India’s incredibly ambitious Rs11 lakh crore ($168 billion) project to interlink its rivers is finally underway. If India’s prime minister, Narendra Modi, gets his way, work could soon begin on a project to link large rivers in the Himalayas and Deccan Peninsula via 30 mega-canals and 3000 dams.
When the work is finished the water network will be will stretch some 15,000 kilometres, twice the length of the Nile, the world longest river, and it will be able to divert water from flood-prone areas to those vulnerable to drought.
The idea of interlinking of rivers in the Indian subcontinent is atleast 150 years old. During the British Raj in India, Sir Arthur Cotton, a British general and irrigation engineer, first suggested linking the Ganga and the Cauvery for navigational purposes.
There are 3 main river systems in India:
1. The Ganga River System
2. The Peninsular River System
3. The Brahmaputra River System
The Ganga and the Brahmaputra river basins are plagued by floods almost every year and there is often acute shortage of water in the Peninsular river system. The Brahmaputra and Ganga basins are water surplus areas, and central and south India are water deficit areas.
Narendra Modi government’s plan to revive the river-linking project, which was first envisioned in 1982, and actively taken up by the Bharatiya Janata Party government under prime minister Atal Bihari Vajpayee in 2002.
Credit: National Institute of Hydrology, Roorkee, India
Here is how the river-linking project works: The big idea is to connect37 Himalayan and peninsular rivers. So, water-surplus rivers will be dammed, and the flow will be diverted to rivers that could do with more water. In all, some 30 canals and 3,000 small and large reservoirs will be constructed with potential to generate 34 gigawatt of hydroelectric power. The canals, planned between 50 and 100 meters in width, will stretch some 15,000 kilometres.
Need for the ILR Project
1. Drought, floods and shortage of drinking water
The average rainfall in India is about 4,000 billion cubic meters, but most of India's rainfall comes over a 4-month period – June through September. India also sees years of excess monsoons and floods, followed by below average or late monsoons with droughts. This geographical and time variance in availability of natural water versus the year round demand for irrigation, drinking and industrial water creates a demand-supply gap. This rivers inter-linking projects claim the answers to India's water problem is to conserve the abundant monsoon water bounty, store it in reservoirs, and deliver this water – using rivers inter-linking project – to areas and over times when water becomes scarce.
2. Population and food security
Population increase in India is the other driver of need for river inter-linking. India’s population growth rate has been falling, but still continues to increase by about 10 to 15 million people every year. The resulting demand for food must be satisfied with higher yields and better crop security, both of which require adequate irrigation of about 140 million hectares of land. Currently, just a fraction of that land is irrigated, and most irrigation relies on monsoon. River inter-linking is claimed to be a possible means of assured and better irrigation for more farmers, and thus better food security for a growing population.
India needs infrastructure for logistics and movement of freight. Using connected rivers as navigation is a cleaner, low carbon footprint form of transport infrastructure, particularly for ores and food grains.
4. Current reserves and loss in groundwater level
India’s worsening water problem – critical groundwater levels. India currently stores only 30 days of rainfall, while developed nations strategically store 900 days worth of water demand in arid areas river basins and reservoirs. India’s dam reservoirs store only 200 cubic meters per person. India also relies excessively on groundwater, which accounts for over 50 percent of irrigated area with 20 million tube wells installed. About 15 percent of India’s food is being produced using rapidly depleting groundwater. The end of the era of massive expansion in groundwater use, is going to demand greater reliance on surface water supply systems. Proponents of the project suggest India’s water situation is already critical, and it needs sustainable development and management of surface water and groundwater usage.
Source: ribhuv.wordpress.com, newscientist.com, qz.com