Oyan River Dam

Oyan River Dam
Location	Ogun State, Nigeria
Coordinates	7°15′30″N 3°15′20″E / 7.25833°N 3.25556°E / 7.25833; 3.25556Coordinates: 7°15′30″N 3°15′20″E / 7.25833°N 3.25556°E / 7.25833; 3.25556
Opening date	29 March 1983
Dam and spillways
Height	30.4 m
Length	1044 m
Impounds	Oyan River
Reservoir
Creates	Oyan lake
Capacity	270 million m3
Catchment area	9,000 km2
Surface area	4,000 hectares
Power station
Turbines	3
Installed capacity	9 MW
Annual generation	0 MW

The Oyan River Dam is in Abeokuta North local government area of Ogun State in the West of Nigeria, about 20 km north west of the state capital Abeokuta. The dam crosses the Oyan River, a tributary of the Ogun River. It is used primarily to supply raw water to Lagos and Abeokuta, but has potential for use in irrigation and power generation.

Structure

The dam was commissioned on 29 March 1983 by president Shehu Shagari, and is operated by the Ogun-Osun River Basin Development Authority. The lake is in the savannah region, with sparse trees and grasses and low fertility. It covers 4,000 hectares and has a catchment area of 9,000 km². The dam has a crest length of 1044 m, height 30.4 m and gross storage capacity of 270 million m³.^[1] It was designed to supply raw water to Lagos and Abeokuta, and to support the 3,000 hectare Lower Ogun Irrigation Project. Three turbines of 3 megawatts each were installed in 1983 but as of 2007 had not been used.^[2]

Impact

During construction, 22 villages were submerged, with the displaced people moved to three settlement camps. Some of the settlers fish the lake and farm vegetables along the fertile shoreline as the lake recedes in the dry season.^[2] A 2009 study of levels of urinary schistosomiasis in the Ibaro-Oyan and Abule Titun communities, which depend on the Oyan Dam for their livelihood, found high levels of infection due to use of untreated water.^[3] An earlier study in 1990-1993 had indicated that the risk of the disease, which is carried by snails, could be greatly reduced if the reservoir were continuously discharged during the hot dry season.^[1]

Operations

In May 2009, after heavy rainfall the dam operators were forced to release exceptional amounts of water from the dam for safety reasons, causing some flooding over an area of 2,800 hectares.^[4] In February 2010 the dam was failing to deliver sufficient raw water for the Abeokuta water works to meet demands. The water works was also struggling with equipment failure due to a power surge.^[5] Residents of Abeokuta were forced to rely on rivers and streams to meet their water needs. The Ogun State Water Corporation attributed the problem to the unreliable supply of electricity from the Power Holding Corporation of Nigeria.^[6]

Potential

In 2010 the federal government budgeted N43 million for construction of the gravity irrigation scheme at the dam and N11 million for dam operations.^[7] The dam was intended to support 3,000 hectares in the first phase, but the land had been lying fallow.^[8] In November 2009 the Minister of Power, Rilwan Lanre Babalola paid an inspection visit to the dam and said the Federal Government had earmarked a substantial sum for rehabilitation of hydro-electric Dams across the country.^[9] The lake is relatively rich in fish and other wildlife, and has potential for ecotourism.^[2]

References

1. ^ ^{a b} I.E. Ofoezie, S.O. Asaolu (1997). "Water level regulation and control of schistosomiasis transmission: a case study in Oyan Reservoir, Ogun State, Nigeria". Bulletin of the World Health Organization, 1997, 75 (5) 435-441 (World Health Organization). PMC 2487010. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2487010. 
2. ^ ^{a b c} Ikenweirwe, N.b., Otubusin, S.O. and Oyatogun, M.O.O. (March 2007). "Fisheries of Oyan Lake, South West Nigeria and Potential for Ecotourism Development". European Journal of Scientific Research Vol 16 No 3. http://www.eurojournals.com/ejsr%2016%203.pdf. Retrieved 2010-05-22. 
3. ^ SO Sam-Wobo, UF Ekpo, IG Ameh, OT Osileye. "Continued high endemicity of urinary schistosomiasis in Ogun State, Nigeria". Nigerian Journal of Parasitology > Vol 30, No 1 (2009). http://ajol.info/index.php/njpar/article/view/43992. Retrieved 2010-05-22. 
4. ^ HOPE AFOKE ORIVRI (26 MAY 2009). "Flood imminent in River Ogun plain’". Nigerian Compass. http://www.compassnewspaper.com/NG/index.php?option=com_content&view=article&id=18526:flood-imminent-in-river-ogun-plain&Itemid=7966. Retrieved 2010-05-22. 
5. ^ KUNLE OLAYENI (20 FEBRUARY 2010). "Power surge destroys Ogun Water Corporation facility". http://www.compassnewspaper.com/NG/index.php?option=com_content&view=article&id=41691:power-surge-destroys-ogun-water-corporation-facility&catid=46:sunday-compass&Itemid=698. Retrieved 2010-05-22. 
6. ^ Dimeji Kayode-Adedeji (February 23, 2010). "Water scarcity bites harder in Abeokuta". Next. http://234next.com/csp/cms/sites/Next/Home/5530447-146/water_scarcity_bites_harder_in_abeokuta.csp. Retrieved 2010-05-22. 
7. ^ "2010 Budget Proposal". Federal Government of Nigeria. http://www.budgetoffice.gov.ng/2010%20budget%20messeage/AGRIC.pdf. Retrieved 2010-05-22. 
8. ^ Ademola Adedeji (May 2, 2009). "Ogun-Osun river basin chairman tasks south-west govts". http://news.onlinenigeria.com/templates/?a=2662. Retrieved 2010-05-22. 
9. ^ "Oyan Dam to boost electricity generation". NIGERIAN COMPASS. 29 NOVEMBER 2009. http://www.compassnewspaper.com/NG/index.php?option=com_content&view=article&id=35014:oyan-dam-to-boost-electricity-generation&catid=111:energy&Itemid=712. Retrieved 2010-05-22.