The Wiwi River, also referred to in some sources as the Wewe River, is an urban river in Kumasi in the Ashanti Region of Ghana. It forms part of the drainage system of the Kumasi Metropolitan Area and is one of the watercourses associated with the Kwame Nkrumah University of Science and Technology (KNUST) campus. The river is significant because of its role in urban drainage, campus ecology, irrigation, wastewater reception, public health studies and biodiversity research. The Wiwi River is located in the south-eastern part of Kumasi. A disaster-risk profile prepared for UNDP Ghana describes the river as flowing in a south-westerly direction through the KNUST campus before joining the Sisan River at Ahensan. The same report identifies Wiwi as one of the four main drainage basins of Kumasi, together with the Subin, Aboabo and Sisan basins. The river has received academic attention because of its links to urbanisation, pollution, agriculture, wetland use and public health. Studies have examined its microbiological water quality, its association with schistosomiasis infection among schoolchildren, the impact of wastewater and land use, and the response of aquatic and riparian invertebrate communities to disturbance.
Course and location The Wiwi River drains part of south-eastern Kumasi and passes through the KNUST campus. UNDP Ghana's disaster-risk profile states that the river flows south-westwards through KNUST and joins the Sisan River at Ahensan. The river is part of Kumasi's urban drainage system, which contains several rivers and streams that drain northern and central parts of the city. Other studies and project reports describe the river as passing through or near communities such as Kotei, Ayeduase, Ayigya and Ahensan, as well as the KNUST campus. A conservation project report on the Wewe River noted that the river provides household and irrigation water for nearby communities and supports a riparian zone within the university environment. The river's location inside and around an urban university environment gives it a distinctive character. It functions both as a natural watercourse and as part of a heavily modified urban hydrological system shaped by campus development, nearby settlements, farms, drains and wastewater flows.
Drainage and urban setting Kumasi has an extensive network of rivers and streams. The Wiwi basin is one of the city's main drainage basins, alongside the Subin, Aboabo and Sisan basins. These basins drain northern and central portions of the city and are affected by rapid urban development, inadequate drainage capacity and increased runoff from built-up surfaces. Urbanisation around the Wiwi River has increased pressure on the river corridor. Built-up land, agriculture, wastewater discharge, stormwater runoff and encroachment into ecologically sensitive areas affect the river and its associated wetlands. Research on land-use activities around surface water bodies in Kumasi has identified weak enforcement of buffer regulations and growing development pressure along urban rivers, including the Wiwi and Subin rivers. The river's urban setting is central to its environmental condition. Where natural vegetation is removed or drainage channels carry greywater and refuse, the river becomes more exposed to sediment, nutrients, pathogens and other pollutants. The condition of the Wiwi River reflects the wider challenge of managing water bodies in fast-growing African cities where settlement expansion, land scarcity and weak enforcement of planning standards place pressure on river buffers and wetlands.
Water use and irrigation The Wiwi River and its riparian area support several local uses. Reports and studies describe the river as a source of water for household use, irrigation and nearby farming activities. The SAVE THE FROGS! Ghana project report noted that the river provides household and irrigation water for communities around KNUST and nearby settlements. The river is associated with dry-season vegetable farming. A study on wastewater management in Kumasi reported that the Wiwi River was intensively used for the cultivation of vegetables such as carrots, lettuce, cabbage and spring onions, especially during the dry season. This use is important for urban livelihoods, but it raises public-health concerns when irrigation water is affected by faecal contamination or untreated wastewater. The use of polluted urban water for vegetable farming is a common challenge in cities where farmers rely on nearby drains, streams or rivers to maintain production during dry periods. In the case of the Wiwi River, this issue is especially relevant because research has identified microbiological contamination levels that make the water unsuitable for domestic use and for irrigation of vegetables consumed raw.
Water quality and pollution The microbiological quality of the Wiwi River has been examined in detail. A study in 2014 assessed water quality along the river's longitudinal gradient by sampling five locations bi-weekly from November 2012 to February 2013. The study tested for total coliforms, faecal coliforms, Escherichia coli, Salmonella species and faecal enterococci. The study found that microbial contamination varied across the river and generally increased downstream. The most upstream sampling site recorded the lowest coliform counts, while downstream areas showed higher microbial loads. The authors concluded that microbial counts in the river exceeded the WHO guideline used in the study, making the water unsuitable for domestic use and for irrigation of vegetables intended for direct consumption. Sources of pollution in the catchment include domestic wastewater, greywater, refuse disposal, runoff from developed surfaces and land-use activities close to the river. Awuah and colleagues reported that wastewater from the KNUST sewage treatment works and greywater sources contributed to water-quality problems. The study noted that part of the wastewater from the KNUST treatment plant entered an adjacent wetland before flowing into the Wiwi River. The pollution of the Wiwi River is not only a local environmental problem. It has implications for food safety, urban agriculture, public health, aquatic biodiversity and the management of university and community landscapes. The river shows how urban water bodies can become receiving systems for waste when wastewater infrastructure, drainage maintenance and land-use control are weak.
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