Bengaluru could show the way

Bengaluru, the IT hub of India, is experiencing a water crisis that is indicative of a global issue that puts at risk both contemporary metropolises and older cultures.

Bengaluru, In spite of having abundant water supplies, the city faces shortages and poor management. The article examines the intricacies and puts out workable ideas for sustainable urban water management in Bengaluru and other cities. A study from the Basel-Switzerland-based Multidisciplinary Digital Publishing Institute (MDPI) has concluded that the extended water crisis has caused the collapse of some of the glorious ancient cities and societies across the world, such as the Easter Island, Mayas, Sumerians, Nazca, Ancient Megafauna of Australia, Anasazi, and probably Minoans. The challenge has continued over the centuries. As per the WHO estimates, water scarcity impacts 40 per cent of the world’s population, and as many as 700 million people are at risk of being displaced as a result of drought by 2030.

Indeed, cities have come to be the engines of growth and have reshaped the economic structure of every part of the world from being predominantly agriculture-based to industry- and service-based. Cities have made it possible to get higher economic gains from investment in all types of resources, be it human resources, land, or any material resource—Bangalore being one significant example.

The current water crisis in Bengaluru has caused widespread concerns, as the city is considered a shining jewel among the fast-developing cities, proving quality employment to millions of people from all parts of the country and even beyond. The city has a high GDP, the best of the high rises, hospitals, shopping complexes, educational institutions, and general social harmony. It is also a hub of international trade and commerce for many sectors, IT being the most prominent one.

However, Bengaluru faces the seemingly complex phenomenon of flooding in the rainy season and water scarcity in the summers. Most cities face the same challenge. There is a continuous demand in cities like Bengaluru to sink more and more borewells and to lay pipelines to fetch water from flowing bodies of water that could be scores of miles away. But the emerging challenge in most cities is that the water challenge remains unresolved, despite investing thousands of crores of rupees in augmenting the water supply. The existing borewells keep drying up fast, and the new borewells require deeper drilling as the aquifers are depleting.

Bengaluru has an estimated population of 1.4 million. Its water supply is managed by two agencies: the Bengaluru Water Supply and Sewerage Board (BWSSB) and the Bruhat Bengaluru Mahanagara Palike (BBMP). The area of BBMP is approximately, 800 sq km, including the Bengaluru Core Area of 245 sq km, 8 merged urban local bodies (seven city municipal councils and one town municipal committee) of 330 sq km, and 110 villages of 225 sq km. At present, BWSSB is supplying treated Cauvery Water to Bangalore City under the Cauvery Water Supply Scheme (CWSS) Stage I, II, III, and Stage IV, with a total installed capacity of 1440 million litres per day (MLD) to provide water supply to the core areas of BBMP and the erstwhile seven CMCs and one TMC areas, covering a total area of 575 sq km, but excluding 110 village areas of BBMP covering 225 sq km.

In order to provide water supply to the newly added 110 villages, which are part of BBMP, BWSSB has undertaken implementing CWSS Stage V to add an additional 10 TMC (775 MLD) of Cauvery Water for Bangalore city . The project is estimated to cost `5,500 crore and is expected to be completed during the current year (2024). In addition to the Cauvery water, 650 MLD is extracted from borewells.

The city seeks 135 litres per capita per day (LPCD) as per the standard norms, and this works out to about 1,900 million litres per day (MLD). However, as stated above, at present, it gets 2,050 MLD of water, of which 1,400 MLD comes from the Cauvery and 650 MLD from borewells. Therefore, at the gross level, there is no shortfall at all. Moreover, with the commissioning of CWSS-V, the availability of water to the city would be augmented by 775 MLD, reaching a whopping figure of 2,825 MLD. The ever-existing water scarcity in many parts of the city, in the face of the humongous volume of water availability, indicates that there is obviously more to the water scarcity of Bengaluru than meets the eye. Let us examine the details to locate where the devil of the scarcity lies.

Water requirement assessment

The Ministry of Housing and Urban Affairs had traditionally recommended water supply for multi-story condominiums at 135 litres per capita per day (LPCD). The break-up of this estimation is as follows:

• Bathing: 55 litres
• Toilet flushing: 30 litres
• Washing of clothes: 20 litres
• Washing the house: 10 litres
• Washing utensils: 10 litres
• Cooking: 5 litres
• Drinking: 5 litres.

This estimation is highly liberal, as no person needs as much as 55 litres (4 buckets) of water to bathe, for which purpose, 30 litres (2 buckets) should be enough. Moreover, for flushing purposes, recycled water can safely be used, as per the recommendations of the Swachh Bharat Mission. Moreover, the activities of washing the house, clothes, and utensils are family activities, and therefore, the supply for a family needs to be computed.

Keeping all such factors in mind, the major city bodies and regulators are gradually adopting the desirable supply level of 90 LPCD. For a family of 5, this would translate to 450 litres, or 30 buckets of water per day. This is a very large quantity, as per normal requirements. Moreover, the per capita computation gives the same rate (LPCD) for a toddler as for an adult. Hence, 90 LPCD should be acceptable as a fair estimation. Various water savings options narrated late in this article would further justify this proposition.

As per 90 LPCD, for a population of 1.4 crore, Bengaluru would need 1,260 MLD, whereas Cauvery provides 1,400 MLD. So, as per the gross estimation, Bengaluru gets enough water from Cauvery Stages I to IV. In addition, the borewells of the city water supply agencies provide 650 MLD. Therefore, the fact that many parts of the city face acute shortages of water off and on would need a closer examination.

Borewells

According to official data, there are 14,781 borewells in the city (BBMP limits), and 3,297 of them have dried up, while 3,700 have poor yield . In the first instance, borewells should be used only for emergency purposes and ought not to be used as a source of regular water supply. The BBMP justifies the borewells on the ground that the BWSSB pipeline network is inadequate and the uncovered areas depend on borewells. Even so, the fact that almost half of the borewells have either dried up or are yielding poorly indicates the possibility that the borewells are not getting recharged. However, the recharge pits are not being serviced properly and regularly. This is leading to the drying up of the aquifers and, consequently, of the borewells. The solution would lie in a concerted drive to clean up the recharge pits and the storm water drainage network.

Rejuvenation of lakes

Bengaluru was founded in the 16th century with lakes as the water source, as it had no rivers. The city had around 1,000 lakes and was popularly called the City of Lakes. Post-Independence, Bengaluru started attracting more and more residents, owing to its expanding economic activities, salubrious climate, network of higher educational institutions, and good administrative and social environment. However, the growth of the city was accompanied by administrative and planning lapses, which led to the disappearance of the lakes. As of now, less than 100 lakes survive, and most are in poor shape. This has seriously impacted the water situation. Some of the lakes have so many toxins that they
catch fire!

Uses of recycled water

The Swachh Bharat Mission-Urban 2.0, launched in October 2021, has recommended using the treated water for flushing toilets, gardening, agriculture, horticulture, industrial, municipal, and water body rejuvenation purposes. In fact, recycled water has a lot of microbial and other nutrients that are beneficial for crops. Of course, the quality of the recycled water needs to be monitored to ensure that toxins do not reach the crops, and this can be handled at the level of the Sewage Treatment Plant (STP) without much difficulty. Localised smaller STPs of 50 to 100 kiloliters per day (KLD) can be easily installed in localities of 100 to 300 households and would cost about 20 to 50 lakh with an operational cost of about1 lakh per month. This makes the recycled water a bit costly. However, many governments are keen to subsidise water and power for the agriculture sector, and recycled water, being nutrient-rich, would be a good candidate to attract the idea of subsidised water for the agriculture and horticulture sectors. Small-sized STPs can be installed in the parks, where the recycled water can straight away be used for trees, plants, and lawns, with very little investment requirement for the pipeline network.

The technological advancements, including the Moving Bed Biofilm Reactor (MBBR), have made it possible to have the recycled water from households almost as clear as the freshwater, with no obnoxious odour, which becomes absolutely useful and acceptable for flushing purposes. As opposed to 90 litres of fresh water supplied per head per day, we can easily get 50 litres of recycled water. The surplus treated water can be used for public purposes, such as avenue trees, parks, and lawns.

Recycled water is absolutely effective for many industrial purposes, such as in cooling systems and in the construction industry. The residential complexes can sell the surplus recycled water to the manufacturing and construction industries and, in the process, raise some revenues. Besides, lakes can be very well augmented using recycled water. The STPs can be set up in the vicinity of the lakes, and the surplus recycled water can be discharged into the lakes.

Metering water

Unmetered water supplies leave the user with little motivation to avoid wasting the water. Experience has shown that economy in the usage of water can be best achieved by mandating metered supply on a 24×7 basis. Metering has to be coupled with reasonable pricing, which can be made progressive, that is, making the first 30 litres per head per day nominally charged and making every subsequent litre slightly costlier. This would motivate consumers to optimise their water usage.

Using water-efficient appliances

The evolving urban landscape has induced the development of many household appliances that are not only water-efficient, but also cost- and labour-efficient. For instance, a front-load washing machine can clean around 6 kg of clothes with only 60 litres of water, whereas manual washing of the same quantity of clothes would require at least 100 litres of water. Similarly, a standard dishwasher uses around 10 litres of water per wash, while hand-washing generally uses up to 60 litres . A robotic mopping-cum-vacuum cleaner consumes just about one litre of water for wet-mopping around 1000 sq ft of floor, whereas manual mopping would consume 15-20 litres. Using showerheads for baths also saves water and gives better body cleaning as compared to bucket-based bathing. Using aerators in the kitchen sink taps is yet another option for saving on water usage.

Water audit

Owing to highly inadequate metering arrangements, the ‘Unaccounted For’ Water (UFW) is as high as 30 per cent in Bengaluru, though the situation in most other cities is similar, if not worse. UFW, aka NRW (Non-Revenue Water), is broadly described as the difference between the volume of water supplied to a network and the metered consumption plus the accounted-for public use. UFW/NRW includes pipeline leakage as well as illegal tapping, and, for Bengaluru, it amounts to as much as 420 MLD of water per day. A decentralised management system, coupled with metering the water supply at different points in the distribution network, would greatly facilitate identification of the locations of UFW and NRW as well as resolution.

The way forward

All the solutions mentioned above are highly doable, with nominal cost implications. In fact, for every rupee spent on these measures, the city would save one hundred rupees, if not more, and that too within a period of a few months. On the part of the authorities, including the BWSSB and BBMP, this would require strengthening the Water Management and Information System. Concerted efforts to create awareness among the people about the economy of water usage through the various options stated above would be necessary to achieve success in a sustainable manner and quickly. It is going to be a win-win situation not only for Bengaluru but a model way forward for all other cities as well.

Examining Bengaluru’s complex water situation tells a story of poor management, running out of resources, and workable solutions that are essential for urban sustainability.