Abstract:
Water scarcity poses a critical challenge in many regions, including Uganda, due to climate
change, population growth, and poor water management practices. This study presents an
integrated assessment of the current and future water demand dynamics in the Manafwa Sub
catchment, located in Eastern Uganda. Utilizing the WEAP model, the research evaluates sectoral
water demands that is domestic, industrial, livestock, and irrigation under multiple development
and management scenarios from 2020 to 2050. The model was calibrated and validated using
streamflow data with strong statistical performance (NSE = 0.98, R² = 0.98, PBIAS < 1.83%).
Scenario simulations revealed that without intervention, water demand will rise from 40.15 MCM
in 2020 to over 82MCM by 2050, with unmet demand increasing significantly under high
population growth and irrigated land expansion. Management strategies such as improved
irrigation efficiency, reduction in per capita domestic consumption, and rainwater harvesting were
shown to substantially reduce unmet water demand with rain water harvesting showing no any
unmet demand throughout the simulation period. The study highlights the critical need for
proactive, integrated water resources management and provides actionable insights for achieving
sustainable water allocation in the face of population pressure and climate change. The findings
are instrumental in informing future water policies and supporting SDG 6 targets in Uganda.
