In the absence of real-time data on groundwater use in urban India, it is difficult to predict trends in terms of how comparative shares of surface and groundwater shape up through the fourstage transition described above. However, observations across many locations in India indicate that the volumes of surface water pumped from ponds, tanks, and reservoirs, even in surface water-dependent townships, increases with time. Similar trends in groundwater use are extremely difficult to describe in the absence of reliable data. Even in a city like Pune where this has been studied extensively (Deolankar 1977; Lalwani 1993; Kulkarni et al 1997), exact quantification is difficult.
However, based on evidence in National Institute of Urban Affairs (NIUA) (2005), Narain (2012), and extensive discussions with public officials, government agencies, researchers and civil society organisations across different towns and cities in India, a first-cut attempt has been made to capture the shifting significance of surface and groundwater in urban water supply over time (see the figure above). The figure summarises key elements at each stage that a single large city or metro would have gone through over a timeline of the last six decades. This is a hypothesis for future research to test further.
Our conjecture is that the dependence on surface water grows over time. However, groundwater follows a more complex and relatively indeterminate trajectory. In particular, after the stage when the share of surface water becomes higher than that of groundwater in urban water supply, the trajectory of groundwater (given the absence of robust data on well numbers, pumping volumes, and groundwater transfers) becomes indeterminate and could move in three possible directions—(1) it follows surface water trends, (2) it remains stable, or (3) it falls considerably.
The precise trajectory, the specific path chosen, will depend on particular aquifer typologies and socio-economic conditions. But understanding the precise trajectory is significant, both in terms of utility planning and management in urban India.
Groundwater: The Blind Spot in Urban Water Planning
India is the largest consumer of groundwater in the world. India’s annual agricultural use of groundwater resources is in excess of 250 cubic kilometres, the largest in the world, leaving China way behind (Shah 2009). Moreover, 85% to 90% of rural India depends on groundwater resources for drinking water supplies (DDWS 2009; World Bank 2010). Nearly 70% of irrigated agriculture in India depends on groundwater (Ministry of Agriculture 2013). Three recent statistics point to how at least half of urban India clearly depends on groundwater for its various needs.
(1) Averaged for 71 cities and towns, groundwater constitutes 48% of the share in urban water supply (Narain 2012).
(2) In India, 56% of metropolitan, class I and class II cities are dependent on groundwater either fully or partially (NIUA 2005).
(3) Unaccounted water in urban areas exceeds 50%, according to the CGWB’s report on the groundwater scenario in 28 Indian cities (2011).
Privately driven, individualistic pumping of groundwater in large parts of urban India has provided benefits by filling gaps in public water supply schemes. However, it has also led to problems of co-terminal depletion and contamination of aquifers. There are huge gaps in our knowledge about urban aquifers, their characteristics, the significance of their service value, and a comprehensive understanding of the competition and conflicts around groundwater resources. Sustainable management of groundwater is impossible without a much deeper understanding of the types of aquifers within which it is located.
Aquifers in large regions of India act as both sources and sinks for various loads, ranging from sullage to sewage and from industrial waste to agricultural residues such as pesticides and fertilisers. Groundwater resources in growing urban centres are therefore likely to become contaminated as much by residual contaminants from erstwhile agricultural activities and poor rural sanitation as by contamination from more current haphazard waste water disposal.
Only 33% of urban Indians are connected to a piped sewer system and 13%—roughly 50 million urban Indians—still defecate in the open (Census of India 2011). Large parts of the modern cities remain unconnected to the sewage system as they live in unauthorised or illegal areas or slums, where state services do not reach (Shah 2013). Surveys of groundwater quality in many cities, therefore, reveal a large magnitude of waterborne pathogenic contamination—commonly referred to as bacteriological contamination—clear signs of groundwater contamination by sewage.
Groundwater Resources in Urban India
A groundwater typology can be defined by hydrogeological settings, aquifer scales, and the socio-economic factors of a region (Kulkarni and Shankar 2009). Hence, the typology of groundwater decides how and how much the water stored in an aquifer changes as a consequence of groundwater recharge and extraction. The primary basis for a groundwater typology is the geology of a region, given that various geological formations host aquifers, with the characteristics of these aquifers—mainly the transmissivity, storativity, and groundwater quality— determining the groundwater fl ow and stocks in the region. Kulkarni and Mahamuni (2014) divide variously sized towns and cities into six categories.
This was attempted using a geographic information systems (GIS) framework of overlays on the fourfold urban classifi cation described above. This classification is probably a first of its kind and is evolving as the GIS analysis is sharpened. However, it provides a useful indicative typology of groundwater resources in urban India.
Sustainable Groundwater Management
Developing an understanding about groundwater resources is as much a function of the diversity of aquifers as it is of the nature and extent of groundwater use. The aquifer mapping and management programme, one of the highlights of India’s Twelfth Five Year Plan, could be used as an instrument to begin this process. The following key steps could form the building blocks of an urban aquifer management programme in India.
(a) Identifying status of existing groundwater resources in cities through participatory mechanisms, involving citizens, educational institutions and urban utilities.
(b) Assessing groundwater resources through a participatory “aquifer mapping” approach coupled with systematic studies by institutions with appropriate capacities to identify natural recharge areas, groundwater discharging zones, and quantification of aquifer characteristics, namely transmissivities, storativities, and groundwater quality.
(c) Profiling stakeholders, including users, tanker operators, and drilling agencies, and developing mechanisms for registering water sources.
(d) Ascertaining quantitative and quality-related groundwater security, including groundwater recharge, which is allied to the protection, conservation, and upkeep of waterbodies.
(e) Considering hydrogeology during waste disposal, sewage and sullage management, and design of sewerage and sewage treatment.
(f) Developing a framework of regulatory norms around urban groundwater use and protection of urban aquifers by preserving natural recharge areas.
(g) Understanding changes in river flows and quality, and the precise relationship between aquifers, aquifer systems and the river flowing through a town or city.
(h) Finally, developing an institutional structure required for mapping aquifers, and initiating groundwater management as an integral part of urban governance.
*Excerpts from the paper “Urban Water Systems in India Typologies and Hypotheses”, based on a study done for the Indian Council for Research on International Economic Relations and Global Green Growth Institute. Mihir Shah (firstname.lastname@example.org) was Member (Water Resources), Planning Commission, 2009–14. Himanshu Kulkarni (acwadam@gmail. com) is with the Advanced Centre for Water Resource Development and Management, Pune. Click HERE to download the paper