IMPACT OF GLACIER RUNOFF ON BAKER LAKE 
AND THE BAKER RIVER PROJECT

Director: Dr. Mauri S. Pelto Nichols College, Dudley MA 01571
508-213-2168:  peltoms@nichols.edu

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Updated 3/11/2011

 


Lower Curtis Glacier, Mt. Shuksan  showing glacier retreat since 1985. Home page

2003 Deming Glacier-Bellingham Water Supply Study

The North Cascade Glacier Climate Project (NCGCP) has monitored North Cascade glaciers since 1983 to identify their response to climate change.  Within the Baker Lake drainage, the Sulphide, Watson, Lower Curtis, Rainbow, Boulder, Squak and Easton Glacier have been monitored.  Each summer both the accumulated snowmelt from the previous winter is measured and the total melting for the summer season.  This yields the annual mass balance of the glacier (Pelto, 1988; 1996 and Pelto and Riedel, 2001).  In addition the changing area, terminus position and surface profile are mapped periodically determining the longer term response of the glacier to climate change. 

The glaciated area in the basin draining is 11.5 square miles.  On average from July 1-Oct. 1 the average glacier loses 2.7 meter of water equivalent thickness from melting.  This represents 21-22 billion gallons of water.  The flow in the Baker River in Concrete (USGS) yields 137 billion gallons during this period.  Glacier runoff then represents 16% of the total flow during this period, peaking at 24% in August.  However, the contribution is larger during dry summers and is higher for Baker Lake, which is a smaller basin area.  In fact in a dry year such as 1998 glaciers yielded 28 billion gallons of runoff to Baker Lake, while other sources were below average, which amounted to 45% of the total basin flow.  The melt rate is determined from repeat probing and stakes drilled into the glacier recording the actual surface melt.

As a glacier retreats its area available for melting declines and so does glacier runoff in the summer.  During the early portion of the melt season May and June, glaciers store meltwater in their thick snow and firnpack, thus reducing the magnitude of high spring flows.  As they retreat this ability declines.  Thus, glacier retreat leads to an increase in spring runoff and a decline in summer runoff.

Glaciers are natural reservoirs that yield their resource primarily on warm dry summer days when other sources are at their lowest yield.  This natural tempering of drought conditions will be reduced. 

What happens when a glacier melts away?  Changes occurring due to glacier retreat have been observed in the Lewis Glacier Basin.  The Lewis Glacier Basin had a total area of 0.2 km2, comprised of steep bedrock and ice covered areas in 1985.  By 1990, the former ice-covered areas were exposed gravels and boulders.  In August 1985, Lewis Glacier had an area of 0.09 km2 and released 0.15 x 106 m3 of runoff.  By August 1990, Lewis Glacier had disappeared, runoff from the former glacier basin was 0.04 x 106 m3, only 27% of the glaciated flow, despite the presence of some relict glacier ice, and that total monthly precipitation was the same.  

Glacier retreat has been substantial in the Baker Lake drainage since 1980 (Table 1).  This retreat represents a loss in glacier area that will be mapped in 2001 and 2002.  The result is less late summer glacier runoff.

TYPE 1

LIAM-1950

1950-1979

1979-1997

Slope

Glacier Size (km2)

Altitude (m)

Latitude

 

Longitude

Rainbow

-1370

512

-225

0.37

1.6

1850

48 48

121 46

Easton

-2420

608

-165

0.35

2.9

2250

48 45

121 50

Squak

-2500

305

-160

0.45

2.1

2350

48 45

121 49

Talum

-1975

275

-161

0.55

1.8

2400

48 45

121 48

Boulder

-2560

743

-290

0.50

3.4

2350

48 46

121 47

Lower Curtis

-645

225

-82

0.36

0.8

1650

48 50

121 37

Sulphide

-1775

210

-101

0.38

2.4

2100

48 49

121 07

Watson

-320

-21

-55

0.4

0.5

1650

48 41

121 06

Table 1.  Retreat, in meters, of North Cascade glaciers for three intervals since the LIAM.   The longitude and latitude of each glacier is noted in degrees and minutes, the mean slope of the glacier surface, the mean altitude of the glacier, and the surface area of the glacier are also listed. 

In addition to the measured retreat we have measured the surface profiles of these glaciers, measured annual snowpack on the glaciers and annual ablation.  Glaciers are critical to the water balance of Baker Lake in late summer.  USDA's Snotel sites provide a good measure of low elevation snowfall and consequent snowmelt in May and June, but they have no sites in the area that retain snow into July.  Thus, we need to continue to monitor glacier ablation.  Table 2 contains the observed annual balance of glaciers in the basin and Figure 1 the observed August Snowpack on two of the glaciers.

Easton Glacier 1916 Easton Glacier 1998
Glacier 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
Lower Curtis 0.39 -0.16 -0.22 -0.56 -0.06 -0.29 -0.51 0.04 -1.76 -0.48 -0.55 -0.21 -0.18 0.27 -1.38 1.55 -0.25 -1.88
Rainbow 0.58 0.04 0.2 -0.26 0.43 -0.24 -0.46 0.44 -1.65 -0.8 -0.72 -0.2 0.12 0.51 -1.49 1.84 0.15 -1.71
Easton -0.58 0.41 -1.67 -1.01 -0.92 -0.31 0.22 0.53 -1.87 1.61 -0.1 -1.93

Table 2.  Annual balance of North Cascade glaciers in the Baker Lake Drainage.


Easton Glacier in 1999

Rainbow Glacier surfacial glacial stream

Boulder Glacier in  1993

 

Glacier Home Page

References

1988.  Annual balance of North Cascade glaciers,  Washington, measured and predicted using an activity-    index method.  Journal of Glaciology, 34, 194-200.

 1991.  Glacier runoff into Baker Lake, Washington.  EOS,     April 23, 1991, 130.

 1993.  Current Behavior of Glaciers in the North  Cascades and Effect on Regional Water Supplies.  Washington Geology, 21(2), 3-10.  

  1996, Annual Net Balance of North Cascade Glaciers, 1984-1994.  Journal of   Glaciology, 42(140) 3-9.  

 1996, Honeycomb Glacier.  Pack and Paddle, 26-27.  

 1996, Changes in Glacier and Alpine Runoff in the North Cascade Range, Washington USA 1985-1993.
 Hydrological Processes, 10, 1173-1180.   

 2000. Summer snowpack variations with altitude on Mount Baker, Washington 1990-1999: A comparison with record 1998/99 snowfall.  Proceedings of the Eastern Snow Conference.

2001:  with Jon Riedel.  The spatial and temporal variation of mass balance on North Cascade glaciers., Hydrological Processes.