“For irrigation purposes, especially for fresh vegetable cash crop production in water deficit areas, water is collected in ponds from springs or small streams. The ponds are lined and sealed with sheet membranes (200 g/m2 fibre-reinforced plastic sheets, Silpaulin). The sheets are water proof; less affected by earth-movements, affordable for small farmers and can be easily repaired in case of small tears. However the sheets are photosensitive and tend to become brittle when directly exposed to the sun, especially when ponds are empty or filled with less water.
Here’s the rainwater cistern from dream to (almost) done! Built with earthbags and a custom liner.
Check out my new how-to article at Instructables.com on building earthbag water tanks. I pulled together content from previous blog posts, added a drawing and edited everything into one concise article. Let me know what you think. Instructables.com is a major site that’s been very effective in promoting my natural building projects.
I wrote in a previous blog post how I’m loving earthbag water tanks. My fascination with these water tanks jumped up a notch after reading an article about the difficulties of building a concrete water tank. From what I’ve recently learned by visiting Vanuatu and assisting in water tank design and construction, I know earthbag water tanks are much faster, easier and lower cost to build than concrete tanks.
We were pleasantly surprised to see this earthbag water tank just down the road from a house we (Liz’s group) were building. The church group saw our project and on their own figured out how to use the same earthbag techniques to make their water tank. No plans, no technical assistance, nothing.
We’ve nearly finished an earthbag water tank with narrow tubes that cost $200 in materials. Plastic tanks this size retail for around $1,350 in Vanuatu, so this design costs far less than the main competing product. It won’t blow away in a hurricane, break down from UV rays or taint the water with plastic chemicals. Our water tank includes a domed ferrocement top that’s exceptionally strong. It can be built in 2-3 days by four workers with minimal skill, although plastering skill is very helpful. There’s a huge water shortage on the islands here in Vanuatu, as well as many other places. Those who learn this method could make a lot of money selling water tanks since demand is high and cost of labor is cheap.