Valuation of On-site Gully Erosion Control Benefits in Gombe Metropolis, Gombe State, Nigeria

Abstract

Soil erosion remains a significant environmental concern globally, with gully erosion identified as one of the most severe forms contributing to land degradation, particularly in rapidly urbanising areas like Gombe Metropolis, Nigeria. This study examines the economic benefits of gully erosion control measures implemented at two major sites within Gombe Metropolis, GSU-Mallam Inna-Kagarawal and FCE (T)-Jauro Abare-Jauro Kuna-M/Inna-Wuro Kesa-Tukulma. Using a combination of market-based, non-market-based, and value transfer economic valuation methods, the research quantifies the avoided damages and on-site benefits of erosion mitigation projects. Data were gathered through satellite image analysis, interviews with affected populations and officials, and document reviews. Findings reveal that while both sites demonstrated substantial on-site benefits, the FCE (T) gully site yielded significantly higher economic returns due to its scale and the number of communities affected. The total discounted benefit for the GSU site over 30 years was ₦2.61 billion, whereas the FCE (T) site generated a discounted benefit of ₦21.23 billion. The study highlights the importance of integrating comprehensive control strategies, including structural, biological, and socio-economic interventions, to enhance the sustainability and effectiveness of gully erosion mitigation efforts.