Impact of Climate Variability on Surface Water Resources in Homa Bay County

Abstract

Climate variability is a natural process that affects the atmospheric general global circulation system causing short term fluctuations on seasonal or multi-seasonal time scale with implication on water resources globally and it manifests through fluctuations in flooding, drought occurrences, surface water-levels, river volume flows, surface water quantities, precipitations and water vapour. This project focused on the impacts of rainfall and temperature variability on the river discharge in Homa Bay County. In order to assess the variability impacts, the main objective of the project was to determine the relationship between climate variability (rainfall and temperature) and the availability and spatial distribution of surface water resources. A purposeful spatial survey design method was used in this project. The main rivers studied were; Kibuon, Tende and Riana. The study relied on secondary data sets, the climate data were both in-situ data sourced from Kenya Meteorological Department and proxy data sourced from Global Weather Database. The river discharge data was sourced from Water Resources Authority, all were estimated using Soil and Water Analysis Tool model (SWAT). Data was analysed using both descriptive statistics and spatial analysis techniques to determine trends, seasonality, abnormal conditions in climate of Homa Bay County in relation to river volume flows and included; correlation, regression and time series analysis and these largely relied on the SWAT model. A long term mean variability as a measure of the trend in rainfall, temperature and river volume flows was determined using time series analysis, regression analysis technique was applied to determine the relationship between climate variability and surface water resources being assessed in relation to availability, distribution and Water Yield. The variability was in spatial and time context in relation to surface water resources and significant tests were at α 0.05. The study establishes that rainfall and temperature variability have an impact on the availability and distribution of surface Water resources in Homa Bay and recommends public education on climate variability impact, Hydrologic modelling at a Micro scale, considering data sources, Collection, retrieval and storage, policy interventions since Climate variability is an environmental challenge and impacts the hydrological cycle and needs to be addressed to improve surface Water resource conservation, utilisation, planning and management.