Wiley, Hydrological Processes, 15(29), p. 3276-3293, 2015
DOI: 10.1002/hyp.10443
Full text: Unavailable
Recent hydro-climatological trends and variability characteristics were investigated for the Lake Naivasha Basin with the aim of understanding the changes in water balance components and their evolution over the past 50 years. Using Bayesian change point analysis proposed by Barry and Hartigan (1993) and modified Mann-Kendall tests time series of annual mean, maximum, minimum, and seasonal precipitation and flow, as well as annual mean lake volumes were analyzed for the period 1960-2010 to uncover possible abrupt shifts and gradual trends. Double cumulative curve analysis was used to investigate changes in hydrological response attributable to either human influence or climatic variability. The results indicate a significant decline in lake volumes at a mean rate of 9.35 × 106 m3yr-1. Most of the river gauging stations showed no evidence of trends in the annual mean and maximum flows as well as seasonal flows. Annual minimum flows, however, showed abrupt shifts and significant (upward/downward) trends at the main outlet stations. Precipitation in the basin showed no evidence of abrupt shifts, but a few stations showed gradual decline. The observed changes in precipitation could not explain the decline in both minimum flows and lake volumes. The findings show no evidence of any impact of climate change for the Lake Naivasha basin over the past 50 years. This implies that other factors, such as changes in land cover and infrastructure development, have been responsible for the observed changes in stream flow and lake volumes. This article is protected by copyright. All rights reserved.