Integrated Water Resources Management in a Changing Climate: The Implication of Anthropogenic Activities on the Tana and Athi/Sabaki Rivers Water System for Sustainable Development

Abstract

This paper highlights the effects of damming and farming activities on the Tana and Athi/Sabaki Rivers’ water system. The two activities are responsible for freshwater shortages, pollution, and habitat and community modification downstream. Damming has resulted in modification of the stream flow, and in changes in the water table; while nutrient loading and sedimentation from irrigated agriculture, human settlements and industrial activities upstream are responsible for the pollution effect. The resulting effects were evaluated using the Global International Waters Assessment scoping methodology backed with hindsight experiences of the team members in both environmental and socio-economic issues. The individual scores when averaged led to the following results: 1) the effect of damming the river system was scored at 3 in a scale of 1–3, signifying a severe impact as attested by the freshwater shortages experienced downstream; 2) the effect of nutrient loading and sedimentation, using the same scale, was score at 2, a score that exhibited a moderate pollution problem. The degree of impact from nutrient and sediment loading varied with seasons. It was localized and more pronounced in hot spots in the dry season; while in the wet period, it occurred throughout the system as flooding occurred; 3) reduced stream flow and pollution affected ecosystem functions, resulting in habitat and community modification, 4) the impact of global climate change was difficult to score at the river basin level. However, deforestation resulting from slash and burn agriculture and harvesting of wood to meet domestic energy needs were practiced in a large scale, reducing the action of forests as carbon sinks, while promoting the emission of carbon-dioxide, which contribute to global climate change. This study concluded that freshwater shortages and pollution were issues of major concern and they were causing socio-economic conflicts. To address the concerns, a proactive approach borrowing from the tenets of Integrated Water Resources Management, Ecosystem Based Management and Integrated Coastal Zone Planning and Management, need be adopted as the vehicles that would promote sustainable development in the river basin.