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Wells, shafts and boreholes
General features
Design of recharge wells can vary considerably and include the construction of boreholes in the base of wells and backfilling the well with graded filter material to restrict ingress of suspended solids that would rapidly clog the system, and restrict inflow of contaminants. Recharge wells are advantageous when land is scarce. However, recharge water quality requirements are usually significantly higher for borehole injection than for groundwater recharge by means of surface spreading.
Advantages of ASR wells are that costs are minimized and clogging is removed during the recovery cycle. ASR systems can usually meet water management needs at less than half the capital cost of other water supply alternatives. However, to successfully apply ASR, extensive research and ASR pilot testing is needed, to evaluate permeability of aquifers, chemical changes in aquifer, the quality of recovered water, the efficiency of schemes and environmental impact.