Need to Bridge the Critical Knowledge Gaps to Arrest Groundwater Depletion
Whichever approach is adopted, the management of GW resources must be based on the erlier mentioned inextricable linkages, especially aggressive to depletion and degradation; and adequate knowledge of a clear aggregate situation of groundwater system and its replenishment.
However, there is no way to evaluate the maximum exploitable volume in advance or in absolute terms. Moreover, public demand and use of groundwater in the socioeconomic context, and the consequences of these have been characterized scarcely. Some of the important parameters of interest to the planners and managers are rechargeability of groundwater; its quantity and quality; location of recharge intake areas; inter-linkage between groundwater and surface water; sources of pollution, etc. However, most of the groundwater development research has been largely fragmented, technocratic and relates to groundwater flow and remediation. Moreover, the typical studies on measurements of water table fluctuations and pumping tests do not provide all the necessary information needed to find solution to the problems outlined above. Hence, the highly technical knowledge of the aquifer systems is of little use for practical management purposes.
More research is needed on dynamics of pollutants in the groundwater; its attenuation capacity for pollutants under natural and exploited conditions, based on well-designed monitoring network. The pollution sources should be identified; and strategies be framed to contain pollution spreading from known sources; and develop groundwater vulnerability maps. Based on these maps, the potential groundwater recharge zones and protection zones need to be clearly delineated with land use changes, to restrict/eliminate unplanned waste disposal and agro-chemicals application in these areas. So far, no practical solution exists to account for water and energy efficiency at the withdrawal point. For climate resilient water management, it may be useful to create an integrated system of adequate water supply, based on spatial and temporal variation in different timescales of groundwater recharge.