Khatling Bamak (Glacier) is the headwaters of the Bhilangana River in Uttarakhand, India. The Bhilangana River flows into the Tehri Reservoir(2400 MW), that along with the Bhilangana River’s three small hydropower projects (50 MW), make these glaciers key contributors to regional hydropower. The glacier was formerly joined with the Ratangrian Glacier as indicated by the map, but the two have separated with the Ratangrian Glacier now terminating 1.7 km upvalley of this former connection. The 10 km long glacier is fed by several mountain peaks including Jaonli over 6000 m. The lower section of the glacier is debris covered.
Here we examine satellite imagery from 1998, 1999, 2011 and 2013 to identify recent changes. The yellow arrow in the images indicates the lower limit of the clean ice in 1998, the pink arrow the lower limit of the clean ice in 2013. The red arrow indicates a significant tributary to Khatling Glacier joining from the south. The terminus is not evident in the Landsat images, but can be observed in the Google Earth imagery.
In 1998 the southern tributary joins the Khatling Glacier at 4500 m, 2.5 km upglacier of the terminus. The clean ice extends to within 1 km of the terminus. In the 1999 image the same connection with the southern tributary and location of the clean ice is evident. By 2011 the southern tributary is no longer connected to the glacier, red arrow. The clean ice does not reach the yellow arrow. The spread of the debris cover is not from additional avalanche input or flow from upglacier. The spread occurs as a glaciers ablation melts the clean ice faster and the debris cover where thick slows ice melt. This leads to topographic highs covered by debris cover that than slide-tumble down onto the clean ice. Without much input from upglacier the debris within the ice is melted out and can continue to concentrate at the surface. This is common among retreating glaciers with debris cover to have the debris begins to spread across the glacier. By 2013 the clean ice extent has retreated 1000 m from 1998 to the pink arrow of 2103. The southern tributary has retreated 200 m from its former junction. The terminus of the glacier has retreated 400 m from 1998-2013. A close up of the terminus from 2011 Google Earth imagery indicates the outlet river (pink arrow) issuing from beneath the stagnant debris covered ice (DC) and the distance from the terminus to the clean ice (CI). The lateral moraines of the Khatling and Ratangrian Glacier are also shown. The hummocky thin nature of the lower 700 m of the glacier is evident, light blue arrows, indicating an area that will be lost from the glacier soon. Khatling Glacier retreat is similar to that of nearby Gangotri Glacier and Jaonli Glacier that also feed Tehri Dam.
1998 Landsat image
1999 Landsat image
2011 Landsat image
2013 Landsat image
2011 Google Earth image
Ratangrian Glacier is adjacent to Khatling Glacier and with that glacier is at the headwaters of the Bhilangana River. The Bhilangana River flows into the Tehri Reservoir(2400 MW), that along with the Bhilangana River’s three small hydropower projects (50 MW), make these glaciers key contributors to regional hydropower.
In the 1998 Landsat image the glacier terminus is at the red arrow, which is at 4150 m and downhill of the stream from the glacier labelled SG. The map above indicates the glacier was joined with Khatling Bamak at 3950 m, the lateral moraines (L-on second image below) indicate this too. The glacier is quite steep in its last mile descending from 5000 m to 4150 m in 1.5 km. The glacier is also not debris covered unlike many of its neighbors Khatling, Gangotri or Jaonli Glacier. A 2011 Google Earth image indicates the glacier has retreated to the blue arrow, where the outtlet stream from the glacier SG reaches the Ratangrian valley. By 2013 the glacier has retreated above the location where the outlet stream reaches the valley and is at the yellow arrow. The total retreat in 15 years is 400-450 m. The terminus of the glacier has risen from 4150 m to 4500 . The glacier is following the path of retreat of the nearby Gangotri Glacier and Jaonli Glacier that also feed Tehri Dam. The retreat is more rapid proportionally for the size of the glacier, probably due to the lack of debris cover. The slopes in the basin feeding the glacier are mostly covered by the glacier itself. If they were steeper and were not as ice covered, than avalanches could sweep debris onto the glacier.
1998 Landsat image
2011 Google Earth Image
2013 Landsat image
2013 Landsat image-closeup
The Tons River is in Uttarakhand India. The watershed is fed by more than 50 glaciers. The largest are Jaundhar Barak and Bandarpunch, the glaciers of Tons valley are notable for a thick mantle of debris cover, due to the terrain characteristics, and the avalanche fed nature of the glaciers (Pankaj et al, 2012). The Tons River Basin has one significant operational hydropower unit, the Mori Hanol Hydro Power Project (70 MW) with a diversion dam downstream of Mori village. There are other proposed projects in the basin. Mehta et al (2013) observed the spatial changes of Jaundhar Barak, Jhajju and Tilku glaciers in the Tons River basin between 1962 and 2010 using Landsat Satellite data, topographic maps and field surveys. They estimated the overall loss in area to be 3.6 km2 (5.4%) and frontal retreat of 1,700 m, ∼ 800 m and ∼ 700 m for the Jaundhar Barak, Tilku and Jhajju Glaciers. The debris cover (DC) makes it quite difficult to easily identify terminus (T) position using Landsat imagery, Google Earth Imagery is not good either.
Map of Tons River basin glacier from (Pankaj et al, 2012)
Jaundhar Barak Glacier in 2012 arrows indicate flow Debris cover=DC and Terminus=T, tributary glaciers of note discussed below A-E.
Here we use Landsat imagery to identify the retreat of five tributary glaciers that have fed or are feeding into the Jaundhar Barak from the ridge to its north from 2000 to 2012. Jaunhar Barak is a 19 km long glacier with a north and south arm, here we focus on the north arm. The glacier begins near 6000 m and quickly drains into the main valley, at 4900 m the debris cover begins and the lower 13 km of the glacier are debris covered to the glacier end at 3900 m . The tributary glaciers are each a potential income stream for the main glacier, which when lost lead to less snow and ice “income” for the main glacier and then thinning and retreat will follow. The Jaundhar Barak Glacier is The five tributaries are labelled A-E. A comparison of the 2000, 2011 and 2012 images below indicate that: At Point A in 2000 two arms of the tributary glacier joined and it flowed out of the high alpine basin it was in, by 2011 and 2012 the two glacier arms have separated and the glacier is confined to the upper basin. At Point B there is a well established glacier tongue that extends halfway from the tributary to Jaundhar Barak, and by 2012 this tributary terminus has pulled back 200 m, which is nearly 200 m of elevation change also. At Point C in 2000 this tributary joins the main valley glacier and a small tongue of blue ice, its contribution can be seen heading downglacier. By 2012 the Point C tributary no longer reaches the main glacier. At Point D in 2000 the tributary joins the main glacier and like the previous tributary contributes a small tongue of blue ice that heads down the Jaunhar Barak Glacier. By 2011 the Point D tributary is no longer reaching the main glacier. At Point E in 2000 this accumulation area for the glacier is nearly all covered with glacier ice, with only a couple of small bedrock areas seen below the Point. By 2012 the bedrock exposed has coalesced into a one kilometer region separating a portion of the upper glacier from the main valley glacier. The ice from this tongue still may reach the lower glacier via avalanching. The last decade of loss on tributary glaciers more than 10 kilometers above the terminus of Jaundhar Barak indicates that downwasting and retreat of this glacier will continue. This glacier follows the pattern of other glaciers in the Garhwal of the Himalaya in its retreat and downwasting, Jaonli Glaicer, Gangotri Glacier, Satopanth Glacier . It also will feeds hydropower projects as do the other glaciers.
2000 Landsat Image of tributaries on north side of Jaundhar Barak Glacier.
2011 Landsat image
2012 Landsat image
Jaonli Glacier is in the Pilang basin which feeds the Bhagirathi River in Uttarakhand. The glacier is 20 km west of the well known Gangotri Glacier and 30 km east of Jaundhar Barak. The glacier is one valley north of the well studied Dokriani Glacier. Jaonli has a heavily debris covered terminus which slows the retreat of the actual terminus, while upglacier thinning has been quite rapid. Here we examine Landsat imagery from 2000 to 2012 to illustrate the change due to increased melting. The glacier provides hydropower as it passes three Hydropower plants generating 1430 MW, including the 1000 MW Tehri Dam and reservoir, which also provides flood control, such as this past week of June 17, 2013(second image). The Tehri Reservoir level rose 25 m within 48 hours which is a storage of approximately 1.3 billion cubic meters. Jaonli Glacier is a heavily avalanche fed from the huge wall of rock on its northeastern flank, as noted by light blue arrows. In each image the yellow and orange arrows indicate the same location for comparison of the width of debris cover. The purple and red arrow indicate where two tributaries flow down to meet the Jaonli Glacier.
In 2000 the clean ice region of the main valley tongue of the Jaonli Glacier is 400 m wide at the yellow arrow and 500 m wide at the orange arrow. The eastern tributary at the red arrow joins the main valley glacier. At the purple arrow two small ponds are developing as the tributary that does not reach Jaonli melts back. By 2012 the debris free ice surface is 100 m wide at the yellow arrow and 200 m wide at the orange arrow. The debris cover spreads across the glacier as the clean ice melts faster thinning, and the debris covered area is then on an increasingly wide and high ridge above the clean ice and the debris then falls and oozes down onto the cleaner ice. The tributary at the red arrow still reaches the main glacier but is now covered by debris. The two ponds have merged at the purple arrow to create a larger terminus lake. IN Google Earth the images are from 2011. The first is a cross ice view towards the red arrow tributary, indicating the same locations and the extent of the debris cover. The second image is a closeup of the terminus, with a pink arrow indicating the 2011 terminus, note river issuing here and large ice face. However, there are two other developing termini with lakes forming 1 km upstream of the main terminus, green arrows. This stagnant ice in between will continue to melt and collapse. The glacier has retreated 160 m from 2000 to 2012, but will undergo an additional one kilometer retreat to reach the lake locations. This glacier fits well the overall retreat in the region (Kulkarni et al, 2007).Dokriani Glacier retreated at a rate of 17 m/year from 1962-2000 (Bhambri and Bolch, 2011). In the nearby Tons River Basin Mehta et al (2013) noted the 1962-2010 retreat of three glaciers Jaundhar (34 m/year), Jhajju (15 m/year) and Tilku Glacier (13 m/year).
In India the Gangotri Glacier is the largest glacier at the headwaters of the Bhagirathi River. The false-color image below provided by NASA shows the retreat of Gangotri Glacier, situated in the Uttarkashi District of Garhwal Himalaya. It is one of the larger glaciers in the Himalaya, and like all of the nearby Himalayan glaciers is retreating significantly. The Bharigrathi River has the Tehri Dam, a 2400 mw hydropower facility. With an area of 286 square kilometers Gangotri Glacier (Singh and others, 2006) provides up to 190 cubic meters per second of runoff for this river. Gangotri Glacier provides hydropower as it passes three hydropower plants generating 1430 MW, including the 1000 MW Tehri Dam and reservoir and maneri Bhali I and II, see map below. The Tehri also provides flood control, such as this past week of June 17, 2013. The Tehri Reservoir level rose 25 m within 48 hours which is a storage of approximately 1.3 billion cubic meters. Below is a view of the Tehri Reservoir, images of the dam and its operations are here.
Map from the Southeast Asian Network on Dams, Rivers and People
Gangotri Glacier retreated 26.5 meters per year form 1935-1971. From 1968-2006 the glacier retreated 800 meters, close to 20 meters per year (Bhambri et al, 2012). Srivastava et al (2013) indicate the retreat rate of 21 m/ year from 2004-2010. The glacier continues to thin and tributary inflow decline, while the thick heavily insulated by debris terminus retreat is slow. Srivastava (2012) published a report with numerous terminus pictures though they do not have a common reference point beginning on page 90. Where the river exits the glacier is referred to as Gomukh.
Here we compare both Landsat and Google Earth images during the 2000-2013 period. First the 2000 and 2013 Landsat images. A 2000 and 2013 landsat image pinpoint the terminus change, the yellow and red arrows converge on the 2000 location of Gomukh. The blue arrow indicates the mouth of a side valley from the east that is at the terminus in 2013 and actively cutting the face, which is not the case in 2000. The orange dots indicate the course of this stream. A 2006 Cartosat image from Bhambri et al (2012) can be compared to the 2010 and 2013 Google Earth images. In Google Earth the 2010 image gives a clear view of Gomukh which can be compared to the 2006 Cartosat image from Bhambri et al (2012). In 2000 and even 2006 this was not the case. A 2013 Google earth also indicates this point,with the glacier having retreated to the side valley from the east. The retreat from the location of Gomukh in 2000 to 2013 is 240-270 m, approximately 20 m per year as noted by Srivastava et al (2013) for a shorter interval.
2000 Landsat image
2013 Landsat image
2006 Cartosat image
2010 Google Earth image
2013 Google Earth image
2013 Google Earth image
This glaciers remains over 30 km long, and is not in danger of disappearing anytime soon. The lower section of the glacier is heavily debris covered, which slows melting. The debris cover prevents black carbon-soot from enhancing melt over most of the ablation zone. The upper reaches of the glacier extends above 6000 meters and remains snow covered even during the summer melt season June-August, as this is also a main accumulation season due to the summer monsoon. This is different from other alpine regions, where the melt season is also the dry season, here it coincides with the wet season and the accumulation season on the upper glacier. Compare the differences in hydrographs from Thayyen and Gergen (2009) Figure 3 and 4. The new snowcover on the upper glacier also limits the impact of black carbon or soot on ablation. The glacier is fed from avalanches off of the even larger area of mountains above 6000 meters adjacent to it. This is one of many glacier in the Himalaya that is being tapped for hydropower. The retreat is slower than that of nearby Malana Glacier and Samudra Tupa Glacier but similar to Durung Drung Glacier.