[[Image:infiltration wells.png|right]]
[[Image:InfiltrationWell.JPG|thumb|right|250px200px|Infiltration well in Madagascar. Eric Fewster, BushProof.]]
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Also called interception wells, these are shallow wells which put (or draw) water into (or from) a natural aquifer outside of a riverbed, but which have a partial lining. They can be used to either drain a catchment area or recharge groundwater, especially where recharge of the aquifer is low due to low rock/soil permeability (the well penetrates through this). Water extraction, however, is a secondary activity, as the water levels will be lower and the amount extracted will be more limited.
Rocks, coarse wood chips or straw can be used as filtering material. Wells made of straw are constructed like permeable trenches and do not have a coiled drain, which can limit their infiltration capacity. Water extraction can be done with [[Handpumps]] or [[Small and efficient motor pumps]]. Handpump cylinders will need to physically be able to fit inside the screen that has been installed.
===Suitable conditions===
* Site where water table is within 5 metres of ground surface, and where soils are stable.
* Site where water demand is low, e.g. for small communities.
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! width="50%" style="background:#efefef;" | Advantages
! style="background:#ffdeadf0f8ff;" | Disadvantages
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| valign="top" | - Lower cost than making a fully lined well due to less lining needed <br>
===Resilience to changes in the environment===
====Drought====
'''Effects of drought''': Less recharge of aquifer due to less rainfall; Increasing population & water demand; Size of aquifers – e.g. limited sand volume; Wells not sunk deep enough into water table; Incorrect siting; Graded gravel around pipe not correctly done.
More information on managing drought: [[Resilient WASH systems in drought-prone areas]].
===Construction, operations and maintenance===
'''General advice on cement''': A common cause of cracks in structures and linings (e.g. in tanks, dams, waterways, wells) is errors in mixing and applying the cement. First of all, it is important that only pure ingredients are used: clean water, clean sand, clean rocks. The materials have to be mixed very thoroughly. Secondly, the amount of water during mixing needs to minimal: the concrete or cement needs to be just workable, on the dry side even, and not fluid. Thirdly, it is essential that during curing the cement or concrete is kept moist at all times, for at least a week. Structures should be covered with plastic, large leaves or other materials during the curing period, and kept wet regularly.
Lastly, infiltration wells and separate drain outlets must be inspected frequently to evaluate the condition of the structures as well as their efficiency in improving surface drainage and reducing erosion problems.
==Costs== ==Field experiences== ==Manuals, videos, and links===
* [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCYQFjAA&url=http%3A%2F%2Fwww.agrireseau.qc.ca%2Freferences%2F6%2FFiches_MAPAQ-AAC_Erosion%2FPuitsdInfiltration_EN_web.pdf&ei=2OiFT6SyH5HJiQKPpoXmDQ&usg=AFQjCNHB9NNqUldcGONNvh-vZjj2chsjQA&sig2=aX6lmpw7gCOou3UhFHg0RQ Infiltration wells Factsheet]. Agriculture and Agri-Food Canada (AAFC) and the Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec (MAPAQ).
* [http://www.samsamwater.com/library/Artificial_groundwater_recharge_for_water_supply_of_medium-size_communities_in_developing_countries.pdf ARTIFICIAL GROUNDWATER RECHARGE FOR WATER SUPPLY OF MEDIUM-SIZE COMMUNITIES IN DEVELOPING COUNTRIES.] E.H. Hofkes and J.T. Visscher. December, 1986.
===Acknowledgements===
* CARE Nederland, Desk Study: [[Resilient WASH systems in drought-prone areas]]. October 2010.
* [http://www.agrireseau.qc.ca/references/6/Fiches_MAPAQ-AAC_Erosion/PuitsdInfiltration_EN_web.pdf Infiltration wells Factsheet]. Agriculture and Agri-Food Canada (AAFC) and the Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec (MAPAQ).
