By Rakhi Anil
The erstwhile “garden city” of Bangalore has grown leaps and bounds in the past few decades. This exponential growth has brought in a lot of economic benefits and its own share of woes with it. Civilisations have thrived and perished due to abundance or lack of water. The great cities of the world have all been built around a water source. Emperor Akbar had to abandon his capital of Fatehpur Sikri when the source of water dried up. Bangalore city has also faced water problems since the colonial times and different rules and provisions were made at different times to fulfil the water needs of the city. With the advent of drilling technology, accessing water hidden deep in the bowels of the earth became easier and the success story of Bangalore’s economic growth can be attributed to the availability of groundwater. Groundwater, the water from Cauvery supplied through BWSSB (Bangalore Water Supply and Sewerage Board) and rainwater received from the skies sums up the water received by the city.
The water supplied to Bangalore city is truly a scarce and expensive resource. The BWSSB spends 65% of its revenue on power bills to bring the water of the Cauvery against gravity into the city, and the fossilised water that is drawn from the ground from a depth of 800 feet or more may be centuries old. The city uses a combination of both of these as BWSSB is unable to supply water to the entire city area covered by BBMP (Bruhat Bengaluru Mahanagara Palike). With rapid urbanisation, increasing population and a demanding burgeoning middle class, the thirst of the city seems to be never ending.
An average individual in an urban area consumes about 135 litres of water every day. About 60 to 70% of the water intake of the human body goes out as urine and faeces. In modern toilets 6 to 10 litres of water goes down the drain with a single flush. Even if we make a conservative assumption of 70% of the water used by an individual everyday being returned to the sewers it comes to 95 litres of waste water per person per day. 16% of the population of the state of Karnataka lives in Bangalore city. If one takes the trouble of doing the math, the city generates a large amount of black (from toilet and kitchen) and grey (from bathrooms) water every day. Where does all this water go?
The sewerage networks carries this sludge to an STP (Sewage Treatment Plant), where the solids are separated, the water treated and let out into the lakes and tanks of Bangalore, which eventually goes and joins a river. This is how the network is supposed to work. In the old areas of Bangalore this may work to a certain extent but in the new areas of Bangalore that were included under the BBMP in 2006–7, the network is still being constructed and not connected to STPs in most locations. In the former scenarios also many a time’s pipes are broken and sewage enters SWDs (storm water drain) directly and thus enters lakes. The wastewater from industries also gets mixed into this from multiple locations. Bangalore receives sufficient rainfall every year with an annual rainfall average of 850 mm. The copious water received during the rains gets mixed with the sludge and fills the cities SWDs and lakes. Through the networked channels this water then reaches the Arkavathy, Cauvery and Ponnaiyar rivers.
The KC (Koramangala Challaghatta) valley project was undertaken to fill the lakes and tanks of parched districts of Kolar and parts of Chikkabalapur. Secondary treated water from the STP at Bellandur is sent via underground pipes to Laxmisagara lake at Kolar and it flows on to the other lakes through the SWD network mostly by gravity and pumped up wherever required. The idea is that the groundwater table in these areas will get restored by water percolation through the lakebeds. The water is not meant to be used directly but for indirect recharge through the ground. Kolar has been left dry due to successive droughts over the years. Agriculture based industries such as dairy farming, sericulture, floriculture, vegetable farming etc. are the major sources of employment in the district. Citizens are dependent on bore well water for irrigation as well as drinking water. Though this project was plagued with issues and a case in the Supreme Court, there are reports confirming the positive effects of the project. Water in wells have been rising and bore wells are coming back to life in the region. The long term effects of the project on water, soil and biodiversity maybe known only sometime in the future. The demand for water (even wastewater) is so high that Tamil Nadu has objected to this project in the Supreme Court as this would mean that the discharge to the Ponnaiyar River would be substantially reduced.
This is an interesting example of multiple government agencies working together towards a single cause. Agencies such as BWSSB, Minor Irrigation Department, Panchayats, KSPCB (Karnataka State Pollution Control Board) etc. are involved in the project. A report by KSNDMC (Karnataka State Natural Disaster Monitoring Centre) mentions that 156 of 176 taluks of Karnataka are drought hit. With more than 80% of its land ravaged by drought Karnataka is the second driest state in the country after Rajasthan. Considering the drought situation and unpredictable weather due to climate change, such projects though controversial may provide the needed respite to the farming community as well as optimum usage of a scarce resource. KC valley project forms a minor part of the waste water generated in the city. There are already rules in place for using only treated water for horticulture, construction purposes and mandatory rainwater conservation that need to be adopted based on sital area. Adherence to the rules, better management of wastewater, KC valley type of projects etc. can go a long way in conservation of resource as well as improve the economic situation of farmers.
