Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - I: Automatic Identification and Mapping of Glacial Lakes > Annexure - II: List of Glacial Lakes
Type: table
Table

| S.No. | Glacial Lake ID No | Lat | Long | Subbasin | GL Type | Area (ha) | Elev (m) |
|---|---|---|---|---|---|---|---|
| 5315 | 0162J0205315 | 30.570 | 82.064 | Satluj | E(o) | 0.36 | 5,679 |
| 5316 | 0162J0205316 | 30.557 | 82.035 | Satluj | E(o) | 0.91 | 5,447 |
| 5317 | 0162J0205317 | 30.556 | 82.036 | Satluj | E(o) | 0.39 | 5,451 |
| 5318 | 0162J0205318 | 30.547 | 82.016 | Satluj | E(o) | 0.88 | 5,653 |
| 5319 | 0162J0205319 | 30.545 | 82.120 | Satluj | E(o) | 0.68 | 5,528 |
| 5320 | 0162J0205320 | 30.543 | 82.156 | Satluj | E(o) | 1.79 | 5,442 |
| 5321 | 0162J0205321 | 30.523 | 82.164 | Satluj | E(o) | 0.35 | 5,554 |
| 5322 | 0162J0305322 | 30.456 | 82.006 | Satluj | E(o) | 0.48 | 5,170 |
| 5323 | 0162J0305323 | 30.452 | 82.005 | Satluj | O | 2.01 | 5,164 |
| 5324 | 0162J0305324 | 30.450 | 82.002 | Satluj | O | 0.36 | 5,168 |
| 5325 | 0162J0305325 | 30.450 | 82.006 | Satluj | O | 0.89 | 5,164 |
| 5326 | 0162J0305326 | 30.448 | 82.002 | Satluj | O | 1.15 | 5,163 |
| 5327 | 0162J0305327 | 30.441 | 82.000 | Satluj | O | 0.55 | 5,161 |
| 5328 | 0162J0305328 | 30.428 | 82.010 | Satluj | E(o) | 0.87 | 5,171 |
| 5329 | 0162J0305329 | 30.418 | 82.004 | Satluj | O | 1.10 | 5,175 |
| 5330 | 0162J0305330 | 30.417 | 82.005 | Satluj | O | 0.62 | 5,173 |
| 5331 | 0162J0305331 | 30.408 | 82.005 | Satluj | O | 0.36 | 5,174 |
| 5332 | 0162J0305332 | 30.380 | 82.021 | Satluj | M(o) | 1.08 | 5,543 |
| 5333 | 0162J0305333 | 30.376 | 82.020 | Satluj | M(e) | 11.62 | 5,493 |
| 5334 | 0162J0305334 | 30.374 | 82.016 | Satluj | M(e) | 3.80 | 5,502 |
| 5335 | 0162J0605335 | 30.732 | 82.357 | Satluj | M(e) | 1.50 | 5,730 |


Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - I: Automatic Identification and Mapping of Glacial Lakes > Annexure - II: List of Glacial Lakes
Type: text

GLACIAL LAKE ATLAS OF INDUS RIVER BASIN


Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - III: Glacial Lakes of Indus River basin greater than 50 ha
Type: text

There are 34 lakes having an area greater than 50 ha, which is just 0.63% of the total glacial lake count, but cover total of 20.26% of the total glacial lakes area. Spatial distribution of these very large sized lakes i.e. > 50 ha in area has been represented below in Figure 122 and details of these are given in Table 99, along with its area, type, geographic as well as hydrological location, and elevation at which they are situated. Among the 34 lakes, 22, 9 and 3 lakes are in the lake area range of 50-100 ha, 100-200 ha and greater than 200 ha respectively. Out of these 34 large lakes, maximum (13) are other glacial lakes and minimum (1 each) are other moraine dammed and glacial ice-dammed lakes. These very large sized lakes are situated within the elevation range of 3,486 to 5,709 m amsl, the largest one being in Gilgit subbasin at 4,286 m, followed by second largest in Shyok subbasin at 5,709 m.

GLACIAL LAKE ATLAS OF INDUS RIVER BASIN


Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - III: Glacial Lakes of Indus River basin greater than 50 ha
Type: table
Table: Table 99: List of glacial lakes with area greater than 50 ha

| S.No. | Glacial Lake ID No | Latitude | Longitude | Subbasin | GL Type | Area (ha) | Elevation (m) |
|---|---|---|---|---|---|---|---|
| 1 | 0143J1301449 | 34.845 | 74.809 | Indus Middle | E(c) | 50.44 | 3,992 |
| 2 | 0161F0704829 | 34.341 | 81.257 | Shyok | E(o) | 51.89 | 5,298 |
| 3 | 0143N0802065 | 34.094 | 75.498 | Jhelum | O | 52.27 | 3,575 |
| 4 | 0162E0405009 | 31.182 | 81.195 | Satluj | E(o) | 52.48 | 5,413 |
| 5 | 0143E0500769 | 35.949 | 73.289 | Gilgit | E(o) | 54.23 | 4,228 |
| 6 | 0161D1504804 | 32.423 | 80.865 | Indus Upper | O | 58.84 | 4,452 |
| 7 | 0152C1603156 | 33.159 | 76.984 | Indus Upper | M(e) | 59.78 | 4,479 |
| 8 | 0162F1505296 | 30.385 | 81.930 | Satluj | M(e) | 59.79 | 5,224 |
| 9 | 0143J0901397 | 34.920 | 74.521 | Jhelum | M(e) | 60.60 | 4,041 |
| 10 | 0161F0304813 | 34.299 | 81.202 | Shyok | O | 61.15 | 5,274 |
| 11 | 0152J0803836 | 34.233 | 78.426 | Shyok | O | 64.78 | 5,350 |
| 12 | 0143N0201885 | 34.697 | 75.137 | Jhelum | E(o) | 64.95 | 4,103 |
| 13 | 0152J1203868 | 34.151 | 78.553 | Shyok | E(o) | 65.02 | 5,566 |
| 14 | 0143E0500774 | 35.945 | 73.365 | Gilgit | E(c) | 67.34 | 4,162 |
| 15 | 0143K1001561 | 33.519 | 74.584 | Jhelum | E(o) | 70.83 | 3,934 |
| 16 | 0143N0201897 | 34.666 | 75.179 | Jhelum | E(o) | 74.54 | 4,234 |
| 17 | 0152H0203651 | 32.526 | 77.220 | Chenab | M(e) | 77.59 | 4,069 |
| 18 | 0143N0401975 | 34.140 | 75.148 | Jhelum | E(c) | 82.93 | 3,780 |
| 19 | 0143E0900941 | 35.865 | 73.746 | Gilgit | E(o) | 84.31 | 4,140 |
| 20 | 0143J0101363 | 34.829 | 74.062 | Jhelum | E(c) | 93.90 | 3,681 |
| 21 | 0152J0303811 | 34.457 | 78.136 | Shyok | M(o) | 95.68 | 5,295 |
| 22 | 0143A0900591 | 35.944 | 72.595 | Gilgit | O | 96.35 | 3,761 |
| 23 | 0142H1000208 | 36.644 | 73.646 | Gilgit | O | 105.07 | 3,821 |
| 24 | 0143K1401588 | 33.512 | 74.769 | Jhelum | O | 128.54 | 3,486 |
| 25 | 0152H1103771 | 32.499 | 77.547 | Chenab | M(e) | 128.69 | 4,150 |
| 26 | 0143N0101839 | 34.991 | 75.236 | Indus Upper | O | 129.62 | 4,138 |
| 27 | 0152K0703939 | 33.455 | 78.498 | Shyok | O | 147.89 | 5,308 |
| 28 | 0162E1105115 | 31.274 | 81.595 | Indus Upper | O | 156.89 | 5,229 |
| 29 | 0143J1501489 | 34.432 | 74.924 | Jhelum | E(c) | 161.04 | 3,571 |
| 30 | 0152K0703940 | 33.427 | 78.488 | Shyok | O | 177.73 | 5,284 |
| 31 | 0162F0705180 | 30.431 | 81.433 | Satluj | E(o) | 192.62 | 5,484 |
| 32 | 0143A0900583 | 35.994 | 72.613 | Gilgit | O | 201.58 | 3,622 |
| 33 | 0161B1504757 | 34.316 | 80.858 | Shyok | I(d) | 232.34 | 5,709 |
| 34 | 0142H0900200 | 36.879 | 73.704 | Gilgit | O | 262.57 | 4,286 |

S.No.
Glacial Lake ID No
Latitude
Longitude
Subbasin
GL Type
Area (ha)
Elevation (m)

Chenab
Gilgit
Indus Middle
Indus Upper
Jhelum
Satluj
Shyok


Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - III: Glacial Lakes of Indus River basin greater than 50 ha
Type: text

***

GLACIAL LAKE ATLAS OF INDUS RIVER BASIN


Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - III: Glacial Lakes of Indus River basin greater than 50 ha > Annexure - IV: Glossary
Type: text

**Ablation:** The process that reduce the mass of the glacier (Cogley et al., 2011).

**Ablation area/zone:** The part of the glacier where ablation exceeds accumulation in magnitude, that is, where the cumulative mass balance relative to the start of the mass-balance year is negative. The extent of the ablation zone can vary strongly from year to year (Cogley et al., 2011).

**Accumulation:** The process that add to the mass of the glacier (Cogley et al., 2011).

**Accumulation area/zone:** The part of the glacier where accumulation exceeds ablation in magnitude, that is, where the cumulative mass balance relative to the start of the mass-balance year is positive. The extent of the accumulation zone can vary strongly from year to year. The accumulation zone is not the same as the firn area (Cogley et al., 2011).

**Altitude:** The vertical distance of a point above a datum, which is usually an estimate of mean sea level. Altitude and elevation are synonyms in common usage (Cogley et al., 2011).

**Aspect:** The compass direction towards which a slope faces; measured clockwise in degrees from the North.

**Attribute:** Non-spatial descriptive characteristics of a real-world phenomenon, often a measurement or value associated with spatial locations.

**Attribute:** Non-spatial descriptive characteristics of a real-world phenomenon, often a measurement or value associated with spatial locations.

**Avalanche:** A slide or flow of a mass of snow, firn or ice that becomes detached abruptly, often entraining additional material such as snow, debris and vegetation as it descends. The duration of an avalanche is typically seconds to minutes (Cogley et al., 2011).

**Band:** One layer of multispectral image representing data values for a specific range of the electromagnetic spectrum of reflected light or heat.

**Climate:** Climate is usually defined as the average weather or as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period for averaging these variables is 30 years. The relevant quantities are most often surface variables such as temperature, precipitation and wind (Pandey, 2019).

**Climate change:** Climate change refers to a change in the state of the climate that can be identified by changes in the mean and/or the variability of its properties and that persists for an extended period, typically decades or longer. UNFCCC defines climate change as: 'a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods'. (Pandey, 2019).

**Climate variability:** Climate variability refers to variations in the mean state and other statistics (such as standard deviations, the occurrence of extremes, etc.) of the climate on all spatial and temporal scales beyond that of individual weather events. Variability may be due to natural internal processes within the climate system (internal variability), or to variations in natural or anthropogenic external forcing (external variability) (Pandey, 2019).

GLACIAL LAKE ATLAS OF INDUS RIVER BASIN


Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - III: Glacial Lakes of Indus River basin greater than 50 ha > Annexure - IV: Glossary
Type: text

the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods ' . ( Pandey , 2019 ) . * * Climate variability : * * Climate variability refers to variations in the mean state and other statistics ( such as standard deviations , the occurrence of extremes , etc . ) of the climate on all spatial and temporal scales beyond that of individual weather events . Variability may be due to natural internal processes within the climate system ( internal variability ) , or to variations in natural or anthropogenic external forcing ( external variability ) ( Pandey , 2019 ) . GLACIAL LAKE ATLAS OF INDUS RIVER BASIN

**Cryosphere:** The cryosphere is the part of the Earth system that contains ice, for example snow on the ground, glaciers, ice sheets, lake ice, river ice, sea ice, seasonally and perennially frozen ground (GCW 2016).

**Database:** An organized, integrated collection of data related by a common fact or purpose.

**Debris-covered glacier:** A glacier that is covered at its tongue with supra-glacial debris across its full width (Kirkbride, 2011). In the accumulation zone any deposited debris is buried by later snowfalls, but in the ablation zone debris remains at the surface and englacial debris is added to the surface layer from beneath as ice ablates away. The debris cover affects the rate of ablation, with very thin debris resulting in accelerated melt and debris thicker than a few tens of millimetres reducing the melting rate (Cogley et al., 2011).

**Digital Elevation Model (DEM):** An array of numbers representing the elevation of part or all of the Earth’s surface as samples or averages at fixed spacing in two horizontal coordinate directions (Cogley et al., 2011).

**Disaster:** A serious disruption of the functioning of a community or a society at any scale due to hazardous events interacting with conditions of exposure, vulnerability and capacity, leading to one or more of the following: human, material, economic and environmental losses and impacts (UNISDR 2017).

**Disaster risk:** The potential loss of life, injury, or destroyed or damaged assets which could occur to a system, society or a community in a specific period of time, determined probabilistically as a function of hazard, exposure, vulnerability and capacity (UNISDR 2017).

**Early warning system:** The set of capacities needed to generate and disseminate timely and meaningful warning information to enable individuals, communities and organizations threatened by a hazard to prepare to act promptly and appropriately to reduce the possibility of harm or loss (Pandey, 2019).

**Electromagnetic spectrum:** The spectrum of wavelengths of electromagnetic radiation.

**Englacial:** Pertaining to the interior of the glacier, between the summer surface and the bed (Cogley et al., 2011).

**Exposure:** The presence or situation of people, livelihoods, species or ecosystems, environmental functions, services, and resources, infrastructure, or economic, social, or cultural assets in places and settings, and other tangible human assets located in hazard-prone areas that could be adversely affected (UNISDR, 2017; Pandey, 2019).

**Feature:** A real-world phenomenon, often used in cartography to name classes of elements shown on a map.


Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - III: Glacial Lakes of Indus River basin greater than 50 ha > Annexure - IV: Glossary
Type: text

* * Pertaining to the interior of the glacier , between the summer surface and the bed ( Cogley et al . , 2011 ) . * * Exposure : * * The presence or situation of people , livelihoods , species or ecosystems , environmental functions , services , and resources , infrastructure , or economic , social , or cultural assets in places and settings , and other tangible human assets located in hazard - prone areas that could be adversely affected ( UNISDR , 2017 ; Pandey , 2019 ) . * * Feature : * * A real - world phenomenon , often used in cartography to name classes of elements shown on a map .

**Firn:** Snow (in which the pore space is at least partially interconnected, allowing air and water to circulate) that has survived at least one ablation season but has not been transformed to glacier ice (Cogley et al., 2011).

**Flood:** The overflowing of the normal confines of a stream or other body of water, or the accumulation of water over areas not normally submerged. Floods include river (fluvial) floods, flash floods, urban floods, pluvial floods, sewer floods, coastal floods and glacial lake outburst floods (Pandey, 2019).

**Format:** The pattern into which data are systematically arranged for use on a computer.

**Geographic Information System (GIS):** A set of tools for collecting, storing, retrieving, transforming, and displaying spatial data from the real world for a particular set of circumstances.

GLACIAL LAKE ATLAS OF INDUS RIVER BASIN

**Glacial Lake Outburst Flood (GLOF):** Flood caused by the outburst of a glacial lake due to rapid accumulation of water in it, resulting to extreme damage in loss of lives and infrastructure in the downstream area.

**Glacial Lake:** As a result of glacier thinning and retreating, melt water gets accumulated at terminal moraines or on it covered by glacier ice, is known as glacial lake.

**Glacier Erosion Lake:** These are the water bodies formed in a depression after the glacier has retreated in a form of cirque or trough valley, might be isolated and far away from the present glaciated area, and mostly stable in nature.

**Glacier:** A perennial mass of ice, and possibly firn and snow, originating on the land surface by their crystallization of snow or other forms of solid precipitation and showing evidence of past or present flow (Cogley et al., 2011).

**Global Positioning System (GPS):** A GPS is a position-fixing system that uses the time taken for signals to travel from at least three GPS satellites in a known orbit to a receiver on the ground.

**Hazard:** The potential occurrence of a natural or human-induced physical event or trend or physical impact that may cause loss of life, injury, or other health impacts, as well as damage and loss to property, infrastructure, livelihoods, service provision, ecosystems and environmental resources (Pandey, 2019).

**Ice-dammed Lake:** An Ice-dammed Lake is produced on the side(s) of a glacier, when an advancing glacier happens to intercept a tributary/tributaries pouring into a main glacier valley.


Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - III: Glacial Lakes of Indus River basin greater than 50 ha > Annexure - IV: Glossary
Type: text

GPS satellites in a known orbit to a receiver on the ground . * * Hazard : * * The potential occurrence of a natural or human - induced physical event or trend or physical impact that may cause loss of life , injury , or other health impacts , as well as damage and loss to property , infrastructure , livelihoods , service provision , ecosystems and environmental resources ( Pandey , 2019 ) . * * Ice - dammed Lake : * * An Ice - dammed Lake is produced on the side ( s ) of a glacier , when an advancing glacier happens to intercept a tributary / tributaries pouring into a main glacier valley .

**Impacts:** The term impacts is used primarily to refer to the effects on natural and human systems of extreme weather and climate events and of climate change. Impacts generally refer to effects on lives, livelihoods, health, ecosystems, economies, societies, cultures, services and infrastructure due to the interaction of climate changes or hazardous climate events occurring within a specific time period and the vulnerability of an exposed society or system. Impacts are also referred to as consequences and outcomes. The impacts of climate change on geophysical systems, including floods, droughts and sea level rise, are a subset of impacts called physical impacts (Pandey, 2019).

**Latitude:** Angle measured in a north-south direction from the Earth’s center to locations on the Earth’s surface.

**Longitude:** Angle measured in an east-west direction from the Earth’s center to locations on the Earth’s surface.

**Layer:** Usually represents a theme or a feature type within the database.

**Map:** An abstract representation of the physical features of a portion of the Earth’s surface graphically displayed on a planar surface. Map display signs, symbols and spatial relationships among the features.

**Melt water:** The liquid resulting from melting of ice, firn or snow (Cogley et al., 2011).

**Moraine-dammed Lake:** In the retreating process of a glacier, ice tends to melt in the lowest part of the glacier surrounded by Lateral-moraines and End-moraines, and forms into a lake known as Moraine-dammed Lake or Proglacial Lake.

**Pixel:** Smallest discrete element that makes up an image, generally represents either a small square or portion of the Earth’s surface, scanned by satellite or aircraft.

GLACIAL LAKE ATLAS OF INDUS RIVER BASIN

**Precipitation:** Liquid or solid products of the condensation of water vapour that fall from clouds or are deposited from the air onto the surface (Cogley et al., 2011).

**Remote sensing:** The technique of obtaining data about the environment and surface of the earth from a distance, e.g. from an aircraft or satellite.

**Resolution:** It is the accuracy at which a given map scale can depict the location and shape of geographic features.

**Retreat:** Decrease of the length of a flow line (in case of glacier which is its terminus), measured from a fixed point. Advance is the opposite of retreat, that is, advance of the terminus (Cogley et al., 2011).


Document: GL Atlas Indus 12Nov2020 Final
Section: Annexure - III: Glacial Lakes of Indus River basin greater than 50 ha > Annexure - IV: Glossary
Type: text

al . , 2011 ) . * * Remote sensing : * * The technique of obtaining data about the environment and surface of the earth from a distance , e . g . from an aircraft or satellite . * * Resolution : * * It is the accuracy at which a given map scale can depict the location and shape of geographic features . * * Retreat : * * Decrease of the length of a flow line ( in case of glacier which is its terminus ) , measured from a fixed point . Advance is the opposite of retreat , that is , advance of the terminus ( Cogley et al . , 2011 ) .

**Risk:** The potential for consequences where something of value is at stake and where the outcome is uncertain, recognizing the diversity of values. Risk is often represented as probability or likelihood of occurrence of hazardous events or trends multiplied by the impacts if these events or trends occur. In this report, the term risk is often used to refer to the potential, when the outcome is uncertain, for adverse consequences on lives, livelihoods, health, ecosystems and species, economic, social and cultural assets, services (including environmental services) and infrastructure (Pandey, 2019).

**Scale:** The ratio or fraction between the distance on a map, chart or photograph and the corresponding distance on the surface of the Earth.

**Slope:** A measure of change on surface value over distance, expressed in degrees or as a percentage.

**Snow:** Solid precipitation in the form of ice crystals, chiefly in complex branched hexagonal form and often agglomerated into snowflakes; or an accumulation of the same on the Earth’s surface. It is also known as solid precipitation that has accumulated on the summer surface on a glacier and that transforms to firn at the end of the mass-balance year (Cogley et al., 2011).

**Subglacial:** Pertaining to the glacier bed or to the material below the bed (Cogley et al., 2011).

**Supra-glacial Lake:** Water bodies develop within the ice mass in any position of the glacier, but away from the terminal moraines are known as Supra-glacial lakes. Its basic characteristics are shifting, merging, and draining.

**Terminus:** The lowest end of a glacier, also called glacier snout, glacier front or glacier toe (Cogley et al., 2011).

**Tongue:** The lower, elongate part of a valley glacier or outlet glacier or a floating extension of a glacier or ice stream, laterally unconfined but markedly longer than wide (Cogley et al., 2011).

**Topographic Map:** A map showing the features that describes the surface of a particular place or region. It contains contours indicating lines of equal surface elevation (relief), often referred to a topo maps.

**Vulnerability:** The propensity or predisposition to be adversely affected. Vulnerability encompasses a variety of concepts and elements including sensitivity or susceptibility to harm and lack of capacity to cope and adapt (Pandey, 2019).

Prepared under: National Hydrology Project

National Remote Sensing Centre
Indian Space Research Organisation
Department of Space, Government of India
Hyderabad - 500 037


Document: Glacial Lake Atlas Ganga Basin NRSC
Type: text

National Hydrology Project (NHP) was taken up by Department of Water Resources, River Development & Ganga Rejuvenation (DoWR, RD&GR), Ministry of Jal Shakti with the aim of improving the extent, quality and accessibility of water resources information and to strengthen the capacity of targeted water resources management institutions in India. National Remote Sensing Centre (NRSC), one of the premier centres of Indian Space Research Organisation (ISRO) is taking part in this initiative of DoWR, RD&GR as one of the Implementing Agencies under NHP.

Water resources availability and the ability to derive its information using modern tools like remote sensing and GIS with high temporal and spatial coverage, will usher in a new era of efficient and equitable water management. In the era of satellites, with the availability of voluminous data, big data analytics, artificial intelligence and other information extraction methods provide access to rapid and reliable information on water resources even from inaccessible areas.

The might Himalayas on the northern boundary of the country stand high with large number of glaciers and glacial lakes. It is important to map the glacial lakes in detail due to the increasing incidents of flash floods in the Himalayas. The prime objective of detailed mapping of glacial lakes is to reduce the damage to the downstream areas from the devastation that is caused by Glacial Lake Outburst Floods (GLOF). Glacial Lake Atlas of Ganga River Basin containing a wealth of information about 4,707 glacial lakes is prepared to assess GLOF risk for the Ganga River Basin. The Atlas, written in a well-structured manner, would be of benefit to experienced professionals and subject experts.

Since the Atlas will be accessible through the India-WRIS and BHUVAN portals, this would be a step forward in making available all the water related data and products from different Central and State Organisations available on one platform, ensuring ease of access to the end user.

I compliment the initiative of NRSC team for successful completion of this important task under NHP, and look forward to the logical continuation of this effort in the form of GLOF risk assessment study and its outcome in the form of Disaster Risk Reduction (DRR) from GLOF in the Indian Himalayan Region.


Document: MESSAGE
Section: MESSAGE
Type: text

Snow and glaciers play a crucial role in the interaction between atmospheric and land surface processes in high mountains areas like the Himalaya. Retreat and thinning of glaciers could lead to formation of glacial lakes with the accumulation of water near their snout. Breach of such lakes may result in Glacial Lake Outburst Floods (GLOF), a potential hazard for the people and infrastructure in the downstream reaches. Hence, identification and monitoring of glacial lakes is very critical for reducing the associated risk. Multispectral, multi-temporal data from the Indian Remote Sensing satellites enable systematic inventory and monitoring of glacial lakes in the Himalayan Region.

National Remote Sensing Centre (NRSC)/ISRO is one of the Implementing Agency under National Hydrology Project, funded by DoWR, RD&GR, Ministry of Jal Shakti, Govt. of India. Among the many work components which are being carried out by NRSC as part of NHP, the atlas of Glacial Lakes of Ganga River Basin is also generated. This atlas provides various information such as the type, hydrological & topographical characteristics etc., of glacial lakes of equal to more than 0.25 ha size in the Ganga River Basin. It will serve as a scientific source of information for technical & administrative management, supporting disaster risk reduction and climate change induced impact assessment.

I appreciate the efforts of technical team of NRSC/ISRO, Hyderabad, for bringing out this atlas of Glacial Lakes in the Ganga River Basin. I am sure that the atlas will be of great use for researchers, professionals and administrative personnel, in strengthening the disaster risk reduction activities and climate change studies.


Document: MESSAGE
Section: FOREWORD
Type: text

Snow and glaciers provide major source of fresh water for major river systems originating from Himalayas thereby supporting the livelihood of millions of people, particularly in summer months. As the glacier retreats, glacial lakes form around the margins of glacier which store its melt water impounded by the moraines. These glacial lakes occasionally release large quantities of glacier melt water from associated moraine failure, resulting in devastating floods in the downstream reaches. Many such catastrophic floods occurred in the recent past in the Himalayas resulting in loss of lives and damaging critical infrastructure like hydro-power plants, bridges, etc. It is highly imperative to have the knowledge on location of glacial lakes and the consequences of related flood risk. Earth Observation satellite data is highly helpful in identifying and monitoring of glacial lakes, which by traditional ways is practically difficult due to their inhospitable and inaccessible location and highly rugged topography.

The Ganga River Basin atlas is brought out as part of an activity on “Glacial Lake Outburst Flood (GLOF) Risk Assessment of Glacial Lakes in the Himalayan Region of Indian River Basins”, taken up under the National Hydrology Project, funded by the Department of Water Resources, River Development and Ganga Rejuvenation (DoWR, RD&GR), Ministry of Jal Shakti, Government of India. Under this activity, glacial lakes of size greater than 0.25 ha are mapped using high resolution satellite data from the Resourcesat-2 LISS-IV MX. Using this geo-database, an atlas titled ‘Glacial Lake Atlas of Indus River Basin’ has already published and in continuation to that the present atlas titled ‘Glacial Lake Atlas of Ganga River Basin’ is prepared. This atlas is first of its kind depicting spatial distribution of glacial lakes of size greater than 0.25 ha in the Ganga River basin within India and transboundary hydrologic catchments. The details of glacial lakes are systematically documented at basin, subbasin, administrative, and transboundary region level, including lake type, area, and elevation distribution.

The Ganga River Basin Atlas forms as an authentic and recent reference data, and is useful in monitoring glacial lake dynamics, GLOF risk assessment, and long-term climate change impact analysis.

I appreciate the study team for taking up this initiative to bring out an exclusive “Glacial Lake Atlas of Ganga River Basin”. I wish that this exhaustive atlas will be of immense value to Central/State Water Resources, Environmental, and Disaster Management Organisations, and as well as to professionals and academicians.

**(Raj Kumar)**

भारतीय अन्तरिक्ष अनुसंधान संगठन Indian Space Research Organisation


Document: MESSAGE
Section: GLACIAL LAKE ATLAS OF GANGA RIVER BASIN > SUMMARY
Type: text

National Remote Sensing Centre (NRSC), Indian Space Research Organisation (ISRO), Hyderabad as one of the Implementing Agency under the National Hydrology Project (NHP), is carrying out hydrological studies using satellite data and geo-spatial techniques. As part of this, detailed glacial lake inventory, prioritization for Glacial Lake Outburst Flood (GLOF) risk, and simulation of GLOF for selected lakes are taken up for entire catchment of Indian Himalayan Rivers covering Indus, Ganga, and Brahmaputra River basin. Under this activity, an updated inventory of glacial lakes using high resolution satellite data was prepared for the Indus River basin and published in December 2020 (NRSC-RSAA-WRG-WRAD-Nov2020-TR-0001702-V1.0), and currently an updated inventory of glacial lakes has been prepared for the Ganga River basin, and same for Brahmapurta River basin will be made soon. 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 2,47,110 Km².

The study portion of Ganga River basin covers part of India and transboundary region. Ganga River basin has been divided into 11 subbasins on the basis of confluence of major rivers contributing into the system viz., Yamuna joining the main river on the right, whereas rivers like Sarda, Ghaghara, Gandak, and Kosi joining on the left. Elevation in the river basin varies from the minimum 45 m to the maximum 8,848 m above mean sea level (amsl). In India, Ganga River basin extends in two states viz., Himachal Pradesh and Uttarakhand.

In the present study, glacial lakes with water spread area ≥ 0.25 ha have been mapped using Resourcesat-2 (RS-2) Linear Imaging Self Scanning Sensor-IV (LISS-IV) satellite data using visual interpretation techniques. Based on its process of lake formation, location, and type of damming material, glacial lakes are identified in nine out of ten different types, majorly grouped into four categories viz., Moraine-dammed, Ice-dammed, Glacier Erosion, and Other Glacial lakes.

A total of 4,707 glacial lakes have been mapped in the Ganga River basin using a total of 105 high resolution multispectral RS-2 LISS-IV images, with a total lake water spread area of 20,685.12 ha. Each glacial lake has been given a 12 alpha-numeric unique glacial lake ID, along with several attributes that include hydrological, geometrical, geographical, and topographical characteristics. About 4,035 (85.72%) lakes are with < 5 ha lake area contributing to 23.13% of total lake area. The remaining lakes with ≥ 5 ha in size are 672 (14.28%) contributing to 76.87% of total lake area in the basin. There are only 58 glacial lakes in the Ganga River basin having an area of ≥ 50 ha. Other Glacial Erosion lake type are found to be the maximum with 1,744 (37.05%) occupying a total lake extent of 4,612.02 ha at 22.30% in the basin. More than half (i.e. 59.25%) of the lakes are situated in the very high altitude range of greater than 5,000 m amsl and dominated by Other Moraine Dammed lake type i.e. 48.97%.

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN
SUMMARY


Document: MESSAGE
Section: GLACIAL LAKE ATLAS OF GANGA RIVER BASIN > SUMMARY
Type: text

87 % of total lake area in the basin . There are only 58 glacial lakes in the Ganga River basin having an area of ≥ 50 ha . Other Glacial Erosion lake type are found to be the maximum with 1 , 744 ( 37 . 05 % ) occupying a total lake extent of 4 , 612 . 02 ha at 22 . 30 % in the basin . More than half ( i . e . 59 . 25 % ) of the lakes are situated in the very high altitude range of greater than 5 , 000 m amsl and dominated by Other Moraine Dammed lake type i . e . 48 . 97 % .

Out of 11 subbasins, only 6 subbasins contain glacial lakes, which are predominantly distributed in Kosi subbasin (51.77%) followed by Ghaghara subbasin (26.77%), with a total lake extent of 14,604.34 ha and 3,536.39 ha at 70.60% and 17.10% respectively in the entire basin. In terms of very large size lakes i.e. ≥ 50 ha, Kosi subbasin has majority i.e. 54 out of 58 large lakes within it. Minimum number of glacial lakes are present in Yamuna subbasin (0.76%) and then in Sarda subbasin (1.17%). Other Glacial Erosion lakes, which are dominant lake type in Ganga River basin are uniformly distributed in all subbasins, and found maximum in count in Kosi subbasin. However, Glacier Ice-dammed lake is only one in the entire Ganga River basin and is located in Gandak subbasin. Upper Ganga subbasin consists of higher number of Supra-glacial Lakes in the entire Ganga River basin, whereas Gandak subbasin contains higher number of Lateral Moraine Dammed Lake with Ice.

***

Gandak
Ghaghara
Kosi
Sarda
Upper Ganga
Yamuna


Document: MESSAGE
Section: GLACIAL LAKE ATLAS OF GANGA RIVER BASIN
Type: text

A total of 369 (i.e. 7.84%) glacial lakes lies within Indian region covering 2.92% of the total lake area, whereas remaining 92.16% of lakes are located in transboundary region with a 97.08% of the total lake area.

In Indian region, majority of glacial lakes are of Other Moraine Dammed type (29.81%), followed by Supra-glacial (28.73%) and Other Glacial Erosion type (21.41%). Uttarakhand state shares 93.50% of lake count, followed by 6.50% in Himachal Pradesh, with a total lake area of 90.70% and 9.30% respectively. Majority of lakes in Uttarakhand and Himachal Pradesh are predominantly of lake area < 5 ha, but lying in high (4,001 - 5,000 m) and very high altitude range (> 5,000 m) respectively. Lakes in Himachal Pradesh are only situated above 4,000 m elevation.

In this atlas, map sheets (plates) are prepared in correspondence with the Survey of India (SOI) toposheet index (1:250,000 scale) which are 42 in number covering the entire Ganga River basin. Out of 42 plates, only 23 plates have glacial lakes and corresponding plates are incorporated in atlas. The map sheets are arranged in such a way that glacial lake map is on the right page and its corresponding satellite image is on the left page. At the end of the atlas, an annexure is provided containing list of all glacial lakes inventoried in the Ganga River basin with their unique glacial lake ID, latitude, longitude, subbasin, glacial lake type, area (ha), and elevation (m). Glacial Lake ID number of 12 alpha-numeric character has 3 characters with dark red colour depicting the corresponding toposheet number of the SOI of 1:250,000 scale.

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 1. INTRODUCTION > 1.1 About Project
Type: text

The National Hydrology Project (NHP) sponsored by Department of Water Resources, River Development and Ganga Rejuvenation (DoWR, RD&GR), Ministry of Jal Shakti, Government of India (GOI) with financial aid from the World Bank. The objective of the project is to improve the extent and accessibility of water resources information and strengthen institutional capacity to enable improved water resources planning and management across India. The mission is to establish an effective and sound hydrologic database and Hydrological Information System (HIS), together with the development of consistent and scientifically based tools and design aids, to assist in the effective water resources planning and management of the implementing agencies.

NHP is intended for setting up of a system for timely and reliable water resources data acquisition, storage, collation and management. It will also provide tools/systems for informed decision making through Decision Support Systems (DSS) for water resources assessment, flood management, reservoir operations, drought management, etc. NHP also seeks to build capacity of the State and Central sector organisations in water resources management through the use of Information Systems and adoption of State-of-the-art technologies like Remote Sensing. NHP will improve and expand hydrology data and information systems, strengthen water resources operation and planning systems, and enhance institutional capacity for water resources management. NHP will contribute to the GOI Digital India initiative by integrating water resources information across State and Central agencies.

National Remote Sensing Centre (NRSC), as one of the Implementing Agencies under NHP, is engaged with generation of geo-spatial products & services pertaining to water resources sector, generation of high resolution Digital Elevation Models (DEM), development of flood early warning systems, decision support system development for irrigation water management, modelling & dissemination of hydrological products to support water resources management and capacity building to NHP stakeholders. The satellite data based geo-spatial products & services, mainly encompassing the following:

* Satellite Data/Geo-Spatial Data Hosting & Services through Bhuvan Web Portal
* Water Resources Information Products & Services (Satellite/Model derived – Bhuvan/India- Water Resources Information System (India-WRIS)/National Water Informatics Centre (NWIC))
* Customized Applications Development (Flood Forecasting, Irrigation Water Management)
* Hydro-conditioned Digital Elevation Model (Satellite & Aerial)
* Capacity Building (Customized Training & Hand Holding)

As part of various NHP technical studies carried out, NRSC has taken up “Glacial Lake Outburst Flood (GLOF) Risk Assessment of Glacial Lakes in the Himalayan Region of Indian River Basins”. In this activity, it was proposed to prepare an updated inventory of glacial lakes, prioritization and selection of critical glacial lakes based on certain characteristics (such as glacial lake, glacier, topography and others), GLOF modelling and flood inundation simulation for selected few lakes using high resolution Digital Elevation Model (DEM) for downstream of the lakes along their river reach, and to assess GLOF risk.

As a result of initial outcome of this activity, an updated inventory of glacial lakes in Indus and Ganga River basin was generated using multispectral (MX) high resolution satellite data of Resourcesat-2 (RS-2) Linear Imaging Self Scanning Sensor-IV (LISS-IV) for mapping lakes with size ≥ 0.25 ha. The geo-spatial database of glacial lakes

***

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 1. INTRODUCTION > 1.1 About Project
Type: text

) , GLOF modelling and flood inundation simulation for selected few lakes using high resolution Digital Elevation Model ( DEM ) for downstream of the lakes along their river reach , and to assess GLOF risk . As a result of initial outcome of this activity , an updated inventory of glacial lakes in Indus and Ganga River basin was generated using multispectral ( MX ) high resolution satellite data of Resourcesat - 2 ( RS - 2 ) Linear Imaging Self Scanning Sensor - IV ( LISS - IV ) for mapping lakes with size ≥ 0 . 25 ha . The geo - spatial database of glacial lakes * * * GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

has been used to prepare “Glacial Lake Atlas of Indus River Basin”, already published NRSC-RSAA-WRG-WRAD-Nov2020-TR-0001702-V1.0 (Rao et al., 2020) and presently the “Glacial Lake Atlas of Ganga River Basin”.


Document: MESSAGE
Section: 1. INTRODUCTION > 1.2 Glacial Lakes
Type: text

Indian Himalayan Region (IHR) contains the world’s largest number of glaciers and snow outside the Polar Regions and are aptly called third pole of the world. Many studies undertaken globally showed that glaciers around the world have been retreating since the industrial revolution, which began around eighteenth century. As the glaciers are thinning and retreating, resulting in associated glacier melt water lakes are expanding in size and new lakes continue to form. The lakes receiving melt 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.

GLOFs are characterized by extreme peak discharges, with an exceptional erosion/transport potential; therefore, they can turn into flow-type movements (Emmer, 2017). Failure of such lake happens due to many factors which include erosion process, increase in water pressure, merging of an avalanche/rock into lake, nature of the damming materials etc., and this may lead to a GLOF event which could be highly disastrous in nature and create long-term degradation in the valleys, both physically and socio-economically (Mool et al., 2001b). Accordingly, Emmer et al., (2016) showed an annual nonlinear increase in the number of scientific publications focusing on GLOFs recently. Hence, monitoring of glacier associated lakes is very useful in the IHR to identify critical glacial lakes, for which a detailed inventory of glacial lakes and its type is required. According to their position relative to the glacier and damming mechanism, these glacial lakes can be classified into several types (Panda et al., 2014).

Inventorying glacial lakes located in these remote mountain areas with rugged terrain and inclement weather by traditional means is very tedious and difficult, hence Remote Sensing (RS) data plays a greater role in generating information on glacial lakes (Kulkarni, 1991; Berither et al., 2007; Wagnon et al., 2007; Raj, 2010; Cogley et al., 2011; Pratap et al., 2016; Gupta et al., 2019, Guru et al., 2019). Satellites with high spatial, spectral and temporal resolution sensors are useful in deriving lake information with better accuracy and repeatedly.


Document: MESSAGE
Section: 1. INTRODUCTION > 1.3 Previous Studies
Type: text

Several studies have been taken up in the past to assess the glacial lake distribution in the Hindu Kush Himalayas (HKH), covering parts of eight countries viz., Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal, and Pakistan, and lies within five river basins of Amu Darya, Indus, Ganga, Brahmaputra, and Irrawaddy (Komori, 2007; Gardelle et al., 2011; Wang et al., 2011; Wang et al., 2012; Nie et al., 2013; Raj et al., 2013; Wang et al., 2013; Worni et al., 2013; Che et al., 2014; Bambari et al., 2015; Zhang et al., 2015; Nie et al., 2017; Rounce et al., 2017; Nagai et al., 2017; Gupta et al., 2019; Guru et al., 2019; Shugar et al., 2020). But only few glacial lake inventories are available in public domain, amongst which the first inventory was prepared by the International Centre for Integrated Mountain Development (ICIMOD), Nepal, for the entire HKH region (covering the entire IHR within it), using satellite data of the Land Observation Satellite (Landsat) Thematic Mapper (TM) of the United States Geological Survey (USGS) and the Indian Remote Sensing satellite (IRS-1D) Linear Imaging and

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

Self-scanning Sensor-III (LISS-III) during 1999-2005, along with topographic maps published between the 1950s and 1982 (Mool et al., 2001a; Mool et al., 2001b; Mool et al., 2003; Bhagat et al., 2004; Roohi et al., 2005; Sah et al., 2005; Wu et al., 2005, Ives et al., 2010). This inventory has been revised in 2018 using Landsat TM and Enhanced Thematic Mapper Plus (ETM+) data of years 2004-07 ± 3 (Maharjan et al., 2018). Both glacial lake inventories prepared by the ICIMOD, have mapped lakes with size > 0.3 ha.

Second inventory of glacial lakes and water bodies in the IHR (within India only) was carried out by the NRSC, Hyderabad in collaboration with the Central Water Commission (CWC), New Delhi (NRSC-RS&GISAA-WRG-CWC-Lakes-May2011-TR255). Glacial lakes and water bodies located in all three major basins of Indus, Ganga, and Brahmaputra, of size > 10 ha were mapped using Indian Remote Sensing (IRS) Advanced Wide Field Sensor (AWiFS) data for the year 2009 (NRSC, 2011). Subsequently, monthly monitoring of these lakes (> 50 ha) was carried out using satellite data for the months of June to October during the years 2011 to 2015.

Third latest glacial lake inventory is prepared by the Space Application Centre (SAC), Ahmedabad i.e. “National Wetland Atlas: High Altitude Lakes of India”, using IRS-P6 LISS-III, comprising high altitude lake information of the IHR, within Indian administrative region only (Panigrahy et al., 2012). In this atlas, wetlands of size > 2.25 ha were mapped as a polygons and less than that were mapped as a points, using satellite data for the period of 2006-08.


Document: MESSAGE
Section: 1. INTRODUCTION > 1.4 Highlights of the Atlas
Type: text

**The highlights of the present atlas:**
* The present atlas is first of its kind depicting spatial distribution of glacial lakes of size ≥ 0.25 ha in Ganga River basin mapped using high resolution satellite data
* The atlas provides the details of all the glacial lakes in entire catchment of Ganga River basin, both within Indian and transboundary region
* The atlas contain details of area range-wise glacial lakes along with 9 categories of types. Further, the atlas present the distribution of glacial lakes in terms of area vs. type, elevation, area vs. elevation and type vs. elevation, at basin, subbasin, administrative and transboundary regions
* The atlas also provides comprehensive list of all glacial lakes with unique ID considering hydrological, geometrical, geographical, topographical attribute information

**The expected utility of the atlas:**
* The atlas provides a comprehensive & systematic glacial lake database for Ganga River basin
* In the context of climate change impact analysis, the atlas can be used as reference data for carrying out change analysis, both with respect to historical and future time periods
* 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
* The information on glacial lakes like their type, hydrological, topographical, and associated glaciers are useful in identifying the potential critical glacial lakes and consequent GLOF risk
* Central and State Disaster Management Authorities can make use of the atlas for disaster mitigation planning and related programs
* Can be used in Detailed Project Report (DPR) preparation for new hydropower/multi purpose project

1. INTRODUCTION
1.4 Highlights of the Atlas


Document: MESSAGE
Section: 2. STUDY AREA > 2.1 Overview
Type: text

The IHR consist of three major river systems of Indus, Ganga, and Brahmaputra, stretches over four countries viz., India, China, Nepal and Bhutan, and on the basis of physiography it has been divided into four mountain regions viz., Eastern Himalayas, Central Himalayas, Western Himalayas, and the Karakoram Mountain range. The Ganga River basin is unique in the sense that it contains 9 of the 14 highest peaks in the world over 8,000 m in height, including Mt. Everest which is the high peak of Ganga River basin. The other peaks over 8,000 m in the basin are Kanchenjunga, Lhotse, Makalu, Cho Oyu, Dhaulagiri, Manaslu, Annapurna, and Shishapangma. The Ganga River basin extends over Central Himalayas in India, Nepal, Tibet (China), and Bangladesh.

The Ganga River originates as the Bhagirathi from the Gangotri group of glaciers in the Himalayas at an elevation of about 7,010 m amsl, in the Uttarkashi district of Uttarakhand, which has been joined by the Alaknanda at Devprayag, and the combined stream assumes the name 'Ganga' (origin and confluence has been shown in Figure 1). River flows through the highly terrain mountain region and debouches into the plains at Sukhi (near Rishikesh). It is joined by a large number of tributaries on both the banks in the course of its total run of about 2,525 Km before its outfall into the Bay of Bengal. The delta of the Ganga River is said to begin at the Farakka barrage in West Bengal, where the river divides into two arms namely the Padma which flows to Bangladesh and the Ganga which flows through West Bengal. Ganga River basin from its origin to the foothills of Himalayas with a catchment area of 2,47,110 Km² is considered in the present study, which extends from latitude 26.35° N to 31.46° N and from longitude 77.05° E to 88.95° E.


Document: MESSAGE
Section: 2. STUDY AREA > 2.2 Hydrological Divide
Type: text

Major river flowing in the Ganga River basin is Yamuna, joining the main river on the right, whereas rivers like Sarda, Ghaghara, Gandak, and Kosi joining on the left. Considering hydrological setting of the aforesaid rivers, Ganga River basin is divided in 11 subbasins viz., Yamuna, Upper Ganga, Ramganga, Sarda, Ghaghara, Rapti, Gandak, Bhagmati, Kamla, Kosi, and Lower Ganga. Figure 2 shows the location of the study area with RS-2 LISS-IV satellite images. Table 1 shows the catchment area of each of the above subbasins.


Document: MESSAGE
Section: 2. STUDY AREA > 2.2 Hydrological Divide
Type: table
Table: Table 1: Details of subbasins of Ganga River basin

| S. No. | Subbasin | Area (Km²) | Area (%) |
| :--- | :--- | :--- | :--- |
| 1 | Bhagmati | 7,635 | 3.09 |
| 2 | Gandak | 36,465 | 14.76 |
| 3 | Ghaghara | 53,072 | 21.48 |
| 4 | Kamla | 6,106 | 2.47 |
| 5 | Kosi | 59,709 | 24.16 |
| 6 | Lower Ganga | 6,543 | 2.65 |
| 7 | Ramganga | 11,455 | 4.64 |
| 8 | Rapti | 11,423 | 4.62 |
| 9 | Sarda | 17,326 | 7.01 |
| 10 | Upper Ganga | 25,675 | 10.39 |
| 11 | Yamuna | 11,701 | 4.73 |
| | **Total** | **2,47,110** | **100.00** |


Document: MESSAGE
Section: 2. STUDY AREA > 2.3 Hydrology
Type: text

All the principal tributaries of the Ganga River system are fed by snow and glaciers in the upper parts of their mountainous catchments. The snow accumulation in their upper catchments usually starts from October to March months reaching peak in January/February. The river flows are at minimum during the winter months of December to March. When snow and glaciers start melting during summer months of April to June, river flows gradually increase and accelerated further by rains during July to September. The Ganga River basin carries average annual water potential of about 525 Billion Cubic Metre (BCM), of which total utilizable surface water resource in the basin is 250 BCM. The Ghaghara, Kosi, and Gandak combined carry almost half, and the Yamuna, Ramganga, and other major and minor tributaries combined constitute the remainder of the total supply of the system (Ganga Basin Report, 2014).

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 2. STUDY AREA > 2.4 Topography
Type: text

The study area mainly resides in the Central Himalayan region, which is also known as one of the main topographic division of the Indian subcontinent (Ganga Basin Report, 2014). The Central Himalayas comprises the Himalayan ranges including their numerous snow peaks rising above 7,000 m and each of these peaks is surrounded by snow fields and glaciers. All the tributaries are characterized by well regulated flows and assured supply of water throughout the year by these glaciers. The elevation of the study area ranges between 45 m and 8,848 m amsl, where glaciers and glacial lakes are mostly distributed in the higher altitude region. The mean elevation of the study area is 4,374 m amsl. Slope in the entire study area varies up to a maximum of 86.60°, while the mean slope in the Ganga River basin is 22.31°. Hypsometric curve is a graph which shows the proportion of land area that exist at various elevations by plotting relative area against relative height, as shown in Figure 3 for the study area.


Document: MESSAGE
Section: 2. STUDY AREA > 2.4 Topography
Type: figure
Figure: Figure 3: Hypsometric curve of the study area

**Figure 3: Hypsometric curve of the study area**


Document: MESSAGE
Section: 2. STUDY AREA > 2.5 Climate
Type: text

Climate over the Ganga River basin is mainly tropical and subtropical to temperate subhumid on the plains. The higher elevation zones in the Himalayan ranges especially in parts of Uttarakhand and Himachal Pradesh, experience lower temperatures than the other parts of the basin within India. Lowest annual precipitation < 500 mm is observed in the lowlands to a maximum of > 2,200 mm in upper region. The study area receives total average annual precipitation of approximately 1,200 mm. The average temperature in the basin ranges between 9°C to 40°C, where the minimum temperature is usually high mainly because of the lower plains of the basin.

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 3. DATA USED
Type: text

Earth observation satellites capture the data repeatedly in various spectral ranges and at different spatial and radiometric resolutions. For inventorying glacial lakes, high to medium resolution datasets are proved to be useful by many research studies (Bolch et al., 2010; Mergili et al., 2013; Wang et al., 2013; Zhang et al., 2015; Gupta et al., 2019, Guru et al., 2019). Data captured between September and December were mostly used because the presence of snow or cloud cover during this period is minimum. USGS satellite data of Landsat 5 and 7 (TM and ETM+) has been used widely for mapping glacial lakes due to free accessibility. Whereas, IRS satellite data from sensors of AWiFS, LISS-III, LISS-IV has also been used for such inventory.

In the present study, high resolution Resourcesat-2 LISS-IV satellite images with spatial resolution of 5.8 m covering a swath of 70 × 70 Km have been used for inventorying glacial lakes. Most of the images used for inventorying were of 2016-18 (84%) and remaining images pertain of previous years due to non-availability of cloud-free and snow-free images for the recent years. Majority of images were of September and December months (78%) due to less snow and cloud cover, and rest 22% images were of other months. Figure 4 shows the layout of the RS-2 LISS-IV scenes (path-wise) procured for the Ganga River basin along with its details in Table 2. The layout of satellite scenes is divided into paths (shown in separate colours) and rows (row numbers shown in the layout).

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 3. DATA USED
Type: table
Table: Table 2: Details of satellite scenes used for inventory

| | Other Months | Sep - Dec | Total |
|---|---|---|---|
| **Prior to 2016** | 5 | 12 | 17 |
| **2016-18** | 18 | 70 | 88 |
| **Total** | **23** | **82** | **105** |


Document: MESSAGE
Section: 3. DATA USED
Type: text

Digital Elevation Model (DEM) of Cartosat satellite with 10 m spatial resolution has been used for topographic information and watershed boundary generation. Figure 5 shows elevation range map of the study area i.e. Ganga River basin. Other information like names of lakes and rivers has been gathered from digital toposheets available from University of Texas - Toposheet Library at 1:250,000 scale and Tibet Map Institute at 1:100,000 scale (U.S. Army Map Service 1955; Andre 2017).


Document: MESSAGE
Section: 4. METHODOLOGY > 4.1 Satellite Data Interpretation
Type: text

The spectral reflectance curve of water in the visible spectrum starts with a low in Blue region (0.4 to 0.5 μm), reaches peak in Green region (0.5 to 0.6 μm), decreases in Red region (0.6 to 0.7 μm) and probably the most distinctive characteristic is the energy absorption at Near InfraRed (NIR) wavelengths. Identifying and delineating water bodies with remote sensing data are carried out easily in near infrared wavelengths because of this absorption property in IR region. However, various physical conditions of water bodies (water depth, turbidity, chlorophyll content, etc.) manifest spectral changes. As a result of various conditions of lakes, the water in satellite images in False Colour Composite (FCC) ranges in appearance from light to dark blue to black. In the case of frozen lakes, it appears white.

Glacial lake sizes are generally small, having circular, semi-circular, or elongated shapes with very fine texture and are generally associated with glaciers in high altitude areas. Certain types of glacial lakes, like erosion and cirque lakes are not necessarily associated with glaciers. Knowledge of the physical characteristics of the glacial lakes, and their associated features is always essential for the interpretation of the images.

Satellite data interpretation can be done using visual image interpretation keys such as colour, size, tone, texture, pattern, association, shape, shadow, and orientation. A number of remote sensing methods had been developed for glacial lake detection and mapping or development of inventory (Kääb 2000; Mool et al., 2001a; Huggel et al., 2002; Huggel et al., 2006; Ives et al., 2010). Manual or automated lake mapping methods have certain difficulties in identifying the lakes, which are described in the following section. An attempt was made to study the accuracy of mapping of glacial lakes using multiple automated methods along with visual interpretation, the details of which are given in Annexure-1. From this study, it was concluded that visual interpretation method was best accurate method. Hence, in the present study glacial lakes and their different types are identified and mapped using RS-2 LISS-IV multispectral images using visual interpretation method.

4. METHODOLOGY
4.1 Satellite Data Interpretation


Document: MESSAGE
Section: 4. METHODOLOGY > 4.1 Satellite Data Interpretation > Difficulties in Lake Identification:
Type: text

Glacial lake identification can be done either using visual interpretation or automatic mapping methods. The automatic mapping procedures have limitations due to varying terrain conditions like lakes situated in the shadow portions of mountains, presence of snow cover, cloud cover, and partly frozen lakes, etc. In the presence of snow cover on the glacier tongue or glacier’s ablation area where many Supra-glacial lakes may present, both methods have limitations and difficulties.

As lake water absorbs the incident radiation making it appear in darker tone and colour in the standard FCC of satellite data, similar response also prevails over shadow region of clouds or mountains on surface, which may lead to incorrect mapping. In fact, a mountain shadow covering a lake partly/completely within its vicinity, making it difficult to accurately map the lake boundary.

Many lakes due to inclement terrain condition, can be under shadow of high peaks and will get missed in both ways of mapping. On the contrary, a lake can also present in white colour while it is in frozen form due to cold weather conditions over the area, then definitely it will not get classified when mapped with automatic algorithm. Whereas, frozen lakes can be identified and mapped using visual interpretation to some extent.

4. METHODOLOGY
4.1 Satellite Data Interpretation
Difficulties in Lake Identification:


Document: MESSAGE
Section: 4. METHODOLOGY > 4.1 Satellite Data Interpretation > Challenges in Automatic Mapping:
Type: text

In the IHR, due to high and inclement terrain surface and due to near vertical acquisition of satellite images, some lakes get covered with shadows of mountains, which create problems in identifying glacial lakes. Also identification of lakes with high turbidity, partial ice covered lakes and the lakes in shadow areas are misclassified by automatic methods. Glacial lake mapping is always a semi-automatic approach because even after applying any of that methods, it should always be followed by the post processing i.e. correcting the errors using visual interpretation. Even in all cases, automatic mapping will never give the exact and accurate boundary of the lake, leading to necessary manual corrections.

4. METHODOLOGY
4.1 Satellite Data Interpretation
Challenges in Automatic Mapping:


Document: MESSAGE
Section: 4. METHODOLOGY > 4.1 Satellite Data Interpretation > Reasoning for Visual Interpretation:
Type: text

Although automatic mapping methods can speed up the detection of glacial lakes, but these methods could not be applied to the entire Himalayan region due to lot of variations in satellite scenes (seasons/years) and problems mentioned above. For example, if lakes are frozen or covered with snow or cloud and lies in a shadow area, they cannot be detected using these automatic methods. In such cases, the manual interpretation method will be helpful to map these lakes. Thus, any mapping of glacial lakes can be automated up to a certain extent only. So, visual image interpretation keys and technique will give accurate results and avoids misclassification. Therefore, in this present study, glacial lakes and its type identification, and its mapping for the entire Ganga River basin (within IHR) has been done manually using visual interpretation. High resolution satellite data available on Bhuvan/Google Earth has been used on need basis in finalizing various features of glacial lake database.

4. METHODOLOGY
4.1 Satellite Data Interpretation
Reasoning for Visual Interpretation:


Document: MESSAGE
Section: 4. METHODOLOGY > 4.1 Satellite Data Interpretation > Limitations:
Type: text

The RS-2 LISS-IV MX data used for glacial lake database preparation sporadically covered with cloud and seasonal/permanent snow. Also, the Himalayan region being highly varying topography with steep slopes, the satellite data has hill shadows. Thus few glacial lakes would not have been mapped owing to the following constraints:

* Presence of snow or cloud over the glacial lakes
* Glacial lakes under frozen condition
* Glacial lakes under mountain shadow

4. METHODOLOGY
4.1 Satellite Data Interpretation
Limitations:


Document: MESSAGE
Section: 4. METHODOLOGY > 4.2 Types of Glacial Lake
Type: text

Various researchers have proposed glacial lakes classification schemes based on dam type, process of lake formation, topographic feature, and geographical position (Hewitt 1982; Liu and Sharma 1988; Clague and Evans 2000; Mool et al., 2001a, 2001b). Lakes located on the glacier surface can be mapped using satellite data, but there are englacial and subglacial lakes that may also exist, but cannot be mapped from aerial/optical satellite images, requires ground based instrument (Yao et al., 2018). Majorly surface glacial lakes are classified in 4 classes and 10 subclasses, i.e. Moraine-dammed lake, Ice-dammed lake, Glacier Erosion lake (also known as Bed-rock lake), and Other Glacial lake. Two character symbol has been used for glacial lake classification, in

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

which first letter (uppercase) represents lake type and second letter (lowercase) within brackets represents lake subtype, for example, M(e) for End-moraine dammed lake. Details of types of lakes are given in Table 3 and their appearance in satellite images are shown in Figure 6.

4. METHODOLOGY
4.2 Types of Glacial Lake


Document: MESSAGE
Section: 4. METHODOLOGY > 4.2 Types of Glacial Lake
Type: table
Table: Table 3: Glacial lake types and their identification keys

| S.No. | Lake Type | Lake Subtype | Code | Identification Keys |
| :--- | :--- | :--- | :--- | :--- |
| 1 | Moraine-dammed Lake | End-moraine Dammed Lake | M(e) | Lake dammed by end (terminal) moraines |
| 2 | Moraine-dammed Lake | Lateral Moraine Dammed Lake | M(l) | Lake dammed by lateral moraine(s) not in contact with glacial ice |
| 3 | Moraine-dammed Lake | Lateral Moraine Dammed Lake (with Ice) | M(lg) | Lake dammed by lateral moraine(s) in contact with glacial ice |
| 4 | Moraine-dammed Lake | Other Moraine Dammed Lake | M(o) | Lake dammed by other moraines |
| 5 | Ice-dammed Lake | Supra-glacial Lake | I(s) | Pond or lake on the surface of a glacier |
| 6 | Ice-dammed Lake | Glacier Ice-dammed Lake | I(d) | Lake dammed by glacier ice with no lateral moraines |
| 7 | Glacier Erosion Lake | Cirque Erosion Lake | E(c) | A small pond occupying a cirque |
| 8 | Glacier Erosion Lake | Glacier Trough Valley Erosion Lake | E(v) | Lakes formed in the glacier trough as a result of the glacier erosion process |
| 9 | Glacier Erosion Lake | Other Glacial Erosion Lake | E(o) | Bodies of water occupying depressions formed by the glacial erosion process |
| 10 | Other Glacial Lake | Other Glacial Lake | O | Lakes formed in a glaciated valley, and fed by glacial melt, but damming material not directly part of the glacial process |

S.No.
Lake Type
Lake Subtype
Code
Identification Keys


Document: MESSAGE
Section: 4. METHODOLOGY > 4.2 Types of Glacial Lake
Type: text

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 4. METHODOLOGY > 4.3 Lake Attribute Information
Type: text

A total of 22 attributes has been given to all mapped lake features in the geodatabase, which are broadly consisting information grouped in five different categories as shows in Table 4.

4. METHODOLOGY
4.3 Lake Attribute Information


Document: MESSAGE
Section: 4. METHODOLOGY > 4.3 Lake Attribute Information
Type: table
Table: Table 4: Details of glacial lake attributes

| S.No. | Category | Attribute |
| :--- | :--- | :--- |
| 1 | Hydrological | Basin, subbasin, river, lake name |
| 2 | Geometrical | Maximum length, mean width, surface area |
| 3 | Geographical | Latitude, longitude, region, state, district, toposheet 250k, toposheet 50k |
| 4 | Topographical | Elevation, aspect |
| 5 | Lake Information | Feature types, glacial lake type, lake ID |
| 6 | Data Source Information | Source of database, source of elevation, date of pass |


Document: MESSAGE
Section: 4. METHODOLOGY > 4.3 Lake Attribute Information
Type: text

Typically, lake ID is given in 12 alpha-numeric character format like “0253N1300271”, where first two digits ‘02’ refers to Basin code which is Ganga (01-Indus and 03-Brahmaputra), next five characters ‘53N13’refers to the 1:250,000 (53N) and 1:50,000 (53N13) scale SOI Toposheet number, and the last five digits refers to the sequential number of each lake sorted from top left to bottom right. A typical example of the glacial lake database generated is given below in Table 5 along with fields and format.


Document: MESSAGE
Section: 4. METHODOLOGY > 4.3 Lake Attribute Information
Type: table
Table: Table 5: Typical example of glacial lake attribute database

| S.No. | Database Fields | Type | Format / Unit | Lake Attribute |
| :--- | :--- | :--- | :--- | :--- |
| 1 | ID No | String | Text | 0253N1300271 |
| 2 | Toposheet 250K | String | Text | 53N |
| 3 | Toposheet 50K | String | Text | 53N13 |
| 4 | Latitude* | Float | Decimal Degree | 30.901 |
| 5 | Longitude* | Float | Decimal Degree | 79.754 |
| 6 | Basin | String | Text | Ganga |
| 7 | Subbasin | String | Text | Upper Ganga |
| 8 | River | String | Text | Dhauliganga River |
| 9 | Type (GL/WB) | String | Text | Glacial Lake |
| 10 | Name | String | Text | Basudhara Tal |
| 11 | Glacial Lake Type | String | Text | M(e): End-moraine Dammed Lake |
| 12 | Surface Area | Float | ha | 22.035 |
| 13 | Length | Float | Km | 0.791 |
| 14 | Mean Width | Float | Km | 0.270 |
| 15 | Elevation* | Integer | m (amsl) | 4677 |
| 16 | Aspect | String | Text | SE |
| 17 | Source of Database | String | Text | RS-2 LISS-IV |
| 18 | Date of Pass | Date | DDMMYYYY | 20112016 |
| 19 | Source of Elevation | String | Text | Cartosat DEM |
| 20 | Region | String | Text | India |
| 21 | State | String | Text | Uttarakhand |
| 22 | District | String | Text | Chamoli |

S.No.
Database Fields
Type
Format / Unit
Lake Attribute


Document: MESSAGE
Section: 4. METHODOLOGY > 4.3 Lake Attribute Information
Type: text

\* Latitude, longitude, and elevation has been taken at the centroid of the lake

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 5. RESULTS
Type: text

The mapped glacial lakes are analyzed for their distribution in terms of area, type, and elevation, at basin, subbasin, administrative and transboundary level. Area of mapped glacial lakes is ranging from a minimum of 0.25 ha to a maximum of 540.55 ha. Details of glacial lakes inventoried for the Ganga River basin is given in Annexure-II. The results are discussed in subsequent sections:


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics
Type: text

**Area range-wise Distribution**

A total of 4,707 glacial lakes (≥ 0.25 ha) were identified and mapped using RS-2 LISS-IV images for the entire Ganga River basin, with a total lake water spread area of 20,685.12 ha. Glacial lakes has been distributed in 6 different classes of area ranges viz., 0.25 - 0.5 ha, 0.5 - 1 ha, 1 - 5 ha, 5 - 10 ha, 10 - 50 ha and ≥ 50 ha, where area ranges indicate values ranging from the lower value (including) up to the upper value (excluding), for ex: 0.25 - 0.5 ha range include values ranging from 0.25 ha up to < 0.5 ha. Table 6 and Figure 7 shows the area range-wise distribution for the entire basin. About 4,035 (85.72%) lakes are with < 5 ha lake area contributing to 23.13% of total lake area. The remaining lakes with ≥ 5 ha in size are 672 (14.28%) contributing to 76.87% of total lake area in the basin. Details of lakes ≥ 50 ha is given in Annexure-III.

5. RESULTS
5.1 Ganga Basin Level Statistics


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics
Type: table
Table: Table 6: Area range-wise distribution of Glacial Lakes (GL) in Ganga River basin

| S. No. | Lake Area Range (ha) | No. of Lakes | Total Lake Area (ha) | Total Lake Area (%) |
| :--- | :--- | :--- | :--- | :--- |
| 1 | 0.25 - 0.5 | 1,279 | 452.30 | 2.19 |
| 2 | 0.5 - 1 | 1,157 | 824.04 | 3.98 |
| 3 | 1 - 5 | 1,599 | 3,508.94 | 16.96 |
| 4 | 5 - 10 | 315 | 2,184.89 | 10.56 |
| 5 | 10 - 50 | 299 | 5,938.21 | 28.71 |
| 6 | ≥ 50 | 58 | 7,776.74 | 37.60 |
| | **Total** | **4,707** | **20,685.12** | **100.00** |

S. No.
Lake Area Range (ha)
No. of Lakes
Total Lake Area (ha)
Total Lake Area (%)


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics
Type: text

***

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Type-wise Distribution**

Distribution of different types of glacial lake in the entire Ganga River basin is given in Table 7 and Figure 8. Out of 10 types of lake described in the previous section, 9 types of lake are present in the basin except Glacier Trough Valley Erosion Lake (Ev). Amongst 9 types of glacial lake, Other Glacial Erosion lake is found to be the maximum with 1,744 (37.05%) occupying a total lake extent of 4,612.02 ha at 22.30% in the basin. Two other types of lake, namely, Other Moraine Dammed and Supra-glacial lakes are 1,740 (36.97%) and 617 (13.11%), extend over an area of 4,489.35 ha (21.70%) and 566.14 ha (2.74%) respectively.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics
Type: table
Table: Table 7: Type-wise distribution of GL in Ganga River basin

| S. No. | Code | Types of Glacial Lake | No. of Lakes | Total Lake Area (ha) | Total Lake Area (%) |
| :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | M(e) | End-moraine Dammed Lake | 260 | 8,591.78 | 41.53 |
| 2 | M(l) | Lateral Moraine Dammed Lake | 100 | 568.12 | 2.75 |
| 3 | M(lg) | Lateral Moraine Dammed Lake with Ice | 9 | 5.48 | 0.03 |
| 4 | M(o) | Other Moraine Dammed Lake | 1,740 | 4,489.35 | 21.70 |
| 5 | I(s) | Supra-glacial Lake | 617 | 566.14 | 2.74 |
| 6 | I(d) | Glacier Ice-dammed Lake | 1 | 2.45 | 0.01 |
| 7 | E(c) | Cirque Erosion Lake | 123 | 973.77 | 4.71 |
| 8 | E(o) | Other Glacial Erosion Lake | 1,744 | 4,612.02 | 22.30 |
| 9 | O | Other Glacial Lake | 113 | 876.01 | 4.23 |
| | | **Total** | **4,707** | **20,685.12** | **100.00** |

S. No.
Code
Types of Glacial Lake
No. of Lakes
Total Lake Area (ha)
Total Lake Area (%)


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics
Type: text

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Area range-Type-wise Distribution
Type: text

Glacial lake distribution by area range vs. type-wise is given in Table 8 and Figure 9. The lakes with < 5 ha in size (85.72%) are dominant with Other Moraine Dammed lake type (38.74%) followed by Other Glacial Erosion (38.64%) and Supra-glacial lake (14.94%). The lakes with ≥ 5 ha (14.28%) are dominated by Other Glacial Erosion lakes (27.53%) followed by End-moraine Dammed lake (27.23%) and Other Moraine Dammed lake (26.34%). All types of Moraine-dammed glacial lakes, which constitute about 44.81% are predominantly with < 5 ha in water spread.

5. RESULTS
5.1 Ganga Basin Level Statistics
Area range-Type-wise Distribution


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Area range-Type-wise Distribution
Type: table
Table: Table 8: Area range-wise vs. Type-wise distribution of GL in Ganga River basin

| S. No. | Lake Area Range (ha) | M(e) | M(l) | M(lg) | M(o) | I(s) | I(d) | E(c) | E(o) | O | Total |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | 0.25 - 0.5 | 5 | 22 | 4 | 462 | 354 | 0 | 4 | 400 | 28 | 1,279 |
| 2 | 0.5 - 1 | 12 | 24 | 4 | 484 | 166 | 0 | 5 | 433 | 29 | 1,157 |
| 3 | 1 - 5 | 60 | 35 | 1 | 617 | 83 | 1 | 49 | 726 | 27 | 1,599 |
| 4 | 5 - 10 | 41 | 6 | 0 | 106 | 6 | 0 | 34 | 115 | 7 | 315 |
| 5 | 10 - 50 | 100 | 9 | 0 | 68 | 8 | 0 | 31 | 65 | 18 | 299 |
| 6 | ≥ 50 | 42 | 4 | 0 | 3 | 0 | 0 | 0 | 5 | 4 | 58 |
| | **Total** | **260** | **100** | **9** | **1,740** | **617** | **1** | **123** | **1,744** | **113** | **4,707** |

S. No.
Lake Area Range (ha)
M(e)
M(l)
M(lg)
M(o)
I(s)
I(d)
E(c)
E(o)
O
Total


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Area range-Type-wise Distribution
Type: text

***

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: text

Elevation ranges over the entire study area has been classified into four different categories viz., low altitude (up to 3,000 m), medium altitude (3,001 - 4,000 m), high altitude (4,001 - 5,000 m), and very high altitude (> 5,000 m). Table 9 and Figure 10 shows the distribution of the glacial lakes in the Ganga River basin as per elevation range-wise. Majority of glacial lakes are situated above 4,000 m elevation i.e. 4,644 (98.66%) with total lake area of 20,451.70 ha (98.87%) and remaining 1.34% glacial lakes are below 4,001 m elevation.

5. RESULTS
5.1 Ganga Basin Level Statistics
Elevation range-wise Distribution


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: table
Table: Table 9: Elevation range-wise distribution of GL in Ganga River basin

| S. No. | Elevation Range (m) | No. of Lakes | Total Lake Area (ha) | Total Lake Area (%) |
| :--- | :--- | :--- | :--- | :--- |
| 1 | up to 3,000 | 1 | 9.87 | 0.05 |
| 2 | 3,001 - 4,000 | 62 | 223.55 | 1.08 |
| 3 | 4,001 - 5,000 | 1,855 | 7,374.89 | 35.65 |
| 4 | > 5,000 | 2,789 | 13,076.81 | 63.22 |
| | **Total** | **4,707** | **20,685.12** | **100.00** |

S. No.
Elevation Range (m)
No. of Lakes
Total Lake Area (ha)
Total Lake Area (%)


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: text

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Area-Elevation range-wise Distribution**

Glacial lake distribution has been analyzed as per area range vs. elevation range-wise, given in Table 10 and Figure 11. It is noted that, about 59.25% of glacial lakes (2,789) are situated in very high altitude range i.e. > 5,000 m amsl, which also constitutes maximum total lake area within that range i.e 63.22%. However, very few glacial lakes (63) lies up to 4,000 m amsl, has maximum of its lakes with 0.25 - 0.5 ha lake area range. Figure 11 shows that maximum of lakes lying in very high altitude range is of size ranging 1 - 5 ha (i.e. 928), followed by lakes in high altitude range within in 1 - 5 ha (i.e. 659).


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: table
Table: Table 10: Area range-wise vs. Elevation range-wise distribution of GL in Ganga River basin

| S. No. | Lake Area Range (ha) | Elevation Range (m) up to 3,000 - No. of lakes | Elevation Range (m) up to 3,000 - Total Lake Area (ha) | Elevation Range (m) 3,001 - 4,000 - No. of lakes | Elevation Range (m) 3,001 - 4,000 - Total Lake Area (ha) | Elevation Range (m) 4,001 - 5,000 - No. of lakes | Elevation Range (m) 4,001 - 5,000 - Total Lake Area (ha) | Elevation Range (m) > 5,000 - No. of lakes | Elevation Range (m) > 5,000 - Total Lake Area (ha) | Total - No. of lakes | Total - Lake Area (ha) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 0.25 - 0.5 | 0 | 0.00 | 21 | 6.90 | 486 | 173.33 | 772 | 272.07 | 1,279 | 452.30 |
| 2 | 0.5 - 1 | 0 | 0.00 | 17 | 12.44 | 426 | 305.22 | 714 | 506.38 | 1,157 | 824.04 |
| 3 | 1 - 5 | 0 | 0.00 | 12 | 33.16 | 659 | 1,465.56 | 928 | 2,010.22 | 1,599 | 3,508.94 |
| 4 | 5 - 10 | 1 | 9.87 | 5 | 34.15 | 137 | 967.00 | 172 | 1,173.87 | 315 | 2,184.89 |
| 5 | 10 - 50 | 0 | 0.00 | 7 | 136.90 | 128 | 2,392.37 | 164 | 3,408.94 | 299 | 5,938.21 |
| 6 | ≥ 50 | 0 | 0.00 | 0 | 0.00 | 19 | 2,071.42 | 39 | 5,705.32 | 58 | 7,776.74 |
| | **Total** | **1** | **9.87** | **62** | **223.55** | **1,855** | **7,374.90** | **2,789** | **13,076.80** | **4,707** | **20,685.12** |


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: figure
Figure: Figure 11: Area range-wise vs. Elevation range-wise distribution of GL in Ganga River basin

**Figure 11: Area range-wise vs. Elevation range-wise distribution of GL in Ganga River basin**


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: text

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Type-Elevation range-wise Distribution**

Glacial lake distribution has been analyzed as per type-wise vs. elevation range-wise, given in Table 11 and Figure 12. The dominant lake type in the basin i.e. Other Glacial Erosion lake (37.05%) is predominantly located in the elevation range of 4,001 - 5,000 m (52.18%). The two other dominant lake types, namely, Other Moraine Dammed and Supra-glacial lake are mostly distributed in both > 5,000 m and 4,001 - 5,000 m elevation ranges. 75.82% of Moraine-dammed glacial lakes, which constitute 44.81% of the total lakes, lies in the very high altitude range of > 5,000 m amsl. Elevation range-type-wise spatial distribution of glacial lakes has been represented in Figure 13.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: table
Table: Table 11: Type-wise vs. Elevation range-wise distribution of GL in Ganga River basin

| S. No. | Elevation Range (m) | Types of Glacial Lake - M(e) | Types of Glacial Lake - M(l) | Types of Glacial Lake - M(lg) | Types of Glacial Lake - M(o) | Types of Glacial Lake - I(s) | Types of Glacial Lake - I(d) | Types of Glacial Lake - E(c) | Types of Glacial Lake - E(o) | Types of Glacial Lake - O | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | up to 3,000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 |
| 2 | 3,001 - 4,000 | 3 | 1 | 0 | 8 | 14 | 0 | 1 | 23 | 12 | 62 |
| 3 | 4,001 - 5,000 | 77 | 54 | 1 | 366 | 286 | 0 | 93 | 910 | 68 | 1,855 |
| 4 | > 5,000 | 180 | 45 | 8 | 1,366 | 317 | 1 | 29 | 810 | 33 | 2,789 |
| | **Total** | **260** | **100** | **9** | **1,740** | **617** | **1** | **123** | **1,744** | **113** | **4,707** |

S. No.
Elevation Range (m)
Types of Glacial Lake - M(e)
Types of Glacial Lake - M(l)
Types of Glacial Lake - M(lg)
Types of Glacial Lake - M(o)
Types of Glacial Lake - I(s)
Types of Glacial Lake - I(d)
Types of Glacial Lake - E(c)
Types of Glacial Lake - E(o)
Types of Glacial Lake - O
Total


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: figure
Figure: Figure 12: Type-wise vs. Elevation range-wise distribution of GL in Ganga River basin

**Figure 12: Type-wise vs. Elevation range-wise distribution of GL in Ganga River basin**


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: text

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Area range-wise Distribution**

In Gandak subbasin, glacial lakes has been distributed in all 6 different classes of area ranges. Table 12 and Figure 15 shows the area range-wise distribution of glacial lakes for the Gandak subbasin. About 551 (88.30%) lakes are with < 5 ha lake area contributing to 31.97% of total lake area. The remaining lakes with ≥ 5 ha in size are only 73 (11.70%) but contributing to 68.03% of total lake area in the subbasin.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: table
Table: Table 12: Area range-wise distribution of GL in Gandak subbasin

| S. No. | Lake Area Range (ha) | No. of Lakes | Total Lake Area (ha) | Total Lake Area (%) |
|---|---|---|---|---|
| 1 | 0.25 - 0.5 | 189 | 66.76 | 3.50 |
| 2 | 0.5 - 1 | 157 | 109.48 | 5.72 |
| 3 | 1 - 5 | 205 | 435.25 | 22.75 |
| 4 | 5 - 10 | 36 | 242.86 | 12.70 |
| 5 | 10 - 50 | 35 | 628.84 | 32.87 |
| 6 | ≥ 50 | 2 | 429.65 | 22.46 |
| | **Total** | **624** | **1,912.84** | **100.00** |


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: text

***

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Type-wise Distribution**

Distribution of different types of glacial lake in the Gandak subbasin is given in Table 13 and Figure 16. All 9 types of glacial lake are present in the Gandak subbasin, where Other Moraine Dammed lake is found to be the maximum with 312 (50.00%) occupying a total lake extent of 897.92 ha at 46.94% in the subbasin. Other Glacial Erosion lakes are second majority of lakes i.e. 125 (20.03%) and extend over an area of 259.63 ha (13.57%).


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: table
Table: Table 13: Type-wise distribution of GL in Gandak subbasin

| S. No. | Code | Types of Glacial Lake | No. of Lakes | Total Lake Area (ha) | Total Lake Area (%) |
|---|---|---|---|---|---|
| 1 | M(e) | End-moraine Dammed Lake | 37 | 491.14 | 25.68 |
| 2 | M(l) | Lateral Moraine Dammed Lake | 18 | 54.64 | 2.85 |
| 3 | M(lg) | Lateral Moraine Dammed Lake with Ice | 6 | 3.00 | 0.16 |
| 4 | M(o) | Other Moraine Dammed Lake | 312 | 897.92 | 46.94 |
| 5 | I(s) | Supra-glacial Lake | 101 | 80.91 | 4.23 |
| 6 | I(d) | Glacier Ice-dammed Lake | 1 | 2.45 | 0.13 |
| 7 | E(c) | Cirque Erosion Lake | 4 | 31.79 | 1.66 |
| 8 | E(o) | Other Glacial Erosion Lake | 125 | 259.63 | 13.57 |
| 9 | O | Other Glacial Lake | 20 | 91.36 | 4.78 |
| | | **Total** | **624** | **1,912.84** | **100.00** |


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Area range-Type-wise Distribution
Type: text

Glacial lake distribution by area range vs. type-wise is given in Table 14 and Figure 17. The lakes with < 5 ha in size (88.30%) are dominated by Other Moraine Dammed (51.91%) followed by Other Glacial Erosion type (20.33%). Lakes with ≥ 5 ha (11.70%) are dominated by Other Moraine Dammed (35.62%) followed by End-moraine Dammed type (30.14%). All types of Moraine-dammed lakes, which constitute about 59.78% are predominantly with < 5 ha in water spread.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Area range-Type-wise Distribution
Type: table
Table: Table 14: Area range-wise vs. Type-wise distribution of GL in Gandak subbasin

| S. No. | Lake Area Range (ha) | Types of Glacial Lake - M(e) | Types of Glacial Lake - M(l) | Types of Glacial Lake - M(lg) | Types of Glacial Lake - M(o) | Types of Glacial Lake - I(s) | Types of Glacial Lake - I(d) | Types of Glacial Lake - E(c) | Types of Glacial Lake - E(o) | Types of Glacial Lake - O | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 0.25 - 0.5 | 1 | 4 | 4 | 85 | 59 | 0 | 0 | 35 | 1 | 189 |
| 2 | 0.5 - 1 | 0 | 6 | 2 | 89 | 25 | 0 | 0 | 28 | 7 | 157 |
| 3 | 1 - 5 | 14 | 6 | 0 | 112 | 15 | 1 | 2 | 49 | 6 | 205 |
| 4 | 5 - 10 | 6 | 0 | 0 | 17 | 1 | 0 | 1 | 9 | 2 | 36 |
| 5 | 10 - 50 | 15 | 2 | 0 | 8 | 1 | 0 | 1 | 4 | 4 | 35 |
| 6 | ≥ 50 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 2 |
| | **Total** | **37** | **18** | **6** | **312** | **101** | **1** | **4** | **125** | **20** | **624** |

S. No.
Lake Area Range (ha)
Types of Glacial Lake - M(e)
Types of Glacial Lake - M(l)
Types of Glacial Lake - M(lg)
Types of Glacial Lake - M(o)
Types of Glacial Lake - I(s)
Types of Glacial Lake - I(d)
Types of Glacial Lake - E(c)
Types of Glacial Lake - E(o)
Types of Glacial Lake - O
Total


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: text

Elevation range-wise distribution of the glacial lakes in the Gandak subbasin has been shown in Table 15 and Figure 18. Majority of glacial lakes are situated above 4,000 m elevation i.e. 601 (96.31%) with total lake area of 1,834.70 ha (95.91%) and remaining 3.69% glacial lakes are below 4,001 m elevation.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: table
Table: Table 15: Elevation range-wise distribution of GL in Gandak subbasin

| S. No. | Elevation Range (m) | No. of Lakes | Total Lake Area (ha) | Total Lake Area (%) |
|---|---|---|---|---|
| 1 | up to 3,000 | 1 | 9.87 | 0.52 |
| 2 | 3,001 - 4,000 | 22 | 68.27 | 3.57 |
| 3 | 4,001 - 5,000 | 220 | 1,060.56 | 55.44 |
| 4 | > 5,000 | 381 | 774.14 | 40.47 |
| | **Total** | **624** | **1,912.84** | **100.00** |


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > Elevation range-wise Distribution
Type: text

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

***

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: text

The Ghaghara subbasin is the second largest subbasin of the Ganga basin covering a total area of 53,072 Km² i.e. 21.48% of the total basin area (Figure 22). Karnal and Bheri are the two major tributaries of the subbasin and after their confluence the river assumes the name ‘Ghaghara’. Karnal River is the largest river draining into the river Ghaghara, which has many various tributaries viz., Humla, Mugu, Tila, and West Seti. The West Seti River rises near Api mountain peak and flows in south-easterly direction to join the Karnal. The Bheri River rises in the higher reaches of Dhaulagiri massif and drain into the mainstream in the lower hills of Nepal. A total of 1,260 glacial lakes has been mapped, covering a total area of 3,536.39 ha i.e. 0.06% of the total area of the subbasin.

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Area range-wise Distribution**

In Ghaghara subbasin, glacial lakes have been distributed in all 6 classes of area ranges. Table 18 and Figure 23 shows the area range-wise distribution of glacial lakes for the Ghaghara subbasin. About 1,090 (86.51%) lakes are with < 5 ha lake area contributing to 36.66% of total lake area. The remaining lakes with ≥ 5 ha in size are only 170 (13.49%) contributing to 63.34% of total lake area in the subbasin.

5. RESULTS
5.1 Ganga Basin Level Statistics
5.2.2 Ghaghra Subbasin


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: table
Table: Table 18: Area range-wise distribution of GL in Ghaghara subbasin

| S. No. | Lake Area Range (ha) | No. of Lakes | Total Lake Area (ha) | Total Lake Area (%) |
|---|---|---|---|---|
| 1 | 0.25 - 0.5 | 334 | 118.99 | 3.36 |
| 2 | 0.5 - 1 | 321 | 232.49 | 6.57 |
| 3 | 1 - 5 | 435 | 945.22 | 26.73 |
| 4 | 5 - 10 | 84 | 594.54 | 16.81 |
| 5 | 10 - 50 | 84 | 1,507.18 | 42.63 |
| 6 | ≥ 50 | 2 | 137.97 | 3.90 |
| | **Total** | **1,260** | **3,536.39** | **100.00** |


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: figure
Figure: Figure 23: Area range-wise distribution of GL in Ghaghara subbasin

**Figure 23: Area range-wise distribution of GL in Ghaghara subbasin**


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: text

***

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Type-wise Distribution**

Distribution of different types of glacial lake in the Ghaghara subbasin is given in Table 19 and Figure 24. Out of 9 types of glacial lake, 8 types of lake are present in the Ghaghara subbasin, where Other Glacial Erosion lakes are found to be the maximum with 549 (43.57%) occupying a total lake extent of 1,284.57 ha at 36.32% in the subbasin. After that, Other Moraine Dammed lakes are in majority with 485 (38.49%) and extend over a total area of 880.87 ha (24.91%). All Moraine-dammed lakes constitute about 45.71% of all lakes in the subbasin.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: table
Table: Table 19: Type-wise distribution of GL in Ghaghara subbasin

| S.No. | Code | Types of Glacial Lake | No. of Lakes | Total Lake Area (ha) | Total Lake Area (%) |
|---|---|---|---|---|---|
| 1 | M(e) | End-moraine Dammed Lake | 61 | 710.41 | 20.10 |
| 2 | M(l) | Lateral Moraine Dammed Lake | 27 | 158.60 | 4.48 |
| 3 | M(lg) | Lateral Moraine Dammed Lake with Ice | 3 | 2.48 | 0.07 |
| 4 | M(o) | Other Moraine Dammed Lake | 485 | 880.87 | 24.91 |
| 5 | I(s) | Supra-glacial Lake | 73 | 45.27 | 1.28 |
| 6 | I(d) | Glacier Ice-dammed Lake | 0 | 0.00 | 0.00 |
| 7 | E(c) | Cirque Erosion Lake | 27 | 311.33 | 8.80 |
| 8 | E(o) | Other Glacial Erosion Lake | 549 | 1,284.57 | 36.32 |
| 9 | O | Other Glacial Lake | 35 | 142.86 | 4.04 |
| | | **Total** | **1,260** | **3,536.39** | **100.00** |

S.No.
Code
Types of Glacial Lake
No. of Lakes
Total Lake Area (ha)
Total Lake Area (%)


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: figure
Figure: Figure 24: Type-wise distribution of GL in Ghaghara subbasin

**Figure 24: Type-wise distribution of GL in Ghaghara subbasin**


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: text

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Area range-Type-wise Distribution**

Glacial lake distribution by area range vs. type-wise is given in Table 20 and Figure 25. The lakes with < 5 ha in size (86.51%) are dominant with Other Glacial Erosion (44.59%) and Other Moraine Dammed lakes (41.19%). Lakes with ≥ 5 ha (13.49%) are also dominated by Other Glacial Erosion type (37.06%). All types of Glacier Erosion lake, which constitute about 45.71% are predominantly with < 5 ha in water spread.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: table
Table: Table 20: Area range-wise vs. Type-wise distribution of GL in Ghaghara subbasin

| S. No. | Lake Area Range (ha) | M(e) | M(l) | M(lg) | M(o) | I(s) | I(d) | E(c) | E(o) | O | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 0.25 - 0.5 | 2 | 7 | 0 | 133 | 43 | 0 | 1 | 139 | 9 | 334 |
| 2 | 0.5 - 1 | 6 | 6 | 2 | 152 | 21 | 0 | 0 | 124 | 10 | 321 |
| 3 | 1 - 5 | 14 | 7 | 1 | 164 | 9 | 0 | 8 | 223 | 9 | 435 |
| 4 | 5 - 10 | 13 | 3 | 0 | 21 | 0 | 0 | 8 | 38 | 1 | 84 |
| 5 | 10 - 50 | 25 | 3 | 0 | 15 | 0 | 0 | 10 | 25 | 6 | 84 |
| 6 | ≥ 50 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 |
| | **Total** | **61** | **27** | **3** | **485** | **73** | **0** | **27** | **549** | **35** | **1,260** |


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: text

***

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Elevation range-wise Distribution**

Elevation range-wise distribution of the glacial lakes in the Ghaghara subbasin has been shown in Table 21 and Figure 26. Majority of glacial lakes are situated above 4,000 m elevation range i.e. 1,252 (99.36%) with total lake area of 3,477.48 ha (98.33%) and remaining 0.64% glacial lakes are below 4,001 m elevation.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: table
Table: Table 21: Elevation range-wise distribution of GL in Ghaghara subbasin

| S. No. | Elevation Range (m) | No. of Lakes | Total Lake Area (ha) | Total Lake Area (%) |
|---|---|---|---|---|
| 1 | up to 3,000 | 0 | 0.00 | 0.00 |
| 2 | 3,001 - 4,000 | 8 | 58.91 | 1.67 |
| 3 | 4,001 - 5,000 | 563 | 1,842.89 | 52.11 |
| 4 | > 5,000 | 689 | 1,634.59 | 46.22 |
| | **Total** | **1,260** | **3,536.39** | **100.00** |


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: text

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Area-Elevation range-wise Distribution**

Glacial lake distribution has been analyzed as per area range vs. elevation range-wise, given in Table 22 and Figure 27. It is noted that, 54.68% of glacial lakes (689) are situated in very high altitude range i.e. > 5,000 m amsl, which constitutes a total lake area of 46.22%. However, majority of glacial lakes (614) of size < 5 ha lies above 5,000 m. 83.66% of lakes lying in high altitude range are < 5 ha, predominantly of size ranging 1 - 5 ha (i.e. 207), followed by lakes of size 0.25 - 0.5 ha (i.e. 148). It has been further noticed that, 54.12% of lakes ≥ 5 ha are lying within high altitude range i.e. 4,001 - 5,000 m, majority of them falling in size range of 10 - 50 ha.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: table
Table: Table 22: Area range-wise vs. Elevation range-wise distribution of GL in Ghaghara subbasin

| S. No. | Lake Area Range (ha) | Elevation Range (m) - up to 3,000 - No. of Lakes | Elevation Range (m) - up to 3,000 - Total Lake Area (ha) | Elevation Range (m) - 3,001 - 4,000 - No. of Lakes | Elevation Range (m) - 3,001 - 4,000 - Total Lake Area (ha) | Elevation Range (m) - 4,001 - 5,000 - No. of Lakes | Elevation Range (m) - 4,001 - 5,000 - Total Lake Area (ha) | Elevation Range (m) - > 5,000 - No. of Lakes | Elevation Range (m) - > 5,000 - Total Lake Area (ha) | Total - No. of Lakes | Total - Lake Area (ha) |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | 0.25 - 0.5 | 0 | 0.00 | 0 | 0.00 | 148 | 53.23 | 186 | 65.76 | 334 | 118.99 |
| 2 | 0.5 - 1 | 0 | 0.00 | 4 | 2.98 | 116 | 83.46 | 201 | 146.04 | 321 | 232.49 |
| 3 | 1 - 5 | 0 | 0.00 | 1 | 1.68 | 207 | 465.99 | 227 | 477.55 | 435 | 945.22 |
| 4 | 5 - 10 | 0 | 0.00 | 1 | 8.93 | 44 | 302.77 | 39 | 282.84 | 84 | 594.54 |
| 5 | 10 - 50 | 0 | 0.00 | 2 | 45.31 | 47 | 875.12 | 35 | 586.75 | 84 | 1,507.18 |
| 6 | ≥ 50 | 0 | 0.00 | 0 | 0.00 | 1 | 62.33 | 1 | 75.65 | 2 | 137.97 |
| | **Total** | **0** | **0.00** | **8** | **58.90** | **563** | **1,842.90** | **689** | **1,634.59** | **1,260** | **3,536.39** |


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: figure
Figure: Figure 27: Area range-wise vs. Elevation range-wise distribution of GL in Ghaghara subbasin

**Figure 27: Area range-wise vs. Elevation range-wise distribution of GL in Ghaghara subbasin**


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: text

***

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

**Type-Elevation range-wise Distribution**

Glacial lake distribution has also been analyzed as per type-wise vs. elevation range-wise, given in Table 23 and Figure 28. The dominant lake type in the subbasin i.e. Other Glacial Erosion lake (549) with 43.57% is predominantly located in the elevation range of 4,001 - 5,000 m (59.02%). The other dominant lake type i.e. Other Moraine Dammed lake is distributed predominantly in > 5,000 m and 4,001 - 5,000 m elevation ranges with 72.99% and 26.80% respectively. Majority of all types of Moraine-dammed and Glacier Erosion lake lies above 4,000 m elevation at almost equal numbers i.e. 574 and 573 respectively. Elevation range-type-wise spatial distribution of glacial lakes has been represented in Figure 29.


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: table
Table: Table 23: Type-wise vs. Elevation range-wise distribution of GL in Ghaghara subbasin

| S. No. | Elevation Range (m) | Types of Glacial Lake - M(e) | Types of Glacial Lake - M(l) | Types of Glacial Lake - M(lg) | Types of Glacial Lake - M(o) | Types of Glacial Lake - I(s) | Types of Glacial Lake - I(d) | Types of Glacial Lake - E(c) | Types of Glacial Lake - E(o) | Types of Glacial Lake - O | Total |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | up to 3,000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 2 | 3,001 - 4,000 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | 3 | 8 |
| 3 | 4,001 - 5,000 | 17 | 10 | 1 | 130 | 40 | 0 | 18 | 324 | 23 | 563 |
| 4 | > 5,000 | 43 | 17 | 2 | 354 | 33 | 0 | 9 | 222 | 9 | 689 |
| | **Total** | **61** | **27** | **3** | **485** | **73** | **0** | **27** | **549** | **35** | **1,260** |


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: figure
Figure: Figure 28: Type-wise vs. Elevation range-wise distribution of GL in Ghaghara subbasin

**Figure 28: Type-wise vs. Elevation range-wise distribution of GL in Ghaghara subbasin**


Document: MESSAGE
Section: 5. RESULTS > 5.1 Ganga Basin Level Statistics > 5.2.2 Ghaghra Subbasin
Type: text

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN

***

GLACIAL LAKE ATLAS OF GANGA RIVER BASIN