EFFECT OF FLOODING ON GROUNDWATER RECHARGE POTENTIAL USING GIS TECHNIQUES

Abstract

The effect of flooding on groundwater recharge was investigated in the study. After soil samples were collected, soil permeability and textural analyses were carried out in a lab. Using the interpolation method, maps showing the spatial distribution of clay, silt, sand, permeability, rainfall, and hydraulic conductivity were produced. In order to create land use and lineament maps for the research area, supervised classification analysis was performed on LandSAT imaging software. The surface analyst method was also used on ASTER dem to create an elevation map, and the hydrological algorithm was applied to ASTER_dem to create a drainage map. Maps of hydraulic conductivity and overburden thickness were produced using the characteristics of the drill data. Multi-criteria analysis was used to create maps of the study area's groundwater potential and flood-prone areas by taking particular considerations into account. Every element that was taken into consideration was reclassified, and their weight was assigned using the AHP model. The association between groundwater potential and flood prone areas was examined using regression analysis, with a significance level of P ≤ 0.05. The impact of each of the twelve raster-based thematic maps—which include soil permeability and texture, drainage density, lineament density, hydraulic conductivity, flood plain, elevation, overburden thickness, land use, and rainfall—on groundwater and flood spread was methodically ascertained. After assessment, the research area's ground water potential was divided into three categories: fair, good, and very good, with coverage percentages of 2%, 80%, and 18%, respectively. Additionally, the research area's flood-prone area was divided into three categories: severely vulnerable (8%), moderately vulnerable (83%), and non-vulnerable (9%). When the correlation between groundwater potential and flood-prone zones was evaluated, the p-value was 0.06. The study's conclusion was that the study area's groundwater recharge potential and its flood-prone areas are positively correlated. Ofatedo, Gbodofon, Awosuru, and Gbonmi identified strong regions that are both extremely susceptible to flooding and have good groundwater potential.