Assessment of temporal and spatial variability of irrigation groundwater quality on the flanks of Mount Meru, northern Tanzania

Abstract

The study focuses on assessing the suitability of groundwaters used for irrigation on the flanks of Mount Meru in Northern Tanzania and providing a map showing the spatial variability of irrigation water quality for proper irrigation and crop management in the area. Results of irrigation water quality index (IWQI) show that the groundwaters (F⁻-rich NaHCO3 alkaline waters) used for irrigation on the eastern, northern, western, and south-western flanks of Mount Meru are not suitable for irrigation; only 1% (n = 1) of the inventoried groundwater points (n = 76) is classified as good for irrigation use, while 99% (n = 75) of the points are classified as poor to unsuitable for irrigation use. Hence, the study recommends the treatment of groundwaters used for irrigation in the study area by reducing the Na+ concentration and Total Alkalinity (HCO3⁻ + CO32⁻) using appropriate quantities of amendments. This study would be helpful for water resources management in other similar geological settings.