Reverse Engineering the Rivers
All life depends on the rivers. They are our single largest source of fresh water here in India and no wonder we worship them. However the fate of the rivers is quite appalling when we really look into it. The number of dams that have been constructed on each major river system is astounding. Take the Godavari for example – 350 major and minor dams constructed in a basin that spans 1450km. Thats a dam every 5 km!! How is this sustainable? What happens to all the life when a river changes from flowing water to a standing reservoir? Can we look at the river and think beyond just water? Can we look at it as a functioning system with many many parts – one of which is the flowing water?
On a recent trip to warangal, I remember being surprised at the number of lakes that i came across. Along the road i was on, there was a lake in almost every village i passed. I remember thinking about the old design of the Kakatiyas – the chain of lakes flowing into a river. The idea of distributed storage was pretty powerful. The needs of a place would differ every 10-15 km. One village might need water for the rice fields, while another might need a lot lesser for their orchards. Another village closer to the city might need water for commercial reasons – say a factory or a rice mill. The beauty of this design was that a village could choose what to do with the water it was receiving without having to negotiate water utilisation with another village. It was up to the village, to administer, maintain and distribute the tank and its resources amongst themselves as they saw fit. It is not something unique to the erstwhile Kakatiya kingdom, although the design is named after them. Even Bangalore has a series of linked tanks that were once water sources for the city. What has changed now? How did something that had worked for a thousand years before become obsolete and irrelevant?
I don’t think there is a simplistic single answer for that but what really happened with the British starting major irrigation projects is that it began to sound easier and most importantly placed the power of the decision in a central body. This appealed to the powers that be and slowly over the years the focus of water supply shifted to major projects. The most recent one on the Godavari – the Kaleshwaram Project has been in the news. It is an engineering marvel expected to irrigate an astounding 18L acres across 13 districts in the Telangana state, built at a cost of Rs.80,000 crores. Indeed it is the largest lift irrigation project in the world and surely a feather in the state government’s cap. A first look deeper into the project and its evolution over the past years presents a different picture though. Not because it is not as great it is made to sound but it definitely forces me to think if this was the only way to cater to the drought hit areas of Telangana?
The story started ages ago in 1975, with the Godavari Water Disputes Tribunal awarding what was then Andhra Pradesh, a share of 160TMC of the water from the Godavari Basin. For this originally a barrage was proposed at Tummidihatti village to divert this share for A.P. Ideally, its great if all the intended water supply can be gravity fed. It is the easiest way of distributing water. So the location was chosen and a Full Reservoir Level (FRL) of 152m was arrived at for the required 160TMC. Since this was significantly upstream, a 152m tall dam at Tummidihatti meant thousands of acres of submerged land on Maharashtra to irrigate A.P. This was the fly in the ointment. To avoid this submergence, a lower height of 148m was proposed. However at that height, the divertable water available was only 44TMC as opposed to the 160 TMC awarded! Remember that this water availability study happened in 2015 (almost 40 years after the award). The state of Telangana had just been created. Naturally the euphoria ran high and there was a need for the ruling government, the first government of the state, to prove its mettle that it could deliver the water that was ‘due’ to the state, a right that was long denied and almost single handedly led to the creation of a separate state. So an ingenious plan was devised to move the barrage/dam almost 150km downstream to Kaleshwaram on the main stream of the Godavari river system. The problem was not the move, but the districts that would be upstream to this dam. Hence was conceived the largest LIFT IRRIGATION project in the world!
Through a series of Seven Link Systems and Three dams, the plan is to not only irrigate, 18L acres of unirrigated land, but also pump water back up into existing tributaries of the Godavari to stabilise upstream reservoirs with water from downstream!!! Beat that. So on one hand, the water is pumped up in the reverse direction along tunnels to fill up water tanks and distribution reservoirs in several districts (remember that this is the exact reversal of the Kakatiya system) and on the other hand, through another link, pump water back up and drop it into two tributaries of the Godavari – the Haldi and the Manjeera. Essentially, this translates to taking lots of water lifting it all the way back into the upstream tributaries so that the tributaries now have increased flow thus irrigating the upstream districts as well. Crudely put, this is equivalent to reversing the flow of a portion of the river using a giant pump. No wonder it costed Rs.80K crores.
Let me pull back to our original question. Is there another way? Why not revert or fall back to the good old Kakatiya mechanism? Well, for one, that would not have worked straight away. Remember in our other posts, we have discussed how the carbon content across the deccan plateau has degraded from 3% to 0.3%. This means, soil in general is just not capable of holding water anymore. So these tanks and lakes are not depressions on a giant sponge that holds water and oozes it out into the lakes and streams but more like a bowl of steel that fills up when it rains and just evaporates or floods over and the water eventually just runs off. So can we not then revive the quality of the soil? The defence that the project irrigates drought prone districts in the state ignores the fact that most districts become drought prone from a rice perspective. They are just not able to grow three seasons of rice. The 30 year average precipitations have been roughly the same in India. There is no mandal in Telangana with less than 600 mm of annual rainfall. So can we then improve the soil quality, so that the soil stores water and the lakes fill up and then we use the water in the lake? When the lake overflows, it flows into the stream which drains into the river. What would it cost? Well in our collective in Hyderabad we are working on landscapes that see a little over 600mm of rain and we can safely say that in about 5 years, the soil carbon content can be raised following some natural principles by a few percentage points. So in a decade, we can revive the magic number of 3%. In four decades (the time it took for the tribunal award to translate to water availability), these 18L acres would have been dense forests. It costs us roughly around 2.5-3L per acre in our collectives to do this. Even if we ignore the economies of scale, when you extend that as a few thousand distributed village level projects of state-mandated eco system rejuvenation, we are looking at around 45k crores to rejuvenate the said 18L acres – saplings, checkdams, lake maintenance, swales etc etc included. That is almost half the cost and whats more? We would have kickstarted a permanent loop of restoration. So the system gets better and better and better with each year.
The idea here is to not belittle this giant feat of engineering or to play a left liberal critic of everything the government does but to show that simple distributed measures done at scale, and governments have the power to do them at scale, can be as powerful as these marvellous dams. Infact, for a long time it seemed that the state government of Telangana was following this as well with the harita haram project, a sapling planting drive that fizzled out. So this is not new, in fact it can even go hand in hand with the big dams and take the heat off the major irrigation projects by a distributed capture of water.
Long long ago, the Qutub Shahi kings set up the city of hyderabad on the banks of a stream (then a perennial river), the Musi. In 1920, the city had grown to an extent where the water had to be dammed and thus was born Gandipet Lake – the Osman Sagar and Himayat Sagar. They fed the city for a very long time. Soon, the city outgrew these reservoirs and we looked further away to a bigger river, a tributary of the Godavari, the Manjeera. By 1998, most of the city was being fed from a new dam on this river. By 2005, the city had outgrown the Manjeera and we looked further away towards bigger rivers – the Krishna and the Godavari. A decade later, we are lifting water from downstream Godavari as the supplies upstream are not enough. I wonder what we are planning to do once we outgrow the Godavari? Would we venture further north into the central highlands or would we atleast then look back towards another marvellous feat of engineering – the chain of lakes.!!
The thinking cap is on.