Title :Quarry Rehabilitation in Vihiga County, Kenya
Audience :Stakeholders in excavation industry, Farmers and Extension Agents
Category :Land Management
Currently in Kenya there is an increasing demand for raw materials mined from the earth for use in the construction industry, and infrastructural programmes. Some of the programmes such as road construction use murram, a material excavated from land areas rich in laterite soils, which have high concentration of iron and aluminum. After excavation of the murram, the quarry sites are generally abandoned, creating wastelands, dotted with deep gapping pits. Some negative effects of quarrying include top and sub-soil depletion and topographical alteration that negatively impact local ecosystems and social environment. However, these impacts can successfully be addressed and mitigated, through development and implementation of effective quarry rehabilitation practices. Vihiga County in Kenya is one region where abandoned quarries have been successfully rehabilitated through actions such as tree planting.
Vihiga County is located in the Lake Victoria Basin at an altitude of between 1,300 m and 1,800 m above sea level and has a gently sloping topography. The terrain of the County include scattered hills and valleys with streams that drain into Lake Victoria. The County experiences well distributed rainfall throughout the year with an average annual precipitation of 1900 mm. Temperatures range from 14ºC - 32ºC with a mean of 23ºC. The soils are mainly red loamy sand derived from sedimentary and basalt rocks.
The objectives of quarry rehabilitation include:
• Reclaiming abandoned excavated site
• Demonstrating quarry rehabilitation technologies
• Improving land value and productivity
The need for quarry rehabilitation in Vihiga County was identified through Participatory Rural Appraisal (PRA) and Rapid Rural Initiatives (RRI) undertaken through an ICRAF/KEFRI collaborative programme.
Mr Joel Akaki of Vihiga County is one farmer who has successfully rehabilitated an abandoned quarry site. To reclaim the site, Mr Akaki leveled the quarry by backfilling it with top soil collected from nearby sources including soils excavated from on-going road construction works, hence transforming waste land into an arable land. Tree seedlings for initial planting were obtained from ICRAF/KEFRI project and established on different farm niches, and under various arrangements which included; border planting, hedgerow planting, windbreaks, fruit orchard, woodlot and homestead planting. On steep edges, soil and water conservation structures such as terraces and retention ditches were constructed.
The tree species planted included; Eucalyptus species, Grevillea robusta
and fruit trees mainly mangoes and avocadoes. Calliandra calothyrsus
was planted for fuelwood and bee forage. Jatropha curcas
was also introduced. Further farm improvement is undertaken with advice from research, governmental and non-governmental institutions working within the region.
|An abandoned quarry
||Water collects in a abandoned quarry
||Trees on boundaries on rehabilitated
|Bee hives set in area planted with
different tree species in rehabilitated
• Productive use of once abandoned land
• Increased vegetation cover and biodiversity
• The technology has diversified sources of income for the farmer through sale of tree products including; poles, timber, and honey.
• The technology has been up-scaled through field days and educational tours resulting into other quarries being rehabilitated through tree planting and establishment of soil and water conservation structures.
• Improvement of socio-cultural status through owning land which was achieved by rehabilitating a quarry into a productive farmland.
• Contributed to food and nutritional security, aesthetic value of land, and availability of wood biomass on farm.
• Elimination of hazards associated with abandoned quarries such as drowning, waste disposal site and flooding.
Innovation and success factors include the following:
• Substitution of maize farming with exclusive tree growing
• Introduction of bee keeping for honey production
• Use of Calliandra mainly for bee forage as opposed to use of species for soil fertility improvement for which it was introduced
• Replacement of fish farming, with a more secure practice of tree growing
• Use of local materials from the farm to reduce construction costs of chicken pens, bee hives
• Proper management of coppices and replanting of cut trees to ensure sustainability
• Creating awareness and building capacity of community members to out-scale quarry rehabilitation activities.
Some of the constraints include;
• Relatively high initial labour cost to back fill the quarry
• Large population of birds of prey within the farm which hunt free ranging domestic chicken.
Lessons learnt from the practice include;
• Planting trees is the main foundation for biodiversity improvement and land reclamation
• Availability of market is a motivation for adoption of a good practices e.g. Jatropha curcas introduced on the farm as biofuel was not a viable venture since there was not market for oil from the plant
• The practice can be sustained by selling tree and tree products, replanting and managing tree coppices.
Quarry rehabilitation using trees is a successful practice which has positive ecological, economic and social-cultural impacts. The practice can be widely adopted in other areas that have abandoned quarries.