The research team, led by Kuma J. Ayua of Federal University Lokoja, together with Arya J. Akbar and Anthony J. Ilozobhie, set out to close a gap that has frustrated policymakers for years. Ranching is frequently championed as a replacement for open grazing, and several Nigerian states have already passed anti-open-grazing laws, yet ranches fail quickly if they are built where water is unreliable. Previous studies had diagnosed the causes of the violence, including resource competition, population growth and religio-cultural tensions, but few had asked the practical hydrogeological question: which specific patches of ground can actually sustain a ranch? The new work translates groundwater science directly into siting guidance.

The technical backbone of the study is a set of ninety-six vertical electrical soundings, acquired during the dry seasons of 2017 and 2022 so that groundwater conditions were measured at their most stressed. Using an ABEM SAS 1000 terrameter with a Schlumberger array, the team measured how electrical resistivity changes with depth, then interpreted the curves through partial curve matching and one-dimensional inversion with WinResist software. Only models achieving a root-mean-square error below five percent were accepted, ensuring that the derived geoelectric layers, from which aquifer resistivity, thickness, hydraulic conductivity, transmissivity and longitudinal conductance were computed, faithfully represented the subsurface.

Because groundwater in this region hides in fractures as much as in pores, the researchers also hunted for structural clues from above. Lineaments, the surface traces of faults, joints and fractures, were extracted from Landsat 8 imagery and from high-resolution aeromagnetic data using the Canny Edge Detection algorithm, chosen for its superior noise handling, hysteresis thresholding and precise edge localization compared with simpler operators. The aeromagnetic data, collected in 2007 with cesium vapour magnetometers along 500-meter flight lines, were corrected for the International Geomagnetic Reference Field and reduced to the equator before edge detection. The composite analysis revealed 6,683 lineaments dominated by a northeast-southwest trend, matching the known structural grain of the Benue Trough, with the highest lineament densities, up to 3.89 per square kilometer, concentrated along the southeastern margins of the study area.

Geology complicates the picture considerably. Parts of the area sit on crystalline basement rocks of the Eastern Nigerian Basement complex, which are inherently poor aquifers with limited porosity and permeability; groundwater there exists only where weathering and fracturing have created secondary porosity. Other portions lie within the sedimentary fill of the Benue Trough, including the Eze-Aku formation’s sandstones and shales, where aquifers are unconfined, variable in thickness, and modest in yield. Boreholes in the sedimentary terrain rarely exceed 0.3 liters per second, though optimal yields of 4 to 12 liters per second have been reported where brittle structures such as faults and fractures are intercepted. Aquifer thickness across the study area ranged from just 4.4 meters to a substantial 96.7 meters.

To fuse these disparate data streams into a single map, the team turned to the Analytical Hierarchy Process, a pairwise comparison method that converts expert judgment into consistent numerical weights. Seven factors were weighed against one another: lithology, composite lineament density, hydraulic conductivity, transmissivity, aquifer thickness, longitudinal conductance and aquifer resistivity. Lineament density emerged as the dominant control, carrying a weight of 33 percent, while aquifer thickness was least influential at 4 percent. The consistency ratio of the pairwise matrix was 0.08, comfortably below the 0.1 threshold that would signal arbitrary judgments. The weighted layers were then overlaid in ArcGIS to generate a groundwater potential map classifying the land as low, moderate or high potential.

The results are striking in their asymmetry. Low and moderate potential zones together cover roughly 87 percent of the study area, coinciding with basement complex lithology and clay-rich shale terrain where lineament density, transmissivity and conductance are all unfavorable. The high potential zone, by contrast, occupies only about 417 square kilometers, or 13 percent of the area, and clusters along the floodplains of the Katsina-Ala River, where dense lineaments intersect permeable sandstone, alluvium and fractured basement. This spatial coincidence confirms the river’s role as a primary recharge source and suggests that the most promising ranching locations are also the most hydrologically sensitive.

The model’s credibility rests on two independent checks. Validated against thirteen borehole yield records, the map correctly classified 84.61 percent of observations, a strong result the authors temper by noting the limited number of validation points. A sensitivity analysis then perturbed each factor weight by plus or minus twenty percent across fourteen scenarios, rescaling the remaining weights each time. The high-potential area shifted by at most 5.62 percent, in response to changes in lineament density, confirming that the map is robust and that lineament density is simultaneously the most influential and the most uncertainty-carrying input. Transmissivity, hydraulic conductivity and aquifer thickness each induced changes below three percent.

The practical implications are considerable. The 417 square kilometers of high-potential ground constitute a spatial blueprint for ranch siting, offering state and federal governments an evidence-based alternative to politically fraught land allocations. The authors argue the map can serve as a neutral arbiter, reframing disputes between pastoralists and farmers as collaborative planning for shared resource security. Yet they are candid about the limits of hydrogeology. The high-potential zones are not empty: they include active farmsteads at Mbacher and Iwar and built-up areas such as Ikurav-Tiev and Katsina-Ala Township, so siting ranches there without resolving land tenure could displace rather than dissolve the conflict.

There is also an environmental paradox at the heart of the plan. Concentrating cattle on the Katsina-Ala floodplains, precisely where aquifer recharge is strongest, risks contaminating the very groundwater the ranches depend on, with nitrate and pathogen leaching from ranch effluent a particular concern. The researchers recommend a groundwater quality monitoring network, legally demarcated recharge protection zones, lined waste containment systems and integrated manure management as preconditions for any development. Their conclusion is measured: the map provides a scientifically robust foundation for the difficult conversations ahead, but it cannot replace them. Solving Nigeria’s farmer-herder crisis, the study suggests, will require pairing precise earth science with equally careful attention to land governance, equity and trust.

Subject of Research: Groundwater potential mapping for ranch site selection to mitigate farmer-herder conflict in the Central Benue Valley, Nigeria

Article Title: Multi-factor amalgam for subterranean water prognostication: ramifications for grazier-agrarian conflict resolution in water-scant Central Benue Valley

Article References: Ayua, K. J., Akbar, A. J., & Ilozobhie, A. J. (2026). Multi-factor amalgam for subterranean water prognostication: ramifications for grazier-agrarian conflict resolution in water-scant Central Benue Valley. BMC Environmental Science, 3(1), Article 2. https://doi.org/10.1186/s44329-025-00043-5

Image Credits: AI Generated

DOI: 10.1186/s44329-025-00043-5

Keywords: groundwater potential, hydrogeology, Benue Valley, farmer-herder conflict, Analytical Hierarchy Process, vertical electrical sounding, lineament density, remote sensing, GIS, ranch siting, Nigeria, water scarcity