Rural–urban material flows and environmental and socioeconomic implications of manufactured sand and gravel production in Mekelle, Ethiopia

Rapid urbanization in Mekelle, Ethiopia, has increased demand for manufactured sand and gravel, linking urban construction with rural extraction. This study quantifies aggregate production, resource consumption, operational greenhouse gas emissions, land-use and land-cover (LULC) changes, and associated socioeconomic and environmental conditions across the rural–urban supply system. Data were collected from seven production sites and three urban trading centers, and LULC changes were assessed for 2005–2025. Annual production was estimated at 88,880 m³ of sedimentary rock (manufactured sand) and 84,480 m³ of hard limestone (manufactured gravel), yielding 366,300 metric tonnes of aggregate, with 318,655 metric tonnes (87%) as useful output. Annual resource consumption included 300,346 L of diesel and 739,450 kWh of electricity. Operational greenhouse gas emissions totaled 812,924.25 kg CO₂e/year (2.55 kg CO₂e per metric tonne of useful aggregate), with diesel accounting for 97.91% of emissions. Extraction-related bare land expanded substantially. At Messebo, bare land increased from 6.01 to 115.40 ha (1,820.13%) between 2005 and 2025, while farmland and bushland decreased by 78.57 and 30.83 ha, respectively. At Hareko, bare land increased by 20.31 ha (1,025.76%), alongside declines in farmland and bushland. Only seven of 17 licensed plants were functional. These findings highlight manufactured aggregates’ contribution to urban construction and rural livelihoods, alongside material losses, land-cover transformation, dust exposure, and operational emissions. Improving material recovery, dust control, environmental monitoring, progressive site rehabilitation, and coordinated rural–urban aggregate management could reduce these pressures.