This is not a new topic and has been discussed by various experts from multi-disciplines in different forums. Yet a holistic view is yet to emerge for any practical planning or operational implementation. Broadly the issues include surface and groundwater management on a sustainable basis. The surface water management depends on topography, location (geography), rainfall/ runoff, land use, urban landscape (imperviousness) and proper storm water drainage system. The groundwater management depends on all above factors besides hydrogeology. It is important to view and manage the two in an integrated manner. In simplistic terms effective management implies conserving and utilising the water resource for pubic benefit without any adverse conditions such as water logging with due regard to monsoon type of rainfall conditions in India. This is accomplished through efficient drainage and rainwater harvesting structures. Rainwater harvesting structures serve numerous purposes such as water conservation, artifificial recharge etc.
Practical considerations for groundwater management relate to groundwater abstraction, recharge and its quality. At present the law does not prevent abstraction if you own the land from which water is pumped. There is no limitation to the amount of water one can draw from any depth. However groundwater environment is is a directly affected by recharge from disposal from abstracted water and rainfall in terms of urban infrastructure, policies and programs. Some efforts by CGWA (Central Ground Water Authority) and a few state agencies (e.g. Tamilnadu) are in progress in terms of registration, licensing and notifications for regulation. However they lack scientific basis.
Till date policies and programs have been formulated mainly from politico-socio-economic considerations. More often knowledge base relating to hydrology/ hydrogeology is viewed in isolation from supply and demand point of view. For example roof top harvesting structures are blindly promoted to augment recharge in the urban areas. However a recharge in one area may result in water logging in adjacent areas depending on hydrogeology, soil and existing conditions on a future date. Similarly if no restriction for abstracting groundwater (public/ private) is imposed it may result in falling water tables, saline water upconing or contaminant migration in a city like Delhi.
While groundwater abstraction (or movement) is guided by physical laws (or hydro-geology) its objective is often based on socio-economic considerations. Therefore there is a clear need to integrate the two. This is possible through groundwater planning models wherein groundwater structures are first simulated within socio-economic frameworks before evolving policies for planning and operational levels. In other words groundwater abstraction/ recharge structures are hydrologically simulated repeatedly in terms of location/ magnitude/ extent and the scenarios are generated within socio-economic constraints. The optimal scenerio should be implemented. These models can be updated periodically with revised data for planning purposes. Also these models can be evaluated for operational purposes before evolving policy guidelines in the form of regulatory instruments.