Groundwater extraction higher in central parts of Pune: Study

A groundwater aquifer mapping survey, conducted by Advanced Center for Water Resources Development and Management ( ACWADAM), NGO working in the field of groundwater, has highlighted the potential of aquifers in 3 wards in Pune city

According to a groundwater survey conducted across three wards, 25% of the city’s municipal supply is derived from groundwater extracted from borewells in the central areas.

As per the report, sources of groundwater tapped by different types of residential and commercial establishments (bungalows to large housing societies to community dwellings including ‘gaothans’) were inventoried from 9344 survey numbers. (REPRESENTATIVE PHOTO)

The wards included Kasba Peth- Somwar Peth ward occupying 0.91 KM2 area, Rasta Peth-Raviwar Peth area spreading over 0.9 km2 and Shanivar Peth-Sadashiv Peth occupying an area of 1.75 KM2.

A groundwater aquifer mapping survey, conducted by Advanced Center for Water Resources Development and Management ( ACWADAM), NGO working in the field of groundwater, has highlighted the potential of aquifers in 3 wards in Pune city.

The survey report was released in the last week of November and also highlighted that groundwater extraction is higher in the central parts of the city.

The report also revealed that societies are the major encroachments over the aquifers in the city’s central area.

A city expands, outwards from the nucleus the normal assumption is that the central/old parts of the city have assured municipal supplies for water and those supplies usually from surface water sources within or outside the city.

At the same time, the outer suburbs and peri-urban areas of such a growing city have less assured municipal supplies and have to often augment their demands from informal supplies that are largely groundwater-fed. It was with this assumption that ACWADAM ventured to test out the hypothesis in three core city wards of the Pune Municipal Corporation (PMC).

“Earlier in 2019 the organisation made a report on the city’s aquifers and the recent report is considered as the second part of the earlier report. It will still be a continuous process as the organisation also planned mapping aquifers from other areas of the city,” said Himanshu Kulkarni, executive director, ACWADAM.

Developing a hundred per cent inventory of groundwater sources, a quick measurement of groundwater levels and in-situ groundwater quality in a limited set of sources and a systematic survey of the nature, patterns and quantities of groundwater pumped from each surveyed source, were the main focus of the study and twenty interns from Fergusson College, Nowrosjee Wadia College and Poona College participated in this survey.

As per the report, sources of groundwater tapped by different types of residential and commercial establishments (bungalows to large housing societies to community dwellings including ‘gaothans’) were inventoried from 9344 survey numbers.

There are 1016 bore wells, 264 dug wells and 32 hand pumps in the three wards. Dug wells and energised bore wells dominate the Shaniwar Peth-Sadashiv Peth ward, while hand pump-fitted bore wells prevail in the Rasta Peth-Ravivar Peth ward.

The report also highlighted that these three wards from the core city area also show a high density of groundwater sources.

Rastapeth-Ravivarpeth shows a density of 4.1 groundwater sources (wells) per hectare, Shanivarpeth-Sadashivpeth has 4.3 groundwater sources per hectare and Kasbapeth-Somvarpeth shows a density of 2.1 groundwater sources per hectare.

Shanivarpeth -Sadashiv peth areas see the highest groundwater extraction with an annual extraction of over 1.2 million m2.

The resultant values from the study indicate that Pune’s groundwater extraction today is nearly 4 TMC, at very conservative estimates. This implies a groundwater extraction only from bore wells, is equivalent to about a quarter of the formal municipal supplies.

Speaking about the overall observation Kulkarni said, “Pune is underlain by a complex aquifer system from which there is a significant amount of annual groundwater extraction. The city has a large surface-water endowment in its public water supply system, however, Pune’s groundwater extraction is not small by any means. Therefore it is necessary to develop a focused system of groundwater management and governance keeping the hydrogeological and socio-economic factors surrounding groundwater resources in the city.”

Steps to balance groundwater extraction

*Decision–support system that is based on information and data from systematic mapping and measurement of aquifer systems and their various dimensions

*Strategic conservation of water, based on hydrology and hydrogeology; this should include using Managed Aquifer Recharge (MAR) as a means of planning public recharge programmes.

*Enabling a system that provides inputs to the efficient use of sources

*Demand management of groundwater through self-regulatory mechanisms.