What is a sand dam?
A sand dam is a groundwater-based natural storage solution to make more water available for domestic use, livestock and for regeneration of the ecosystem through water seepage. It is a structure built across a seasonal riverbed in Arid and Semi-Arid Lands (ASALs) and is typically constructed using local materials such as stones, sandbags, wood and cement. It is designed to enable it to capture and store water, allowing it to percolate into the sand and then be stored underground for a longer period thus creating a groundwater reservoir.
Sand dams are particularly beneficial in ASALs where rainfall patterns are unpredictable and, hence, surface water is scarce. This helps communities secure a more consistent water supply for smallholder farming and for their livestock. The sand dams, therefore, help mitigate the effects of droughts and contribute to improved resilience against climate change.
Sand dams as a great alternative to sand harvesting
Sand dams are a sustainable and environmentally friendly alternative to sand harvesting activities that are carried out on dry seasonal riverbeds in Kajiado and other ASALs. Many households resort to sand harvesting activities a
s an income source in ASALs due to poverty and unemployment. Sand harvesting activities have contributed to land use and land cover changes that are impacting the ecosystem. The most notable environment effects of sand harvesting include the drying of groundwater aquifers, riverbank and riverbed erosion and pit formation.
Many sand harvesting activities are undertaken because households lack alternative sources of income. In the ASALs counties of Makueni and Kitui, sand dams have provided an environmentally friendly alternative to sand harvesting activities because they provide the water and time necessary to farm productively. A year-round availability of water enables smallholder farmers to invest in improved smallholder farming.
A case for more sand dams
Sand dams offer the following benefits, particularly in ASALs that are prone to droughts and water scarcity issues:
Water conservation: sand dams capture and store water for domestic, smallholder agriculture and livestock use during dry periods.
Soil conservation: reforestation around sand dams helps in stabilizing soil, preventing erosion, and reducing the risk of sedimentation in water bodies.
Biodiversity enhancement: when water percolate through the sand, it sustains plants and trees during the dry seasons leading to reforestation that attracts a variety of flora and fauna, promoting biodiversity conservation.
Carbon sequestration: trees planted as part of reforestation aid in carbon sequestration, mitigating climate change by absorbing carbon dioxide from the atmosphere.
Improved livelihoods: communities involved in smallholder farming along riverbeds are able to have year-round availability of water for smallholder farming.
Overall, sand dams represent a holistic approach to environmental conservation and sustainable development, offering multiple benefits to ecosystems and communities in water-stressed regions like Kajiado.
References:
Sand dams freeing dryland communities from water crisis - https://nation.africa/kenya/health/sand-dams-freeing-dryland-communities-from-water-crisis-4496914
Kajiado sandpits, where boys sell their future on the cheap -https://nation.africa/kenya/counties/kajiado/kajiado-sandpits-where-boys-sell-their-future-on-the-cheap-3877742
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