As soon as practicable, displaced person camps should be provided with facilities to store an adequate reserve of water. In nearly all systems, it will be necessary to store water in covered tanks between the source and distribution points to provide an essential reserve and to facilitate distribution. Storage tanks ideally should have the capacity to store an amount of water equal to at least 1 day’s consumption, thus providing a reasonable reserve capacity with the added benefit of allowing sediment to settle overnight. The size of the tank will depend on the number of people, the nature of the water supply system, and certain logistical issues. Using internal dimensions and overflow pipe heights, capacities are calculated as follows.
- Rectangular tanks: length x breadth x height (in meters) x 1,000 = capacity in L
- Cylindrical tanks: height x (radius squared (in meters) x 3.14) = capacity in L
OFDA stockpiles include 10,000-liter water bladders with tap stands, portable water treatment units, and 10-liter collapsible water containers. See appendix B for more information on OFDA stockpile commodities.
In areas with pronounced dry and rainy seasons where alternative sources of water are limited, the construction of in-ground reservoirs to collect water should be considered. An erosion-protected spillway should be provided. Catchment tanks for the collection of rainwater and surface runoff can also be considered in drier parts of the world. Pits can be dug into the ground to catch and hold water that runs off hard ground during heavy storms. Reservoirs, tanks, and pits need special synthetic or clay linings to hold water, and should be covered if possible. Treatment of the water collected in such structures will be required in most instances. Protection from pollution and issues related to potential mosquito breeding in malarious areas must be given careful consideration.
TOC: C. Water