Himalayan River System

GEOGRAPHY/ ENVIRONMENT

Topic:

• GS-1: Indian Physiography

Himalayan River System

Importance

• The Himalayas-Hindu Kush region (known as the Third Pole because of the amount of water stored as ice) is home to 10 major river systems.
• More than half of India’s water resources are supplied by the tributaries of these river systems. 
• The melting glaciers supply year-round water and the average economic productivity of the Himalayan rivers is nearly twice that of peninsular river systems. 
• Beyond the large rivers are three million springs, which feed 64% of the irrigated land in the Indian Himalayan Region (IHR). 
• These springs are the lifeline of mountain communities (50 million people across 12 Himalayan states), even as the larger rivers support the livelihoods of more than 500 million in the Indo-Gangetic plains.

These rivers are facing multiple stresses

Reduced water flow 

• The Himalayan glaciers have been receding at alarming rates.
• Low rainfall and absent snowfall impact the springs, rivulets and rivers that moderate the hydrogeology of the region.
• NITI Aayog reported that nearly half the springs in IHR were drying up.

Pollution 

• More than six billion litres of sewage is dumped into the Ganga daily, but the capacity to treat it is just a fifth of that quantity.
• Water pollution is affecting the upper reaches of the Himalayan rivers.

Construction and deforestation

• The construction of large dams, canal diversions and hydropower projects has direct and indirect impacts. 
• Obstruction of the river flow, even for run-of-the-river projects, increases siltation, reduces the efficacy of hydropower projects over time, while reducing farm productivity downstream.
• For non-glacial rivers (such as Gomti, Panar, Kosi), deforestation is the main threat, thanks to ill-planned construction.
• As a result, water infiltration into the ground reduces. So, even when erratic rains arrive, mountain springs do not get recharged nor do non-glacial rivers get their water supply.

Climate Crisis

• Decadal rise in temperatures in the Himalayan region is 0.4°C higher than the global average.
• Himalayan glaciers would retreat 45% by 2100 if surface temperatures rose by 1.8°C. Basically, even if the goals of the Paris Agreement were met, IHR is likely to face severe impacts.
• Pollution concentrations would also increase during droughts; warmer water temperatures and reduced dissolved oxygen reduce the self-purifying capacity of Himalayan rivers.

Way Ahead

• IHR needs alternative development pathways, the absence of which makes the construction industry the default option. 
• More sustainable models — high-valued-added agriculture, less water-intensive natural farming, food processing, ecotourism, investments in non-hydropower forms of renewable energy, or monetising the preservation of natural capital — cannot be restricted to pockets or pilots. 
• Alternatives must be designed and deployed at scale to get buy-in from communities and policymakers.
• Decentralised water governance, especially of springs, is imperative. 
• Then communities can understand the conditions of their spring waters, determine appropriate use, and protect or increase forest cover, because their livelihoods depend on replenished water resources.