Determining the recharge rate/recharge capacity of a recharge well

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Hi All, Please can you help with best methods to determining the recharge rate/recharge capacity of a well.

Much appreciated

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3 Answers

  1. Hi Lalit, hope you find the attached document useful

  2. The option of recharging the well depends on the objectivity as the natural hydrological cycle takes care of this unless disturbed by human interference.  Having said that, there are many options - 1. if you have a good  idea of the hydrological network, you can think of recharging at appropriate places (multiple) and reach the objective. 2.  Secondly, you have to have the data on water depletion of the well and the amount of recharge you desire and the frequency as well.  Piezometers would be very handy  to guage the extent of recharge level and you may stop once you reach your target. 

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  3. Depending upon volume of water to be injected, number of injection wells, location (geophysical).etc. This depends mainly on storage coefficient, availability of storage space and permeability. Very high permeability results in loss of recharged water due to sub-surface drainage where as low permeability reduces recharge rate. In order to have good recharge rate and to retain the recharged water for sufficient period for its use during lean period, moderate permeability is needed. Older alluvium, buried channels, alluvial fans, dune sands, glacial outwash etc. are the favourable places for recharge. In hard rock areas, fractured, weathered and cavernous rocks are capable of allowing high intake of water. The basaltic rocks i.e. those formed by lava flows, usually have large local pockets, which can take recharge water.

    With Injection Well In this technique at the bottom of recharge shaft a injection well of 100 - 150 mm diameter is constructed piercing through the layers of impermeable horizon to the potential aquifers to be reached about 3 to 5 meter below the water level.  • Ideally suitable for very deep water levels (more than 15 meters) • Aquifer is over lain by impervious thick clay beds • Injection well can be with or without assembly • The injection well with assembly should have screen in the potential aquifer at least 3 – 5 meter below the water level. • The injection well without assembly is filled with gravel to provide hydraulic continuity so that water is directly recharged into the aquifer • The injection well without assembly is very cost effective. • Depending upon volume of water to be injected, number of injection wells, can be increased to enhance the recharge rate. • The efficiency is very high and rate of recharge goes even up to 15 lps at certain places.