Water Resource Management at the Mpala Conservancy (Laikipia District, Kenya)

Abstract

The Mpala Conservancy, located in Kenya’s semi-arid Rift Valley, faces the pressure of water scarcity and the challenge of using that resource sustainably. This report provides the Mpala Conservancy with recommendations on how to increase their water security by quantifying water demand, assessing the availability of water sources, and improving water quality. Demand was measured quantitatively by metering flow at 26 strategic locations throughout the property, spanning the research center, Ranch, and distribution system at large. Daily bednight records were used to normalize demand per capita. The current water demand of the Mpala Research Centre (MRC) is approximately 400L/day/person. Kenyans living in the MRC Village use significantly less water with a demand of approximately 15L/day/ person. The total water demand at the Ranch, including the Top Spray Race, was measured at about 30,000L/day. To meet this demand, Mpala draws from water sources that include the Ewaso Nyiro River, the Miocene Aquifer, rooftop harvested rainwater, and the Nanja weirs. Assuming average rainfall, the Nanja weirs can meet Mpala’s water demand throughout the year. However, evaporation and rainfall patterns strongly influence whether or not the weirs can capture and store enough water during the rainy season to provide sufficient water through a drought. Demand prediction and weir volume estimation tools were developed to aid future monitoring and management. Water quality analysis was conducted during both the rainy and dry seasons at primary sources, rainwater storage tanks, and main points of use such as showers, kitchen faucets, and potable water units. Measured water quality parameters included: total and fecal coliforms, nitrate, phosphate, hardness, total suspended solids (TSS), total dissolved solids (TDS), turbidity, and dissolved oxygen (DO). Based on high turbidity and biological contamination in weir and river water, full water treatment is recommended for drinking and cooking. Pretreatment such as roughing filtration is sufficient for bathing, and when followed by slow sand filtration and disinfection, will provide high quality drinking and cooking water. Based upon the analysis of Mpala’s water resources presented here, a suite of behavioral, managerial, and technical recommendations are provided regarding future water use and management at Mpala. These recommendations include relying on the Nanja weirs as the primary water source and installing storage tanks and roughing filters on the supply lines to MRC and the Ranch. Mpala should also link projected demand at MRC, based on expected bednights, with current water storage in the Nanja weirs to predict and plan for potential water shortages. Monitoring of water quality, availability, and use should be continued.