Archive for February, 2008


Rainwater harvesting in greenhouses

February 29, 2008
I visited China and was struck by the intelligent use of rainwater in Poly houses. Persuading a student to repeat the experiment here was the hard part and harder still was getting a lousy Rs 25,000/- to help Anil Kumar set up this experiment. TIDE came forward and helped the student. It is to the credit of Svati Bhogle and Chandankeri of TIDE that they have persisted with the idea and set up at least 3 more poly houses with the same idea. The are very excited about it and have written up a proposal and got funds for setting up 10 more 200 square metre poly houses. Now imagine there is a potential to integrate the small and marginal farmer with value added agriculture and improve his income dramatically and THIS IS A RAINFED POLYHOUSE. No bore well, no energy,no carbon emissions and IMAGINE again if we make it completely organic and use ECOSAN as fertiliser. What a gain? But who will help take this idea forward?Suppose we set it up on a fluoride affected area. Villagers can grow fluoride free crops and also take back 20 litres of Fluoride free water to drink every day. The same in Arsenic affected area.Will we rise to the occasion? Poly-houses for rainwater harvesting, an Indian and Chinese experience
S VISHWANATH discovers how sustainable poly houses possess the potential to solve the ongoing water problem in Karnataka.

Rainwater harvesting is the process of collecting and storing rainwater for future productive use.

Its role and significance are seeing a revival today owing to the enormous pressures on our limited water resources, depleting ground water levels. Apart from providing water security, the role of rooftop rainwater harvesting can also be in providing food security and growing value added crops.

China, for example, has pioneered the low cost poly-house model with rain water harvesting and drip irrigation to grow crops in a hostile terrain. In the Chinese model, poly-houses are built using a mud wall, mostly bamboo structural roofs coupled with steel and a plastic sheet for the roof. Since sources of water such as surface and ground water are simply not available, rainwater falling on the roof is collected and brought inside the poly-house where it is stored in an underground cellar.


The water is then pumped by using a manual or electrical pump and a gravity-based drip irrigation system has been adopted to water the plants inside the poly-house. Excellent results have been reported with many crops, vegetables and flowers.

The State of Karnataka is the second largest drought prone state next only to Rajasthan. India as a whole suffers from drought at regular intervals. In such a situation it is imperative that answers be found for food security for our rural agricultural sector where more than 70 per cent of our population resides. Steps ahead lie in the introduction of these poly-houses for the growth of value added plants in a safe, controlled environment devoid of pests, where crops/vegetables/flowers can be grown in carefully monitored conditions. The floriculture industry has already adopted the poly-house technology.

Economical poly houses

Poly-houses however should be made of more economical, easy for assembling and efficient, so that it can reach more and more farmers.

With the introduction of drip irrigation, it is possible to reduce the amount of water used for the same. Water availability however is still an issue because groundwater levels are falling and there is high content of salts in the groundwater in many places. One solution in Karnataka also could be the systematic collection of rainwater falling on the rooftop of the poly-houses, storing them and using the drip irrigation system for the plants inside.

Preliminary work has suggested that the total water requirement for vegetables such as capsicum or flowers such as anthurium can be met through poly-house rooftop rainwater harvesting. For example, the rough annual demand for a 175 square metre poly-house is of the order of 52,000 litres.

The semi-annual demand for a crop of duration six months is 26,000 litres of water. In a place with an annual rainfall of 400 mm, the rainwater falling on the roof of the poly-house is of the order of 70,000 litres.

Assuming a collection efficiency of 80 per cent, 56,000 litres of rainwater can be harvested, which is more than the annual demand.

In theory at least, the poly-house becomes self sufficient for its annual water and power requirement. With the annual rainfall as low as 200 mm, a semi-annual crop can be cultivated.

This methodology has the potential of creating a substantial armoury of drought proofing our agriculture. Further research is needed in developing efficient systems of collecting rainwater without losses and low cost storage systems.

A student of GKVK, Shri Anil Kumar T D, studying in II year M Tech (soil and water conservation engineering ), is currently carrying out a research titled – Studies on Techno-economic feasibility of roof water harvesting system with greenhouse. It is being carried out under the guidance of Dr S B Batagurki, Associate Professor in the U A S Hebbal Extension Unit with assistance from Shri Krishna Manohar and Shri T N Tulasidas.

Such and future research will establish the applicability of the technology of rooftop rainwater harvesting for poly-houses in the Karnataka context which show an exciting potential.


Green deserts and the stupidity of money

February 28, 2008

IT cos waste water on lawns

IT cos waste water on lawns
The Times of India

Bangalore: Chew on this: An estimate says IT companies use 10,000 to 1 lakh litres of potable water daily to water the lawns.
•Each square metre of such lawns needs seven litres of water.
•Lawns are watered twice or thrice daily, especially in summer.
•An IT company buys 60,000 litres of water daily just to keep an artificial lake on its campus full.

Where does all this water come from? In the case of IT companies, it comes from borewells in the surrounding city municipal councils (CMCs) or from wells. At Mahadevapura CMC, for instance, locals say water is found only at depths as low as 850 feet. Yet, tankers do a brisk business, pumping water to the nearby ITPL.

Groundwater exploitation is not new and it’s accentuated further in the summer. Rainwater Club founder S. Vishwanath says: “Using up borewell water deprives the locals of their share of water. It’s a crime. It’s stupid to waste drinking water on lawns.’’ Mahadevapura CMC officials express helplessness. “We cannot prevent tankers from using private borewells,’’ CMC assistant engineer T.C. Kodantaram says. A Government Order issued two years ago banned the use of potable water for gardening, washing cars and construction purposes. The law is applicable only in BCC areas, where it’s violated with impunity. Well, BCC itself uses borewell water to green the medians!

So, does a borewell holiday help? “Not unless it’s a practical alternative,’’ says Vishwanath. In the absence of such a ban, companies could at least adopt less water-intensive methods. “They could plant species that need little water, or opt for rainwater-harvesting.’’

There is a silver lining, though. Some companies have woken up to the danger of using water unsustainably.

WeP Peripherals, for example, harvests rainwater on its 22-acre Mysore factory campus and plans to replicate it at its Bangalore head office. Ditto with Denso Kirloskar in Nelamangala. But why lawns? An IT company official admits: “It’s a western image. A lawn looks ‘green’ though everyone knows it’s anything but green.’’


Go for Zen look, use stone formations et al
Plant the likes of cacti that need very little water
Keep an ‘edible’ landscape — grow pomegranate, chikkoo, sitaphal
Better still, grow ragi, the crop that can be harvested too!


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- – 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 ( 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?


The Persian Wheel revisited- Araghatta

February 23, 2008

The ‘ara-ghatta’ or rope-pot system of lifting water from open wells was probably invented in erstwhile India of the past. With its use in Iran and perhaps its discovery there it came to be called the Persian wheel.

The araghatta itself became the Rahat or reghat or gharat in North India. Ubiquitous everywhere in India it has all but disappeared with the lowering of the water table in many parts of India and the coming of the diesel and electric pump. As a device it is my surmise that the pulley which became the wheel was first discovered around water. The well itself is a remarkable discovery. A hole in the ground which yields water allowed mankind to ‘conquer’ the open spaces and unyoke itself from the tyranny of being tied to rivers and lakes. The Persian wheel still exists in some parts of remote India and with its disappearance will go a water culture and history. Here Avinash plays the Araghattikka , the person working the Araghatta. Usually bullocks, elephants or camels did the job of moving in circles to lift water.

The biggest confusion amongst authors and people is between the Water wheel and the Persian wheel. The water wheel-the noria- is perhaps an Egyptian invention and is stream or river based water lifting device and a water mill at times.

In the above the Noria or the water wheel is a water mill and not a water lifting device. It uses the strength of the current to move and to translate that to a grinding action.

The Persian wheel is the saqia and is a land based water lifting device from wells, more in the nature of a pump. In fact in parts of Kolar in Karnataka it is called a ‘bucket pump’.

As ground water levels decline in India Persian Wheels cannot reach the water to draw them out from open wells. One such Persian wheel stands forlorn and frustrated as the water table has dipped in Kolar Karnataka India. This wheel has worked for the last 80 years and 2007 was the first time that the water table fell so low that the wheel could not work for day. A nearby open well which draws copious water with an electric pump is suspected of causing the dip. The Rainwater Club works with farmers to ensure efficient use of water and allow the Persian wheel- a symbol of sustainable and carbon free water use- to continue its existence as a living, century old water culture of India.

Ananda K Coomaraswamy argues in his monograph The Persian Wheel argues that it is not justified to draw its origins to Persia. Its mention in the Panchatantra and the Rajatarangini as the cakka-vattakka or the ghati yantra.

The FAO document on water lifting devices is an excellent one to compare the efficiencies of various lifting devices for water

”’ As it states

The Persian wheel, is a great improvement on the mohte, as its chain of buckets imposes an almost constant load on the drive shaft to the wheel. Persian wheels are usually driven by some form of right angle drive. The first is the most common, where the drive shaft from the secondary gear is buried and the animals walk over it; this has the advantage of keeping the Persian wheel as low as possible to minimise the head through which water is lifted. The second example is a traditional wooden Persian wheel mechanism where the animal passes under the horizontal shaft. The sweep of a Persian wheel carries an almost constant load and therefore the animal can establish a steady comfortable pace and needs little supervision.”

Noria and Saqiya: 

Needham, in Science and Civilisation, Vol. IV(2), gave a clear definition of the two forms, the noria having the containers fixed to the rim of the wheel, and the saqiya on the rope or chain flung over the wheel (p. 356). Having done so, he was able to follow up the evidence gathered by Coomaraswamy and Laufer, and argue that the earliest water-wheel in India was the noria, and that, moreover, India was probably the country of origin of this device. The reasons Needham adduced for this conclusion were two-fold: first of all, the noria was in the Hellenistic world in the first century BC and in China in the second century AD, and this proximity of date in such distant civilisations suggested an intermediate source of diffusion. Secondly, he located the earliest recorded reference (derived presumably from Coomaraswamy) to the noria in the term cakkavattaka (turning wheel) used in the Cullavagga Nikaya (assigned to ca. 350 BC) for one of the three permissible models of water-lift.  Source: D.P.Agarwal Needham on Early Indian Inventions of Hydraulics, Cotton-Gins and Alcohol Distillation


Building an ecological swimming pool

February 7, 2008

Taking a re-look at the swimming pool

One of the joys of village life captured in many a celluloid film was the old well or tank acting as a swimming pool. Many a summer holiday was spent in splashing around and learning the fine art of swimming, diving and cooling off. Cut to modern times and urban affluence, all high end apartments and quite a few houses boast a swimming pool and club house as recreational facilities for the residents. The notion of the swimming pool in a city is that of clean blue waters with a lot of chlorine in it. In fact a recent visit to a large software giant’s campus was revealing. About 4 kgs of bleaching powder was being applied daily to ensure residual chlorine and to kill the bacteria and germs in the waters.

Swimming pools have generally been seen as water wasters. Not only is evaporation of water a major issue but also the cleaning of the pool regularly meant that a large volume of water was discharged to the drains. Recycling systems have reduced this loss of water and made swimming pools much more water efficient. Recycling systems however are energy intensive and unless a pool has UV treatment systems chlorine continues to be used a lot to clean the waters. The challenge therefore is how do you reduce or eliminate water losses, reduce the use of chemicals and finally reduce the use of energy to a minimum yet have a good pool to swim in. The answer designers are exploring is the bio-pool.


What is a bio-pool? The idea of the bio-pool comes from the idea of bio mimicry. By learning from nature and the balance that nature seeks it is the paradigm that one can do away with or minimize. A bio-pool mimics a natural pond. It has several depths of water to move it thermally instead of using a pump. A selection of special, but usually locally growing, plants is placed strategically to make use of their cleansing as well as oxygenation properties. Typha or bulrush or cattail is a favorite choice because of its ability to establish itself and vetiver is another. Plants with a rhizome (an underground stem) such as canna are also preferred. The usual idea is to remove as much of the nitrates and phosphates as possible. This is done to prevent the excessive growth of algae and the subsequent eutrophication of the waters. An anoxic zone is created in certain parts to help fix nitrates and in other parts.

Care has to be taken not to allow the temperature of the water to go too high. This is done with appropriate shading trees in the right directions. The usual maintenance measures would include the removal of leaves using a skimmer and cleaning the pool of organic material as much as possible.

The bio pool itself is divided into two parts, one with the planted filter and stones called the water regeneration part and the other which is the water part where one swims. The pools are lined at the bottom to prevent seepage of water usually with a UV resistant and tear resistant plastic and then lined with earth.

One such bio-pool perhaps one of the first in the region and definitely in the Bangalore area is at the Eco resort in Hessarghatta called Our native village. Enjoy the swimming there with the usual inhabitants of water bodies such as dragon flies hovering over you and tadpoles at a safe distance in a natural pool.


Water wise is certainly about enjoying the gift of water in an ecologically sensitive manner.


With a little bit of help-rainwater harvesting is a community effort -Kannada

February 4, 2008

Neighbour’s plunge in to help place the stone slab covers for the rainwater tank in a house in the village Arjunabetahalli near Bangalore. With a little bit of help from friends systems work better and additional water is available for household use.
Kavya, all of 8, is fascinated by the operations as much as the camera. She however lets the cameraman know that a ‘Totti’ (tank) is being built to collect rainwater. She also know that the first rain separator allows the initial dirty water from the roof to flow out. The clean rainwater collected can be used for washing clothes, for animals to drink and other such uses.
The stone slabs being placed are a local slate called Cuddapah stone after the place here it is prevalent. This is the cheapest covering available though heavy. Once placed on top, the gaps between two pieces of stone are sealed with mud mortar to prevent mosquito breeding.
Late evening gives the film a Bergmanesque touch :):).


Fighting fluorosis through rooftop rainwater harvesting

February 3, 2008

This old couple in a home in Laghumuddepalli village, Bagepalli Taluk,Kolar district,Karntaka,India have devoted an entire room of their home  for constructing a large rainwater tank. They started to build an underground tank below the floor but then struck hard rock. Since the room was not really being used, the children having moved out, they decide to build a tank over the ground anyway to store rainwater.This tank collects water from the rooftop which is filtered before it is sent in to the storage tank. A hand pump draws the water out.  10 litres of water from the tank is also sent to their daughter and son-in-law in a town about 7km. away daily.

The rainwater tanks are being built under SACHETANA project of the Government of Karnataka is being implemented by BIRD-K an NGO in 64 villages across 4 talukas and 4 districts in Karnataka.

This project and rainwater harvesting is worth emulating in all fluoride and arsenic affected areas of the world to provide fluoride free and arsenic free water for drinking and cooking right through the year.