Differences in Water Quality In Relation To Human Activities along River Shimiche Ecosystem, Western Kenya

Abstract

A vast majority of inland water bodies are rapidly undergoing degradation or drying up mainly due to human influences and climate change. These water bodies and especially those that supply domestic water to human populations should be given more attention for management and conservation. The main objective of this study was to determine the differences in water quality in relation to economic land use practices along River Shimiche in Western Kenya. The River's ecosystem drains three land use types; forested environment in the upper course, sugarcane plantations and urban settlement in the middle and small-scale mixed farming activities in the lower course. Sampling was done at nine sampling stations once a month from January 2014 to August 2014. The sampling stations were selected to represent the main land uses along the course of the river determined by direct surveys and observations. Water temperature, pH, electrical conductivity and total dissolved solids were measured in-situ in triplicate, using appropriate meters. Water samples were also collected randomly in triplicate at each station and taken to the laboratory for determination of total suspended solids and enumeration of Escherichia coli, a coliform bacterium. Statistical analyses were done using Statistical Analysis System (SAS) version 9.1. Mean, variance and standard error were used to assess the spread of the data. The means of the parameters and one-way analysis of variance (ANOVA) were calculated to compare the mean values of observations based on land use. Where ANOVA showed significant differences, the means were separated through difference of the least square analysis. Pearson correlation co-efficient explored the relationships between physico-chemical parameters and E. coli concentrations. The means of all the physico-chemical variables at the three land uses were significantly different (p<0.05); indicating that land use variation impacts on physico-chemical conditions in the river's ecosystem. Mixed agriculture and urban settlements areas recorded the highest concentration of the E. coli. Changes in riparian land uses in the watershed therefore impact on the river physico-chemical conditions which consequently affect concentrations of E. coli, a biological indicator of water quality. There is need for the establishment of effective management schemes by different stakeholders for sustainable utilization of land along the course of River Shimiche and other similar small rivers.