Lok Sabha Question No. 1712 (UNSTARRED), answered on 2024-12-05
Subject: Water Supply and Sewerage Board
Ministry: JAL SHAKTI
Asked by: Shri Basavaraj Bommai

## GOVERNMENT OF INDIA MINISTRY OF JAL SHAKTI DEPARTMENT OF DRINKING WATER AND SANITATION

## LOK SABHA

## UNSTARRED QUESTION NO-1712 ANSWERED ON 05/12/2024

## WATER SUPPLY AND SEWERAGE BOARD

## 1712. SHRI BASAVARAJ BOMMAI:

Will the Minister of JAL SHAKTI be pleased to State:

(a)  whether  the  Government  is  aware  of  the  Bengaluru  Water  Supply  and  Sewerage  Board's (BWSSB) initiative of supplying blended water mixed with Cauvery water particularly in south and west Bengaluru and if so, the details thereof;

(b) whether the Government has conducted any study on the water quality issues especially the hardness due to stagnation and the long-term effects of blending in water; and

(c) if so, the details thereof and if not, the reasons therefor?

## ANSWER

## MINISTER OF STATE FOR JAL SHAKTI (SHRI V. SOMANNA)

(a) to (c) Since August 2019, Government of India, in partnership with States, is implementing Jal Jeevan Mission (JJM)-Har Ghar Jal to enable every rural household in the country, to have assured potable  water  through  tap  connection.  Drinking  water  is  a  State  subject,  and  hence,  the responsibility  of  planning,  approval,  implementation,  operation,  and  maintenance  of  drinking water  supply  schemes,  including  those  under  the  Jal  Jeevan  Mission,  lies  with  State/UT Governments. The Government of India supports the States by providing technical and financial assistance.  As  such  details  of  individual  projects/  schemes  for  rural  water  supply  are  not maintained at Government of India level.

The Status of implementation of Bengaluru Water Supply and Sewerage Board's initiative, as informed by State Govt. of Karnataka, is annexed.

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## Annex referred in Lok Sabha Unstarred Question No.1712 for reply on 05.12.2024

## Status of Implementation of Bengaluru Water Supply and Sewerage Board's Initiative

As informed by State Govt. of Karnataka, the Thippa Gondnahalli (TG Halli) reservoir was used as potable water source to Bangalore city from 1935 to 2012. Since the year 2012, the rainfall in the catchments of Arkavathi and Kumudvathi streams was extremely low, accordingly pumping from reservoir was stopped. In 2018, DPR was prepared for revival of TG Halli Reservoir with several options:

- i. Blending of  Yettinahole water with TG  Halli reservoir water
- ii. Dilution of TG Halli water with Secondary treated water from Vrishabhavathi catchment.
2. Subsequently  the  project  of  Revival  of  TG  Halli  water  supply  Scheme  Phase-I  was approved and allocation of 1.7 TMC/year of Yettinahole water to TG halli was done by State Government and the project work was taken up in March 2019.
3. Usually, the Water Treatment Plant have process of (1). Areation (2). Alum dosing, prechlorination (3). Agitators (4). Flocculator (5). Clarifiers (6). Filter Beds (7). Post Chlorination and (8). Storage tanks/Clear water Reservoir.
4. Since the TG Halli Reservoir catchment has issues with contamination, the Project has 20 MLD STP for treating  the  Arkavathi  catchment  water  (operational  since  September  2023)  in upstream of the reservoir and the 110 MLD WTP (Water Treatment Plant) at TG halli was designed with Ozone as oxidizing agent for disinfection and treating both organic and inorganic load in addition to post chlorination. Further the filter beds are having 3-layer filter media 1. Activated Carbon granules filter 2. Sand filter 3. Pebbles.
5. Further the Dredging of Reservoir was conducted in project work after scouring of the Water from Dam and long-standing Stagnated water was removed.
6. During monsoon of 2022, High inflow water was received at TG Halli, the reservoir was fully filled (3.345 TMC) and excess water was discharged along with scouring of leftover water from Reservoir/Dam outlet valves. The Yettinahole project is under progress and water is probable to reach TG halli in the year 2026.
7. Subsequently Indian Institute of Science (IISc) was consulted and  IISC had opined for blending of disinfected water from TG halli with Kaveri water in ratio of 1 :20 and can be used for potable purpose.
8. The WTP plant at TG halli was completed in June 2024 and several treated water samples were collected and given to 3 rd party agencies (NABL approved, BIS approved) for testing the sample as per IS 10500 and the agencies have complied that treated (ozonized) water is meeting the parameters. But based on the IISC opinion, the TG halli water (10 MLD) is mixed/blended in the ratio 1:25/30 at Hegganahalli GLR and supplied.
9. The hardness of TG Halli water is 750 800 TDS at surface and depth. Blended/Mixed water is meeting the standards IS 10500 (potable water).