Posts Tagged ‘bangalore’

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Towards a water sensitive city

April 23, 2014

 

The imagination of water in a city should not be limited to its delivery and withdrawal in pipes alone. A good water management plan would mean and include the many roles of water such as the spiritual, the cultural, the ecological and the recreational in addition to the functional..

In the hierarchy of the development of water infrastructure in a city there is first the arrival of piped water supply. Drainage and sewerage follow after some time.  The city then starts to understand and manage its surface water like lakes, rivers and canals. Attention then usually shifts to groundwater management. If all this is done  and fountains dot the landscape , where rivers and lakes become clean and spots of recreation and where all waste-water streams are managed the city starts educating its citizens especially its young ones on water and spreading water literacy. This city can be said to have become water sensitive. Singapore comes to mind as one such city. Stockholm and Oslo also manage their waters accordingly and celebrate it. Seoul is getting there or nearly there. We in India are on the painful ladder and it will take time but the vision has to stay firm. Of course in a water sensitive city all citizens will have equal access to the resource and there will be no deprivation and appropriation of the commons.

In Coimbatore through a citizen government partnership the Big Tank the Ukkadam was de-silted and made ready to receive rainwater which it has collected in plenty. In Dindigul de-silting has begun of the old tank. In Karnataka State ,  Tiptur has refurbished and improved a large tank so have the towns of Sira and Tumkur.

In Bangalore the Bangalore Development Authority has invested over Rs 110 crores in improving over 14 tanks. Of these tanks Jakkur in the Northern part of the city seems to offer a potential comprehensive role of creating a water ecosystem which fits the role of what a water body can do in a city – as they say to function as its kidney.

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The vast water spread of Jakkur Tank

The tank itself was a beautiful irrigation tank with a command area which grew paddy. As the city has caught up the role of the tank has now changed. There is a wetland on the upstream end which receives water from a waste-water treatment plant. The wetland further purifies the waste-water . The tank itself with a water spread of 53 Hectares is full and harbours lots of fish. Birds nest and a virtual array of them can be seen during the year.

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Treated Waste-water comes in to a wetland

The tank has recharged groundwater in the surrounding areas and the some of the remaining water heritage of the city – the traditional wells- are full to the brim. Boys learn to swim in one of them. Another well is used for large scale irrigation of coconut and banana plants. The tank has a place for immersion of Ganesha idols in one place. Storm-water inlets to bring in rain when it occurs have well designed silt traps to allow only water to come in and not debris and solid waste.

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Full wells – thanks to a recharged aquifer

The tank ecosystem fulfills many a function, from the ecological, to the cultural and spiritual, from the educational to that of recharge and many more.

This is truly a microcosm of what is called Integrated Urban water management in practice. Here we see the transformation of waste-water through a physical process of treatment followed by a biological process to drinking water.

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Fish feeds the city with proteins and provides livelihood to fishermen

Water in a city is much beyond what flows in pipes. If designed and managed well it can enhance and provide for the needs of nature and man in myriad forms. The Jakkur Lake should be managed well so that it becomes a living lab for our citizens to see and learn how urban waters can be managed. This experiment can then be repeated in most other tanks of the city and also in other cities. Bangalore has been a pioneer in many ways to urban water management. Can it take a lead in this one too? In that would lie water wisdom.

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Build the institution Bangalore – the water is there

December 18, 2013

Water – the Bangalore story

It is a strange place to have placed four towers and have started a city but perhaps Magadi Kempegowda was not thinking of water when he had his grand dream. The city now has outgrown those four towers and the one small stream which was the only part of a running water landscape is now desecrated beyond measure and called the Vishabhavati (the poison river) from the original Vrishbhavati (that which originates from the mouth of a bull) .

As early as the 1850’s the British were complaining about the water and sanitation systems. It also did not help matters that sewage was being left into the very source from where water was being drawn. Both Ulsoor and Dharmambudhi Lake being the source and the sink.

In a pioneering effort of its kind, most probably aided by the fact that this was city not near a perennial water source and there was always a sense of shortage, the city started to search for water from far. Hessarghatta on the Arkavathy reservoir 24 km away was first developed as a storage dam. Steam engines were used to pump water into the city and when electricity came that then replaced the steam engines. In each case Bangalore was a pioneer in the use of steam and electricity to pump water to itself. Hessarghatta was found short to slake the cities thirst and Thippagondanahally on the junction of the Kumudvathi and Arkavathy came into being as a new reservoir in addition to the Arkavathy in the mid 30’s. The city continued to grow and in the 1970’s the Cauvery was tapped at Torekadinahalli, pumped to a distance of 95 kilometres and 300 metres high to quench the city’s thirst. This was a remarkable engineering feat by a remarkable institution the Bangalore Water Supply and Sewerage Board- BWSSB – the first exclusive city level water and sanitation utility created in India. Stages 1, 2, 3 and 4 and phases 1 and 2 of stage 4 have kicked in and one of the costliest water in Asia comes after being pumped in three stages into the city. Alas the limit to drawal also has been reached and there is no more water for the city unless there is a redrawing of the water requirement between the irrigation and the urban sector in the Cauvery basin part of Karnataka.

In the meantime the city found out an uncomfortable truth, not all of it was in the Cauvery basin. In fact 2/3rds of it was outside the basin and in a river called the Dakshina Pinakini or the Ponnaiyar so that part was not entitled to water from the Cauvery basin or so said the tribunal.

In true government style a committee was formed to find out how the growing needs of the economic and domestic demand of the city could be met. Proposals include getting water from the Hemavathi, the Sharavathy as well as the west flowing rivers. These of course are huge projects involving lots of money and energy, something which should get the construction lobby salivating.

In the meantime there are practical proposals such as rooftop rainwater harvesting, the rejuvenation of the remaining lakes of the city, the recharging and the management of the groundwater in the city and most importantly the treatment and reuse of waste-water which show tremendous opportunities.

While the city gets 1400 million litres of piped water supply, the equivalent of 3000 million litres per day falls as rain on it. The total volume of wastewater available for reuse is 1100 million litres and the amount of groundwater that can be drawn sustainably is close to 600 million litres per day provided it is adequately recharged.

Do the math then

Average demand 200 Litres per capita per day 

Total; available water 

From Cauvery   1400 million litres per day

From groundwater 600 million litres per day

From recycled waste-water 1100 million litres per day

From rainwater 600 million litres per day ( 20 % rain harvested)

Total  3700 million litres per day

Good enough for a population of 18.50 million

…and if we get demand efficiency right and demand down to 100 litres per dapita per day

37 million people of Bangalore can be served ( current population 9 million)

 

Unfortunately the institution in charge of water supply is not completely geared to undertake a water management approach. It has no skill set for example in lake management or in hydro-geology.

If institutional capacities are built up, if there is a strong vision and an accountable authority created Bangalore in its pioneering way can overcome its water shortage problems. Else it will be forever condemned to become dependent on a tanker economy. The choice is ours and the time is now. 

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On the sump tanks of Bangalore

October 31, 2013

On the ubiquitous sump tanks of urban India

 

One of the significant urban features of India is the permanent HDPE tank on buildings. Usually black but with an assortment of colours including a somber black, a bright blue and a brilliant yellow with a shining white also thrown in. This reflects the water and electricity reality of cities, intermittent supplies of both which means storage is the only way that 24/7 supply can be ensured.

There is another ubiquitous structure which is also present in most buildings but which goes unnoticed because it is below the ground and hidden from view and that is the sump tank. Since water is not provided for construction purpose by the water utility the first construction on a site is an underground water storing tank called a sump. This sump is built even before a watchman’s shed sometimes. Here water will be purchased from private water tankers and stored to be used for construction. One estimate has it that there a million sumps in the city alone with an average capacity of 6000 litres. This means that the water storage capacity created is a staggering 6000 million litres. Remember that the city gets in about 1000 million litres every day.  Added to the fact that there is about 1000 million litres stored in overhead tanks the water storage by the city far outstrips that created by the utility.

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A sump tank under construction – Every building in Bangalore has one

 

Once the construction is completed the very same sump tank will be used to store the intermittent supply from the water utility. From here a pump will send it to the overhead tank to be reticulated by gravity to all the water points in the building.

Usually the sump tank is located in the North East corner of the site, especially for those who believe in Vaastu. The overhead tank is located in the South West for that is supposed to be the highest point of a building. Beliefs aside there are many technical things that should be carefully thought through to ensure that the sump delivers efficiently what it is supposed to.

The sump should be based on firm earth and with a good bed concrete. If the soil below is clayey or non-homogeneous it is better to build a RCC raft slab below. The side walls should not be compromised on and should be with good brick work using a nine inch wall. Alternately concrete blocks or hollow concrete blocks of good quality can be used. In high water table areas or areas of loose soil both sides of the wall should be plastered. The inside of the sump tank wall should be plastered with a waterproof compound on a wire mesh base. This will ensure that the sump tank does not leak.  After it is built the tank should be filled with water and checked that there is no leak. Any leak should be detected and fixed immediately.

Sump tanks are extremely unsafe spots on a site especially for children of construction workers and for others. They should immediately have a cover slab cast with an inspection cover securely locked. The sump cover should be rust proof. Aluminum covers are now available which are excellent.

The other things to remember are to use a submersible pump which is energy efficient. The submersible pump will save space being inside the sump. The pipeline from the sump to the overhead tank should be as straight as possible and with as few bends as possible. PVC or GI pipes of the right gauge and size should be used.

A ball valve regulates the water intake into the sump. This should be of good quality and should function effectively. In Bangalore the sump can also double up as a rainwater harvesting structure thus being multi-purpose in use. During the rains rainwater and during the non-rainy season water from other sources can be stored.

While digging in most places in the city good red earth will be obtained. This can be used for gardening and even for the making of earth blocks for the building.

An annual cleaning and maintenance is recommended preferably without wasting the water inside it.  During summer and during water borne disease outbreaks it is best to dose the sump water with bleaching powder and to measure the residual chlorine as 2 mg per litre after about 4 hours of the dosing. This will keep waterborne infections like cholera at bay.

Even though hidden from view the sump tank has an important role to play in the use of a building. A good design and maintenance will help extend its life and for it to perform optimally. In this understanding lies water wisdom.

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The well diggers of Bangalore – a craft in renaissance

June 10, 2013

Well digging has been the forte of the ‘Mannu Vaddar’ community in Bangalore. They are the people who work with earth for many centuries. They have dug the many lakes of Bangalore and also the many wells that dotted the landscape. Then their cousins the ‘Kallu Vaddars’ would take over and line the well with stones . The craft is at least 6000 years old in India.

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The stone lined wells of South Karnataka

Since the 1980 ‘s , especially during a period of 3 continuous years of bad rainfall, the construction of wells stopped and people shifted to the bore-wells. This rendered the well diggers jobless and they shifted to digging foundations for buildings as well as digging pits for toilets.

With the recent rainwater harvesting interest in the city and the coming in of the bye-law , wells are being dug again, only this time to recharge water from the rooftops and from storm water drains.

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Muniyappa – is now known as ‘Bhavi’ Muniyappa or Well Muniyappa in Bangalore

People like Muniyappa have dug more than 2000 recharge wells . He is a legend in the community. Of course strong competition has cropped up and there are many more well diggers in Bangalore.

A good policy , such as the rainwater harvesting policy , introduced in Bangalore not only works for ecological benefits such as increasing the groundwater table , preventing floods , supplementing the water needs of citizens but also provides social benefits such as work to many well diggers. This is truly the ‘green economy’ kicking in and traditional crafts being revived.

Even though the well mentioned by Mr Balsubramanian is more than 30 years old he still remembers Arumugham who dug it for him, everyday he says.

http://www.youtube.com/watch?v=42E-wjDa2xE

The memory of the well is crucial to Bangalore. On groundwater will depend the city s future. Well diggers and the recharge wells they dig will become the water warriors of the city. Time to salute ‘em.

 

 

 

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Functional , beautiful and a heritage – the need to integrate wells into our water plans.

June 6, 2013

This large beautiful well is close to Jakkur Tank in the Northern part of the city . The farmer draws 50,000 litres from the open well over a 12 hour time frame. Another 50,000 litres is drawn from a bore-well which is drilled inside the open well. This magnificent structure is about 50 years old. It is fed by the large Jakkur Lake with a 50 Hectare waterspread. The tank itself is designed to receive an eventual 10 million litres per day of treated waste water which should keep the lake full for the whole year. This well too will be full . Can we preserve and integrate the well into the water plans of the city ?

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A nutrient recycling system – looking at urban sanitation differently

May 30, 2013

City Ecosystem services and their management

A city needs a vast hinterland to support its population base as well as its economic engine. From here will come the food, water and other resources to keep it going. Of these water is a crucial limiting factor in the sense it has to be physically managed in large volumes to be delivered to every household daily.

Managing the catchment of the rivers which are the primary source for water will need to figure high on the list of priorities if a city wants to be sustainable and just.Catchment management will ensure that the forests and the groundwaters are protected so that the rivers continue to flow with high quality and quantity of water. These are upstream interventions for a river.

Catchment management can also mean taking care and protecting the water bodies within the city . Lakes and groundwater need to be kept away from pollution and encroachment as well as recharged with rainwaters.

Downstream needs : On the other hand the city also needs large areas of land downstream in a certain sense to manage the vast streams of waste that flow from it. Solid waste generated need land-fills as disposal areas. Liquid waste flowing through streams need large areas too for absorption of the nutrients.

In a strange conundrum the valley of the Vrishbhavati river is one of the greenest areas around Bangalore while the surrounding areas suffer from drought and a shortage of water. The city generates waste-water in the millions and about 500 million litres per day should flow out in the Vrishabhavati valley. The Byramangala reservoir , spread over 420 acres of land , receives all this water. It is a surprisingly scenic spot and deceptively beautiful .  Built in 1940 this reservoir continues to provide irrigation water through canals to many a farm field. The reservoir itself used to be a breeding ground for fish but all that has gone with the introduction of the African catfish into it.

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The deceptively beautiful Byramangala lake receives about 50 % of the citys waste-water

Downstream the waste-waters undergo a remarkable transformation. The soil , the vegetation and farmers transform this nutrient rich water into a green bounty. Slowly and surely as the river progresses one sees an improvement in the quality of the waters and by the time it joins the Arkavathy it can hardly be recognized as a foul smelling black stream which leaves the city. The Ecosystem services provided by nature is truly remarkable.

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Slowly but surely nature transforms black-water into better quality

This is not to say that there are no problems. Industrial effluents should not enter the stream at all . Domestic sewage too should be treated to a certain minimum standards before release to the river. Groundwater in around 50 % of the bore-wells was reported as contaminated especially with nitrates and bacteria according to a study. Farmers and field workers too have been reported to suffer from skin disease and other ailments.

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How green is my nutrient laden valley ?

While source control and elimination of the problem there is the best way it is still true that these waters are now essential for the livelihoods of hundreds.

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Can waste-water irrigation be integrated with the ecosystems approach of managing it?

Can the city think of identifying the entire area of the Byramangala reservoir and its command area as a zone which produces ecological benefits and for which the city should support the land and its cultivators ? Can this land be bought by the city and managed with the farmers and a palate of crops developed which will not enter the food chain of the residents of Bangalore? Can the villagers downstream be supported to access safe water and also be rid of the disease impact of using the waste-water? Can we think other than conventional waste-water treatment plants but say vast bio-diverse managed wetlands to clean the sewage that emanates from our city and for which each and every citizen is personally responsible? Can the institutions in our city rise up to the challenge and can the  city become ecological and water wise ? If any city can be the first this city has a fair shot at it.

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Water Blindness – a modern urban disease

May 30, 2013

 

2013 has been a strange year. April and May is seeing a staggering case of ‘water blindness’ in Bangalore. The media is full of reports on how the Krishna Raja Sagara dam on the Cauvery ( about 14 km. from Mysore City ) has reached dead storage level. The new Chief Minister of the State of Karnataka, India had to be consulted and water released from an upstream dam at Gorur on the Hemavathi River to the KRS dam. Police protection had to be ensured so that no farmers ‘stole’ the water en-route from one dam to the other.  Water is released from the KRS dam and it reaches the Shiva Anicut downstream, from here the water is diverted to the Netkal balancing reservoir and is then pumped a distance of 95 kilo-metres and to a height of 300 metres to be distributed to the thirsty population of Bangalore.

As this riverine drama was going on, it was raining on the city itself. In the months of April and May, the driest and hottest months all across India, it poured all of 163 mm on the city. If you did the math, on the city of 1250 sq. km. which is the Comprehensive Development Plan area, the total volume of rain that fell would be a staggering 1,87,500 million litres. At the demand from the city of 1200 million litres per day, this water if harvested would have provided for 156 days of requirement. Granted that not all of it can be harvested and some is required for nature but even 50 % efficiency in collection would mean 78 days of supply.

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Measuring rain is the first step to understanding it 

Bangalore has made rainwater harvesting mandatory (www.bwssb.org). All old sites with over 240 sq mt plot area and all new sites with 120 sq. mt. mt. of plot area must have a rainwater harvesting structure. The rules are also simple – create 20 litre storage or recharge structure for every square metre of roof area. For the paved area on the plot, create storage or recharge structure of 10 litres for every square metre. The recharge structure itself should be 1 metre in diameter and at-least 3 metres deep.

If the good citizens of Bangalore follow the law there should be no water shortage in the fair city.

Individual examples: Some fascinating examples stand out. Mr. Balasubramanian, in the layout called Vidyaranyapura,in the northern suburbs of Bangalore has an old open well. The well which is 5 feet in diameter and about 30 feet deep had gone dry . He has recharged it using a simple drum filter filled with sand. The rooftop rainwater comes in through the filter and into the well. Since 2008 his well has not gone dry and provides him water right through the year. The water too costs him Rs 2.30 /- a kilo-litre, the cheapest water in the city. The quality of water in the well is only improving with time and recharge.

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Mr Balasubramanian recharges the old open well in his house from rooftop rainwater

The well provides him all the water he needs for the year

Such is also the case with Mr. Chandra Shekar of Jayanagar 3rd Block in the Southern part of the city of Bangalore. He too has rejuvenated a well which is 50 years old. The fact is that rainwater harvesting keeps these wells alive and in an emergency even when there is no power water can be drawn through buckets thus providing electricity independent water.

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The 50 year old open well of Mr Chandra Sekhar , recharged with rooftop rainwater and now full

Dr B.R. Hegde on the other hand has built a separate rainwater sump tank of 5000 litres capacity. He stores the rooftop rainwater and uses it for non-potable purpose.

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Dr Hegde stores rooftop rainwater in a 5000 litre sump tank with the steel cover.

Rainwater Harvesting Theme Park: The Bangalore Water Supply and Sewerage Board have set up a theme park on rainwater harvesting in Jayanagar 5th Block. Here citizens can see more than 50 different types of rainwater harvesting possibilities including recharge structures as well as landscape and storm-water design which is rain friendly. A free consultation is also available with Engineers for a basic rainwater harvesting design. The BWSSB will also put you in touch with trained plumbers to carry out the job.

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Rainwater harvesting theme park in Jayanagar  40th Cross,5th Block Bangalore

All in all rainwater harvesting is slowly but surely establishing its foothold in Bangalore. Once it becomes a mass movement, water should no longer be a constraint for the growth of this city. It is time to look to the skies and act rather than to look to the dams and complain.

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