Effects of Human Activities on the Utilization of Some Dams in Kano State

Abstract

Rapid population growth coupled with climate variability especially inconsistent rainfall necessitates the construction of dams/reservoirs to augment the inadequacy of rainfall for food production, water supply and sustainable development. This study identified and assessed the effects of human activities on the function and utilization of some dams in Kano State, through field observations, interview and analysis of relevant data. The results indicated that various human activities such sand excavation along the spillway, clearing of vegetation for irrigation and farming within the perimeters of the dams have led to serious gulley erosion and consequently large quantities of sediment transported and deposited (siltation) in the bed of the dams, while the use of agrochemical for irrigation led to rapid emergence and growth of aquatic grasses due to eutrophication, thus leading to increase in turbidity and channel blockage which impedes smooth water supply in the downstream areas. The result also shows that the reservoirs installation capacities are declining with age at different alarming rates due to sedimentation. Marashi dam remarkably declined by 18%, Pada and Magaga dams each reduced by 15.5% and Guzu-Guzu dam suffered 15.4% reduction. Watari dam is reduced by 14% while Gari, Tomas, Karaye and Challawa-Gorge dams declined by 6.4%, 7.5%, 8.5% and 9.08% respectively. This rate of capacity reduction of the reservoirs due to sedimentation spanned within 45years of existence (1971-2016) which makes the state losing a whopping 5.75M 3 Mil of water annually. The study thus; proffer some precautionary measures on the optimal functioning and utilization of the dams.