Event Title

Water Balance of Glacial Lakes: Comparison among the Nepal Himalaya and the Wasatch Range and Uinta Mountains of Utah

Presenter Information

Joseph Carlson

Location

ECC 305

Event Website

http://water.usu.edu/

Start Date

4-3-2012 2:30 PM

End Date

4-3-2012 2:50 PM

Description

It is widely assumed that retreat of glaciers in the Himalaya due to global warming will result in the filling of glacial lakes, which will increase the probability of glacial lake outburst floods (GLOFs). However, glacial lakes will not necessarily fill if they are sites of groundwater recharge. The objective of this study was to carry out measurements of the water balance of glacial lakes in Nepal Himalaya and the Wasatch Range and Uinta Mountains of Utah in order to determine whether these lakes are sites of groundwater recharge or discharge. The present-day water balance of glacial lakes also has implications for determining whether the lakes were formed by direct glacial action or by the thawing of permafrost after glacial retreat. The study was carried out in July and August 2009 in 11 glacial lakes in Utah and in June 2011 in the glacial lakes downstream from Eastern Lirung Glacier, Khyimjung Glacier, and Salbhachum Glacier in the Langtang Valley of Nepal Himalaya, about 8 km from the Tibetan border. For each glacial lake, stream discharge was measured in the outlet stream and multiple inlet streams using the USGS Pygmy Flowmeter or USGS Price Flowmeter, depending upon the stream velocity. The electrical conductivity was measured in each inlet and outlet and at ten locations in each lake as a proxy for total dissolved solids (TDS). The lake levels were monitored for two weeks in Utah and for periods ranging from four hours to four days in Nepal. The water balance data were consistent with groundwater recharge in McPheeter Lake (2.1 × 104 m3/mo) in the Uinta Mountains, Lake Blanche (7.9 × 104 m3/mo) and White Pine Lake (7.4 × 104 m3/mo) in the Wasatch Range, and the lake below Eastern Lirung Glacier (8.5 × 105 m3/mo) in Nepal Himalaya. On the other hand, the water balance data required groundwater discharge in Lake Lillian, Lake Florence, Upper Red Pine Lake, Lower Red Pine Lake and Silver Lake in the Wasatch Range, and in Amethyst Lake, Ryder Lake and BR-24 Lake in the Uinta Mountains. The estimates of the magnitude of groundwater discharge and the evaporation rate at sites of groundwater discharge require an empirical relationship between groundwater and inlet stream TDS for granitic and high-grade metamorphic terranes, which is currently under development. Further results, including water balance data for the remaining glacial lakes in Nepal Himalaya, will be reported at the meeting.

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Apr 3rd, 2:30 PM Apr 3rd, 2:50 PM

Water Balance of Glacial Lakes: Comparison among the Nepal Himalaya and the Wasatch Range and Uinta Mountains of Utah

ECC 305

It is widely assumed that retreat of glaciers in the Himalaya due to global warming will result in the filling of glacial lakes, which will increase the probability of glacial lake outburst floods (GLOFs). However, glacial lakes will not necessarily fill if they are sites of groundwater recharge. The objective of this study was to carry out measurements of the water balance of glacial lakes in Nepal Himalaya and the Wasatch Range and Uinta Mountains of Utah in order to determine whether these lakes are sites of groundwater recharge or discharge. The present-day water balance of glacial lakes also has implications for determining whether the lakes were formed by direct glacial action or by the thawing of permafrost after glacial retreat. The study was carried out in July and August 2009 in 11 glacial lakes in Utah and in June 2011 in the glacial lakes downstream from Eastern Lirung Glacier, Khyimjung Glacier, and Salbhachum Glacier in the Langtang Valley of Nepal Himalaya, about 8 km from the Tibetan border. For each glacial lake, stream discharge was measured in the outlet stream and multiple inlet streams using the USGS Pygmy Flowmeter or USGS Price Flowmeter, depending upon the stream velocity. The electrical conductivity was measured in each inlet and outlet and at ten locations in each lake as a proxy for total dissolved solids (TDS). The lake levels were monitored for two weeks in Utah and for periods ranging from four hours to four days in Nepal. The water balance data were consistent with groundwater recharge in McPheeter Lake (2.1 × 104 m3/mo) in the Uinta Mountains, Lake Blanche (7.9 × 104 m3/mo) and White Pine Lake (7.4 × 104 m3/mo) in the Wasatch Range, and the lake below Eastern Lirung Glacier (8.5 × 105 m3/mo) in Nepal Himalaya. On the other hand, the water balance data required groundwater discharge in Lake Lillian, Lake Florence, Upper Red Pine Lake, Lower Red Pine Lake and Silver Lake in the Wasatch Range, and in Amethyst Lake, Ryder Lake and BR-24 Lake in the Uinta Mountains. The estimates of the magnitude of groundwater discharge and the evaporation rate at sites of groundwater discharge require an empirical relationship between groundwater and inlet stream TDS for granitic and high-grade metamorphic terranes, which is currently under development. Further results, including water balance data for the remaining glacial lakes in Nepal Himalaya, will be reported at the meeting.

https://digitalcommons.usu.edu/runoff/2012/AllAbstracts/35