The Great Kwa River flows through Cross River State

Cross River State

Cross River State is a coastal state in southeastern Nigeria, bordering Cameroon to the east. Its capital is at Calabar, and it is named for the Cross River , which passes through the state...

, Nigeria

Nigeria

Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...

, draining the east side of the city of Calabar

Calabar

Calabar is a city in Cross River State, southeastern Nigeria. The original name for Calabar was Atakpa, from the Jukun language....

. The river ecology is under threat from human activity.

Location

The river originates in the Oban Hills

Oban Hills

The Oban Hills are a range of hills in Cross River State, Nigeria.They lie within the Oban Hills Division of the Cross River National Park.-Geography:The hills are rugged, rising from in the river valleys to over in the mountains....

, in the Cross River National Park

Cross river national park

The Cross River National Park is a national park of Nigeria, located in Cross River State, Nigeria.There are two separate sections, Okwangwo and Oban ....

, and flows southwards to the Cross River

Cross River (Nigeria)

Cross River is the main river in southeastern Nigeria and gives its name to Cross River State.It originates in Cameroon, where it takes the name of the Manyu River....

 estuary.
The river is known for the dramatic Kwa Falls in Cross River National Park.
Its lower reaches are tidal, with broad mud flats. and drain the eastern coast of the city of Calabar

Calabar

Calabar is a city in Cross River State, southeastern Nigeria. The original name for Calabar was Atakpa, from the Jukun language....

.

Human activity

Human activity in the Great Kwa basin has traditionally been limited to small scale farming, aquaculture and artisanal fisheries, mainly for shrimp.
However, Calabar is growing, due in part to the Calabar Free Trade Zone

Calabar Free Trade Zone

The Calabar Free Trade Zone is an area just north of the port of Calabar, Cross River State, Nigeria that is occupied by companies engaged in manufacturing, trading, provision of services and oil and gas related activities...

, causing growing numbers of houses and factories to be built in the freshwater and mangrove swamps of the Great Kwa.
The University of Calabar

University of Calabar

The University of Calabar - also known as UNICAL - is a university situated in Calabar, Cross River State, southeastern Nigeria. It is one of Nigerian's second generation universities. The University of Calabar was a campus of the University of Nigeria until 1975...

 covers a 17 hectares (42 acre) site between the Great Kwa River and the Calabar River

Calabar River

The Calabar River in Cross River State, Nigeria flows from the north past the city of Calabar, joining the larger Cross River about to the south. The river at Calabar forms a natural harbor deep enough for vessels with a draft of ....

.
The university has acquired more land on both banks of the Great Kwa for future development.

Pollution

Calabar Municipality has no waste treatment facilities, and heavy rains wash human and industrial wastes into the river.
A 2008 study of Vibrio

Vibrio

Vibrio is a genus of Gram-negative bacteria possessing a curved rod shape, several species of which can cause foodborne infection, usually associated with eating undercooked seafood. Typically found in saltwater, Vibrio are facultative anaerobes that test positive for oxidase and do not form...

bacteria in shellfish in the Great Kwa River estuary showed that the water was constantly faecally polluted, and the shellfish had high levels of infection.
This posed a health risk for consumer, including a risk of cholera epidemics.