Delhi: Groundwater
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Availability and quality of water
As in 2017
Proposal To Ban Extraction From 1Km-Zone On Either Side Of Najafgarh Drain
The Central groundwater Board has categorised groundwater in Delhi into four zones according to availability and quality of water and issued guidelines for managing them. It has also recommended the cessation of all extraction of groundwater from a 1km-zone on either side of Najafgarh drain and from landfill and industrial sites because of the water there being highly polluted.
In its report called “Hydrogeological Framework and Groundwater Management Plan of NCT Delhi,“ released recently , CGWB has recommended extraction in Zone 1 areas, where groundwater is available at a depth of less than 8 metres below the ground. However, the report also said that many areas in this zone had poor quality water and this should be used for salt-tolerant crops or blended with clean water for non-drinking purposes.
The board said extrac tion projects should not be allowed in areas with declining water level (zone III).These included Delhi Cantonment, Vasant Vihar, Hauz Khas, Kalkaji, Chanakyapuri, Connaught Place, Punjabi Bagh, Paharganj, Preet Vihar and Vivek Vihar.CGWB has said if pumping continued at the current rate here, it would result in saline water. It has recommended rainwater harvesting and use of tertiary treated waste water for recharge of these areas.
The report warned that overexploitation was not only depleting water resour ces, but turning groundwater saline. Of the 13,491 million cubic metres (MCM) of groundwater in Delhi, 10284 MCM, or 76%, was brackish or saline. Among affected areas were Darya Ganj, Sa raswati Vihar, Punjabi Bagh, Najafgarh, Civil Lines, Defence Colony , and Delhi Cantonment. “Poor quality groundwater can be used for growing salt-tolerant crops like cotton, whe at, gaur, chickpea, soyabean, sugarcane and others,“ the report advised.
As for places abutting the Najafgarh drain, the report stated that the “presence of heavy metals has been re ported in groundwater along the drain. Therefore, groundwater in this zone is unsuitable for drinking and irrigation purposes...pesticides and bacteriological parameters have also been reported in isolated pockets.It is recommended that landfill sites should be selected after concluding hydrogeological surveys to minimise the risk of groundwater pollution“.
Shashank Shekhar, assistant professor of geology at Delhi University , who had conducted an independent study on the Najafgarh drain, pointed out, “Fluoride and even arsenic in groundwater in water samples of the Najafgarh drain can be attributed primarily to anthropogenic sources. Some heavy metals are, of course, found naturally in the environment, but they are not found in levels that are dangerous to human use.High nitrate contamination was also discovered in Timarpur, with fluoride levels above permissible limits in 20% of the samples.“
CGWB has identified a “potential aquifer zone“ along the western Yamuna canal which can yield around 5 million gallons per day (MGD) of water (the city's need is estimated to be 1,140 MGD by the 12th Five Year Approach Plan paper). The board also mapped tehsil-wise groundwater level trends between 2003 and 2013. Kalkaji tehsil showed the highest groundwater development at 277%, or much higher exploitation than the recharge capacity . It was followed by Vasant Vihar at 268%, Hauz Khas at 260% and Rajouri Garden at 232%.
2017/Mangar groundwater unfit: CPCB
Shilpy Arora, CPCB finds Mangar groundwater unfit, September 8, 2017: The Times of India
Villagers Helpless; Report Sent To NGT
The worst fears of green activists about contamination of groundwater due to flow of leachate from the defunct Bandhwari waste treatment plant have come true.Central Pollution Control Board (CPCB) has found that the groundwater in Bandhwari and Mangar villages are polluted to such a level that it is unfit for drinking. The board submitted its report to National Green Tribunal (NGT).
The green tribunal had asked CPCB in July to conduct laboratory tests of the groundwater in and around Bandhwari in the wake of a plea filed by environmentalist Vivek Kamboj in 2016. In its petition, Kamboj alleged that leachate from the solid waste management plant in Bandhwari, which has been lying defunct for the past four years, was flowing into underground aquifers, thereby contaminating the groundwater of the area.
“Nitrate in the groundwater samples from Mangar village and Bandhwari village are not complying with the drinking water standards, hence groundwater at Mangar and Badhwari villages is not fit for drinking purpose, but water can be used for bathing and irrigation purposes,“ states the report.
The board has blamed leachate formation at the defunct Bandhwari waste treatment plant for high levels of chloride, manganese, calcium and boron in the groundwater of these villages. “High values of manganese, calcium, boron and chloride content at a borewell at landfill site and a borewell at Dera village, (located) 500 metres away from landfill site are observed. Such contents... are higher than the acceptable upper limits for drinking purposes... This may be attributed to contamination of the borewells from landfill leachate,“ states the report.
While chlorides at a borewell has been found to be 888 mgl (milligrams per litre) -three times higher than the desirable limit -nitrate level at another borewell is 101.7 mgl (two times higher than desirable limit). The desirable limit of chlorides and nitrates should be below 250 mgl and 45 mgl, respectively . Similarly, highest levels of manganese, calcium and boron are 14.11 mgl, 285 mgl and 0.6 mgl, respectively . The desirable limit of manganese, calcium and boron, on the other hand, should be below 0.1 mgl, 75 mgl and 0.5 mgl, respectively .
The board also said in its report that there are chances that groundwater contamination could rise in the area. “Parameters like TSS (total suspended solids), TDS (total dissolved solids), BOD (biochemical oxygen demand), COD (chemical oxygen demand), arsenic and chloride are not complying with the discharge standards of the leachate and (it is) found that there is no proper management system for storage and treatment of leachate at the site,“ the report states.
