Asian Journal of Water, Environment and Pollution, Vol. 12, No. 2 (2015), pp. 59–71. Effect of Flood on Water Resources in North-Central Nigeria Joseph Terlumun Utsev, Chidozie Charles Nnaji 1 * and Mama Cordelia Nnennaya 1 Department of Civil Engineering, University of Agriculture, Makurdi, Nigeria 1 Department of Civil Engineering, University of Nigeria, Nsukka, Nigeria * chidozie.nnaji@unn.edu.ng Received November 21, 2014; revised and accepted March 19, 2015 Abstract: Surface and groundwater quality of selected states within the North-Central, Nigeria were investigated to ascertain the effect of food on water quality over a period of six months. Statistical, standardized principal component and water quality index analyses were used to interpret the results. Increase in some groundwater parameters are 198.7% for hardness, 541% for colour, 169.8% for iron, 200% for chromium and 117.6% for calcium. The increase in some surface water quality parameters after the food is as follows: colour (316.76%), turbidity (171%), total suspended solids (156.65%), conductivity (180.5%), chromium (300%) and sulphate (121.2%). Overall groundwater quality decreased from a fair status (69.1%) before the food to a marginal status (55.3%) after the food. In the same vein surface water quality decreased from a fair status (72.53%) before the food to a marginal status (55.1%). There was a 27% reduction in surface water quality and 20.4% reduction in groundwater quality. Key words: Flood, surface water, groundwater, pollution. Introduction A food is an overfow of water that submerges land which is usually dry. Flooding is one of the major environmental crises of the century. Occurrence of food is the most frequent among all natural disasters, affecting about 178 million people in 2010 (Jha et al., 2012). Increased urbanization has caused problems with increased fash fooding after sudden rain. The immediate causes of food are heavy rain and rise in sea level resulting from climate change, exacerbated by blocked, collapsed and poorly designed drains. Surface runoff (also known as overland fow) is the fow of water that occurs when excess water from rain, meltwater , or other sources fows over the earth’s surface. This might occur because soil is saturated to full capacity, or because rain arrives more quickly than soil can absorb it. Surface runoff is a major component *Corresponding Author of the water cycle. It is the primary agent in soil erosion by water (Horton, 1933; Beven, 2004). Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source. If a nonpoint source contains man-made contaminants, the runoff is called nonpoint source pollution. A land area which produces runoff that drains to a common point is called a drainage basin. When runoff fows along the ground, it can pick up soil contaminants including, but not limited to, petroleum, pesticides or fertilizers that become discharge or nonpoint source pollution (Mackenzie and Masten, 2011). In addition to causing water erosion and pollution, surface runoff in urban areas is a primary cause of urban fooding which can result in property damage, damp and mold in basements, and street fooding. Runoff carrying industrial effuents can contaminate drinking water supplies. Indusries which use large amount of water in their processes include: