As Ken-Betwa project barrels ahead, new research finds river interlinking could worsen drought

Subject :Geography

Section: Physical geography

Context:

The Ministry of Environment, Forest and Climate Change awarded the final forest clearance to the Ken-Betwa river interlinking.
National Water Development Authority is overlooking river interlinking in India.

Details:

Research study done by IIT Bombay.
New evidence suggests large scale river interlinking could have unintended consequences on rainfall patterns.
River interlinking could change groundwater levels, introduce alien invasive species and reduce sediment deposits downstream.
10 percent of the Panna Tiger Reserve stands to be submerged due to the Ken- Betwa river interlinking project.
Moving vast amounts of water could impact the atmospheric feedback loops that regulate evapotranspiration and precipitation. It can lead to a deficit in rainfall by up to 12 percent.

River- interlinking project:

National River Linking Project was first proposed in 1980, with the aim of transferring water from “surplus” river basins to “water-deficit” ones to improve irrigation along drought prone tracts.
Of the 30 basins identified for interlinking, 16 are in peninsular India and 14 in the Himalayan region.
Together, these projects would transport 174 billion cubic meters of water each year through a network of canals.
Impact of river- interlinking”
- The cooling resulting from the evaporation can cause fluctuations in temperature across different land regions, changing wind patterns, moisture transport and rainfall.
- When soil moisture is changed in one basin, it can cause changes in neighboring basins by affecting evapotranspiration, cooling and precipitation.
- Reduced rainfall: The highest median reductions in rainfall in September were found to be in Odisha (12 percent), Andhra Pradesh (10 percent), Rajasthan and Gujarat. (9 percent). Parts of central India in the core monsoon zone also show a decline in rainfall of 8 percent, along with declines in the western Himalayan foothills in Uttarakhand and east-central India (6.4 percent).
- It can decrease silt deposition in the Ganga and Brahmaputra deltas by 30 percent.

Source: Mongabay