Introduction

The semi-arid savannah environments (SASE) (commonly referred to as arid and semi-arid lands (ASAL) in Kenya) covers 83% of the country, carries 35% of the population and more than 50% of the livestock. Water is the major limiting factor to food production and socio-economic development in general. The main occupation is subsistence small-scale rainfed agriculture and livestock production, which normally compete for the limited water resources. This is aggravated by land use changes related to human settlements and intensification of agriculture in semiarid environments, where a balance is needed between different water users and ecological functions. Moreover, there is limited knowledge on hydrological impacts on water resources management at river basin scale.