water Article Projected Climatic and Hydrologic Changes to Lake Victoria Basin Rivers under Three RCP Emission Scenarios for 2015–2100 and Impacts on the Water Sector Lydia A. Olaka 1,2,3,* , Joseph O. Ogutu 4, Mohammed Y. Said 2 and Christopher Oludhe 2,5 1 Department of Geology, University of Nairobi, P.O Box 30197, Nairobi, Kenya 2 Institute for Climate Change and Adaptation, University of Nairobi, P.O Box 30197, Nairobi, Kenya 3 Stellenbosch Institute of Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, 7600 Stellenbosch, South Africa 4 Biostatistics Unit, Institute of Crop Science, University of Hohenheim, 70593 Stuttgart, Germany 5 Department of Meteorology, University of Nairobi, P.O Box 30197, Nairobi, Kenya * Correspondence:
[email protected] Received: 21 March 2019; Accepted: 25 June 2019; Published: 13 July 2019 Abstract: Rivers in the Lake Victoria Basin support a multitude of ecosystem services, and the economies of the riparian countries (Kenya, Tanzania, Uganda, Rwanda, and Burundi) rely on their discharge, but projections of their future discharges under various climate change scenarios are not available. Here, we apply Vector Autoregressive Moving Average models with eXogenous variables (VARMAX) statistical models to project hydrological discharge for 23 river catchments for the 2015–2100 period, under three representative concentration pathways (RCPs), namely RCPs 2.6, 4.5, and 8.5. We show an intensification of future annual rainfall by 25% in the eastern and 5–10% in the western part of the basin. At higher emission scenarios, the October to December season receives more rainfall than the March to May season.