Abstract:
This study focuses on the assessment of the impact of change of LULC on groundwater recharge
in Furfuro watershed, Silte zone, Ethiopia. In the study area, there is no potential surface water
resource, so the investigation and utilization of groundwater resources are in the catchment
very crucial. However, no systemic study has been conducted on the impact of change of LULC
on groundwater recharge in the study area. This study aims to assess the impact of the LULC
change on GWR in the Furfuro watershed in the period between 2000 and 2020. Remote sensing
and GIS techniques integrated with the WetSpass model were used for studying the impact of
change of LULC on groundwater recharge in the Furfuro watershed. The satellite images
obtained for the years 2000 (TM), 2010 (TM), and 2020 (OLI) and hydro-meteorological data
for years between 1988 and 2018 were used. LULC classification was made using supervised
image classification. There are five classified LULCs in the study area, which are built-up
areas, forests, farms, shrubs, and bare land. Maximum-likelihood classification algorithm
analysis showed an overall accuracy of 91.6%, 90.1%, and 89.6% for 2000, 2010, and 2020
images, respectively. The Kappa coefficients associated with the classification resulted in
87.5% for 2000, 84.7% for 2010, and 82.5% for the 2020 LULC image data. The change
detection analysis showed that Furfuro watershed catchment experienced an increase in
agricultural and buildup areas by 37.3 km2 and 6.91 km2, respectively over the past two
decades. On the other hand, forest, shrubs, and bare land were decreased by 20.3 km2, 9.73
km2, and 14.14 km2, respectively. WetSpass model estimated the average annual spatial water
balance components for 20 years period and the results showed that the average annual actual
evaporation was 387.5mm (35.42%), surface runoff was 574mm (51.9%), and GWR was 137
mm (12.7%). Model response the LULC changed for 2000 produced GWR was 149.84 mm, for
2010 analysis GWR was 141.46 mm and finally 2020 GWR was 138 mm from average rainfall
1085.1mm for thirty yraes. These results showed that there was a gradual decrease in GWR in
two decades due to LULC changes. Generally, because of the change in LULC over the last 20
years, the GWR decreased by 11.84mm. This study shows the negative impact of change of
LULC on GWR and hence implementing appropriate land use management strategies shall be
helpful to conserve the groundwater resource by enhancing the recharge rate.
