Exhausting a renewable resource  

PART – 1

Ramgarh Lake is situated about 30 km away from Jaipur city at Jamwa Ramgarh. The dam was commissioned by the Maharaja of Jaipur Sawai Madho Singh II and was completed in 1903.

It was developed as a multi-purpose project aiming to provide the irrigation facilities to nearby area and the water supply for Jaipur city. It started supplying water to the city in 1931.

In 1961, it was reserved only for water supply to Jaipur city and till year 2000, the lake had been a source of water for the Pink City.

The dam was constructed on Banganga River near Jaipur in 1903 having a catchment area of about 769.20 sq. km. spread over four Tehsils and capacity of 75.0 MCM

The Ramgarh Lake is a man-made water body covering an area of 15.5 sq. km. During monsoon, the lake once presented the most alluring scenic beauty for visitors. It was an interesting place for bird watchers as they got to see flocks of birds including migratory birds around this artificial lake.

The thick forest near Ramgarh Lake was home to many wildlife species such as Neelgai, Chital and lions and was once a hunting ground for the Maharajas of Jaipur. Ramgarh was pronounced a Wildlife Sanctuary in 1982, by the Government of India.

Ramgarh Lake became famous during the 1982 Asian Games when the clean and beautiful waters of this lake were the host for the rowing competitions.

In the present time, the four rivers, Roda, Banganga, Tala and Madhoveni, which used to bring water to the lake, have gone dry due to the deforestation and mining activity carried out in the catchment area.  The dam which was once the home of reptiles and other aquatic wild life is dry since 2006, leaving no food like little fish to feed on and has resulted in disappearance of all aquatic life.

We shall discuss the factors responsible for drying of Ramgarh dam and about the possibility of restoration this lake in part 2 of this blog.

At the moment we are picking up one very specific aspect of Dam management in relation to Ramgarh lake i.e. RESERVOIR SEDIMENTATION, especially because this is a man made reservoir and such dams and reservoirs are made to ensure availability of water & energy and to reduce risk of flood.

The questions which arise are:

1. Whether Ramgarh lake was designed to be renewable or exhaustible resources?

2. Whether Ramgarh lake was maintained and operated as a renewable or exhaustible resource?

There is an engineering thought process where the structure is designed to have a certain life span, which could range from 10 years to 100 years. In such dam or reservoir design it was only targeted to remain operational till its desired life/age and there after it was nobody’s concern if it did not remain a reservoir at all due to continued sedimentation.

Was such the thought behind the designing of Ramgarh Lake?

Interestingly, life cycle approach is in conflict with the sustainable development goals which were aimed at creating assets which could be used by generations to come hence this concept would not have been followed while designing Ramgarh lake.

Most projects like construction of tankas, step wells, or dams or reservoirs undertaken by the Kings/rulers of ancient India were sustainably developed and cared as a renewable resource so that it could satisfy the need of the current as well as future generations.

The then king of Jaipur would not have wanted or allowed the reservoir to fill with sediment, meaning hereby that he must not have thought of Ramgarh Lake to be an exhaustible resource. However, it became an exhaustible resource because those who were entrusted to look after the lake did not care to implement reservoir sedimentation management approach to save the storage space or reduce the storage loss due to sedimentation.

We wish that those responsible for maintaining Ramgarh dam had maintained the storage volume till eternity. This would have benefited both present and future generations and would have prevented a renewable resource from becoming an exhaustible resource.

In India we make fresh ponds, lakes and reservoirs somewhere or the other everyday to increase the water holding capacity of these structures but tend to neglect the fact that in the absence of our attention the existing structures are becoming shallower due to deposit of sediment and one should not be surprised if serious analysis indicates that despite of building of new structures each year, the total holding capacity of all structures combined together is reducing each year.

Interestingly the average global storage loss due to reservoir sedimentation is estimated to be on the order of 0.8% to 1% per year globally. The reservoir benefits are lost if the reservoir is allowed to get filled with sediment and thereafter it becomes very difficult to restore the reservoir.

In our opinion when designing/operating a dam or a pond or a reservoir for the purpose of maintaining water storage keeping the aspect of sedimentation management in mind will make the reservoir a renewable resource.

There are more than a dozen methods which can be adopted to Manage/reduce Reservoir Sedimentation. It will be interesting to note that SILVERON while constructing two small ponds at Dhundhariya and Bighana for SABMiller India, still took care to  design an extremely simple structure in the flow path of rain water to reduce the quantity of sediments entering the pond.

During monsoon the rain water flows in from higher level and falls in the sedimentation chamber and settles in the pit while water with less sediments flows through the openings down a stone pitched ramp into the pond.

To be continued …

Rain water harvesting is an interesting field for people who have passion for water, who are inquisitive, who have imagination, who are keen observers, who like to learn, who love experimentation, who are not afraid of failure, who have perseverance and who have innovative minds.

Rain water harvesting is different from other disciplines of science and engineering because it is not a standard formula based subject. Every factor involved is a variable, like for example the rain fall quantum, its intensity and days are unpredictable while an important factor like soil formation is variable from location to location.

Interestingly, we at Silveron have come across situations where the results of the same rain water harvesting efforts differ astonishingly at different locations even though all factors and conditions seem identical at both locations. This is what makes rain water harvesting so challenging.

At Silveron, we value the wisdom of the old residents of any village where we plan to work and to begin with our experienced team interacts with the village elders and tries to evaluate what the situation was like in that area, may be a decade ago and what the situation is in the present time and their opinion about the factors which have resulted in the difference.

Team Silveron, thereafter uses regular tools and data to draw their own inferences but at no stage ever we ignore the experience and wisdom of the local village elders. There have been occasions where we ignored the instrumental data & inferences and in favor of  the observations and advise of the local elders and we never had reason to regret.

Like every child is different for the parents, every shaft is different for us. Even today, every Silveron recharge shaft constructed is treated as the first shaft. Every aspect is examined including intake capacity and speed. Nothing is taken for granted on the basis of our years of experience in the field of water conservation.

Where ever possible, especially where the roof top water is diverted through pipe towards the recharge shaft, Silveron places meter in the flow path of water to measure the quantum of water actually recharged by the structure during the monsoon/year.

Very often team Silveron can be seen conducting field trials in order to create rain water harvesting designs which are easy to built and maintain while being of top grade in performance and cost effective so that the rain water ‘harvesting movement’ can be sped up with the participation of more and more people and our planet be saved from water starvation.

In India, there is an unending list of activities being undertaken by business houses and industries towards the fulfillment of their social responsibility while every individual also keeps doing some act of charity on his own.

There is no argument on the fact that water is one of the most essential natural resource needed by all living beings on earth. There is no denying of the fact that ground water levels are fast declining.

Rain water harvesting if done properly, is the most sustainable long lasting and beneficial act which can be done for the society at large.

We at SILVERON consider rain water harvesting as the ultimate Corporate Social Responsibility and charity which any individuals as well as corporates can do. In rain water harvesting, the harvester does not know who shall be the beneficiary and the beneficiaries do not know whose action has benefited them. This is why we consider Rainwater Harvesting as the ultimate charity.

We wish that all individuals and industries commit to make more rain water harvesting structures each year. These will add on to the already existing structures and hence each year the quantum of water recharged will keep increasing and a time will come when the recharge quantum will match the water withdrawal quantum and this will lead to the arrest of the decline in ground water table. The subsequent year may see improvement in ground water levels and increased quantum of available water.

The water situation in India has already reached an alarming level and we are already late for taking remedial action. It high time the Government spell out loudly to the people about the crisis and how it plans to deal with it. There is no time to play hide and seek on this subject and those in authority must stop trying short term remedies to manage the water crisis by transporting water from one location to the other. We have seen enough of water trains on the rail tracks and water tankers on the roads.

The water policy has to be re-looked into and redesigned. Who takes responsibility for water crisis – State or Central Government? Who takes responsibility for remedial planning? Who takes exclusive responsibility of formulating rules and ensuring monitoring of implementation?

Existing policies like, in a notified area the government will not give permission to anybody to dig a fresh tube well irrespective of all the Rainwater Harvesting efforts and structures he makes in that area while those who already have old operative running tube wells are permitted to continue to draw water even if they have done no effort to harvest rain water.

What difference will it make on the load on ground water if one person who can withdraw water starts selling water to the person who does not have permission to withdraw water?

With this regulation in place, who will make rain water harvesting efforts in notified area? Who will deposit money in that bank from which withdrawal is not permitted? This policy will surely squeeze every notified area dry and make it uninhabitable and lead to exodus of residents. The shifting population will generate additional load on the ground water resource of that area where they go.

Ultimately, will the situation drive us back to the same river banks from where our early civilization started?

Sincere Rainwater Harvesting effort is the only solution in hand which can help reverse the ground water shortage and declining water table issue. It is the need of the hour that all stake holders act immediately and that too on a large scale.

It is time for the government to motivate people and industries to go for rain water harvesting projects by giving them subsidy and tax exemption for all rain water harvesting works they do.

Team SILVERON, on the basis of their experimentation, experience and analysis conclude that for rain water harvesting, ‘diameter has very little meaning and it is the depth which is more important’.

In simple terms, since the strata keeps changing as we drill down the earth, we are likely to encounter some soil strata which absorb more water, some which absorb less and some which absorb none.

The idea of only digging a rain water collection pond for recharge purpose is partly successful  since the base of the freshly dug pond will permit percolation of rain water but in due course of time it will become hard and non permeable. The diameter of the pond will increase the water holding volume of the pond but will also at the same time increase surface area from where water will evaporate. The depth of this pond may be say  5 to 10 ft so at the edges of the pond we get exposed ground strata of only 5 to 10 ft. and this is too less.

On the basis of these observations, SILVERON excavates and develops ponds in the low lying area and simultaneously constructs recharge shafts in appropriate numbers to allow rain water to flow into the pond during rains and find passage to percolate into the ground and enrich the ground water. 

This makes recharge through pond a 100% successful project and SILVERON a premier solution provider for rain water harvesting.