Challawa Gorge Dam
Coordinates: 11°44′34″N 8°1′2″E / 11.74278°N 8.01722°E
The Challawa Gorge Dam is in Karaye Local Government of Kano State in the Northwest of Nigeria, about 90 km southwest of Kano city. It is a major reservoir on the Challawa River, a tributary of the Kano River, which is the main tributary of the Hadejia River.
The Challawa Gorge reservoir project was started by the Water Resources and Engineering Construction Agency of the Kano State Government, and was later handed over to the Federal Government who funded the project. The dam is owned and operated by the Hadejia-Jama’are River Basin Development Authority, a Federal agency.
The dam was built by Julius Berger Nigeria in 1990 - 1992 using rock fill construction. It is 42 m high and 7.8 km in length. The dam has a full storage capacity of 904,000,000 m3. The direct catchment area is 3857 km2.
The dam was designed with the potential for hydro power generation in mind, and may have a capacity of 3MW on average - more in the rainy season and less in dry season. However, power would cost considerably more to deliver than current retail prices, and it is not clear how a project to install the generating equipment would be financed.
The soil in the immediate catchments of the dam has not been stabilized, so the reservoir may be silting up. Silt is also being deposited in the Challawa River, affecting the intake structures of Kano City Water Supply. The dam has disrupted the natural balance along the river. Upstream areas are now subject to flooding while downstream riverine wetlands and croplands have dried out.
A 2002 study noted that while the dam was intended to support irrigation projects, none had been started, although much farmland had been covered by the dam. The water was being used only to supply Kano city. The Challawa dam and the nearby Tiga Dam have also had adverse effects on the downstream Hadejia-Nguru wetlands. Several studies have shown that these dams have delivered negative economic value when their effect on downstream communities was taken into account.
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