Answer by Barath Mahadevan:
Although there have been a large number of research and impact assessment studies already done in this regard, I will try to give an overview of the project here, covering what the problem is, what the project is about, what are its ecological and economic implications, similar projects in other countries and some long term solutions to the problem.
Short answer to the question: The project might have positive implications in terms of short-term economic development and prosperity but the negative implications on the ecological and social front will be more permanent and irreversible and in the long run, it will far outweigh any temporary economic gains perceived.
I. About the project:
The Indian Rivers Inter-link is a proposed large-scale engineering project that aims to join the majority of India's rivers by canals so as to reduce persistent water shortages in parts of India. The inter-link would consist of two parts, a northern Himalayan River Development component and a southern Peninsular River Development component.
Here’s a map showing the water scarcity problem in India:
White regions indicates little to zero scarcity and darker regions indicate greater scarcity.
Here is a map showing what the project aims to do (Red lines indicate the links envisaged):
II. Ecological Implications
1. Impact on Flooding:
Some quick facts first:
- Flooding of rivers is a natural process. Slow-flowing flood-water on a floodplain performs a very important function: it deposits sediments and renews the fertility of croplands. In essence, the rivers are doing what they are supposed to be doing – flood their floodplains and deposit layers of sediments, but humans got in their way. In other words, flood is just an integral part of natural hydrologic process.
- Flooding of land is lot more desirable than not having any floods. We need to get accustomed to this natural phenomenon, and plan our livelihood accordingly. We cannot control flooding; we need to adjust our life style to reduce the damage caused by flooding.
Now, the question is what impact will the project have on the growth and survival of floodplains?
1. Effect of Sea water intrusion:
Such a project will devastate the natural balance of water flow and sedimentation process, which are fundamental to the formation and growth of floodplains. If the rates of sedimentation decline on the delta plain then the rising sea-level might get an upper hand, and may inundate most of the coastal areas, destroying ecosystems including mangrove forests through salinity intrusion. If the amount of sediment influx in the coastal areas is further reduced by diversion of the rivers, then in just over a hundred years a relative sea-level rise of about 1 meter in the Bay of Bengal will severely curtail the delta growth, and actually will result in submergence of about 17% of Bangladesh, displacing over 20 million people.
Below is a graph of salinity intrusion in groundwater in Junagadh district, Gujarat:
This is a graph of salinity intrusion in groundwater in Junagadh district. As you can see, it has been steadily rising in each place. And this is the case with just intra-basin linkages within the immediate neighborhood. So one can imagine the situation after the implementation of such a project. Similar conclusions can be made for peninsular and eastern India as well.
2. Effect of consequent sea water intrusion on agricultural productivity:
The graph below shows the amount of salinity in the Indo-Gangetic Plains
How does this salinity affect agricultural productivity? Here's a table of saline tolerance of various crops:
As can be seen, rice, corn, potato, beans etc are pretty sensitive to salinity and we might soon be unable to grow them!
It is safe to conclude that compared with the monumental functions that the flood waters perform in the long run and its crucial importance in agriculture, damages caused by flooding is relatively insignificant and the only sane way out is to let the river take its natural course.
3. Impact on Fisheries and related industries:
1. Canals and reservoirs: The proposed interlinking of rivers would comprise more than 36 major dams and 30 canal links. In addition, there will be many more irrigation canals and barrages. These major reservoirs, canals and other water harvesting structures will add to the potential fishery resources of the country.
2. Rejuvenation of lakes and rivers: The rivers and lakes in the water recipient zone will bring benefit with increased water perennially, congenial habitat and consequently, higher fish production.
1. Loss of habitat: River interlinking might affect fish feeding and breeding habitats in the rivers and lakes in the water donor zones due to lowering of water volume and enhanced siltation load. The flood plains and wetlands connected with donor rivers would also be affected. River run-offs provide energy for a number of vital processes in downstream estuaries, delta and coastal areas. Reduced river discharge could result in loss of coastal habitats such as mangroves, coral reefs, sea grasses, estuarine and delta regions.
2. Water quality changes due to reduction in self-purifying property of rivers: Significant changes in water quality of rivers, lakes, estuaries and coastal waters could occur due to changes in sediment load, nutrients and contaminant levels. The levels of toxicants and contaminants in donor rivers may go up owing to reduction in self-purifying function of the rivers.
3. Changes in land-ocean interactions: River is a critical component of the delta-estuary-coastal sea ecosystem. Un-impounded rivers provide energy for a number of vital processes in downstream estuaries, delta and coastal areas, upon which healthy fisheries are dependent. The linkage of rivers could alter the timing and quantity of river discharge into the sea, which may alter and affect even coastal fisheries and their numbers.
Despite the perceived positive impacts, I will posit that the negative impacts are more permanent and irreversible and far outweigh any short term economic gain associated with fish production.
Although I have discussed only 3 areas of ecological impact, it is crucial to understand the inter-dependence and relationships between various factors. So, apart from the above mentioned points, it is quite evident that the project will also significantly affect wildlife reserves, human settlements and global climate.
III Economic/Budgetary Implications:
I will probably wait for a good perspective on this, but here are some quick facts:
India’s GDP: Rs 100 trillion
Average annual Budget of the Indian Govt: Rs 3300 billion
Annual Irrigation budget of states: Rs 10 billion
Proposed cost of the project: Rs. 5,600 billion
The proposed cost of the project is 5.6% of India’s GDP and more than 150% of the annual budget! I fail to see how this is feasible without external help from institutions like World Bank etc. Again, such a step would only greatly increase the country’s already fast growing debt which itself is close to 70% of the GDP.
IV Basic Assumptions of the project:
1. There is huge surplus of water in river basins.
False. Most river basins today are overextended in usage and in most regions tension is growing between old rural users of surface water and new industrial and urban users. The Mahanadi basin, which would be linked to the Godavari is a good example of this error.( ).
2. Floodwaters can be effectively channelized.
False. The fact is when one river is in spate so is next river and transferring water would require huge storage facilities. Construction of large reservoirs has massive environmental impacts not considered in the scheme. Many irrigation projects are stalled on this count.
3. Donor states are well irrigated.
False. Here is a graph showing the lack of sufficient irrigation even in donor states:
V Similar Projects in other Countries:
Several countries have explored this idea but in general, they have remained consistently unsuccessful.
1. Central Asia – Aral Sea in former USSR
Result: Largest human-induced environmental degradation caused by upstream
2. Colorado & Klamath Rivers Diversion in USA
Result: Colorado delta has declined in size by 95%
3. Snowy River Diversion in Australia
Result: Largescale land degradation.
VI Possible long-term solutions to the water problem:
A few that I can think of are:
1. Stop growing water-intensive cash crops that deplete the water table:
Look at the water requirements for various crops:
From the above table it can be seen that sugarcane uses five times the amount of water as wheat.
Below is the area-wise distribution of the crops grown in India:
From the above it can be seen that the percentage of area of water intensive crops (sugarcane, tomato, onions etc), adds up to close to 20% with sugarcane area alone being more than 5%!
But instead, have a look at the percentage of sugarcane area over the last few decades (apologies for the shabby Excel work):
The percentage area of sugarcane has actually increased over the last six decades. Clearly this needs to stop and less water-intensive crops must be grown.
2. Minimize use of chemical fertilizers:
Overuse of chemical fertilizers can reverse the fertility of the soil and reduce its productivity. It can also decrease the water table below the soil and absorption of such water by crops can lead to the food being practically inedible due to high acidic content. However, no such effect will take place with manure and other natural fertilizers.
3. Building intra basin linkages for irrigation as opposed to inter basin linkages: While intra-basin too is not without problems, it is certainly a better alternative than inter-basin linkages as it both minimizes transportation costs as well as is not multi-riparian which tend to involve disputes.
4. Rain water harvesting
So, as a general principle, irrespective of which government/politician is in power, one should try and solve such problems using a bottom-up approach, i.e by starting at the village/regional level, optimizing using locally available resources and gradually moving up, rather than a multi-riparian, top-down approach.