HYDROLOGICAL ASSESSMENT FOR SUSTAINABLE GROUNDWATER ABSTRACTION USING VES, MRS, SR AND MODFLOW: A CASE OF NAMANVE INDUSTRIAL AND BUSINESS PARK, MUKONO DISTRICT, UGANDA

Abstract

The increase in demand for water supply in Uganda as a result of high population growth, agricultural and industrial expansion has triggered unplanned groundwater development and use in many parts of the country. This has put the future yield and sustainability of groundwater abstraction in some of these parts into question. This paper investigated a hydrogeological assessment for sustainable groundwater abstraction in Kampala Industrial and Business Park, Namanve. The main aim was to establish the behavioral response of the groundwater system to increased abstraction. This investigation was done using pre-existing groundwater/ borehole data from the area to generate the various aquifer parameters in the area: aquifer geometry, hydraulic properties and finally the hydrogeological conceptual model of the area. These values were further adjusted during the modeling processes to suit the current hydraulic heads in the area. The final modeling results demonstrated that an average recharge of 42 mm year-m/day maintains the natural equilibrium of non-pumping and the model result with pumping scenario shows that the current estimated groundwater abstraction of 2871 m3day-1 in the area did not cause any significant effect on the groundwater levels in the area. Significant effect on the water levels was however, realized after increasing the current abstraction rate by 500%. The sensitivity of the model was tested by systematically changing one parameter or input values at a time and it was found that the model is highly sensitive to changes of transmissivity of the aquifer system and the recharge rate.