Context

The Department of Water Resources, River Development, and Ganga Rejuvenation (DoWR, RD & GR) released the Glacial Lake Atlas of Ganga Basin.

• The NHP –Bhuvan portal was also launched.

About

About the Glacial Lake Atlas

• The present glacial lake atlas is based on the inventoried glacial lakes in part of Ganga River basin from its origin to foothills of Himalayas covering a catchment area of 2,47,109 sq. km.
• The study portion of Ganga River basin covers part of India and transboundary region.
• The Ganga River Basin Atlas is brought out under the National Hydrology Project (NHP).
• The atlas is prepared with the efforts of the National Remote Sensing Centre (NRSC), ISRO under the National Hydrology Project (NHP).

National Hydrogen Project (NHP) National Hydrogen Project (NHP) is a Central Sector Scheme implemented by the Department of Water Resources, River Development & Ganga Rejuvenation (DOWR, RD & GR). Funding: It is funded by the Department of Water Resources, River Development and Ganga Rejuvenation (DoWR, RD&GR), Ministry of Jal Shakti, Government of India. Objective: To improve the extent, quality and accessibility of water resources information and to strengthen the capacity of targeted water resources management institutions in India.

NHP-Bhuvan Portal The NHP –Bhuvan portal is launched by the National Remote Sensing Centre (NRSC).        NHP-Bhuvan Portal is a repository of information on the initiatives undertaken by NRSC under NHP with a facility to download the reports and knowledge products being developed by NRSC.

 About Ganga Basin

• The Ganges River originates in the Himalaya Mountains at Gomukh, the terminus of the Gongotri Glacier.
  • When the ice of this glacier melts, it forms the clear waters of the Bhagirathi River.
  • As the Bhagirathi River flows down the Himalayas, it joins the Alaknanda River, officially forming the Ganges River.
• The Ganges River Basin is sometimes considered part of a larger river basin consisting of the nearby Brahmaputra and Meghna rivers.
• Known as the Ganges-Brahmaputra-Meghna (GBM) River Basin, it is one of the largest river systems in the world.
  

River Basin A river basin is a region that is drained by a river, such as the Ganges, and any of its tributaries. This means that surface water and rainwater in the basin area flow into the nearby rivers.

Utilization of the Atlas

• The atlas provides a comprehensive and systematic glacial lake database for Ganga River basin with size > 0.25 ha.
• The atlas also provides authentic database for regular or periodic monitoring changes in spatial extent (expansion/shrinkage), and formation of new lakes.
• The atlas can also be used in conjunction with glacier information for their retreat and climate impact studies.
• Central and State Disaster Management Authorities can make use of the atlas for disaster mitigation planning and related program.

Glacial Lakes and Glacial lake outburst flood (GLOF) The lakes receiving melting water from glaciers are generally known as glacial lakes. A glacial lake is defined as water mass existing in a sufficient amount and extending with a free surface in, under, beside, and/or in front of a glacier and originating from glacier activities and/or retreating processes of a glacier.  As glaciers retreat, the formation of glacial lakes takes place behind moraine or ice ‘dam’. These damming materials are generally weak and can breach suddenly due to various triggering factors, leading to catastrophic floods. Such outburst floods are known as GLOF.