Evaluation of Impacts of Water, Sanitation and Hygiene (WASH) Activities to the Environment in the Upper Mara Basin Using the WEAP Model

Abstract

Provision of reliable and safe water supplies is an essential element in improving the quality of life for mankind and is critical component for sustainable development. World Wide Fund for Nature (WWF) and Global Water for Sustainability (GLOWS) are working in the Mara basin to improve adequate water supplies, and to ensure sustainable development and conservation of the natural resources in the Mara- Serengeti ecosystem. This study was undertaken to assess public access to water, sanitation and hygiene (WASH) services and to evaluate the impacts of WASH activities on the environment in the upper Mara River basin.

Operational 38 water supply projects, 16 waste water disposal projects and 22 solid waste disposal sites were identified by observations, review of literature and interviews to water users and stakeholders for impact evaluation. Impacts on land and environmental quality for the identified projects were assessed using Land Quality Indicators (LQI); water quality, solid and liquid waste generation and management and soil erosion.

Water Evaluation and Planning (WEAP) model was used to carry out scenario projections of impacts of WASH activities to the water quality and quantity in the Upper Mara Rivers. The projections started with the reference scenario of the current status followed by scenarios with alternative assumptions about future developments and management. Water and sanitation accessibility and water quality data was analyzed using descriptive statistics, SPSS and Genstat software. GIS maps were developed to show distribution of major impacts of the WASH developments in the Upper Mara basin. On average, 63% of the household obtained water from unimproved sources and only 23.4% of the sampled water sources were found suitable for domestic water use according to the Kenya Water Quality regulations. About 38% of the resident lacked human waste disposal facilities. A positive correlation (r = 0.37) was found between E. coli in open water sources and percentage of households within divisions lacking human waste disposal facilities.

Bomet municipal stabilization pond discharged poorly treated wastewater (BOD 5=644mg/l) into Nyangores river thereby posing a pollution threat to the environment. Soil erosion was observed around 17% of the sampled water supply projects shared between humans and livestock while poorly disposed solid waste defaced urban centers.

WEAP model predicted inadequate supply of water demanded in the upper Mara especially along Amala River in future. For instance, in February of year 2030 the total demand for Longisa hospital, Mulot town and Ndakaini farm would be unmet by 95.34m 3(0.88%), 47. 13m 3 (0.6%) and 924.17m 3 (0.89%) respectively in the current hydrological, climatic, water demand and population growth rate (2.44%) scenario.