Gully management in the Maasai Mara, Kenya: a GIS-based soil erosion and intervention modelling strategy

Gully erosion threatens land productivity and biodiversity, yet current management typically lacks spatially precise, evidence-based guidance for designing effective restoration interventions. This study presents a GIS-based intervention modelling approach to develop a targeted gully rehabilitation strategy within the Enarau Conservancy in Kenya. High-resolution topographic data from Unmanned Aerial Vehicle (UAV) surveys, combined with soil and vegetation datasets, were used to simulate water flow and erosion using the Simulated Water Erosion Model (SIMWE). The model captured overland flow dynamics and erosion patterns to evaluate the effectiveness of three management interventions: vegetation plots, woven wooden dams, and sandbags, all aimed at reducing erosion. Results showed that site-specific measures led to a measurable reduction in erosion. The primary gully (S1) exhibited a 4.7 percent decrease in erosion rate, while the secondary gully (S2) showed an 87.9 percent reduction. Analysis across the broader simulation area confirmed that the interventions decreased sediment flux and surface water velocity, which helped mitigate soil loss. This study demonstrates the value of integrating UAV-derived data with GIS-based modelling for designing and assessing adaptable gully restoration strategies. The findings offer practical recommendations for erosion control and support the broader understanding of spatially targeted management in erosion-prone landscapes.