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Rivers are important freshwater resources that are important in supporting and sustaining socioeconomic systems in the world. However, the distribution of these freshwater resources is erratic and unreliable. Thus, man has always tried to exploit these resources by diverting river water to satisfy different needs. In tropical river basins, river water diversions has been done as a flood control measure and also to improve urban and rural water supplies, avail water for irrigation and generate hydropower. 1 The escalating demand for hydropower, irrigation and domestic water is likely to increase water abstractions in rivers. 2-4 River basins in the world are facing multiple stressors including pollution, infrastructure developments like dams, eutrophication and land use changes. 5 Limited studies have been undertaken to determine drivers of water abstraction and river water diversions in Kenya. In addition, the studies undertaken have mainly concentrated on water supplies and urban water demands. There is limited data on the root causes of water abstraction and river water diversion in tropical river basins. This study will fill this gap by establishing the main drivers of water abstraction and river water diversion in South West Upper Tana Basin. In South West Upper Tana, there are many low magnitude river diversions which are not documented. These diversions are necessitated by water needs such as irrigation agriculture, recreation, domestic use, and rural and urban supplies. However, it is not been established which of these water needs is the most dominant in the basin. Poor licensing and monitoring of water abstractions and river diversions in the basin has led to increased water abstractions in the basin and unintended consequences that has greatly affected the flow of rivers in the basin. The declining streamflow in the basin is a major concern since it affects the livelihoods in the region, degrades the aquatic ecosystem and affects the rural and urban water supplies in the area. 6,7 Thus, it is important to understand the main drivers of these abstractions in order to formulate policies and strategies to improve sustainability of the water resources. This study seeks to determine how these drivers interact categorically, synergistically and additively by applying the DPSIR framework. Rivers in South West Upper Tana Basin are important sources of water for Nairobi City. Through Ndakaini dam, rivers in this basin supply 84% of water to Nairobi City (Athi Water Services Board, 2014). Thus, there is a need to understand the drivers of water abstraction in this basin since they may affect the streamflow in the rivers in this basin which could lead to inadequate water supply in the city. In addition, for Kenya to attain Vision 2030 and attain Sustainable Development Goal number 6 of clean water and sanitation, sustainable

The changing patterns of land cover and land use in the tropical river basin over time are critical. The hydrological phenomena at basin and sub basin scale are affected positively or negatively by dynamics of the land cover and land use patterns.

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