Underground water in Kenya: Abstraction, pollution and societal demand; A case study of wells in three Peri-Urban areas of Eldoret town is used to illustrate this scenario

Abstract

The quality of water from different sources is a concern raised by the Sustainable Development Goals. Rapid urbanization has forced most urban dwellers to live in crowded slums that are characterized by poor sanitation and inadequate supply of clean water. They rely on water wells that are often close to sources of pollution. The aim of this study was to analyze the quality of water in wells in three peri-urban centers of Eldoret Municipality. Six wells were randomly selected in each center, and their distances from pit latrines and garbage dumpsites determined by a tape measure. Two other water wells located at the recommended 30 m or above from a pollution source, served as controls. Biochemical oxygen demand (BOD), pH, turbidity, water temperature, nitrogen and phosphorous for each water sample collected two times during the dry season (January to March 2015) and two times during wet season (April to May 2015) were determined using standard methods and procedures. The findings were then compared to the Kenya National Water Quality Standards (KNWQS). In all the centers’, the average distance from water wells to pit latrines (12.9 m) and garbage dumpsites (16.8 m) were below the desirable KNWQS limit, an indication that contaminants could leach from pollution sources into the water wells. The mean temperature, pH (wet season), BOD, phosphorous and nitrogen in each water well were within the permissible limits of 19-30°C, 6.5-8.5, 0.8-5 mg/l, <0.05 mg/l and <0-1 ppm, respectively. However, the mean, pH (dry season) and turbidity in each water well exceeded the permissible limits of, 6.5-8.5, <0.03 g/l, <5 NTU respectively. Analysis of variance (ANOVA) was used to analyze statistical differences in the variables among the water samples. This revealed that there was a significant variation in water pH in Langas, (ANOVA: F 3, 39 =15.73; p<0.0001), while in Huruma the variations were not significant (ANOVA: F 3, 39 =15.73; p=0.6420) in the dry season, at 0.05 level of significance. This study concludes that topography is a key influence on proximity of water wells to pit latrines and garbage dumpsites in the study areas, thus affecting the levels of pH, Turbidity and TSS in ground water. This study recommends the construction and use of standard communal water wells, review of the 30 m location distance of water wells and other water abstraction points from pollution sources and regular monitoring of ground water quality.