Archive for March, 2008

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Groundwater banking

March 22, 2008

With depleting ground water table, water banks are a dire need

Artificial storage and recovery is what every city needs, says S.Vishwanath



Precious: Storing water also recharges aquifers

Groundwater in India is a crucial resource and indeed the very lifeline of our water needs. In a city like Bangalore anywhere between 30 to 50 per cent of the water needs may be coming from groundwater.On the one hand, groundwater tables are falling and borewells are being sunk to depths of 1,250 feet and more. On the other hand, stormwater floods city streets and wastewater flows in storm drains. Groundwater is not being adequately replenished nor is the potential that the ground offers to store water being utilised.

Artificial storage and recovery (ASR) or managed aquifer recharge is a method by which water banks are created using rainwater, stormwater and treated wastewater and this water is drawn in times of need. This essentially makes use of the potential of the ground to store and to a certain extent treat water, preventing evaporation losses.

Hydro-geology Developing a good understanding of the hydro-geology of a place and understanding the nature of the soil and rock is crucial. We must know, for example, the porosity of the soil, the transmissivity, hydraulic conductivity and storage. The thickness, depth and geographical extant of aquifers need to be understood.

The lithology of aquifers also need to be determined. In simple words, the capacity of the ground to absorb, retain and return water needs to be determined.

Rooftop rainwater is ideal because it tends to be the cleanest. If a simple first rain separation is done and the rainwater filtered, it is excellent for artificial recharge. Stormwater running in properly managed catchments without pollution can also be used.

Filters These are usually held in retention ponds and allowed to seep into the ground. If stormwater is to be cleaned, sand filters and wetlands can be designed to remove physical turbidity. The traditional tanks were great recharge structures when they functioned as percolation tanks.

Sewage water, if treated to the adequate levels, can also be used for artificial storage and recovery. In Cubbon Park and Lalbagh in Bangalore, tertiary treatment plants have been set up which are using membranes to treat sewage to high levels.

If the salts, nitrates and phosphates can be removed the water will be ideal for storage. In fact the presence of large open spaces and aquifers nearby provides an excellent opportunity for such controlled experiments.

A limited confined aquifer is ideal. However, the process of ASR can be done in property which have their own sewage treatment plants and a recharge zone.

Failed borewells and open wells provide opportunities for artificial recharge but aquifer characteristics may prevent controlled access to the water so recharged. It is to be understood that the unit of ASR is determined by hydro-geological boundaries rather than surface boundaries.

Potential zones City-level attempts or even neighbourhood-level attempts centered around a surface water body is possible. Each surface water body is topographically located at the lowest point. Sewage flows and stormwater flows are also in this direction.

With a treatment plant located close-by, it should be possible to pick both stormwater and treated sewage water for ASR. In a city all surface water bodies are potential zones for ASR.

Conventionally, treated wastewater has been immediately used for non-potable purpose such as toilet flushing or watering landscapes. Especially during the rainy season the zero discharge policy enforced by the State Pollution Control Boards leads to excess treated wastewater which is difficult to manage.

In such circumstances it is better for the treated wastewater to be of such high quality that it is possible to use the aquifer as a bank to store it and then to use it later during times of need.

A holistic policy of understanding rainwater, surface water and groundwater along with robust knowledge of treated wastewater will enable better sustainable practices to be put in place for water use.

New systems such as high level treatment of sewage and ASR will be the future of better water management and in pursuing the science behind this lies water wisdom for our cities.

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Tears in rain – time to die

March 15, 2008

Blade Runner has been my all time favorite movie, ever since I walked in to Ganesha talkies in Mysore , paid Rs 1.60/- and watched Vangelis, Harrison Ford and above all Rutger Hauer – the Dutch actor- take off in bleak L.A. with rain, rain and more rain .

I´ve seen things you people wouldn’t believe, Attack ships on fire off the shoulder of Orion I watched C-Beams glitter in the dark near the Tannhäuser Gate All those… moments… will be lost in time Like tears in the rain… Time to die.

This particular scene has tremendous pathos and poignancy and Ridley Scott is simply brilliant here with the large back lit fans in the background (soon to be imitated ad nauseum but Ridley was the first to get it). Rutger Hauer put together the speech especially the last line . Look at him hold on to the dove at the beginning of the piece and then after the replicant dies the dove flies towards the bright sky – the soul released if replicants have a soul? .

The metaphor of tears in the rain on the chiselled features of the Dutch actor, the music in the background and this replicant dying in an extraordinarily ‘ batteries go dead’ way as Rutger puts it in an interview is visual poetry.

Harrison Ford – a replicant himself?? in the directors cut- underplays his character very effectively . He is the bruised, battered but lucky guy.

If people can get a copy of Blade Runner and especially the Directors cut watch it.

It appears to me that it is warm rain and not cold rain and therefore tears in the rain would blend even more to be indistinguishable except for the salt in the tears but if the rain is acidic would that be salty too? Hey who is quibbling.

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Leaky wells – Oz way to recharge groundwater

March 15, 2008

WATER WISE

Leaky wells to the rescue

 

S. VISHWANATH

 

When it comes to water management, the Aussies can sure part with several lessons to many parts of the world

 

 

 

 

 

Australia has been in the news for many reasons recently. When it comes to water and its management there indeed are some lessons that Australia can teach the rest of the world. Faced with a prolonged drought and climate change impacts, the Aussies have perforce been taking a look at better water management practices. Since Australia happens to be terribly well urbanised, urban water has fit in as an important blip on their radar.

Amongst other things, storm water has been seen as too good a resource to be wasted and therefore has featured in the solution paradigm for supply of water to their cities.

A handbook for storm water management has been the result. Do we in India have one? The answer is ‘no.’ Do we need one? ‘Yes.’ All our municipal authorities, property developers and even individual house owners will benefit from one. Who then will get one out? A million-dollar question which remains to be answered.

Responsibility

 

As in India, the responsibility of managing storm water lies with local governments. As the handbook “Introduction to storm water management in Australia” puts it, although urban storm water and treated wastewater are recognised increasingly as important economic resources, they are not widely used to augment supplies in expanding urban areas.

Recent research and demonstration projects have shown that storm water and treated wastewater can be exploited in a cost- effective and environmentally-sensitive manner for new urban developments. In this context:

Water reclamation can reduce potable water demand by as much as 50 per cent.

Properly managed storm water flows provide important flow return to streams, offsetting the environmental impact of upstream water supply diversions and reducing the need for costly in-ground storm water infrastructure.

The enhanced use of natural drainage corridors and depressions can provide open space, landscaped and recreational areas and conservation benefits, increasing the amenity of new urban developments (multiple-use corridors).

Treatment of storm water and wastewater closer to source minimises uncontrolled discharge of water containing high suspended solids, nutrients and organic material.

Onsite detention

 

Almost similar to tanks which our ancients had managed to finetune as a water harvesting technique, are detention ponds. The ponds, in the Australian context, are designed to hold back a design flood, let us say one occurring every 20 years.

Since urbanisation and city development leads to increased run-off, this run-off is stored in water bodies specially designed by the property developer or the city council. This prevents flooding downstream and recharges ground water. Topping up the aquifer then provides water for the future. Detention ponds, however, are still seen as not doing enough to control soil erosion and vector breeding. Lack of bio remediation is also a problem.

Designing a combination of urban wetlands and detention ponds seems the way forward because wetlands do a good job of bio remediation as well provide bio diversity and remedy soil erosion.

A new concept called bio basins is being tried, where the basin lined with gravel will remain dry and not allow for mosquito breeding. When water fills up, it will quickly be allowed to percolate into the ground and the basin itself will dry up and remain a dry landscape feature.

Novel idea

 

Akin to our recharge wells, leaky wells do the reverse of what an ordinary well does. Instead of providing water it takes storm water and recharges it to the aquifer through a soil medium adequate to filter pollutants, if any.

Detailed design guidelines are emerging for leaky wells, which enable designers to include them in best practices for storm water management and thereby mitigate the negative impacts of uncontrolled storm water and convert rain into a positive resource.

The way forward

 

A combination of the use of mass media and education is seen as crucial in bringing about behavioural change amongst policy makers and designers to make storm water management a reality.

Investment in R & D will be essential to learn from ‘on the ground’ experiences and translate them into a easy-to-understand-and-use handbook for developers, architects, landscape designers, urban planners and even the home owner so that water is managed wisely. A systematic and structured approach to addressing a water problem and turning adversity into advantage is water wisdom. Will we rise to the challenge?

 

 

www.rainwaterclub.org

www.arghyam.org

 


 

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Bangalore- Urban water issues for the poor

March 11, 2008

Near the Byatrayanpura zonal office of the Bangalore Corporation,is this ‘mini water supply scheme’ as a bore well connected to a cistern is called in this part of the country. People in the suburbs, especially in the low income bracket, get water once in two days near their house. Tis water is apparently not good for drinking or cooking. The dal (lentils) does not get cooked according to this lady. So they collect good water from this cistern. That means queuing up with their plastic pots at 4.00 a.m. in the morning for everybody’s quota of 2 pots of good water for drinking and cooking. Again the process is repeated at 12.00 noon but this time for water which comes in the evening.

Fights and disagreements are regular as is jumping the queue and stealing of pots too. The pots themselves are made of low grade plastic and are not fit for potable water purpose. They crack in the sunlight and need to be replaced ever so often.

Shiva, who helped bring Ganga down from the heavens, taking her force on his matted locks also looks on benignly. The very God’s seem powerless in this day of water shortage.

Question is will not 24/7 water supply help these people? Will they not spend less time and money even if water is privatized as some people claim it will be or already is? For 2 pots of water the lady spends at least 6 hours of her time daily. Even at Rs 5 /- an hour as opportunity cost this translates to Rs 30/- for 30 litres or Rs 1 /- a litre.

Per kilolitre the cost would be Rs 1000/- . Nowhere has this cost been imposed on people by private sector, but this is the cost imposed by the State here with its sheer inefficiency of delivery of goods low quality and even less quantity and no accountability.

Can we not change the system with even private participants who are held accountable for their actions? When shall we do that? When the human right to water is legislated perhaps and when governments are open and transparent in their dealings. On the one hand we have an insensitive state and on the other a passive community not willing to demand what is their right.

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Requiem for our rivers

March 10, 2008

This is a column I have in The Hindu. It appears every Saturday in the supplement called Property Plus. This is last weeks article.

WATER WISE

Requiem for our rivers S. VISHWANATH

Price of development: Copious flows in the Arkavathi is a thing of the past. This is a requiem for the Arkavathi and most of our peninsular rivers. The Arkavathi is a tributary of the Cauvery. Rising in the Nandi Hills to the north of Bangalore it passes through most of Bangalore Rural district and joins the Cauvery at Sangama in Kanakapura district. It flows for 190 kilometres and in hydrological parlance is called a second order stream, meaning it is a tributary of the Cauvery which joins the sea. The Cauvery is a first order stream flowing into the sea, its major tributaries are second order streams and the Vrishbhavathi which joins the Arkavathi is a third order stream. The catchment area from where the water collects in the river is more than 4000 square kilometres. Yet the Arkavathi is dead and barely flows during heavy rains. Why is that so? This is a sorry tale of the death of a river.When Bangalore first ran out of water from within its boundaries in 1894 it was decided that a reservoir at Arkavathi would need to be built to ensure that enough water was available to the city. The Hessarghatta reservoir, about 24 km from the city, was built on the Arkavathi and continued to supply water till about 1934 when the second reservoir on the Arkavathi called the Thippagondanahalli or the Chamaraja Sagara Reservoir was constructed to bring in more water for the increasing thirst of Bangalore.

Both reservoirs were built on the Arkavathi for The Gazetteer of Bangalore Rural says the Arkavathi “is not exactly a seasonal stream, in the summer months it presents the usual aspect of a sandy bed with a small current of water flowing at one side.” In short it was a perennial river. Large tanks such as the Madhure and the Dodballapur ere also constructed on the river and would usually fill up. The town of Dodballapur depended on the Arkavathi for its drinking water requirement as did the town of Ramanagara.

Groundwater was available at 1 to 3 metres below ground level in the Arkavathi basin. Wells ranging from 2 to 10 metres in diameter and depths of between 3 to 12 metres provided up to 60,000 litres of water per day. In summer, well water would fall at best to 4 metres. Wells provided drinking water for all villages as well as agricultural water for irrigation. More than 30,000 wells were present in the Arkavathi basin. This was the situation till the 1980s.

Pressure What killed the Arkavathi? A combination of the natural phenomena of drought and pressure on the catchment of the river. From 1980 to 1987, six out of the eight years were drought years with below normal rainfall. Wells dried up and were replaced by deep tubewells and borewells. Over-pumping resulted in a steep fall in the water table with most wells drying up and a competitive deeper drilling of borewells resulting in depths of nearly 300 metres being reached. With the fall in the groundwater table there was no base flow into the river. It first dried up in summer but then was unable to flow in the rainy season except for a few days. The tanks and the channels leading to the tanks were encroached upon or mismanaged and the links of surface water flows to the river stopped. All the tanks dried up and the Hessarghatta was abandoned as a reliable source of water to the city. The same fate awaits the Thippagondanahalli in a few years when it too will cease to be a reliable source for storage. The Nagarakere or the Dodballapur tank was long since given up as a source and the drinking water situation there is perilous with most water coming from private tankers. Villages struggle for drinking water in the basin especially in summer as borewells go dry.

The change of land use to predominantly agricultural activities resulted in the levelling of land and the construction of field bunds. Ploughing of land was a natural corollary to farming activities. Runoff from the land became zero. Sand mining and granite quarrying disrupted rivers badly and added to the problem.

Then came the industries with their huge water demand. The apparel park set up in Dodballapur in the Arkavathi basin will need water from the Cauvery and so will the international airport in the Dakshina Pinakini basin. The second order streams are dead and the first order Cauvery is the only reliable source. The question is for how long?

What does it mean for property? In the absence of any river basin- level institution even at the second order stream level, who will be responsible for the planning of the rivers and waters both above the ground and below the ground? Who will plan, invest and manage the waters of our rivers and who will be held accountable for failures?

With the coming up of the international airport a property boom is on in Dodballapur. Land prices have skyrocketed and housing colonies, resorts, restaurants and apartments are seeking to locate themselves there. But where is the water for this development?

Unless we create the right institutions at the right river basin level and arm them with the ability to plan and act on the plan, water shortages will be the order of the day and will hinder livelihoods and economic growth. Agencies such as the Bangalore Water Supply and Sewerage Board are woefully inadequate to manage sources and to provide water for all.

This is true of ALL our second order streams and it is a matter of time that climate change hits us and starts affecting first order rivers.

Water wisdom lies in recognising problems at the scales at which they occur and taking remedial action at that scale legally, institutionally and financially so that the problems are overcome.

Economic development and poverty reduction will be hit unless ecological resources are taken care of and that is the responsibility of ALL of us as citizens of the country. Recognise the river basin you are in and take action to revive it.

Water wisdom is leaving things better for the future generations than what we inherited.

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Rainwater harvesting – Vastu certified

March 10, 2008

Tis neighbour of ours is a senior citizen. He obviously has his belief which one respects and therefore ‘Vastu’ proofing his house apparently called for this fluoroscent colours of bright yellow and orange . These are all over the city now and no it is not some post modern fetish sweeping the city it is an old ancient one called Vastu (Indian Feng Shui to those uninitiated).

But the nice part for rainwater harvesting is that he read about it in the newspapers and came a visiting our house alongwith his plumber. They figured out the best way to do rooftop rainwater harvesting. Collect it into a sump tank but if opportunity arises to lead the rain into a small well that he already had. The filter was the key and the blue drum filter of ours was right. He had some difficulty in sourcing the Male threaded adapter and the female threaded adapter (MTA and FTA) something to note for the Rainwter Club and so we were pleased to give this to him.

They now have a full fledged system at work and you can see the result

We expect the water quality in the well to improve and him to get about 150,000 litres of water every year of average rain.

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Ecological homes

March 8, 2008
Himanshu Burte for The Mint

Building a house means different things to different people. For Nishwath Hassan and Prakash Iyer, a Bangalore-based couple in their mid-30s, it has meant putting theoretical beliefs about an appropriate lifestyle into practice.
Last year, they moved into a mud house designed for them by Chitra Vishwanath and her colleagues Chandrakumari and Vickraman, whose work is synonymous with mud buildings in Bangalore. A short walk away, in the same colony, is another mud house, designed by the same firm for Pettachi Muthiah, a businessman, his wife Alagu, a software professional, and their four-year-old son Varun. These designs were executed by a young contractor, Manjunath, whose beliefs blended perfectly with that of the design team.

“It is not about mud per se,” says Vishwanath. “Designing ecologically has always been the overriding concern for us. That means we also look at water in terms of harvesting as well as treatment of waste water.” Mud is, of course, among the oldest building materials around and houses made from it last hundreds of years when correctly designed and built.
Most importantly, in a place such as Bangalore, good quality mud is often available directly on site. Dig a basement and you get mud for the walls nearly free.
So, this is a good deal, particularly for the environment, since, unlike brick and cement, mud is not an energy-intensive material. It is produced naturally without any energy-consuming process of manufacture. And it does not consume fuel in transport.
The only energy it consumes is that involved in excavation, which can be managed manually. The deal gets better once mud buildings are built, as these two houses testify. Few other materials give as much character to a space without additional “finishing” layers of plaster or toxic paint. What you see is what you get, and what you get has character.
The honesty of this wysiwyg (what you see is what you get) logic appealed to Hassan and Iyer, at a time when they were reformatting their lives to align closer with their beliefs.

Chitra Vishwanath with her team and family members

 

Chitra Vishwanath with her team and family members

Both work in education. Iyer has recently quit a career in IT to handle community education initiatives for Wipro while Hassan works with a school. Meanwhile, Alagu and Pettachi, too, were already committed to the idea of an eco-friendly house before they approached Vishwanath.
Building with mud blocks and recycling woodwork bought from owners of dismantled old houses made great sense to them. Both clients, thus, were already oriented towards eco-friendly construction before they chose to build mud houses.
Though built from the same material (mud, stabilized with 6% cement), the two houses are completely different.
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