GIS-based groundwater quality assessment for domestic and irrigation purposes in Ogbia local government area of Bayelsa State, Nigeria

Abstract

Groundwater is germane to human existence. The study assessed the physicochemical attributes of groundwater for domestic and irrigation applications. This was conducted by collecting and subjecting thirty (30) groundwater samples to physicochemical analysis. Thirteen parameters such as pH, electrical conductivity, total dissolved solids, total hardness, magnesium, calcium, sodium, iron, fluoride, chloride, sulphate, nitrate, and phosphate were used to compute water quality index (WQI). While chloride, electrical conductivity, magnesium adsorption ratio (MAR) and sodium adsorption ratio (SAR) were used to characterise the groundwater for irrigation purposes. Inverse distance weighted (IDW) interpolation method was used to develop spatial variation maps for both the WQI and the irrigation indices. Except for iron and fluoride, the results of the physicochemical parameters were within the WHO permissible limits. The WQI values for the boreholes range between 23.53 and 393.72 with a mean value of 108.69. The WQI was classified into excellent water (7.89%), good water (40.00%), poor water (43.34%), very poor water (5.44%) and unsuitable water (3.33%). The results for irrigation indices show that chloride and EC fall within the suitable groundwater status, MAR classified into suitable (46.67%) and unsuitable (53.33%), and SAR delineate the groundwater status into suitable (43.33%) and marginally suitable (56.67%).