Each combined water harvesting system and bio-wastewater filter along with training will cost US$133 per family. The reach is intended to benefit 400 families... with major food, health and livelihood benefits.
"in the remote village of Tuilam, and it will provide a rainwater harvesting system for a village of around 400 inhabitants for a budgeted cost of $40,000 USD."
"Each reservoir holds up to 16,000 L of water, and can be built for a total of about $900." [no filtration, suitable for irrigation only]
Rainwater harvesting from rooftop catchments.
"Annual rainfall ranging from less than 500 to more than 1500 mm can be found in most Latin American countries...
"The following questions need to be considered in areas where a rainwater cistern system project is being considered, to establish whether or not rainwater catchment warrants further investigation:
- Is there a real need for an improved water supply?
- Are present water supplies either distant or contaminated, or both?
- Do suitable roofs and/or other catchment surfaces exist in the community?
- Does rainfall exceed 400 mm per year?
- Does an improved water supply figure prominently in the community's list of development priorities?"
"The water ultimately is stored in a storage tank or cistern, which should also be constructed of an inert material. Reinforced concrete, fiberglass, or stainless steel are suitable materials."
" All rainwater tank designs should include as a minimum requirement:
- A solid secure cover
- A coarse inlet filter
- An overflow pipe
- A manhole, sump, and drain to facilitate cleaning
- An extraction system that does not contaminate the water; e.g., a tap or pump
- A soakaway to prevent spilled water from forming puddles near the tank... "
"The main sources of external contamination are pollution from the air, bird and animal droppings, and insects. Bacterial contamination may be minimized by keeping roof surfaces and drains clean but cannot be completely eliminated. If the water is to be used for drinking purposes, filtration and chlorination or disinfection by other means (e.g., boiling) is necessary."
"A procedure for eliminating the "foul flush" after a long dry spell deserves particular attention. The first part of each rainfall should be diverted from the storage tank since this is most likely to contain undesirable materials which have accumulated on the roof and other surfaces between rainfalls."
"The cost of this technology varies considerably depending on location, type of materials used, and degree of implementation. In Brazil, the cost of a 30-cubic-meter cistern in rural areas of the Northeast is around $900, depending on the material used. In the U.S. Virgin Islands, costs as low as $2 to $5/1000 liters are reported. Construction costs for underground cisterns can vary tremendously, based on the size and the amount of excavation required. In Saint Lucia, the average cost of a 1500 liter plastic tank is $125. In the Chaco region of Paraguay...cost of a 30-cubic-meter cistern...reported to be $2000, while the construction of a 6000-cubic-meter cistern, including windmill-driven pumps and distribution piping, has been estimated at $8400."
A long list of contacts is at the end of the article.
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