CHALLENGES IN WATER RESOURCES AND IMPACT ON POPULATION IN THE KINGSTON BASIN

The Kingston hydrological basin of Jamaica, with a population of >700,000 has shown severe deterioration of the groundwater quality owing to rapid urbanization and poor sewage treatment facilities thereby leading to closure of many groundwater wells used for potable water supply. This has added stress in the water resources especially during drought phases when the surface water sources (Mona and Hermitage reservoirs) fall to <30% of their capacity. Analysis of the well waters has shown NO₃ as high as 56mg/L thus exceeding the Jamaican Ambient Water Quality standard (0.10-7.5mg/L). The high levels of nitrate are due to leakage of sewage from soak-away pits and pit latrines. To address the demand/supply problem as well as source and transport of contaminants within the basin the UWI and Kansas State University thought it is prudent to thoroughly investigate the hydrogeological fundamentals and controlling parameters that govern the pollution of the aquifer. The overall objective of this project was to carry out detail sampling of the wells, both from surface and depth profiles, analyze for the cations (Na, K, Mg, Ca), anions (NO₃, SO₄, Cl, HCO₃) and create a groundwater model showing the possible transport pathways from source to the sink. Chemical analysis were accompanied by creation of contour maps for the different elements (Nitrate as well as N) showing the spatial relationships with population density and housing clusters. This thus aided in delineating zones of high risk for groundwaters which in connection with existing sewer lines map have assisted in zoning areas for additional sewage facilities as well as for upgrade of existing plants which date back to 1950’s. Models of contaminant transport in the future will also aid in showing the possible pathways of migration, thus aiding in zoning of wells which could be reopened based on direction of contaminant transport.