Assessment of Reservoir Storage in a Semi-Arid Environment Using Gould Probability Matrix
This study made an assessment of the existing reservoir capacity of Tiga Dam in Kano State, Nigeria, of 1090 x 106m3 using Gould Probability Matrix method. A generated annual inflow series between (1906 and 2004), rainfall and evaporation loss estimated for the period between 1990 and 2004 coupled with demand data obtained from Bichi (2003) and the Hadejia Jamaare River Basin Authority (HJRBA), are used in this study. The results indicated that the probability of failure approaches zero at a reservoir capacity of 540 x
106m3. Less than 0.25% probability of failure could be achieved with a capacity of 270 x 106m3 and the downstream requirement could be increased to certain substantial amount by reducing the capacity of the dam thereby allowing flow into Hadejia-Jama'are River and
Kumodugu-Yobe system which has been completely regulated. Increasing the downstream flow will alleviate social, economic and environmental trauma that had been subjected to the downstream community.
Keywords: Gould Probability Matrix; Tiga Dam; Probability of Failure; Reservoir Capacity; Downstream
African Research Review Vol. 2 (3) 2008: pp. 35-50