Detection of trends in extreme streamflow due to climate variability in the Lake Naivasha basin, Kenya

ABSTRACT

Variability of streamflow has far-reaching impacts especially in developing countries. This is aggravated by climate change which has adversely affected the water resources and food security. This paper presents the characterization trends in extreme streamflow regimes with a view to providing information for planning local coping mechanisms to climate variability and change using streamflow data recorded from 1959 to 2008 in the Lake Naivasha basin in Kenya. The maxima and percentiles of streamflow distributions were investigated to identify changes in extreme intensity and frequency, respectively, using the Mann–Kendall test. The results indicate significant increases in annual maxima at all gauging stations. The flows in the month of November increased significantly at gauging stations 2GB4 and 2GC4. Flow percentile exceedance revealed that the annual 95th percentile exceedance increased significantly at gauging stations 2GB1 and 2GB5 with a decrease in annual 90th and 97th percentile exceedance at gauging stations 2GB4 and 2GC4. The results presented in this paper are useful for climate change adaptation planning and management especially in water supply, hydropower generation and agriculture.

Keywords:

• Streamflow
• Mann–Kendall trend test
• extreme events
• water resources
• Lake Naivasha
• climate change

Acknowledgement

The authors would like to appreciate the support that they received from the Water Resources Management Authority (WRMA) Naivasha during the fieldwork and data collection. In addition, the authors do appreciate the support from the Faculty of Engineering and Technology, Egerton University.