Modeling of spatial and temporal distribution of groundwater quality parameters in Warri, Delta State, Nigeria
Date
2023-03
Authors
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Publisher
Federal University of Technology, Owerri
Abstract
Groundwater quality has deteriorated as a result of its contamination by anthropogenic and natural activities. Inadequate access to potable water has led to the outbreak of various waterborne diseases and ailments. This study investigated the spatial and temporal distribution of twenty-six (26) groundwater quality parameters (temperature, pH, EC, TDS, DO, turbidity, TH, TSS, BOD, COD, total coliform bacteria, Na, K, Ca, Mg, SO4, NO3, Cl, HCO3, NH4, PO4, Fe, Cd, Cr, Cu, and Pb) obtained from fifty (50) existing boreholes across Warri, Delta State, Nigeria, during the dry season (December, 2019 – January, 2020) and the wet season (June, 2020 – August, 2020). The data obtained from the field and laboratory analysis of the samples were used as variable inputs to evaluate the temporal (seasonal) variation of groundwater quality and the water quality index (WQI). A geo-database was created for the 50 well locations and the Kriging interpolation geostatistical technique of the ArcGIS 10.6 software was used to determine the spatial distribution of the 26 water quality parameters in the study area and prediction maps are produced. The study revealed that most groundwater quality parameters had higher concentrations in the wet season than in the dry season. However, temperature, BOD, Na, K, Ca, Mg, SO4, NO3, Cd, Cr, Fe and Cu had lower concentrations. Cd and Cr had no significant variation in both seasons. From WQI classification, only 34% were placed as Excellent, 44% were Good, 10% were Poor, 10% were Very poor and 2% were unsuitable for drinking purposes in the dry season, while in the wet season 32% were placed as Excellent, 40% were Good, 12% were Poor, 14% were Very poor and 2% were unsuitable for drinking. Results from geostatistics showed that Turbidity, TH, TDS, BOD, Total Coliform, K, Ca, Mg, NH4, PO4, Cd and Pb had strong spatial dependence. Temperature, DO, COD, COD, Na, NO3 and Cl showed moderate spatial dependence, pH, EC, TSS, SO4, HCO3, Fe and Cu showed weak spatial dependence in the dry season. However, in the rainy season, pH, TSS, Na, Mg, SO4, HCO3, Fe and Cd showed strong spatial dependence, while temperature, EC, Turbidity, COD, Ca, NO3, Cr and Cu showed weak spatial dependence, and TH, TDS, DO, BOD, Total Coliform, K, Cl, NH4, PO4 and Pb showed moderate spatial dependence. The groundwater quality maps showed variation of groundwater quality parameters across the studied area with Jeddo (Refinery Axis), Warri Urban, Osubi, Effurun (Airport Road Axis), Pessu Market and Orhunworun Areas being the most contaminated areas. The spatial output maps will aid policy planners and decision makers for efficient management of the groundwater resources. The application of WQI and GIS is found to be effective for monitoring and mapping the spatial distribution pattern of groundwater quality parameters. Recommendations are made that water from the study area should be subjected to specific treatment before consumption.
Description
This thesis is for the award of Doctor of Philosophy (Ph.D) in Water Resources Engineering
Keywords
Groundwater, contamination, water quality index, geostatistics, spatial distribution, kriging, Department of Civil Engineering
Citation
Agori, J. E.(2023). Modeling of spatial and temporal distribution of groundwater quality parameters in Warri, Delta State, Nigeria [Unpublished Doctoral Thesis]. Federal University of Technology, Owerri, Nigeria