Assessing the socio-economic and ecological impacts of gravel mining in the Savelugu-Nanton District of the Northern Region of Ghana

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Gravel mining (GM) plays an important role in the development of socioeconomic infrastructure of communities and constitutes an essential component of materials in the construction of roads, hospitals, schools and housing. Currently, gravel is widely used throughout northern region and it is regarded by many as the fastest developing region in West Africa. However, in the Savelugu-Nanton District, the emergence of GM activities constitutes a major threat to the socio-economic activities of people in the area. The gravel mining also has considerable effect on the air and water. It causes loss of biodiversity, soil pollution and land degradation, reduction of essential nutrients and organic matter of the soil. This study was undertaken to assess the socio-economic and ecological impacts of GM on the people of the Savelugu-Nanton District of the Northern Region of Ghana. Specific objectives were to: examine people’s perception of impacts of gravel mining on their socio-economic activities, assess the impact (in terms of duration after gravel pit abandonment) on above-ground vegetative biomass (trees, shrubs grasses and litter) and assess major soil physicochemical property changes of abandoned gravel mines. Through the administration of structured questionnaires and field observations, information was gathered on respondents’ perception of GM impact whiles soil and vegetation samples were collected and analysed in a laboratory. Data from gravel mines abandoned for 1-5, 6-10 and more than ten years and data from an un-mined site as standard reference were compared. Respondents’ perceived GM to have resulted in the significant reduction of farmlands, and led to poor relationship between residents and gravel miners, caused significant land degradation and promoted the widespread incidence of diseases such as malaria, dysentery and typhoid fever amongst others. Total above-ground biomass (i.e. surface litter+ low growing flora + tree biomass) recorded in the control plot (32.8 t/ha) was found to be significantly higher (p < 0.05) than the abandoned mines which recorded total above-ground biomass of 17.7 t/ha, 18.1 t/ha and 18.6 t/ha dry matter for the 1-5, 6-10 and above ten years respectively. While available potassium (K) and percentage organic carbon (%OC) differed significantly (p < 0.05) between abandoned and un-mined sites, percentage nitrogen (% N), phosphorus (P), Cation Exchange Capacity (CEC) and pH did not differ significantly (p > 0.05). Correlation between the major soil chemical parameters (%OC, N, P, and K) were positive while that of physical parameters (% sand, % clay and % silt) were negative. The study recommends effective collaboration among key stakeholders in GM sector such as Environmental Protection Agency (EPA), Minerals Commission, Forestry Services Commission, Ministry of Food and Agriculture (MOFA) and District Assemblies in order to regulate the activity for controlled GM and improved availability of productive agricultural lands in the area; residents of communities should be made to benefit directly from gravel pits opened in their areas as this could enhance their commitments towards reclamation of abandoned gravel pits; tree planting and Agroforestry practices to increase the slow rate of natural succession by ameliorating unfavourable soil condition and providing a build-up of soil organic matter and higher above ground biomass; the reduction of negative activities such as perennial bushfires, over-cultivation of lands, over-grazing to reduce nutrient depletion rates and finally compliance with the statutory laws including L.I. 1652 of EPA Act 490 is required in order to regulate the conduct of gravel mining on sustainable basis to reduce its negative effects on the environment.
A thesis submitted to the Department of Agroforestry, Faculty of Renewable Natural Resources, Kwame Nkrumah University of Science and Technology, in partial fulfilment of the requirements for the Degree of Master of Science in Agroforestry, 2013