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Traditional hand-dug wells

897 bytes added, 00:24, 21 April 2012

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==Suitable conditions==

{{Climate_change

|heading1=Drought

|text1=- ''Effects of drought'': Can dry up perched aquifers; Groundwater levels dropping in perched aquifers. <br> - ''Underlying causes of effects'': Less recharge of aquifer due to less rainfall; Increasing population & water demand; Size of aquifers – e.g. perched aquifers will be used up faster; Wells not dug deep enough into water table. <br> - ''To increase resiliency of WASH system'': Avoid perched aquifers; Dig wells deeper – de-water well during caissoning within the water table; Allow for subsequent deepening by using telescopic lining; Dig wells during the latter half of the dry season; Recharge aquifer through Managed Aquifer Recharge (MAR) boreholes; Jet in the bottom of the well to provide a means of faster recharge; Increase flow by use of porous concrete or perforated pointed steel pipes driven horizontally into the aquifer.}}

 

* Layers of sand and gravel tend to provide good locations for wells and boreholes. Other good locations are in weathered rock in granite areas, along the edges of valleys in mountainous areas or in a river valley where there may be sandy deposits under the banks.

* Care should be taken to avoid siting wells in perched aquifers (shallow aquifers with limited recharge capacity and water storage).

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Winona

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