Evaluation of groundwater recharge dynamics using the wetspass model in the Usangu Plains, Tanzania
Loading...
Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
TAJAS
Abstract
A comprehensive understanding of groundwater recharge dynamics is of great importance
in enhancing the sustainable management of the groundwater resources and the sound planning
of their utilization. This study aimed at evaluating the groundwater recharge dynamics in the
Usangu Plains (20,810 km 2 ) by the help of a hydrological GIS-based model named WetSpass.
The Water and Energy Transfer between Soil, Plants, and Atmosphere under quasi-Steady State
(WetSpass) model used land use/landcover, soil texture, topography, slope, groundwater table
and hydrometeorology data to simulate the temporal (yearly and seasonal) averages and spatial
differences of groundwater recharge, surface runoff and actual evapotranspiration. The findings
of this study showed that 17.8% of the mean annual rainfall contribute to the groundwater storage
while 66.1% and 16.1% are lost through evapotranspiration and surface runoff, respectively. The
high rates of evapotranspiration occurred in the wet season and in the seasonal/permanent wetlands
and water body. Also, the maximum amount of surface runoff took place during the rainy season
and in the built-up and in bare land vegetation types given the impervious state of their ground
surfaces. About 25% (1.025km 3 /year) of the annual recharge was found to be the groundwater
that can be safely extracted for domestic and economic purposes. Compared to the water lost
through evapotranspiration and surface runoff, the simulated portion of groundwater recharge
is noticeably low. Consequently, it could be wise to initiate the rainwater harvesting technologies
and artificial groundwater recharge strategies particularly in the zones with moderate and low
recharge rates to boost the groundwater storage as its users cannot cease to increase.
Description
Journal Article
Keywords
recharge dynamics, groundwater safe yield, WetSpass, Usangu Plains