Spatial Analysis of Water Quality and Pollution Patterns in the Kaduna River Corridor

The Kaduna River serves as the primary water supply source for Kaduna City and numerous downstream communities but is subject to increasing pollution loading from industrial effluents, agricultural runoff, and domestic wastewater discharges along its corridor. This study conducts a spatial analysis of water quality patterns and pollution sources in the Kaduna River corridor between the Shiroro reservoir outflow and the Kaduna-Kogi State boundary. Water quality sampling is conducted at forty-eight georeferenced monitoring stations covering the main channel and twelve tributary inflows, with samples analysed for pH, dissolved oxygen, biological oxygen demand, nitrates, phosphates, heavy metals, and faecal coliform. Spatial interpolation using kriging generates continuous water quality maps for each parameter, and cluster analysis of the spatial parameter signatures identifies distinct pollution zones. Multivariate source apportionment using principal component analysis characterises the dominant pollution contributors at each zone. Remote sensing analysis of Sentinel-2 imagery is applied to derive turbidity and chlorophyll-a proxy indices validated against field measurements for spatial monitoring between field campaign dates. Results identify three hotspot zones of severe pollution corresponding to the Kaduna Industrial Estate outfall, the Rigachikun abattoir discharge, and diffuse agricultural runoff from irrigated rice cultivation in the Chawai LGA floodplains. The study provides spatial evidence for the Kaduna State Environmental Protection Authority's water quality enforcement programme. Keywords: water quality, spatial analysis, Kaduna River, pollution mapping, kriging.