An approach towards site selection for water banking in unconfined aquifers through artificial recharge

- An attempt has been made for pre-event site selection for groundwater banking.
- An index has been developed to evaluate site-efficiency for well injection.
- The index is based on the normalized ratio of recharge and productivity.
- Formulation of the index and the site-selection method are discussed.
- A case study in the hard-rock Aravalli terrain of India is presented.

Selection of sites for water banking is very crucial for successful recovery of groundwater at the time of need. Attempts were made earlier to demarcate artificial recharge sites, and several indices were proposed for post-event evaluation of site-efficiency. In the present study a step-by-step method has been proposed for pre-event site selection for groundwater banking, based on meteorological, hydrological, hydraulic and hydrogeological parameters. Further, an index has been developed to evaluate site-efficiency. The proposed Normalized Difference Water Recovery Index (NDWRI) is the normalized ratio of water input and output in terms of recharge and productivity. Greater the value of yield, productivity, and the NDWRI higher is the suitability of the site for subsurface water banking. The index assumes a linear relation between recharge and sustainability of well productivity. In this article, the proposed methodology is explained and the related issues are discussed with a case study in the hard-rock Aravalli terrain of India.