidal flats.
The main seagrass that is found in the estuary is Ruppia maritima.