Assessing the sustainability of groundwater resources in Lugazi Municipality

Abstract

Today almost 50% of all the urban water use worldwide is attributed to the groundwater sources due to its relatively low cost and generally high quality. This puts pressure on the future water use and so the only remedy to this is to opt for a groundwater management of a given area so that it is sustainable and the future population can enjoy these benefits. This study focused on assessment of the groundwater sustainability for Lugazi municipality, Buikwe district, central region, Uganda. Therefore, this report covers the impact of water demand on the groundwater aquifers, an evaluation of the groundwater sustainability indicators and lastly assessment of the potential of other water supply options that could be used in order to minimise the pressure on the groundwater aquifers arising from the rapidly growing water demand within Lugazi municipality. The study further presents a water balance method that was used to assess the quantity of groundwater input and output to check the storage of the aquifer per annum if all demand needs are satisfied. A water demand assessment was carried out and at the end of the design horizon (ultimate year (2044)), water demand would be 274 mm/year. Groundwater recharge estimate was found to be 218.5 mm/year using the empirical method approach. The human domestic pressure on the groundwater resources was predicted to be so high and this indicated that the groundwater aquifers would be depleted before they reach the design period. A sustainability yield of groundwater resources was obtained as 54.6 mm/year, this enables the eco-system to co-exist alongside human beings as part of the environment. A simple AHP approach was used to evaluate the current groundwater water indicators and criteria. The sustainability of Lugazi groundwater resources were assessed at a good level of 0.625. In order to minimise the water demand pressure on the groundwater aquifers, the cost-benefit analysis of surface water from the proposed Katosi water treatment was assessed. The NPV was found to be 12,212,143,513 UGX, the Profitability index of 1.91 and the IRR of 16.24% which rendered the project economically viable.