Water Supply & Sanitation
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Water Supply & Sanitation Water Supply & Sanitation Document Transcript

  • Water Supply & Sanitation
  • Water Supply : BackgroundThe main surface sources of water for Bangalore and Arkavathyand Cauvery River. Till 1896, the city was dependent onuntreated water from large number of tanks, local wells &Kalyanis. As the demand grew with the rise in population, theutmost source was identified as Arkavathy River across which atank was constructed at Hessarghatta and the water waspumped through RCC transmission main up to Malleswaramwhen Combined Jewel filters were constructed to filter thewater for supply to the city. The water supply from this sourcewas 36MLD. However, over the years it has been considerablyreduced. As the city grew rapidly, to meet the rising demand, alarger reservoir called Chamarajasagar (CRS) was constructedacross River Arkavathy at Tippagondanahalli (TG Halli), which isdownstream of Hessarghatta Lake. The water was abstractedfrom this reservoir and filtered and treated in a conventionalwater treatment plant and pumped to Bangalore city from theyear 1933 through a 900mm dia. CI main and subsequentlyaugmented in stages through CI pumping mains of 675mm and600mm dia with an immediate pumping station at Tavarekere.The total pumping of water from this source was 140 MLD.However, over the years, the yield has been gradually reducing.However, over the years the inflow into the Hessarghatta andCRS reservoirs reduced considerably, mainly due to theincreased usage of Arkavathy River water upstream of the 2reservoirs for agriculture and other development uses.
  • Water Supply : BackgroundAfter independence, Bangalore grew more rapidly inpopulation. Being the fastest growing city in the country, therequirement of water for human consumption and industriesrose sharply. Hence to meet the immediate requirement andfuture demands, a large source of water viz., River Cauvery wasidentified for development. The total supply of about 180 MLDfrom Arkavathy sources was reduced to about 18 MLD and wasabsolutely to meet the requirement of the city.GoK has allocated about 19 TMC (600 cuses) of Cavery riverwater to Bangalore City for utilization to meet the drinkingwater need from the state’s allocation. The main point fortapping Cavery River is at Shiva Anicut, which is about 90 km, tothe south west of Bangalore city.There is an earlier existing facility erected by KarnatakaElectricity Board (now changed to KPTCL, a limited company), inwhich the water from the Shiva Anicut is drawn through anopen power channel to the Forbes Sagar Balancing reservoirand finally to the Netkal Balancing reservoir at Netkal about8.85 km from anicut, which carries the combined flow or thehydropower generating station at Shimsha and for the watersupply. The Netkal Balancing Reservoir (NBR) serves as theheadworks for drawing the water from River Cavery for watersupply to the city. Since 1974, BWSSB has abstracted waterfrom Cauvery source and augmented the city water supplyunder Cauvery Water Supply Schemes (CWSS), in stages. CWSSStage I was commissioned in the year 1974 to augment thesupply by 135 MLD.
  • Water Supply : BackgroundCWSS Stage II followed and was commissioned in the year 1982 tofurther augment the supply by 135 MLD, CWSS Stage III wascommissioned subsequently in the year 1994 increasing the supply byan additional 270 MLD. BWSSB have more recently implemented CWSSStage IV Phase I in the year 2002 adding an additional 270 MLD oftreated water to the city supplies. For all these 4 stages, the water isabstracted from the headworks at NBR and conveyed to the waterTreatment Plant at Thorekadnahalli (TK Halli), which is located at adistance of 86 km from city, through gravity mains of 9.60 km length.The first gravity mains of 1750 mm dia carries Stage I and Stage IIflows, the 2nd main of 1950 mm carries Stage III flows and the 3rd mainof 1900mm dia Cauvery Stage IV Phase I flows.The raw water is treated in separate water plants for each of the 4Stages. Treated water is pumped in three stages at TK Halli, Harohalliand Tataguni before the water reaches the city. Intermediate PumpingStations are located at the three places for all the 4 Stages of CWSSSchemes. Stage I water is pumped through a head of 160m at eachstage of pumping and conveyed through 1200mm dia MS transmissionmain to the city terminates at South end circle. The water istransmitted through CI mains to Byrasandra, Bull Temple Reservoir,MNK Park Reservoir, Clive Line Reservoir (CLR) and Kempegowda TowerReservoir (KGT) for storage and balancing and distributed throughoutthe city through the existing water supply system. Under Stage II alsothe water is pumped to the city through another parallel 1200mm diaMS transmission mains, the lift at each pumping station being 160m. AtSouth-End Circle, water is transmitted to High Ground Reservoir (HGR)through a 1750mm dia MS main, which also carries the stage III waterwith Stage II augmenting water is supplied to Banashankari (BSK II) andHigh Grounds Reservoir which acts as a balancing reservoir, from wherewater is supplied to reservoirs at KG Tower, Clive Lines andMachalibetta (MBR); pumping of water is 135 MLD.
  • Salient Features of Water SupplyThe salient characteristics of existing water supply for Bangalore issummarized and presented below:Population as per 1991 Census of the Urban Agglomeration (UA) – 41.3lakhPopulation as per 2001 Census of the UA- 60 lakhPresent Population as on 2005 of the UA (Projected) – 70 lakhArea of the UA (sqkm) – 560Population provided with water supply as on 31.3.2004 – (Million) 4.92Source(s) of existing Water SupplyName Cauvery RiverDistance (km) from City 120 kmTotal water produced (MLD) 842Total quality of water supplied (MLD) 842Quantity supplied for domestic use (MLD) 439Quality supplied for industrial/commercial use (MLD) 72Loss of water/ UFW-in (MLD) 330, in 39%Net Average per capital water supply (lpcd) at present 73Distribution network length (km) (APP) 3500Total number of water connections 3,61,294House Service Connections 3500, 049Public Stand Posts 7,174No. of metered connections 3,61,294No. of un-metered connections Nil
  • Salient Features of Water Supply No. of Bulk connections Industrial-71; Commercial – 11071; Institutional- 141 Existing Water Traffic Domestic Water Traffic (Rs. /KL) 06.00 (Lowest slabs) 36.00 (Highest slabs) Commercial Water Tariff (Rs. / KL) 36.00(Lowest Slabs) 60.00 (Highest slabs) Industrial Water Tariff (Rs. / KL) 60.00 + 10% sewage cess Tariff effective from (date) 01.08.2002The MP divides the Bangalore Area into 47 Planning Districts. According to Master Plan – 2015, the water supply status is being addressed highlighting the source (groundwater, BWSSB, private (water) supply, well water, etc).The sanitation position is also addressed which appears to be poor compared to water supply. The BWSSB connections vary from almost zero to 301 connections / 1000 habitants. This may be partially due to newly added wards of BMP to supply BWSSB water. The water supply pipelines are being laid in not only erstwhile in 7 CMCs and 1 TMC but also proposed to lay in the new BDA developed areas such as Banashankari, Visvesvaraya Layout, JP Nagar, etc.
  • Sewerage System : BackgroundSewerage system in Bangalore was in place/existence since 1922 smentioned earlier. Earlier the city was densely populated in civilian andcantonment areas of the old city and since 1920 the decadal growth rate ofpopulation in metropolitan area is more than 19.6 hitting a maximum of94.3 in 1950s. Therefore, in the year 1950 only, major development andsewerage coverage was initiated .Now around 225 sqkm area is being covered by the sewerage system. Thedrawing zone coverage details are: Major Valleys – Vrishabhavathi – 44.88sqkm; K&C- 73.65 sqkm; Hebbal-39.1 sqkm; Minor Valleys –Kethamaranahalli & Arkavathy – 22.91 sqkm; Tavarakere-13.72 sqkm; andKathriguppe – 15.15 sqkm. The existing sewerage system area is dividedinto 3 district major drainage zones, namely, Vrishabhavathi Valley (VValley, 50.08 sqkm), Koramangala and Challaghatta (K&C Valley, 68.48sqkm) and Hebbal Valley (33.77 sqkm), which for the most part cover BMPareas. In the peripheral areas comprising 7 CMCs and 1 TMC, there are 3minor valleys forming separate drainage zones namely kethamaranahalli &Arkavathy (K&A Valley, 30.55 sqkm), Tavarakere (11.89 sqkm) andKathriguppe Valley (20.82 sqkm). Sewage treatment plants were firstconstructed under CWSS Stage I and are in operation since 1974. Thewastewater generated in V – Valley drainage zone covering the westernparts of the city was treated in primary treatment plant at Mysore Roadwith a capacity of 123 MLD (27 MGD). For Koramangala & ChallaghttaValley (K&C Valley) a common wastewater treatment plant with primarytreatment with a capacity of 163 MLD was established. Both these plantswere completed in the year 1973-74. Under CWSS Stage II, Secondarywastewater treatment was provided in both these plants and the capacityof V Valley sewage treatment plant (V Valley STP ) was increased to 180MLD and K&C Valley STP capacity remained the same. The wastewatertreatment plant of 60 MLD Capacity was constructed at Hebbal valleyunder CWSS Stage II and Stage III. In the 3 minor valleys, the sewagecollected was pumped to the existing 3 STPs at V Valley, K&C Valley andHebbal Valley. Three intermediate pumping station (ISPS) were alsoestablished.
  • Proposed Water supply and sewerage Projects in Implementation Period of JNNURM as per JNNURM CDPRehabilitation of Bunk Water Supply TransmissionLines:Rehabilitation of head works;Installation / rehabilitation of bulk meters; andPlugging of leakage in the main transmission line toreduce UFW. The rehabilitation expenses have been estimated at anormative standard of Rs. 2 Crore per kilometer lengthof the main transmission line (98km). 75% of therehabilitation works are proposed to be completed inthe implementation period.
  • Rehabilitation/ Extension of Distribution System Rehabilitation of the existing connection (15% of 3.6 lakhs existing water connection); and Provision of new connections in the uncovered areas.The cost of rehabilitation and installation of new connections has been assumed at Rs. 6,500 and Rs. 8,000 per connection.
  • Rehabilitation/ Extension of Sewerage System & Setting up of Sewage Treatment Plants Rehabilitation of the existing connections (40% of the existing connections); and Provision of new connections in the uncovered areas. Laying of sewers to prevent entry of sewage into storm water drains and avoiding inter-connection of SWD & sewers. Detailed studied would be taken up to identify the specific locations for laying separate sewers and for developing mechanisms for preventing the inflow of sewage into SWDs. The project cost would be estimated based on the studies undertaken. The cost of rehabilitation and installation of new connections have been assumed at Rs. 6500 to 8,000per connection. It is proposed to set up a sewage treatment plant with a capacity of 6 MLD at an estimated cost Rs. 6 Crore.Other Important Works Development of alternative water source Aquifer recharging Computer network analysis Efficient management of water by rezoning Public awareness campaigns Dual water systems Supply recharge Quality monitoring Energy audit studies Studies towards determination of UFW
  • Summary of Issues Water Supply Key Issues in Water Supply Parameter DescriptionInadequacy of resources for  Limited availability of water from Cauvery (afteraugmenting future growth utilization of 600 cusecs)  No water available from adjoining river sources such as Hemavathy, Netravathi etc..  Changing land use patternGround Water  Indiscriminate drawal  Sub-standard water qualityWater quality issues (in  Cross connections back – siphon in distributiondistribution network and raw resulting in water borne diseaseswater)  Raw water deterioration due to pesticides and chemical pollutants from industries and sewage from upstreamUneven Distribution and  Parts of the City receive a higher quantum of waterIntermittent Supply and for a longer duration when compared to certain other areas which receive a lesser quantum and only for a short duration  Erratic growth  Assets needing rehabilitation  Some areas get water only for 3-5 hours on alternate daysNon-availability of water to  Relatively high UFWmeet National Standards of  Non-availability of distribution system in CMCsTMC150 lped and new added BMP wards  Arkavathi source gradually depletingHigh UFW  Absence of reliable source production (bulk metering) on all major water sources  Absence of metering on public fountain consumption  Poor accuracy and serviceability of consumer metering  High non-physical loss due to consumption from unauthorized inoperable meters
  • Summary of Issues SanitationKey Issues in Sanitation Parameter DescriptionInadequate Coverage  Covers only 40% of the areaEnvironmental Concerns  Pollution of lakes  Mosquito GrowthSewage entering drains  Health problemsand lakes  Nuisance to public  Environmental and Bio-diversity problemsInsufficient capacity of  Overflows from manholes Publicsewers (Trunk and Mains) Nuisanceboth primaryAnd secondaryIncreased sewage flows in  Some sewage has to be let out withoutrainy season (due to treatment to river downstream therebymixing of storm water polluting the system (Arkavathy and Cauvery)  Sewage flows on to road and into low- lying areasDamaged sewers  Public nuisance  Mosquito problemsDirect connections of  Flooding in slums and low areassewers from slums and  Back flows during rainy seasons whenlow-lying areas to (primary storm water drains are fulland secondary drains)Strom water drains
  • Summary of Issues SanitationKey Issues in Sanitation Parameter DescriptionSilt, grease and floating  Problem in primary and secondarydebris (plastic, papers, etc) treatment , O&M problemsinto open drains and into  Accessibility problem for manholestreatment plantsEncroachment of sewer  Sewage over-flows into residential areaslines and manholes (slums, low lying areas  Sewer cleaning and removing silt difficult  Nuisance and mosquito growth.Water Supply and Sewerage system are inadequate. A limited inventory mapping of the utility lines has been done specially related to water supply and sanitation. Storm water system has inadequate coverage and is not connected to each other.
  • Policy and Action Plan The city shall develop a plan for water supply, sewer and drainage, which will include comprehensive schedule for regular maintenance of such system and the connection in the city wise infrastructure. The city should separate the sewer and storm water system completely or provide adequate capacity and combined flow. They should ensure that the rain water is not wasted an adequate provision of rain harvesting is made which will also include rejuvenation of cities’ lakes. Additional pavement / concreting of open area in the city should be avoided. Use of permeable pathway / sidewalks and other pavement options alike this proper. Pathway specifically for pedestrians and bicycle tracts should be considered in the areas which are environmentally sensitive. All extension areas (newly added areas into BBMP, new layouts etc.) Should be made functional only after proper water supply and sewer system is laid. In this regard, BWSSB needs to prepare the master plan for the development of these areas. The city shall have a proper transparency in terms of programs and projections undertaken for water supply and sanitation