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[[Image:RechargePit.jpg|thumb|right|300px|Recharge pit constructed for recharge of surface runoff. Rajasthan, India. <br> Photo: [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDgQFjAB&url=http%3A%2F%2Funesdoc.unesco.org%2Fimages%2F0014%2F001438%2F143819e.pdf&ei=uqt8T9_sL6ibiQKTqdzFDQ&usg=AFQjCNFjJrN8OJHYuNSZrDZIrDtZxc_LRg&sig2=J7p3YnDub8Ixn2n4DU-uBw ''Strategies for Managed Aquifer Recharge (MAR) in semi-arid areas.''] UNESCO.]]
Large diameter wells and smaller diameter boreholes can be used to directly recharge or dilute shallow aquifers where low permeability strata (rock) overlies the aquifers and where other infiltration methods are not effective. The important thing is that water of high enough water quality is used for this purpose. Although this method of recharge is practised with deep and high-yielding boreholes, this technique mainly describes recharge at the family level in areas where hand dug wells run dry at the end of the dry season or where groundwater is saline.
==Suitable conditions==
* Site only in areas where rainwater does not infiltrate fast enough where there is high runoff.
* '''Avoid''' where there is a risk of chemical contaminants entering the well, e.g. fertilizers and pesticides from agriculture, and when the final
- Technology needed to construct these structures can be quite complex, requiring engineering skills.
}}
==Resilience to changes in the environment==
====Drought====
'''Effects of drought''': Water levels reduce in wells & boreholes that are being recharged.
'''Underlying causes of effects''': Less recharge.
====Floods====
Shallow wells in areas with a high water table are more prone to contamination from flooding than deep boreholes. Wells near rivers can be contaminated and filled with sand during flash floods.
==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.
[[Image:RoofToAquifer.jpg|thumb|right|300px|Roof to aquifer recharge. Click image to zoom. <br> Drawing: Unicef/Ara Centro. (2009)]]
====Water source considerations====
Water to be recharged should be high quality since blockage due to suspended sediment, microbial growth or chemical precipitation is more likely over the smaller infiltration area of a well or borehole. In Namibia, water from the water treatment works is further treated with granular activated carbon and chlorination before being injected to avoid such problems. In certain cases in India, open large diameter wells that ran dry due to falling water tables (resulting from over-exploitation) are being used to recharge shallow aquifers directly from runoff water that enters the wells – the problem with such structures is that there is no process of water infiltrating through the soil to the aquifer, which would not only reduce sediment and microbiological load, but also have potential chemical contaminants like nitrates and pesticides. Direct recharge of untreated water via open wells is therefore discouraged in preference to infiltration through a soil or sand layer. However, since silt and contaminants can more easily enter through a well, course gravel is sometimes filled into it to act as a filter, which can be replaced if clogging becomes severe.