10.2190/ES.32.3.c D77U4028UKT2612T 3 Impact of Selected Landuse Types on Surface Water Quality Downstream of Asa Dam in Kwara State, Nigeria 221 238 20110304 20110304 20110304 20110304 D77U4028UKT2612T.pdf http://baywood.metapress.com/link.asp?target=contribution&id=D77U4028UKT2612T 3 A. O. Ayeni I. I. Balogun O. A. Adeaga University of Lagos, Nigeria This study examines the impact of selected land use types on surface water quality downstream of Asa dam in Ilorin, Southwestern Nigeria. Water samples were collected at seven points (including a control, 0.50 km from Asa dam). Four-sampling points fall within agricultural land use area, two within light industrial/residential area, and the control was within an undisturbed natural environment. The level/concentration of 10 physico-chemical parameters, color, total dissolved solids, dissolved oxygen, biochemical oxygen demand, total hardness (CaCO₃), calcium hardness, magnesium hardness, chloride, calcium, and nitrate were determined using standard procedures. GIS was used to determine the extent of land cover by Asa dam and its downstream environment including the length of River Asa in respect to sampling points. This was achieved through the map generated from satellite imageries and the use of GPS. This article presents and discusses the results of laboratory analyses undertaken, spatial variability in the level/concentration of the water quality parameters, as well as the consequences of sustained use of River Asa water without treatment for domestic purposes. The results show that the quality of River Asa downstream of the dam was impaired to different degrees using WHO standards for the selected parameters and land use types. Consequently, using the water for domestic purposes, in particular as currently obtained in the area, portends grave danger to human health and the situationwill be worse in the near future if necessary control is not put in place. Abdulrasaq, S. O. (1998). <i>A guide to Ilorin.</i> Nigeria: Ilorin Famost Nigeria Ltd. Aderamo, A. J. (1997). The structure and growth of traditional settlements in Nigeria: The case of Ilorin. <i>Environmental Issue, 2</i>, 41-56. Akinwumi, F. O. (2000). Aquatic lives and the environmental changes. In H. I. Jimoh & I. P. Ifabiyi (Eds.), <i>Contemporary issue in environmental studies.</i> Ilorin: Haytee Press and Publishing. Barbour, K. M., Oguntoyinbo, J. S. Onyemelukwe, J. O. C., & Nwafor, J. C. (1982). <i>Nigeria in maps.</i> London: Hodder and Stoughton. Bullard, W. E. (1972). <i>Effects of land use on water resources in the ecology of man: An ecosystem approach</i>, R. L. Smith (Ed.). New York: Harper and Row. Ifabiyi, I. P. (1997). Variation in water gravity with rainfall incidences: A case study of Ogbe Stream Ile-Ife, Ife. <i>Research Publications in Geography, 6</i>(1 and 2), 139-144. Iloeje, N. P. (1977). <i>A new geography of Nigeria.</i> Ibadan: Longman Nigeria Ltd. Mendie, U. E. (2005). <i>The theory and practice of clean water production for domestic and industrial use: Purified and package water.</i> Lagos: Lacto-Medal Ltd. Ofoezie, I. E. (2003). Environmental assessment of water resources for development programmes. In H. I. Jimoh (Ed.), <i>Techniques in environmental studies</i>, Ilorin: Nathadex Publishers. Ogunkoya, O. O., & Adejuwon, J. O. (1990). Water chemistry of some rivers draining the basement complex in Southwestern Nigeria. <i>Hydrobiology in the Tropics, 23</i>(1), 3-10. Ojekunle, I. A. (2000). Transport and urban environmental Quality in Nigeria. In H. I. Jimoh & I. P. Ifabiyi (Eds.), <i>Contemporary issue in environmental studies.</i> Ilorin: Haytee Press and Publishing. Oyegun, M. O. (1985). <i>Urban sediment problems in Ilorin, Nigeria.</i> Paper presented at the National Conference on Development and the Environment, NISER, Ibadan. Paul, F. H. (2000). Sulphate and chloride concentration in Texas aquifer. In E. A. Ruth (Ed.), <i>Environmental international.</i> USA: Pergamon Publishing. Perlman, H. (2006). <i>Common water measurements USGS science for a changing word.</i> Available at: <a target="_blank" href='http://ga.water.usgs.gov/edu/characteristics.html20/10/2007'>http://ga.water.usgs.gov/edu/characteristics.html20/10/2007</a> Uluocha, N. O., & Ekop, G. (2002). Nigeria: Geography. In A. Osuntokun, D. Aworawo, & F. Masajuwa (Eds.), <i>History and cultures of Nigeria up to AD 2000</i>, Lagos: Frankad Publishers. WHO. (1993). <i>Guidelines for drinking-water quality, Volume 1, Recommendations</i> (2nd ed.). Geneva: World Health Organization. WHO. (2006). <i>Guidelines for drinking-water quality, Volume 1, Recommendations</i> (1st Addendum to 3rd ed.). Geneva: World Health Organization (Electronic version). <a target="_blank" href='http://www.who.int/water_sanitation_health/dwq/gdwq3rev/en/index.html'>http://www.who.int/water_sanitation_health/dwq/gdwq3rev/en/index.html</a>