Published in April 2021
Kenya is categorized as a water scarce country with per capita freshwater endowment of about 527m3 (NWP 2019) against the UN standard of minimum 1,000m3 for countries which are not water stressed. Groundwater is therefore, a crucial resource to the countries efforts of achieving the Sustainable Development Goal (SDG) 6 of ensuring availability and sustainable management of water and sanitation for all. Despite the huge water Policy Brief APRIL 2021 Groundwater Resources Management in the Lake Victoria basin, Kenya Figure 1. Groundwater use is common in Kisumu city and the rural Kano area. This includes boreholes and shallow wells, which are either publicly or privately owned. resources of Lake Victoria, surface water supply for portable purposes in the surrounding areas is still low due to costs of treatment and infrastructure. As a result, dependence on groundwater is high, being driven by high population density (300 persons per km2 ) and economic activities in the region. In parts of Lake Victoria basin-Kenya, groundwater resources accounts for around 30% of portable water supply (Olago 2019).
Nitrate is emerging as the most widespread groundwater contaminant associated with anthropogenic activities. High nitrate concentrations (> 50 mgL-1) in water are both a health and environmental hazard promoting eutrophication, poses high risks to methemoglobinemia (blue baby syndrome) in infants and colorectal cancer (Kendall et al., 2007; Schullehner et al., 2018). Given the high population density, urbanization and industrialization being witnessed in the Lake Victoria basin, groundwater resources have become vulnerable to anthropogenic contaminants. The groundwater pollution risk in the basin’s major urban centers (e.g. Kisumu) is intensified by inadequate sewage network and treatment infrastructure. It is reported that less than 30% of households in these urban centers are connected to sewer system (LVBC, 2017). In addition, unplanned urban expansion have resulted in the mushrooming of slums and high discharge of untreated wastewater (Nyilitya et al., 2020). This happens against the backdrop of limited sciencebased monitoring data in the basin and lack of clear information on groundwater nitrate pollution sources. The purpose of this study was to establish chemical water quality status and sources of groundwater nitrate pollution in the basin using the case of Kisumu City and its adjacent Kano plains.