Posts Tagged ‘climate change’

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On the first water reservoir for Bangalore

November 13, 2013

WATER WISE

Lessons from a reservoir

 Image

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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Climate change and Asian monsoon

January 6, 2009

http://www.scidev.net/en/news/climate-change-linked-to-decline-in-asian-monsoon.html

Climate change linked to decline in Asian monsoon

Wu Chong

29 December 2008 | EN | 中文

Stalagmite_Flickr_Lyubov.jpg

Cave deposits can yield clues to climate change and monsoon strength

Flickr_Lyubov

Evidence that human-induced climate change may be affecting the Asian monsoon cycle has been published by a Chinese-US team.

Zhang Pingzhong, of Lanzhou University in China, analysed a 1,800-year-old stalagmite recovered from the Wanxiang Cave in West China’s Gansu Province, which lies on the current path of the Asian summer monsoon.

The team measured levels of the elements uranium and thorium throughout the stalagmite and analysed its oxygen isotope ratios — different forms of oxygen whose levels are linked to rainfall and thus provide a record of the climate at the time.

Records show that, before 1960, warmer years were associated with stronger monsoons, and the temperature decreased when the monsoon weakened. But the study found a reversed association after this date.

“The rising temperature now leads to less precipitation, which is not a natural pattern,” said Larry Edwards, geologist at the University of Minnesota and co-author of the paper, which was published in Science (November).

“So we came to an important conclusion that the monsoon had started to be affected by man-made causes.”

Using the literature, the researchers linked the changes to human-induced greenhouse gases and aerosols.

Their finding corresponds with previous work by Ding Yihui, a leading Chinese climatologist, on changes in China’s rainfall pattern in the late 1960s.

The fact that recent Asian monsoon decline has taken place in the global warming period rather than in cold periods,” was an important finding, Ding told SciDev.Net.

But he said that more investigations were needed into its causes.

Ding said he is soon to publish another study in Science predicting Asian monsoon activity over the next 100 years.

The team also discovered that weak summer monsoons were highly correlated with the demise of major Chinese dynasties in the past four centuries.

Using the results from the stalagmite analyses, the team was able to match the amount of rainfall to the dates that China’s Tang, Yuan and Ming dynasties rose and fell.

For example, the researchers detected weak summer monsoon periods between 850 and 940 AD. This coincided with the last six decades of the Tang Dynasty. Decreased monsoon strength reduced the rainfall and led to a poorer harvest, which may have sparked unrest and led to the downfall of Tang.

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Climate change- The clearest words from Obama

December 14, 2008

and we look forward with hope to address this issue globally and unitedly

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Ecological Architecture in India

September 7, 2008
House calls
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DOWN TO EARTH: CHITRA VISHWANATH

Far from the madding crowd would be an understatement to describe the location of architect Chitra Vishwanath’s home.“At that time, this was the cheapest plot of land we could find,” she says of the 1,500 sq ft plot.

Set amid bamboo trees and greenery, the house in Vidyaranyapura cost the Vishwanaths Rs 4 lakh to build, 13 years ago.

With a 1,000 sq feet garden, the house stands as a testimony to Chitra’s pioneering work in using earthfriendly construction material.

Her husband Vishwanath is a civil engineer and one of the pioneers for the move to create compulsory water-harvesting in Bangalore city.

“We had to realise that bricks and sand and marble cannot be carted around the country. We had to find ways of using local material that conserve and save energy.”

Chitra Vishwanath�s eco-friendly philosophy is intertwined with her home and lifestyle

Chitra Vishwanath�s eco-friendly philosophy is intertwined with her home and lifestyle

Her home, Chitra admits, was a laboratory of sorts. “There are things you can’t try in a client’s house, but did with ours.We still find things to add,” she says.The house has been built with soil bricks that have not been plastered or painted, terracottacoloured floor tiles and numerous skylights.

It has various levels with the mezzanine floor overlooking the main seating area. And there’s a big surprise: there are no ACs or ceiling fans anywhere in the house. “We’ve never used them; the house never gets hotter than 22° C even in summer,” says Chitra.

The couple’s eco-friendly philosophy is intertwined with their home and lifestyle.

There is a compost pit to handle garbage and water recycling on the terrace. “We even have a toilet upstairs that separates solid and liquid matter,” says Chitra.

There are solar cookers on the terrace cooking the afternoon meal of rice and dal, while rice is being grown on the other side of the terrace.

The architect uses her house to present her case to apprehensive clients.

“Most people are scared of eco-friendly material because they think it’s high maintenance. But once I’ve show them my house, they usually succumb,” she says.

“We want to be able to utilise this land for everything we need: water harvesting, light, ventilation and energy. We’ve grown so many trees around the house that even if the neighbour decides to build a high-rise, it won’t affect anything here,” she adds.

For this couple, eco-friendly is not a fashion statement but a way of life.

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Aerobic rice – one answer to climate change

February 27, 2008

Aerobic rice does away with flooding as a practice in the fields. Due to the deep roots the rice plants develop they are better able to draw nutrition from the soil as well as moisture. The generation of methane gas, a by product of flooding, is also minimized. As strains are crossed and varieties developed, which have the fine grains demanded by the consumer but the drought tolerance demanded by weather conditions, aerobic rice becomes a reality.

Arghyam through the Krishi Vidya Nirantara has sponsored a student to conduct his research on aerobic rice. Professor Shashidhar Reddy- http://www.aerobicrice.in – is working on this strain within the GKVK, the University of Agricultural Science Bangalore.
Manohar, the Ph.D. student explains the advantage of aerobic rice. Prof Srinivasamurthy of the soil chemistry department GKVK also pitches in to explain other advantages. Significant advantages of aerobic rice are Less water requirement. No flood irrigation. Watering once in 5 days.Equal productivity as other rice.less disease.less methane emission.

Huge advantages which need to be worked upon further to take it to our farmers.
Can KVN and Arghyam (www.arghyam.org) too rise to this challenge?

and finally

Climate change needs us to look at various alternatives for more drought tolerant and tougher strains. We need the research fast too. Students like Manohar and Prof Shashidhar Reddy are in the fore front of this research.

Key challenges will emerge. Will new pests develop in the non-flooded regime? How to manage weed growth a primary reason for flooding the crops? How to change the behaviour pattern ingrained in farmers s regards flooding paddy fields? How to improve productivity of the aerobic rice as more and more demands are placed on fields to feed a growing population economically better off than before? How to ensure maximum benefits to small and marginal farmers and increase their return on land?

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Solar cooking- fight climate change

January 25, 2008

Using a solar box cooker is the easiest thing in the world.Try it and you will love it. For us it cooks lunch and dinner for a family of 4