Archive for the ‘Uncategorized’ Category

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Dealing with defunct borewells

April 20, 2014

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It mostly takes a tragedy for us to act as a society. It is possible that India has about 30 million bore-wells, the worlds largest number. The drilling of bore-wells is a flourishing industry where greater and greater depths are recorded but more significantly from a safety and security point of you the diameter of drilling is increasing. From once what was an innocuous 4 inches of diameter, boreholes now are typically 4 ½, 6 ½ and even 10 inches in diameter.

With a complex hard rock structure in the Deccan Plateau and a depleting water table many bore-wells fail to strike water. Some go defunct when the water is extracted and the level falls below the bore-wells. These bore-wells have to be treated with great care else they can become the spots for accidents. Young children falling in, is a serious cause for concern and action.

Recharge: No defunct bore-well should be left unmarked. A bore-well which yielded water and is now dry can become a great source for recharging the aquifer. A clean and sufficient catchment for run-off is a must. The water is then lead to the Borewell around which 3 feet to 5 feet diameter recharge well is dug. The well is lined with concrete rings and can be filled with filter materials or even left without it. Holes are then drilled in the casing of the bore-well and wrapped with a mesh to prevent grit from falling inside. Rainwater and storm-water is directed to the recharge well, filtered and allowed to flow into the casing to recharge the groundwater.

Making a recharge well around a defunct bore-well. Safety should be a concern.

 

Rooftop rainwater can also be led into these defunct borewells again after making sure that the rooftop is clean and ensuring filtration before the water is led in to the Borewell.

Care should be ensured that no polluted water gets in. Care should also be taken to ensure that the electric connections are dis-connected and also that the cover on the recharge well is solid, heavy and not likely to cave in.

Failed borewells: Similarly, in the case of a failed Borewell the tendency is to recover and salvage the casing pipe inserted into the drilled hole. At this instance it should be mandatory to fill up the hole with earth so that there is no chance of an accident. Responsibility is jointly that of the owner of the land where the Borewell is being drilled and that of the drilling operator. A code of procedure should be followed to ensure safety at all times.

Borewells are the lifeline of India , providing water for irrigation, industries and domestic use. Making safety a top priority in the drilling and managing of live and dead borewells is a prime necessity of the times. Developing safety protocols and ensuring that they are applied is a step towards water wisdom.

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Water tariff and free water

January 11, 2014

The price in question

zenrainman@gmail.com

God gave us water so it should be free. Yes but he forgot the pipes. – Quote

The pricing of water in urban areas has firmly entered the political decision making space with the Delhi announcement of 666 litres per connection per day free. Here is a good look at what goes into decision making and how a solution is arrived at.

Cities get water from quite huge distances. Bangalore for example gets its water from the river Cauvery 95 kilometres away and about 300 metre below the city.  Typically there are three components to the investment requirement for water. First is the capital requirement to collect, treats, pump, store, distribute and measure through meters the water supplied to all the myriad connections. Then collect, convey and treat the consumed water which now emerges as wastewater. This is the Capital cost of the system.

Then there is the electricity bill to paid for pumping the water and treating the wastewater, the chemicals required in cleaning the water and wastewater, the salaries of the employees and meter readers , the routine repairs that are needed etc. This is the Operations and Maintenance Cost.

Finally there is a sinking fund to be collected to replace the entire infrastructure when the life of the equipment is over.

As a rough idea in Bangalore it cost Rs 80 for a kilo-litre of water to be produced and delivered to the consumer. The cost in Delhi is reported to be about Rs 28 a kilo-litre.

These three components make up the investments for water supply and waste water collection. There are three ways this can be funded, by the tax payer, by the consumer or by grants from foreign agencies.

Remember the true cost of water is when it is returned back to nature at a quality decided as appropriate not to cause pollution. The ecological cost would also include the preservation and management of the lakes and rivers and their catchments to continue to supply the water as well as the treatment plants needed to treat the sewage to appropriate standards.

Consumer: For the consumer there is usually a connection cost for water supply and sewerage and in a well functioning system a monthly bill based on the volumetric consumption as reported by the meter. In many cases if metering is not there is a flat charge or something linked to property tax.

Now if free water is given to the consumer of domestic connections the only way to recover the cost would be from two other categories of consumers the non-domestic consumers such as hotels and restaurants and from the industrial sector. However if the tariff for these sections go up too high there is a resource substitution with industries shifting to ground water or to private water supply.

Tariff: While it is a fact that no human being should be deprived of water due to the cost of it, it is also a fact that water is an economic good and requires monies to supply. A good via media would appear to be universal connections given to all families and houses in cities, a free 50 litres of water per person per day as prescribed by WHO guidelines and then a reasonable tariff to recover costs. A fact to be remembered is that about 50 % of piped water in a city goes as non revenue water, either physically leaking from the system or simply not billed or collected. It would be important for city utilities to bring this number to less than 20 %.

Way forward: It would be ideal for cities to put the data in public domain and go inform large scale consultations with its citizens on how to arrive at a tariff. With responsible fiscal behaviour will come sustainability and with universal connections will come equity. Sources such as groundwater accessed through hand-pumps can easily be made free if the aquifers are well maintained and are not polluted and do not go too deep.

Innovative dialogue is the way forward and this is the right time for urban India to enter into the dialogue and enter into a compact with its political parties for good water governance.

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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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Water devices in the house

November 30, 2013

Look around a house and it boggles the mind to see the many devices around the use of water. From the pipes that run around and inside a house to the taps which allow you to draw water when you want, the bathtub which allows you to loll around to the showers which dispense water in a spray to the Jacuzzi which does more of the same.

Then there are the mugs and buckets to slosh it around, the washing machine which cleans up your clothes and the dish washer which does the dishes.

For supply of water there was the open well replaced by the modern bore-well. Large dams on rivers to store and reticulate water and the latest rainwater harvesting tanks which do the same.

For storage you have underground sump tanks, large containers in the home and overhead tanks of HDPE or brickwork.

For heating water there is the geyser and the more environment friendly solar water heater. There is of course the basic bio-mass based ‘hunday’- large copper vessels where water is heated using dried coconut fronds-  and the more modern avatar the so called ‘Gujarat boiler’.

Then there the sinks themselves, designed to collect water and send it away, in the bathroom and in the kitchen.

For drinking and purifying water there is a whole range of water filters from the gravity based candle filters to the UV based ones to the most modern R.O filters. These are all upgrades of the old ‘ghada’ or ‘surahi’ the baked mud pots.

For waste water to be taken out there is the good old India W.C and the most modern dual flush European W.C.  The recipient of the waste has moved from pits, to septic tanks to the latest sewage treatments systems which clean up the waste-water and make it reusable.

In terms of the energy used for water, the old ‘pulley ‘in the well has finally become the submersible pump to lift and pressurize water.

In between there is the aquarium to store water for your gold fish and the refrigerator to cool water for a warm sunny day and even to make ice for your favourite drink. To water your garden there is the ubiquitous hose-pipe and the shower caddy.

The many devices which manage water for daily household consumption is remarkably varied and innovative. Many firms and designers are now at work to improve each and every one of them to make them more efficient, elegant and eco-friendly.  It is time to step back and appreciate this water wisdom.

 

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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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On the need for professional plumbing courses in India

October 3, 2013

The crisis of plumbing, where are the skilled plumbers?

 

Everyday miracles occur in our homes and apartments daily and yet we are oblivious to it. You open the tap in the kitchen sink and fresh clean water flows from it to wash the vegetables for cooking. You go and use the toilet and the flush takes away the waste from your sight cleanly and into a vast underground network of pipes which hopefully will then clean it up in a sewage treatment plant somewhere at the end of it. If anything distinguishes a civilized world from a less civilized one, it is plumbing. The provision of treated piped water inside homes and the taking away of waste-water has been the single largest lifesaver ever, decreasing mortality , increasing life span , reducing morbidity and improving quality of life overall. The great cities of the world are those which have built water supply networks bringing potable water home and underground sewers capable of handling all wastes including for a growing population. The invention of the flush toilet, which many regard as one of the world’s greatest inventions, also called for skilled plumbers to connect them to the sewage systems emerging.

From the days of Harappa and Lothal circa 2500 B.C.E or thereabouts, when the cities had a good sewerage and drainage system, to the current day’s plumbers seem to be a non-formal, ‘learn on the job as you apprentice’ trade. Great cities were built in the past and disappeared into the mists of history. Presently a construction boom grips our cities and yet one of the most crucial jobs that of providing water remains in the hands of a trade where there is no formal training institution and which has not professionalized itself. The most expensive fittings in the market for taps , showers , baths and flushes are put in place by untrained hands.

While it is true that skills not necessarily have to be learnt in formal institutions yet that there is no single poly-technic which teaches plumbing as a formal course to those wanting to enter the job market looks like a missed opportunity for the construction sector. There is also a great need to improve the skills of those who are already in the trade and who would want to take their income earning opportunities to the next level , perhaps even as as contractors or entrepreneurs.

Skill training for plumbers will improve the efficiency of design of buildings, improve water and sanitation handling abilities, ensure fire-safety and ensure the increased life of buildings since leaking water and sanitation lines are one of the biggest culprits for the reduction of life of buildings. Leaking pipes cause fungus and mold to develop and directly impact the health of the occupants. Blockages of pipes and sewers are a nuisance taking tremendous efforts to repair once a problem occurs.

Meanwhile Babu goes about his work in putting in place a new plumbing system for the house recently expanded and a first floor built. He has been in the trade for 13 years. He uses the crudest of methods to heat and join pipes. He has no idea on say putting a siphon type rainwater drain-out pipe which can reduce the diameter of the pipe and thus reduce cost for the owner. He has no clue on how to build a rainwater harvesting system which can collect at least 100,000 litres of rainwater for the building annually. The joints of the drainage pipe are reasonably well done but he has no idea how to have a dual pipe system which can reuse grey-water from the building and recycle it. The building owner and the contractor trust him completely and therefore are condemned to a sub-optimal design for the rest of the life of the building.

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Needed-Training institutions and skill up-gradation courses for plumbers

The Indian Plumbing Association, a newly formed body, has brought out its own code for plumbing including a Green Plumbers Code. It is valiantly trying to bridge the skill up-gradation and capacity building gap. They need the assistance of many a poly-technic and the skill up-gradation council of India to develop and deliver a special course to bring trained plumbers into the market. The construction sector will only benefit from such an effort as well as employment opportunities for the young in a trade which is life saving and very important. Water wisdom demands that society invest in skilled plumbers. That time is now.

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On the Twin Leach Pit pour flush toilet -TPPF

September 28, 2013

Of all the countries grappling with a sanitation problem India tops the list. The number of households without access to a toilet and defecating in the open is nearly a staggering 50 % of the total households in India according to the census of 2011. Even where there is a toilet many simply discharge into the open drains and do not ensure safe disposal. An economic loss of 6.4 % of the GDP amounting to a staggering 53.8 billion US dollars annually was one estimate by the World Bank in 2006 for India. Another recent study establishes a distinct link between open defecation and stunting of growth in children having far reaching implications for a young population.

 It is therefore time to revisit a technology more or less developed and fine tuned in India decades ago and which still continues to be extremely relevant for the sanitation sector. This is the Twin pit pour flush toilet – TPPF- to professionals in the sector.

 

The whole toilet users world is divided into sitters and squatters.

Then therImagee are wipers and washers. The Indian populace is largely squatters and washers. Keeping this factor in mind the TPPF has been designed. It makes use of an Indian squatting pan with a steep slope that uses just 2-3 litres of water to flush and clean. It has a trap with a water seal, usually a minimum of 20 mm. This constant presence of water in the seal ensures that there is no foul smell that comes back into the toilet and that no insects or cockroaches come into the toilet. A 75 mm diameter to 90 mm diameter pipe then takes the washed material to an inspection chamber. Here a diversion trap is made wherein at a time one pipe is opened.

These pipes lead to twin pits which are generally honeycombed. A typical pit would be about 1 metre in diameter and about 1 .5 metre in depth with a solid cover on top. The washed material from the toilet ends up in one pit at a time. A pit takes about one year to fill. Once one pit is full at the diversion chamber the pipeline to this pit is blocked and the other pipe is opened to allow the second pit to fill. The distance between the pits is usually at least a minimum of the depth of one pit i.e. about 1.5 mt. This of course depends on the space available.

While it takes one year for the second pit to fill in the meantime through process of bacterial action the first pit is sanitized for most bacteria, virus and worms. This can then be emptied usually using mechanical evacuation methods such as that of the vacuum trucks called Honeysuckers. The emptied material especially in rural areas can be further composted and used as an excellent fertilizer by farmers.

The superstructure of the TPPF can be permanently done with brick or concrete blocks and a roof of sheet or RCC. In other places they can also be temporary with just privacy ensured for use. Typically a TPPF toilet should cost around Rs 10,000 in most places in India.

Water should be made available only in small buckets of 3 litres for ablutions as well as for pour flushing. This will ensure that excess water is not poured into the pit.

Pits can be designed in high water table areas with a concrete bed and with a 50 cm sand cushion all around. The pits should also be a minimum distance of 8 metres from a water source such as a well or a Borewell. Pits can also be lined with charcoal and limestone to further improve performance and remove pollutants.

Experience has shown that a well designed TPPF can provide safe sanitation and containment of excreta and over the life cycle it can also be much safer than toilets connected to underground sewage treatments with no treatment plants which end up contaminating and polluting water bodies such as rivers and lakes.

In urban areas for those without access to sanitation such as construction workers and in rural areas where open defecation is the norm the TPPF should be pursued and made mandatory for all to use, Skills in its construction also can be developed rather easily .

It is time we revisited this sanitation technology seriously and managed it in a safe manner so that all of India becomes open defecation free, safe sanitation is practiced and the health benefits accrue to all especially the young generation.

In safe sanitation lies water wisdom. 

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