Posts Tagged ‘water’

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Airports and water

June 3, 2014

The Airport is located quite far from the city, about 30 kilometres away. It is too far away from city lines and has to depend on groundwater. It needs 9 million litres per day eventually though for now 5 million litres per day will do.  To boot it is located in what was called a ‘dark zone’ by the Central Ground Water Board, meaning groundwater was being exploited beyond recharge potential. An Airport needs water and plenty of it. So what did it do?

For one it requested and sourced fresh water from the city paying Rs 66 a kilo-litre, a high price which gave the water utility supplying it some monies. This fresh water is limited to about 1.5 million litres daily. It then did a smarter thing, it bought tertiary treated waste-water and a full 2 million litres of it daily and it paid Rs 25 a kilo-litre for this treated waste-water. This was separately stored and used for the vast beautiful landscape springing around, a huge bio-diversity of plants and even a small wetland.

For the internal waste-water generated it set up its own sewage treatment plant using extended aeration system. This treated water is then reused for flushing the toilets in the airport premises as well as for the air cooling systems. The sludge generated from the sewage treatment plant is composted and reused as manure for the landscaped area. 

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       An internal waste-water treatment plants treats all waste-water as well as waste from aeroplanes

Runways and the area surrounding it generate large quantities of storm water when it rains. It is therefore very important that this run-off be collected and quickly disposed off and flooding avoided. With more than 310 recharge wells located in the storm water drain or immediately adjacent to it a large volume of the rain is recharged into the aquifer. Well designed storm-water drains then take away the rest of the rainwater to an adjacent lake which is capable of receiving this large flow of rain.

Two things have happened due to these good efforts. Four large open wells which were old existing constructions have been rehabilitated, cleaned up and repaired. Pumps and a filter have been attached and the water quality tested. It is found that this is very high quality, sweet potable water. Thanks to the recharge efforts the wells stay full even during summer. Up-to 800,000 litres of water can be drawn from these open wells daily and in an emergency they can replace the mains water from the city. A landscape which was once a dark zone, given a holiday for high extraction from bore-wells and with enough recharging can be revived to such an extent that open wells can have water.

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                                      Recharge of rainwater has helped aquifers rejuvenate with fresh clean water

From the airport buildings rainwater is stored in large underground sump tanks of about 1.5 million litres capacity and reused after treating. Excess water from the sump tanks is then allowed to flow into storm drains and recharge the aquifer as well as flow into the adjacent lake.

The revival of the adjacent lake also means that villages and towns adjacent to the airport, such as the town of Devanahalli, can now think of sourcing groundwater from adjacent to the lake to fulfill the towns water requirements.

 

 

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                         Sludge drying beds 

Economic activity and service activity like airports are essential for economic growth and to spur the progress of a city. Instead of seeing it as placing demand on water services through innovative design they can absorb waste-water from cities and be able to use it to meet its requirements. Through waste-water treatment and reuse and through rainwater harvesting groundwater aquifers can be revived and lakes kept full. These can then be of great help to surrounding communities. The Kempegowda International Airport at Bangalore showcases just that. This is water wisdom.

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Community Engagement and water walks – Bringing people to water

May 24, 2014

People and water

 Around a recharge well – learning about groundwater

They are a small informal group and call themselves Friends of the Lakes. The group is a motley bunch of enthusiastic young people and wise old stalwarts who have seen it all and they have one purpose in coming together to save three lakes which are in the neighbourhood. They meet every Sunday and go around the lakes cleaning them up of rubbish and persuading morning walkers to become a part of the exercise. The area Corporators and there are two of them have joined in enthusiastically and now lead the initiative. Discussions are sharp and the moot question how can the lakes be protected from encroachment, be kept away from sewage water and be full. The energy is high and the mind positive.

At a waste-water treatment plant

 At a waste-water treatment plant

The group of youngsters are volunteering and learning about urban issues confronting the city. They have come, albeit late, to the sewage treatment plant and for the first time for most are figuring out where the water they use in their homes ends up and what is needed to clean it up. Questions fly in the air and small group discussions take place. Cameras click and the flying foam is of particular interest to capture. They then see a wetland with its rich bio-diversity and its role in polishing treated waste-water and finally relax on the granite steps at the bottom of a large well which is full of water,a water heritage structure.

 

Across towns and cities all over India groups are coming together to help revive their citys lakes and protect them. Mysore, Dindigul, Erode, Hyderabad, Chennai , Coimbatore and in many other towns one can see this movement of citizens getting together with authorities and saying let us get things moving.

It is time that authorities noticed it and stepped in perhaps with the help of NGO’s, perhaps with the help of academia and organize water walks in their towns and cities regularly to make water literate an increasingly interested population. Citizens need to see the challenges ahead in the water front and on the wastewater front and an army of volunteers and professionally engaged people are needed to address the challenge. Bangalore city for example will have 25 wastewater treatment plants one of which converts sewage into potable water. Why should these places not be open to public for guided tours albeit at certain times?

If you learn for example what NOT to put down the sewage line and the kitchen sink you will have done the authorities a big help. No used oil, no personal hygiene products into the toilets and as the famous words go nothing into the underground lines but Numbers 1 and 2 and soap and water , will be a big help to the environment at large and to waste-water treatment .

It may look simple s but people engagement is the key to water wisdom and the moment is now.

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On the likely possible development agenda of the new government

May 17, 2014

 

Development with Gujarati characteristics .

It is a comprehensive win for a model of development now likely to replicate itself in many other states all across India. What could be some of the characteristics of this development strategy ? Clearly it will be an infrastructure led model.

Electricity and the power sector: This is one sector where the Gujarat model is striking and clearly ready for a roll out. Segregating the rural agriculture sector from habitations, ensuring 24 hours supply to homes and then ensuring 8 hours of reliable and robust power to the agriculture sector will not only help farmers but also boost the growth in this area substantially. Urban power supply without any power cut is something almost every household and industry looks forward to. Alternative energy such as solar and wind energy should also get a substantial boost.

Water:  While river inter-linking may have been the rhetoric it is likely that the focus would be back on major irrigation and groundwater. While water for irrigation should get a ramping up in terms of outlay and investments, greater focus will be on increasing efficiency of delivery through canal lining, improved governance et al. Also like the massive Saurashtra model of water harvesting, using soil and water conservation measures at large scale in a partnership with communities will help the groundwater sustainability and availability. India’s dependence on groundwater cannot be overemphasized and this sector will see much attention in the coming years.

In urban areas the Surat model of water and sanitation with an overall goal of 24/7 water supply and full underground sewerage system with waste-water treatment and recycling will roll out all across Indian cities. Rural sanitation should get a solid boost with it having the personal attention of the Prime Minister.

Transport: The Bus Rapid Transport System (BRTS) of Ahmedabad is a model for the rest of the country. For sure mass transportation including metro rail and BRTS will to overcome the gridlock in urban India will be the direction. Atal Behari Vajpayee ‘s National Highway Grid and the Pradhan Mantri Gram Sadak Yojana , both hugely successful initiatives, should see increased focus for finance. It is through this investment that every village in India can be touched and linked to the overall development of the nation.

Housing: This will be a tough sector to deal with and it is not clear how the path ahead lies because there is no Gujarat model to follow here. However it is clear that the private sector will play a much more important role than previously and land reforms in urban areas will take priority.

The policy imperative will demand that a National Energy Policy, a National Water Policy within which an Urban Water and Sanitation Policy and a Groundwater Policy is included and a National Transportation Policy, including roads and railways, amongst many others be articulated to indicate the direction in which the government will move in the coming years.

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On the sludge management and reuse potential in Bangalore

May 12, 2014

One of the many critical factors affecting productivity in Indian soils is the absence of nutrients such as Nitrogen, Potassium and Phosphates. Even Carbon is in short supply as well as micro-nutrients such as Zinc and Boron.  AA substantial part of our artificial fertilizers is imported and we run up quite a huge bill. Fertilizer prices too are shooting up leading to an imbalance in their application. It has been reported for example that Urea which is relatively cheaper is over applied on soils causing more harm than good.

Cut to urban cities. Sewage treatment plants are coming up in large numbers. The Bangalore Water Supply and Sewerage Board –the utility responsible for sanitation and sewage, will eventually be setting up 25 sewage treatment plants treating nearly 1100 Million Litres Per day of sewage. These plants will mostly be secondary and tertiary treatment plants. Each million litre of sewage generates nearly a Tonne of sludge. Imagine 1100 Tonnes of sludge will be generated in the city of Bangalore alone. This is 120 truckloads of sludge.

There are smaller sewage treatment plants dotting the landscape in apartments and layouts too. These too generate smaller quantities of sludge. Overall this represents a management challenge of large proportions.

Research:  Currently at the GKVK-University of Agricultural Sciences – research work is going on to understand the nutrient value of this sludge. A Ph D student is pursuing her Doctorate and is experimenting on field trials using the sludge as manure. The initial test results show very good amounts of Potassium and Phosphates in the sludge.

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Separately sludge is also being picked up from Ecosan toilets. These are source separating composting toilets which segregate urine and solids. The solids are covered with ash after every use and desiccated before application as a fertilizer on soils. Farmers of Kamasamudram and H.D.Kote have such toilets in their homes and are very happy with the fertilizer they get. In fact this compost is priced at Rs 10 a kg.

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Sludge sells for upto Rs 10 a kg.

Similarly the landscape of rural India is dotted with pit toilets, more than 130 million of them at the last count. These too accumulate solid sludge and need to be emptied using mechanical systems. They are also found to be rich in Phosphates and Potassium.

All these various forms of sludge will be taken, tested applied on fields and crop productivity tested under expert supervision.

When research and application come together in a spirit of cooperation, it is possible to find solutions for India’s vast water, food and sanitation problems. At the base, this is a nutrient cycle at play. How we scientifically understand and manage it will show us the path to solutions. If every gram of sludge generated in our Sewage Treatment Plants become useful as manure it will partially solve India’s fertilizer needs and eliminate pollution. It will also increase productivity and richness of our soils as well as enhance the livelihood opportunities of farmers.

Recognizing and converting waste to a resource will help thousand of apartments and layouts, small and medium towns and even metropolis to manage their sewage efficiently for reuse and recycling. This would be water wisdom.

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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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The water pricing and tariff in question

January 1, 2014

Much debate has been ignited by the recent decision of the Aam Aadmi Party in Delhi to give 20,000 litres of water per month per connection free. Here is how water pricing can be seen and choice of water prices determined

First some beliefs

1. We all have to pay for good quality piped water. Directly as a consumer, indirectly as a tax payer or even more indirectly as inflation. It is best to pay as a consumer and keep the utility supplying water fiscally buoyant so as to be able to extend services and keep up the quality of the infrastructure.

2. Eventually both environmental externalities and social externalities will need to be factored in. On the environmental side the continuous availability of good quality water will demand investment in catchments and rivers and groundwater and rainwater. Negative externalities will need to be costed and the treatment cost of waste-water included in the price of water.  On the social front , water is a community property resource and its increased availability upto a point improves health and economic outcomes of communities . This will result in increased productivity , less expenses on medicines and especially a better future for children . However a combination of good water supply , access to safe sanitation and good hygiene behaviour should be encouraged altogether.

Now to the idea of pricing …

Let us assume 100 kilo-litres of water coming in to a city. The cost of the water will include the Capital cost amortized over the life of the project , the Operations and Maintenance cost for running the entire system and a sinking fund to replace the equipment at the end of its life.  For a moment let us assume that this cost of water production is Rs 10 per kilo-litre ( a 1000 litres) Now if a utility is to run as a no profit no loss entity it has to recover the cost from its consumer. However unfortunately there is a lot of loss in the system. Some water leaks out of pipes. Some water gets to consumers who do not pay or are not required to pay. Figures can reach 50 % but let us assume an efficient institution and a figure of 20 %.

Now let us do the Maths

Cost incurred to get and distribute water to the city 100 KL x Rs 10 per KL = Rs 1000

Cost to be recovered from 80 KL (since 20 KL is lost )  = Rs 1000 /80 = Rs 12.50 Kl

Typically consumers in a city are divided into three broad categories of users

Domestic      Non domestic (commercial)  and  Industrial. Typically the later two categories can afford to pay more for water. Let us assume an ideal distribution of the remaining 80 KL of water as follows

Domestic     Non domestic   Industrial               Loss               Total

KL                         KL                    KL                         KL                    KL

52                      16                           12                  20                     100

Now if we charge double the tariff for non domestic consumers (such as hotels ,restaurants, pvt establishments etc) i.e Rs 25 a kilo-litre and four times for Industrial consumers i.e. Rs 50 a kilo-litre we will have the following tariff

Total cost to be recovered  -     1000 Rs

From Non-domestic –   16 x 25 = 400

From industrial =            12 x 50 = 600

Total cost recovered                  Rs  1000

Free water is then possible for the domestic sector without   the institution incurring any loss.

Of course there are caveats.

  1. The 52 Kl coming in to the city should be enough for all the population of the city. At a standard of 140 lpcd , this 52 KL can service a population of 52000/ 140 = 371 people.  For 20 million people like Delhi to have water at 140 lpcd the city will need 20 million x 140 x 100/52 = 5385 million litres a day. It is better to drive consumption down to an efficient 100 lpcd , in which case the requirement would be 20 million x 100 x 100 / 52 = 3847 million litres per day.
  2. Source substitution will occur if prices go up. Both the non-domestic and especially the industrial sector will go for groundwater or private water tanker if that is cheaper than the tariff imposed by the cross subsidization. Hence groundwater and tanker water will need to be regulated and charged at the same price as piped water.
  3. Metering both bulk and retail will be a must. All connections must be individual and all connections must be metered.
  4. If water is free for the domestic sector there will be no incentive to conserve it. Pricing is a must for this sector too. People are not hindered by the price of piped water but by the absence of connections and the initial connection cost. This must be universalized and made free.
  5. It is better to make the WHO guideline of 50 litres per capita per day which is the basic minimum for health and hygiene, free..i.e.50 x 5x 30= 7500 litres per month free. Anything above must be charged at a minimum price of say Rs 4 a KL . Anything above 135 lpcd should be charged at non-domestic tariff.
  6. Special teams will need to be created and dialogues will be necessary to increase the connections and consumption for non-domestic and industrial use.
  7. To get to a 20 % leakage figure will be no easy task but all new pipelines and connections must be designed for 24/7 water.
  8. Wastewater will need to be collected and reused/recycled as non potable water or as ecological flows through wetlands into rivers.

So here then is the final tariff structure

Domestic                 Non domestic                Industrial

Litres                    Rs                               Rs                                    Rs

Slab   0 -7500            Free                      25                             50

7500- 15000         4                                  25                              50

>15000                25                                25                                50

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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 first water reservoir for Bangalore

November 13, 2013

WATER WISE

Lessons from a reservoir

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A little water in a once mighty reservoir on the river Arkavathy

Some insights on how water requirements are catered to and how projects such as Hessarghatta become irrelevant over time with climate change

  Those who do not learn from history are doomed to repeat it – George Santayana.

Located to the west of Bangalore at a distance of 24 km, picturesque Hessarghatta is home to one of the first city water supply schemes located outside of a city. It is more correct to refer to the Hesserghatta reservoir as a ‘once upon a time’ water lifeline for Bangalore rather than a current lifeline. It has been given up as a reliable source by the Bangalore Water Supply and Sewerage Board (BWSSB) the institutional water supplier to the city, since it no longer reliably fills up.

Looking at the history of the reservoir and the water supply scheme for the city will give us some insights as to how water requirements to a city are catered to and how projects become irrelevant and have to be abandoned or are given up in the chase for water. With climate change staring at us, the Hessarghatta story has many lessons for urban India.

A bund was probably built in 1532 on the Arkavathy, creating the Hessarghatta tank which served as an irrigation tank for centuries. It was comprehensively redone in 1894 to become the major water supplier to Bangalore. For the first time the city had reached out for water beyond its tanks such as Dharmambudhi, Sampangi, Ulsoor and Sankey and local wells. A brick aqueduct brought water to a distance and then steam pumps were used to pump it up to Chimney Hills from where the water flowed by gravity to the Jewel Filters at Malleswaram.

Key role

The then Dewan K. Sheshadri Iyer played a key role in the development of the Hessarghatta water supply scheme which came to be called the Chamarajendra Water Works, as did the then Chief Engineer of Mysore M.C.Hutchins. It is now difficult to believe that Hessarghatta was chosen for reasons of long-term availability and purity of water.

D.K.Subramanian, in his seminal essay ‘Bangalore City’s water supply – A study’ mentions that the Chamarajendra Water Works was meant to deliver 55 litres of water per person per day to a population of 250,000 and the filtered water supply started on August 7, 1896.

Till the commissioning of the Thippagondanahalli reservoir in 1932-33, Hessarghatta remained the largest supplier of filtered water to the city. The reservoir last filled up in 1994 and year on year collects less and less water and therefore has gradually been given up as a reliable source of water for the city.

A reservoir with a catchment area of 189 square miles and with 184 tanks in its upper catchment and supplying 36 million litres per day of water becoming virtually redundant indicates the necessity for managing the catchment appropriately and ensuring good practices for free flow of water. Bangalore simply moved from Hessarghatta to Thippagondanahalli and from there to Torekadinahalli for Cauvery water.

The brick aqueduct and volute siphon are amazing water heritage structures fit to be preserved and displayed. It reveals the skills of our water engineers in being able to design and build beautiful systems. They now lie derelict. We need to revive and proudly display them for our future generations.

We need to understand the changes in the catchment of the Arkavathy and look at reviving the river and regenerating flows. The Hessarghatta reservoir has the capacity to supplement Bangalore’s water requirements at a far cheaper cost than any other. It makes ecological and economic sense to look at its revival. In learning from history the right lessons lies water wisdom.

Begun in 1891 and completed in 1896, the Hessarghatta reservoir was designed to provide water for a population of 250,000 people in Bangalore. This anticipated population was reached in 1921 itself and therefore a new project had to be thought of to augment supply of water to Bangalore. The monsoon failed in 1924 and 1925 and the 1926 monsoon too arrived late, leaving the Hessarghatta reservoir almost dry and causing a shortage of water in the city.

Prof D.K. Subramanian reports that by October,1925, tanks upstream were breached and drained to fill up Hessarghatta and provide relief to Bangalore city. Dodda Tumkur tank, followed by Kolathur and Mdure tanks, were breached to bring some water to Hessarghatta. Perhaps for the first time, in a sort of payment for ecological services, the city compensated the farmers dependent on the three tanks for the loss of water and irrigation.

A committee was constituted under Sir M.Visvesvaraya to find a permanent and reliable source of water for Bangalore. The committee suggested the construction of dam across the Arkavathy itself but further downstream after the confluence of the Kumudavathi at Thippagondanahalli (T.G.Halli). The reservoir came to be called the Chamarajendra reservoir and the water to Bangalore started flowing from it in 1933.

Height factor

The Bangalore Water Supply and Sewerage Board (BWSSB) website tells us that the original storage of water in T.G.Halli was 2364 million cubic feet and subsequently it was increased, by raising the height of the reservoir wall, to 3038 million cubic feet. Water was pumped to the city in stages. In the final stage around 135 to 140 million litres of water was pumped from the reservoir to the city daily.

One consequence of shifting from Hessarghatta to Thippagondanhalli was the height to which water had to be pumped to reach Bangalore. From Hessarghatta the head to which water had to be pumped to Bangalore was 131 metres and required only a single stage pumping from Soladevanahalli. From T.G.Halli however, the head was 234 metres and necessitated two-stage pumping with an intermediate pumping station at Tavarekere.

The catchment area of T.G.Halli, 1453 square kilometres, represented a substantial increase over the Hessarghatta catchment area of 474 sq. km. The catchment area was declared a regulated zone under the Prevention of Pollution Act in 2004 following a public interest petition in the High Court of Karnataka. Industrial waste discharge and construction therefore are regulated in this catchment area.

Both the quantity and quality of inflow into the T.G.Halli reservoir is on the decline and it is unlikely to be considered a reliable source for Bangalore in the coming decade.

While the catchment area to satisfy the city’s thirst keeps on increasing, the water footprint too increases. In the absence of a catchment management institution no planning, coordination and investment is done to ensure that the quantity, reliability and quality of flows in our rivers and reservoirs are maintained. In the absence of any form of regulation of water withdrawal in the catchment, unhampered withdrawal of water from tanks and groundwater for irrigation of water-intensive crops leaves rivers and reservoirs dry.

Right solution

Constituting a river basin authority for rivers such as the Arkavathy will enable all stakeholders to participate and a reasonable allocation made to satisfy all needs. Unless such an institution is brought into play, these reservoirs will remain as mute monuments to the cities’ thirst and our mismanagement of our rivers and waters. Conflicts around water will become inevitable. Learning from history and taking steps to prevent repeated failures is water wisdom.

Awareness walk

As a consequence of trying to understand the role of Hessarghatta reservoir in Bangalore’s growth, the Bangalore City Project (http://bcp.wikidot.com/) proposes to organize a walk on the reservoir bund. on December 6. The walk will look at the reservoir and its current state. A siphon provided as an overflow mechanism is another unique structure to be observed. Remnants of a brick aqueduct and a small temple on the bund will also be seen. Experts will explain how the reservoir functioned.

If you want to participate in the event please call Sandhya at 080- 2364 4690 or send an e-mail to rainwaterclub@gmail.com. We have 35 limited seats and the seats will be filled on a first come first serve basis. We propose to organize a bus from Cubbon Park to Hessarghatta and back. You should bring along drinking water and some snacks. The walk will be about 3 km long and will take about two-and-a-half hours.

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On an urban community managed water system

November 11, 2013

The traditional in the modern – a community at work

zenrainman@gmail.com

At first glance you see a protective fence which is not impressive but as you approach the magnificence of the structure strikes you , a beautiful 120 feet diameter open well full of water and you wonder whether this is the Bangalore where groundwater is supposed to have sunk to 1250 feet. This residential layout on the South of the city has done a magnificent job of managing its water purely through community action. A dynamic association has taken charge and the committed team first cleaned up the ‘Rajakaluve’- the main stream linking water above and beyond , passing through the layout. Its attention was then focused on the beautiful heritage well on campus. The well was cleaned and a 100 truck loads of silt removed. The silt was place in the gardens and the open spaces rich in fertile soil.

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A beautiful old well revived and recharged – full of water 

The well now becomes a supplemental source of water for non-potable use and in case of an emergency with treatment for all uses. Each house in the layout has been encouraged to go in for rainwater harvesting. In the storm drains which run around, all of them are maintained clean and percolation wells are being placed so that the road run-off is recharged into the ground. Ultimately all run-off will be sent into the aquifer with the site becoming a zero discharge area for storm-water.

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Modified storm-water drain for silt trap and recharge – easy to replicate

A waste water treatment plant hums daily, treating and cleaning 200,000 litres of sewage from the entire colony. This treated waste-water too is reused in the layout. A 100 trees are planted every year and the waste water is used to feed the trees and the parks.

The community building where the residents meet , collects every drop of rainwater falling on the roof in large rain barrels and reuses them.

Begur 080Rainwater Barrels collect rooftop rain

 

 

On the day one visited the campus children had gathered at a science fair and were demonstrating various experiments that they had set up. Most of them centred around water. A group of them had already been taken for a tour  of the layout explaining what was happening with water and the necessity to keep the roads and storm water drains clean as well as to take care of the trees for the birds that are around.

A turtle was spotted in the well and was swimming about merrily, a cause for some excitement.

When communities come together it is possible to achieve the unthinkable, that is a clean environment and plenty of water with a bit of heritage thrown in. The more we expand thisn space the better for our urban areas. In this community awareness and action lies water wisdom.

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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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