Cisterns
From WaterWiki
Cisterns are an alternative technology for water harvesting.
Contents |
Technical Description
Cisterns are an ancient method of water harvesting, dating back to the early Roman empire. There are artificial reservoirs constructed by excavating bedrock, such as limestone, to depths of between 3 and 7 metres to provide water storage throughout the Roman world. While serving a similar purpose, modern cisterns are usually built with cement blocks or fired bricks.
Cisterns collect water in the form of runoff from a rock-lined catchment or other suitable, nonporous surface. There is commonly a settling basin at the cistern entrance which serves to settle sediments borne by the runoff. A screen is also provided to remove larger particulates
Costs
The cost of implementing this technology is reasonably low, as most of the construction of the cisterns can be done by communities. However, mechanization is increasingly used for the digging of the cistern, which increases the cost.
Advantages
This technology has the advantage of being a simple, low cost technology which can increase the yield of water from rock catchment systems. Also, The use of cisterns to capture runoff has no known negative environmental effects, and can provide water for a variety of environmental purposes in dry areas.
Disadvantages
Use of this technology may require provision of an abstraction system to draw the water from the cistern. Because of the likelihood of contamination from surface sources, this technology is not ideal for use as a potable water source
Further Readings, References, Links
UNEP's comprehensive Sourcebook of Alternative Technologies for Freshwater Augmentation and UNICEF's Handbook on Water offer an in-depth assessment of small scale technologies for water supply, augmentation, waste water treatment for all regions.
Source(s)
Sourcebook of Alternative Technologies for Freshwater Augmentation in Africa]
