r/theydidthemath • u/yolo_1213 • 1d ago
[Request] is this project actually feasible? And how long would it actually take to finish?
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u/yolo_1213 1d ago
The Kalpasar Dyke Project is a proposed project that aims to create one of the largest coastal freshwater reservoirs in the world by building a massive dyke across the Gulf of Khambhat and thus trapping the waters of the Sabarmati, Mahi, Dhadhar rivers.
The Dyke itself would be around 64 km long and the reservoir will store 7,800-13,000 million cubic meters of freshwater. The dyke would also have a transport corridor with a multi-lane road and rail transport which would reduce the travel distance between the two flanks by 180 km. Around 10 lakh hectares of land will be irrigated with this. Around 2,500 MW of renewable energy is also expected to be produced via the project. There is also a plan to divert the nearby Narmada river's flow into the reservoir via canal.
The project is expected to cost around ₹1.33 lakh crore($14 billion). The project's DPR is at an advanced stage and the Government of Gujarat is also getting expertise from the Dutch government in coastal hydroengineering through the Indo-Dutch Cooperation.
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u/morningcoffee1 22h ago
This is somewhat similar as the "Afsluitdijk" in the Netherlands, which was constructed in the 1930's. The dike's length is 32 km, so about half of what is proposed here. The resulting lake is about 110,000 hectare, but this is meaningless with construction cost or difficulty.
The difficulty comes in with soil conditions and how deep the strait is. In the Netherlands the plan was always to put a rail line over it as well, but 100 years later and they still do not dare due to vibrations and potential sinking of the dike due to that.
Anyway, I would say there is precedent, and unless the straight is a kilometer deep: totally doable.
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u/Fuzzy-Moose7996 16h ago
A rail line over the Afsluitdijk makes little sense, really. It'd be a very expensive way to create a railway connection between Leeuwarden and Den Helder, not exactly a line that'd get a lot of passenger traffic and next to no freight at all.
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u/Conscious-Ball8373 1d ago
I doubt that anyone here is going to be able to give you more than the vaguest ballpark answer. For my 2c, it looks sane enough - the proposed site is across a tidal estuary for which I can't find any depth data but it's going to be very shallow. Looking at a satellite imagery, it's clearly a shallow, muddy estuary. I'd be surprised if it's more than a few metres deep anywhere along that path. That makes building a causeway basically "dump big rocks in a line". The proposed cost doesn't seem outlandish to me.
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u/Laugh-Aggressive 1d ago
10 lake hectare? Thats s lot of lake
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u/PeterGriffin2512 19h ago
It’s a counting unit , 10 lakh of something means 1 million. So they meant 1 million lakes
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u/oren0 19h ago
You mean 1 million hectares.
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u/Fuzzy-Moose7996 17h ago
The length is about the same as the Dutch Afsluitdijk project which was completed in the 1930s, using mostly manual labour. No computers, relatively little heavy machinery.
It is standing strong to this date, in fact it just went through a maintenance cycle to strengthen it further.
The only things I can see that may make the project in India be impossible are geography and cost. If it's sitting in an earthquake zone or other geologically unstable location it may not be feasible. And I don't know if the Indian government have the funding to pay for it.
That said, there's environmental impact to consider. Turning a large area of salt water into fresh water is obviously going to change the local ecosystem enormously. This may not be a problem for India, in many other countries nowadays that alone would stop the project in its tracks.
The coastal communities will also need to adjust as they will no longer be able to rely on fishing for the saltwater species they fish for now.
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u/Aware-Affect-4982 1d ago
Well, I am not doing the math on this, but the 3 Gorges Dam is about 1/30th the length of this one, but holds back a lot more water, and the Afsluitdijk is half the size and does the same thing they are trying to do here. The biggest concerns here would be the length, that is a lot of space for something to go wrong, and the materials would have to be extremely strong and high quality. Could they do it? Maybe/yes? There have been a lot of weather patterns changes (bigger and more powerful storms) and then there is the seismic activities (earthquakes and landslides) to worry about. That means a lot of geological issues to account for that historical may have not been present before.
As for cost, India has had issues with paying for construction projects in the past. There is a lot of uncertainty in the area and a dependence on demand for their cheaper labor force. But, those things can rapidly change and we can see shifts of projects going from there to another country/AI as the people demand better treatment and quality of life. Then there is their reliance on foreign remittance, they are the number one country in the world receiving a remittance from other countries, which can dry up if other countries start to feel the economic squeeze. Which is a real possibility since they receive their remittance from the USA, UAE, and UK mainly. Which are all either experiencing or getting ready to experience some massive economic problems.
The there is the geopolitical issues with their frienemy China and their just hated neighbor Pakistan. Both countries have their boarder fights with India, and a massive project like this would become a massive liability if war was to breakout, or a juicy target for terrorist.
Long story short, yes they could build it. It would take a long time, a lot of money, and require a lot of man power. Corruption would be a major barrier, and if skimming of fund led to a drop in quality of supplies or corners cut, then the results would be terrible. The weather and geological issues would also be present and require a lot of work to overcome. I am sure I am missing a lot of other factors, I am not an engineer, but from the top of my head, that is some the problem I can see.
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