Investigating the impacts of impervious surfaces on ground water recharge in Murchison Bay catchment, Kampala District between 1990 and 2020

Abstract

Variations in the rate of impervious surfaces directly impact groundwater recharge. The present study investigated the impacts of impervious surfaces on ground water recharge in Murchison Bay catchment, (Kampala district) between 1989 and 2020. Landsat images from Operational Land Imager (OLI), Thematic Mapper (TM), and Enhanced Thematic Mapper Plus (ETM+), were downloaded for the years 1989, 1995, 2001, 2005, 2010, 2015 and 2020. The study area was classified using Maximum Likelihood Supervised Classification to create one class of impervious surfaces. The groundwater recharge of the study area was obtained using a Soil Water Balance Model. Linear regression was used to establish the relationship between impervious surfaces and groundwater recharge. The results of Maximum likelihood classification show a significant increase in impervious surfaces by 68.8% in a period between 2001 and 2020. The results from the Soil Water Balance Model show a decrease by 11% in groundwater recharge. The study found that statistically there was no relationship between groundwater recharge and impervious surfaces (P-value> 0.05) in the Murchison Bay area for the period between 1990 and 2020. Future studies should investigate on other factors that affect groundwater recharge in Murchison Bay catchment, Kampala District.