IGCP 565 Project Workshops

IGCP 565 Workshop 4: Integration of geodetic observations and products in models of the hydrological cycle Support for water management through hydrological models and data assimilation November 21-22, 2011 Johannesburg, South Africa

Assessing Climate Vulnerabilities and Infrastructure of for Small Scale Water Utilities in the Lake Victoria Basin

Norman L. Miller (1,2), Larry L. Dale (1), Omar Aslam (2), Meshal Mehta (3)
(1) Lawrence Berkeley National Laboratory
(2) University of California, Berkeley
(3) Stockholm Environmental Institute

We analyze three urban water service areas (Masaka, Uganda, Kisii, Kenya, and Bukoba, Tanzania) that rely almost entirely on surface water from the Lake Victoria Basin, a delicately balanced freshwater system controlled primarily by climate conditions. Lake Victoria receives 80% of its water from rainfall and loses 80% to evaporation, thus the lake is highly sensitive to changing weather patterns. An analysis of climate change models for the Lake Victoria region indicates warmer temperatures and greater rainfall over the next 50 years, with future annual rainfall projected to exceed surface water lost to evaporation from warmer rising temperatures. To understand the effects of climate change on urban water utilities around Lake Victoria, scenario analysis is applied to an integrated water supply and water demand model for Masaka, Uganda. Small-scale representation models were created for Bukoba, Tanzania and Kisii, Kenya, but no climate projections on water supply could be devised due to unavailable hydrological data. The integrated model for Masaka forecasts increased rainfall and greater water supplies for a projected 2050s climate compared to current trends. However, current population pressures and inadequate waterworks system capacities remain the near-term impediment to achieving full access to piped-water services. Climate projections for higher net annual rainfall obscure intensified monthly volatility in rainfall, which increases monthly changes to Lake Victoria water levels. With population growth rates already among the highest in the world, the added effects of climate change to Lake Victoria exacerbate a host of socio-economic changes underway in a region heavily dependent on agriculture, fisheries, and hydropower. This dynamic threat from both climate and demographic change to fixed-asset water utilities blurs long-term planning horizons, confounding benefit-cost–based management responses. Thus, to further strengthen the opportunity for cooperative management and adaptive capacity, this report examines water utility management strategies in light of future climate and demographic scenarios and offers recommendations for climate change adaptation.