https://doi.org/10.5194/hess-2021-151 Preprint. Discussion started: 29 March 2021 c Author(s) 2021. CC BY 4.0 License. Land-use and climate change effects on water yield from East African Forested Water Towers Charles Nduhiu Wamucii1, Pieter R. van Oel2, Arend Ligtenberg3, John Mwangi Gathenya4, Adriaan J. Teuling1 5 1Hydrology and Quantitative Water Management Group, Wageningen University & Research, 6700 AA Wageningen, The Netherlands 2Water Resources Management Group, Wageningen University & Research, 6700AA Wageningen, The Netherlands 3Laboratory of Geo-information Science and Remote Sensing, Environmental Sciences, Wageningen University & Research, 6708 PB Wageningen, The Netherlands 4Soil, Water and Environmental Engineering Department, School of Biosystems and Environmental Engineering, Jomo Kenyatta 10 University of Agriculture & Technology, P.O Box 62000 - 00200 Nairobi, Kenya Correspondence to: Charles Nduhiu Wamucii (
[email protected]) Abstract. East-African forested mountain regions are vital in generating and supplying water resources to adjacent 15 arid and semi-arid lowlands. However, these ecosystems are under pressure from both climate and land-use changes. This study aimed to analyze the effects of climate and land-use changes on water yield using the Budyko conceptual framework. For 9 selected forested water towers in East Africa, the amount and distribution of water resources and their decadal changes were analyzed. Results show that most areas inside and outside the water towers are under pressure from human influences. Water yield was observed to be more sensitive to climate 20 changes compared to land-use changes within the selected East African water towers themselves. However, for the surrounding lowlands, the effects of land-use changes have greater impacts on water yield.