Water Management – Increasing water availability in cities
It is very rare that we,in India, hear that the monsoon has been good for successive 5-6 years. With every good monsoon, there are at least 2 failed monsoons in between. Every other year, the Indian economy reels and awaits the rains, all of us looking upwards towards the skies, praying that the heavens will open up, this year.
Despite doing this year on year, we in India have not at all given a serious thought to making ourselves water efficient. Be it rural water management or urban, we face a serious drought and when the rains come, we forget to plan for water in the next year. Nitinji Gadkari has recently said that “we are a rich country full of poor people”, which is definitely true of nation’s water resources.
I have undertaken the task of putting on paper the various means and methods by way of which we can increase water availability in our cities today. Most of these means and methods are already out there, practiced by hundreds of people, installed in buildings, but these have remained just there. Personal interventions. There has not been a concerted effort to take this up at a city level or even to institutionalise it.
I have always maintained that water supply is a public infrastructure and cannot be undertaken by private entities to provide water for themselves. Some years ago, I had visited Kodaikanal, a supposedly beautiful hill town known for its views and lush forests. All I did see there were water pipelines running along one side of the mountain, alongside the roads and reaching every house that nestled in these hills. It was as if, every house-owner was asked to put in his/her own water line, starting at some public water storage tank and ending at the doorstep. What a disaster! And after having laid this utterly leaking and wasteful distribution infrastructure, the city had massive water cuts. So having a water line and having water are of course two very separate things, as most of us, have realised, particularly, when India faces a drought.
But let me come back to the issue of increasing the availability of water, rather than get into the logistics of supplying it first. Because, that’s the core issue. NO WATER! Period.
A study has estimated that about 20 % of the total storage capacity of the dams is lost to evaporation every year. Apart from this storage reservoir evaporation, we have massive additional evaporation losses happening during distribution of water through open canals.
The Canal Solar Power Project in Gujarat proposed over the canals from the Narmada dam is a classic example where evaporation losses will be curbed apart from other obvious benefits. Just the pilot phase of this project, over 750 m canal is estimated to prevent evaporation of 9 million liters of water annually while generating about 1MW of clean energy.
In the city of Pune, according to the City Development Plan, about 31% of all treated drinking water leaks into the ground. Pune has a population of about 38 lakh people and it is estimated that Pune utilizes about 1222 MLD (Million liters per day). Of this, about 866 MLD is lifted from the dams (the four reservoirs of Khadakwasala, Panshet, Temghar and Warasgaon) and about 356 MLD is drawn from the various wells around the city.
Of the 866 MLD, which travels to Pune in leaking underground water supply system, about 31% is lost, thereby the actual supply is around 598 MLD. Of this 598 MLD, Pune is gracious in supplying water to the immediate neighboring villages, estimated to be about 67.5 MLD. So effectively, the total water that is supplied to Pune is 530 MLD or about 139 liters per capita per day (LPCD). So the myth that Pune citizens end up using more than 250 lpcd is busted through this simple calculation.
Now the remaining 356 MLD is accessible to a few as this is drawn from the various groundwater sources in Pune and its distribution is not equitable across the city. So to club this volume of water to derive an average water consumption per person will be a mistake. However, some fortunate citizens who do end up accessing this water, their water consumption goes more than 223 LPCD.
In any developed country, the water leakages are curbed to 2-3%, while we are at 31%. There needs to be systematic effort to upgrade the water supply distribution system. Even if we can curb the water leakages to 5%, we will have about 1094 MLD instead of 850 MLD water to use and with a regulated and equitable supply of 150 LPCD (the standard is 135 LPCD), this same water can suffice about 7.2 million people, instead of 3.8 million currently. That’s a simple 40% increase in service delivery of water with the same storage reservoir capacity.
Reuse of Wastewater
As per global standards, every person requires minimum 135 litres per day for fulfilling the basic needs of drinking, bathing and cleaning. Of this, 80% of the water converts into wastewater. Now considering that Pune, gets 1222MLD per day, 950 MLD of wastewater generated by the city each day. Currently, 50% of this gets treated at a primary level and is let off into the river. The remaining 50% i.e 400 MLD sewage goes directly into the river every day and pollutes it to a point of ensuring that there is no Dissolved Oxygen and hence no aquatic life left in the river adjoining cities. The irony of the situation is that 80% of the wastewater is actually WATER. Removal of the 20% stuff from this water can get us the precious water that we are so mindlessly casting away into our rivers. And in turn causing an even greater problem of river pollution.
Just imagine for a moment that in this drought situation, you were asked to cast away about 400 MLD of potential clean water into a river daily. Well, that's what we are doing all 365 days, all 24 hours in our cities.
A very serious concerted effort to treat our wastewater at the city level can give us an augmented supply of water. The environmental norms established under Ministry of Environment, Forests & Climate Change (MOEFCC), require that most new building complexes should install wastewater treatment infrastructure.. Where this works properly, citizens are benefiting of getting an assured, treated water supply for landscaping, flushing purposes and maintenance of the outdoors. However, this initiative is happening at a building level, often generating large quantities of water which are once again left into the drains. If there is an effort to facilitate the reuse of treated wastewater at the city level, we will be able to reuse this water more efficiently and in a more systematic manner. A massive augmentation of water resources is possible through this. It is estimated that about 665 MLD (a conservative 70% of 950 MLD of wastewater) of treated wastewater can be made available to the city. And guess what? It will also keep our rivers clean. A very important and beneficial outcome, most will agree.
Reuse of Stormwater
The monsoon gives us an opportunity to tap rainwater at one single period in a year. Most of the monsoon rain that falls on surfaces finally ends up as Stormwater – polluted with oils, grease and other pollutants, but nonetheless, an opportunity to tap the Stormwater and treat it for reuse. This needs to happen at the city level. For this, our roads need to have established channels for Stormwater. Presently , the stormwater network along the roads is about 52% as it is available only at selected and major roads. As a priority, if stormwater network is put in place, another beneficial outcome that the city will encounter is that road surface does not disintegrate due to collection and stagnation of stormwater. Thus, the city can save thousands of rupees on road surface repairs, as water will flow into stormwater channels and get carried to a treatment plant. It's difficult to estimate these flows, but looking at the level of concreting in our cities today, we have a potential to tap and reuse thousands of litres of stormwater annually.
One of the major and priority environmental concerns for India, as per the State of Environment Monitor by the MOEFCC is the deletion of groundwater. Maharashtra, including Pune district, shows massive depletion of groundwater sources. We have failed to generate a data in Pune, but informal information shows that there are hundreds of wells in Pune which supply water to the city. This water is neither recorded in our regular water supply nor is it accounted for in our wastewater estimates. But the fact remains, that people are extracting groundwater in cities across India. A mapping of these groundwater sources and again a neighborhood level effort to harvest rainwater and recharge these wells will mean that these water sources are augmented, thereby increasing the overall availability of water in our cities.
Some years ago, an erudite professor and architect Uday Chipalkatty had shared with me a proposal of underground water reservoir for the city of Pune. He had proposed an elaborate system of wells and bore wells that are recharged during the monsoons and a collective city underground reservoir is tapped by the city to augment its water supply. Some such solutions need to be further explored to look at local, decentralized water augmentation options for cities.
Such city level planning and technology solutions have rarely been brought to the fore. At the local level, city corporators/councillors are often busy in giving fix-it solutions to the citizens. A broken pipe here that's fixed, or an illegal connection there that's legalised to augment the water supply.
Cities have the resources and the incentives to work on such mid to long term solutions to create their own reservoirs of water. This needs a systematic plan at the city level, supported by the State and the Centre. Urban water management will also mean more water resources for rural areas and possibly end of reliance on a good monsoon, end of drought year after year.