"The discovery of a lake the size of Delaware beneath a Kenyan desert this month may prove to be a game-changer for precious water needs in arid East Africa.
The new supply of billions of gallons, if managed properly, may make the desert bloom indefinitely, some scientists and UN experts say."
From the Wikipedia entry on Sand Dams we get:
Low cost and maintenance: Sand dams are the lowest cost form of rainwater harvesting known – 3 to 100 times lower cost than other technologies. A sand dam is built to last over 50 years, has no operational costs and requires little maintenance.
Community owned and managed: Most examples of sand dams are built by members of the communities they serve with support local and international development agencies. Community ownership and management is key to their successful operation.
They save time and enable increased food production and tree planting: During drought periods in semi-arid regions, people might have to walk up to 12 hours a day to fetch water, which is often unsafe to drink. Freed from the chore of walking sometimes the whole day to collect the water, farmers are able to improve food production and generate surplus income.
They provide a clean, secure and local year-round water supply in water scarce environments: The sand effectively acts as a large slow sand filter resulting high quality potable water. As the water is held under the sand, evaporation is minimal, people are protected from water-borne diseases and mosquitoes can’t breed – reducing the threat of malaria.
Wider benefits for health, education and communities: In areas where sand dams have been built, communities have observed a dramatic fall in water related disease, an increase in school attendance and a significant increase in household income and food production.
They transform the local ecology: The water held in the sand behind the dam spreads horizontally creating a permanent increase in the water table, allowing trees grow naturally and transforming the local ecology. The dams create a natural buffer that reduces the threat posed by flooding and drought and builds the resilience of communities to cope with the impacts of climate change in semi-arid regions.
While being both relatively easy and hard to build at the same time a Sand Dam can change the lives for the better for hundreds of thousands of people in the dry areas of Africa with little rainfall.
Simple as it is easy technology that almost anyone can do, hard in that you need to have a suitable area to build it plus the proper materials.
If the U.N. would actually get experts and materials to the areas where proper Sand Dams can be built and helps with ensuring that they are built properly. Sand Dams could help end the famine in Africa in less than 20 years.
After the construction of a proper Sand Dam, the entrapped water spreads out horizontally, filing the local aquifer, allowing trees and other plants to grow properly, and still allowing for drinking and irrigation water if properly managed. As like I said, the water travels horizontally. Meaning the area adjacent to each dam will become it's own oasis in the desert with trees, vegetation and more and more wild fauna will come to the area to eat and drink as well.
Looking at the photos in the Wikipedia article, if built using cinder blocks, there is maybe 2 to 3 hundred dollars in blocks. And mortar can be made up on site if the necessary materials can be found. Add in some slotted PVC pipe to be buried behind the wall to allow for the water to move to sides of the dams, and you can have a large clean reservoir of water for thousands of people in as little as two years.
I'd much rather pay for a couple dozen Sand Dams that to keep shipping food that the local Warlords confiscates and sells on the black market to line his own pockets.
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