Hydrological

This study investigated the hydrogeological evaluation of borehole water contamination near a solid waste dumpsite in Iyowa, Benin City, Nigeria. The aim was to assess how dumpsite leachate affects groundwater quality by examining physicochemical, microbiological, and heavy metal parameters. Five borehole samples were collected at varying elevations and distances around the dumpsite (coordinates: 6°27′29″N–6°27′44″N, 5°36′10″E–5°36′37″E) using GPS mapping and WHO-recommended sampling procedures. Laboratory analyses covered pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, nitrate, sulphate, phosphate, and selected metals (Pb, Fe, Cr, Zn) determined by Atomic Absorption Spectrophotometry (AAS), alongside microbial tests for total coliforms and E. coli. The results (Tables 4.1–4.3, Figures 1–2) showed acidic groundwater (pH 5.19–6.14) below WHO limits (6.5–8.5), with low alkalinity (4–6 mg/L) and elevated metal concentrations: Pb (0.106–0.428 mg/L), Fe (2.98–7.51 mg/L), and Cr (0.37–3.87 mg/L), all exceeding the permissible limits of 0.01, 0.3, and 0.05 mg/L respectively. Potassium spiked at 55.8 mg/L in the borehole closest to the dumpsite (Sample 2), indicating direct leachate influence. Microbial tests showed absence of coliforms and E. coli, but minor heterotrophic bacteria (1 CFU/mL). Overall, the acidic and metal-enriched groundwater reveals significant leachate intrusion linked to dumpsite proximity, making the borehole water unsafe for domestic consumption without treatment. The findings highlight the need for controlled waste disposal, borehole siting regulation, and continuous groundwater monitoring in Iyowa.

Flooding, erosion, and inadequate drainage systems have continued to pose significant
hydrological challenges affecting the durability and performance of road infrastructure in
Benin City. One of the most impacted corridors is Temboga Road, situated within the IkpobaOkha Local Government Area. This study employs Geographic Information Systems (GIS)
and Remote Sensing methods to evaluate the hydrological characteristics of the Temboga
area and develop sustainable solutions for resilient hydraulic infrastructure design and
planning. Digital Elevation Models (DEMs) sourced from the Shuttle Radar Topography
Mission (SRTM/ USGS), combined with high-resolution UAV (Phantom 4) imagery and
differential GNSS observations, were processed within ArcGIS Pro and Global Mapper
environments to delineate watersheds, trace flow accumulation pathways, and identify floodprone zones. The Rational Method was applied to estimate peak runoff, while GIS-based
spatial were used to evaluate drainage and erosion-vulnerable locations. Findings indicate that Temboga Road lies across multiple sub-catchments (eight in total)
within the Ikpoba River basin characterized by low-lying topography, high rainfall intensity
exceeding 2,400mm annually, and sandy-loam soils that are highly susceptible to erosion.
The integration of GIS and hydrological analysis proved instrumental for evidence-based
decision-making, enabling engineers and planners to visualize water flow dynamics, mitigate
flood risks, and design drainage systems that strengthen the resilience and sustainability of
road infrastructures. Ultimately, this research demonstrates the value of spatial intelligence in
transforming traditional hydrological assessments into proactive tools for sustainable
infrastructural development along Temboga Road, Benin City.