The Cauvery water and its management in Bengaluru city.
Background :
The Cauvery River 498 mile in length, an inter-state river, runs east and finally empties into the Bay of Bengal. It rises at Talakaveri on the Brahmagiri Range of Hill in the Western Ghats, in Kodagu district of Karnataka, at an elevation of 1.341 m (4,400 ft.). The entire catchment area of the Cauvery Basin is 81,155 sq km and covers three states, and one union territory. The catchment area in Karnataka covers 34,273(42%) sq km, Kerala 2,866(3.5%) sq km, Tamil Nadu 43,868 (54%) sq km, and Karaikkal region of Puducherry 148 sq km
Putting to rest a 126-year-old emotive dispute over the sharing of Cauvery water, the Supreme Court increased Karnataka’s entitlement on 16th February 2018 by 14.75 tmcft to 284.75 tmcft and reduced Tamil Nadu’s share to 404.25 tmcft while keeping allocations for Kerala and Puducherry unchanged. Kerala will access 30 tmcft and Puducherry 7 tmcft and the award that now has the SC’s seal can be re-examined only after 15 years, in 2033.
A bench of Chief Justice Dipak Misra and Justices Amitava Roy and A M Khanwilkar gave a unanimous verdict making a minor change in the 2007 award of the Cauvery Water Disputes Tribunal (CWDT), which had, of the total available 740 thousand million cubic feet (tmcft) of water, out of which, Tamil Nadu was allotted 419 tmcft, Karnataka 270 tmcft, Kerala 30 tmcft and Puducherry 7 tmcft, while keeping aside 10 tmcft for environment protection and 4 tmcft as inevitable discharge into sea.
It is seen that the share of Karnataka was increased by 14.75 tmcft because the CWDT had not taken into account two crucial factors — the availability of 10 tmcft groundwater to Tamil Nadu from the Cauvery basin and 4.75 tmcft of water required to satiate the drinking water requirements of residents of Bengaluru, a city with “global status”.
Discussion:
Bangalore, receives the annual rainfall of 900 mm (3.0 ft) with three different rainy seasons, covering nine months of the year.
The streams between ridges and valleys have been dammed at suitable locations creating a cascade of reservoirs in each of the three valley systems.
Each lake stores rain water from its catchments with excess flows spilling downstream into the next lake in the cascade.
The storm water runs off through drains only. The Greater Bangalore is with an area of 741 sqkm. Bangalore is located at an altitude of 920m above mean sea level, delineating into the watersheds namely, Hebt, Koramangala-Challaghatta and Vrishabhavathu watersheds.
The undulating terrain in region has facilitated creation of a large no of tanks, provided for the traditional uses of irrigation, drinking, fishing and washing. Wet land of Bangalore occupies about 4.8% of the city’s geographical area (741sqkm) covering by urban and non-urban areas. Bangalore has many manmade wetlands, but no natural wetlands. But, it is very unfortunate to see that above landscape pattern has now been changed a lot due to rapid urbanization.
Today, less than 200 of those 1000 lakes remain is no more than sewage tanks. The sewage water contaminates the ground water and percolates into bore well.
One report says that 52 percent of bore well water and 59percent of tap water in Bangalore , is not potable and contain 8.4 percent and 19 percent E.coli bacteria respectively.
It is pertinent to mention that the Wetland / lakes have key role in preventing frequent flooding and micro-climate changes in the city. It captures rainwater efficiently and helps in ground water recharge.
It is seen that there has been a rapid increase in the number of bore wells in Bangalore over last three decades from 5000 to around 4.08 lakhs . About, 40% of Bangalore is dependent on 750 MLD of ground water.
Wetlands act giant sponges, storing, and then slowly releasing ground water, and flood water.
Thus, to get the maximum benefit from the profile of the existing landscape, each locality was subdivided at micro level and linked with particular tank / reservoir and such preserved water resources used to take care of various human needs.
Unfortunately the rapid decline in number of watersheds and their accommodating capacities in the initial landscape, coupled with phenomenal increase in population, fails to provide valuable water resources considerably , but also invite sharp adverse effect in flood management in the city of Bangalore.
In the context of above, it is more important to incorporate the watershed approach as far as possible , within the city development plans itself, especially in sitting of residential colonies and other facilities. This will increase the availability of water for residential areas while reducing energy consumption in transporting water to other locations. It will also lead to reduction in financial expenditure for laying the pipelines and its dependence on important natural resources like water from outside the city limits.
While increasing the potential for water conservation options like rainwater harvesting and aquifer recharge, it is also useful in efficient drainage and storm water management.
But, unfortunately, the original drainage plans of our metro cities are so rigid and obsolete that it fails to accept and cope with the pace of growth of Indian cities and thus, it seems to be difficult to adopt the concept of watershed management in these metro areas ideally for the use of various purposes.
It is pertinent to mention here that the domestic water requirement of Bangalore is met up from mainly two sources i.e i) Kauvery river water ii) bore well pump . But, there is huge losses in the distribution system, about 49% ,according to the BWSSB and may be termed as “non-revenue water” or “unaccounted for water”. It is also revealed from the report that the wastage attributes of two types of distributional losses: First, damages and leakages in the water supply system and, second, unauthorized water connections..
The report also says that Bengaluru consumes 50% of Cauvery water reserved for domestic use in Karnataka . Unfortunately Bengaluru , the state’s capital, though almost entirely dependent on the Cauvery river , wastes half the water it receives, according to an analysis of water-use data.
Bangalore is witnessing a huge growth in its population which is 11.98 million ( approx.) in 2017 against 8.52 million in 2011. Thus , it needs more and more water for domestic use. But , there is a limitation in the availability of Cauvery water in the state of Karnatak as the overall water resources of the said river would have to be shared in the proportionate manner as per S.C order.
It is unfortunate to understand that about 35 % of such precise water meant for the city is wastage in leakage. This means 1400 MLD that Bangalore draws , nearly 500 MLD is lost as leakage , and with 150 MLD allotted to industries , one core Bangaloreans will have to make do with 750 MLD in 2016. This will work out to be 75 litres per capita per day ( LPCD ) for 10 million people, while the govt. of India norm for Metro cities 150 LPCD . Clearly there is huge mismatch between demand and supply of water from the Cauvery.
Over the next couple of years, it is said that the city’s water demand is predicted to be about 2314MLD in 2025 .i.e 30TMC per year.
It may be stated here that out of the 270 thousand million cubic ft (TMC) of Cauvery water as was allotted earlier , to Karnataka by the Cauvery Water Disputes Tribunal, roughly, about 80% is used for agriculture and industry (down from over 90% in 2007). This leaves about 20% for rural and urban domestic use, of which Bengaluru records the highest demand.
At present ,the city receives about 19 TMC ( 1400 MLD approx.) of Cauvery water.
Recently, the Karnataka state urban development department provisionally raised supply by an additional 10 TMC to meet the needs of 110 villages added to the metropolitan area in 2007. A formal proposal to raise the city’s water supply to 30 TMC from the Cauvery basin has been forwarded to the central government.
It is revealed that 30 TMC ( tmcft ) can provide the potable water for 15million of people in 2025 ,if we consider 150 lit per person per day .
The present increase in the share of Karnataka by 14.75 tmcft has been done mainly for the drinking water requirements of residents of Bengaluru, a city with “global status”.
It may be mentioned here that the Cauvery water sources remains at a distance of 100 km, up to a height of 540m, the BWSSB spends nearly 60% of its budget in pumping water to the Bengaluru metropolitan region.
With groundwater reserves over-exploited and polluted, and its other two ageing reservoirs — the 120-year-old Heseraghatta and 83-year-old Thippegondanahalli of Cauvery’s Arkavathi tributary — unreliable, Bengaluru is almost entirely dependent on the disputed river
As there are large water losses, recorded for the last five years at various stages of Cauvery river water supply projects , the efforts to enhance per capita water availability to 150 lt per capita per day (LPCD) to meet World Health Organization (WHO) and Central Public Health and Environmental Organisation (CPEEHO) standards remain unfulfilled.
But, the fact is that if it is not addressed, the situation is only likely to be worsened according to the report study of water demand and availability.
At the moment , a few million residents who don’t get Cauvery water, or get an amount less than their requirement, are dependent on groundwater, which pretty much comes from one of 4 lakh bore wells across the city, most of which are not registered. At 325 bore wells a square kilometre, and 40–50 new ones dug every day, Bengaluru is one of the most ‘bored’ cities. Bangalore gets 900 mm of rainfall. But , the use of bore wells in the city to draw ground water amounts to almost three and half times water drawn than the amount to receive to charge it. Hence, most of the bore well have gone deeper, even up to 1000 ft and the ones which are not as deep have run dry. The greater fear is that even this polluted water may not be available after 2018.
Out of 18 lakhs property , only 44,000 have rain water harvesting structures.
Most residential buildings then rely on water supplied through tankers ,in Bangalore. Apartment blocks have come up around the city, and tankers are the source of water for many homes.
Observation :
Now, let’s see the current situation. There are some important issues which perhaps, that needs to be taken care of :
1. An ever-growing and expanding Bengaluru and nearby villages are heavily dependent on Cauvery water for drinking needs.
2. Hefty BWSSB T&D losses of nearly 35 percent, while transmitting Cauvery water from K.r sagara Dam , located nearly 100 km away, to Bengaluru which rests on an altitude of 3,000 feet above sea and thus , the Cauvery water has to be pumped up, which leads not only to revenue loss but also to physical loss of water through leaky pipelines.
3.It is pertinent to mention that the Cauvery is not Perennial River. With the deficit monsoon more often, the flow of river has been dwindling over the years and thus, fails to meet up the drinking water demands of thirsty Bengaluru which are rising alarmingly.Probably, to overcome such water crisis within the Cauvery river basin, we may have to find out a long time solution.
4.The use of water should be in consistent with the availability of water. Thus, it needs to be reduced the demand and look for ways to augment water supply through alternative means with the application system or improvement of watersheds / lakes etc. including rain water harvesting & renewable water resources at the maximum possible extent .
Conclusion :
We see that the surface water of Bangalore city mainly depend on Cauvery water , the allotted quantity of which has been finalized now. Therefore , as the allotted quantity is fixed , all the alternative sources like the rain water harvesting , water shed management , the using of renewable water etc , may have to be tapped for sustainable water requirement in the global city like Bangaluru for which all the necessary supportive infrastructural activities are to be addressed in a holistic manner.
Unfortunately , it is seen that the original number of water sheds is gradually disappearing and even the remaining tanks, which is about 20%, are getting polluted with the local untreated sewerage water, making the bore well water contaminated through percolation. Thus, the existing watershed / tanks, not only to be protected from incoming untreated sewerage water, but also to be preserved for rain water harvesting / conservation. Besides, more and more apartments are also to be encouraged, for the rain water harvesting to meet up ,at least the partial needs to fill up the gaps between supply and demand .
Apart that , it is also to be seen that the storm water drainage lines is delineated from the domestic sewerage system. All the sewerage effluents need to be properly treated with the sewerage treatment plants as per codified guide lines before discharging into outfall points . This will help to preserve pollution free water in large number of water shed / reservoirs /tanks etc.
Along with, a part of the effluent may be further purified in the treatment plants following WHO standards, using dual-membrane via microfiltration and reverse osmosis and ultraviolet technologies, for using as drinking water. Such reclaimed water resources from alternative sources, may help to reduce the dependence on scared ground water to a large extent.
Apart that , the Bangalore has a great problem related to huge water losses through leakage during the transportation and unauthorized pilferage. This needs to be addressed with utmost effort to manage precious water to the need of the people, otherwise it would be very difficult to combat the drinking water crisis.
It is pertinent to mention that Singapore has transit loss only at 5% in the water supply net works, which may be lowest in the world.
Along with, the implementation of 24x7 water supply distribution system , may be a good approach for long time maintenance and restoration to the capacity of pipelines at the original condition.
Probably ,it is very much essential to understand the value of precious water for our domestic issue and the combined efforts from all sides can only help to meet up the minimum safe water requirement amongst all categories of people as per WHO guidelines
Moreover, it is also required to see that the overall consumption of water is gradually reduced by lowering individual consumption at 140 mgd per day in consideration of future demands of the metro city like Bengalore.
To achieve the goal, perhaps , the people are to also be educated about the value of the water and encouraged them to use low consumption domestic water utility equipment step by step. Along with ,the Govt. also may have to think the proposition to modify the existing water tariff and introduce the balance rate after due consideration of related factors , as applicable in different set ups e.g commercial / housing complexes including private individual buildings.
It may be mentioned that though Bangalore has the largest number of metered water connections in the country, still there is high mismatch with BWSSB’s costs vis a vis its revenues.
