Sensitivity of Marmot Creek Snow
Hydrology to Future Climate Change and
Forest Disturbance
John Pomeroy, Xing Fang, Chad Ellis, Matt MacDonald, Tom Brown
Centre for Hydrology & Global Institute for Water Security
University of Saskatchewan,
117 Science Place, Saskatoon, Saskatchewan
& Coldwater Laboratory, Kananaskis, Alberta
www.usask.ca/hydrology
How Might Marmot Creek Change?
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Forest disturbance
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Pine Beetle
Salvage Logging
Clear-cutting
Burning
Climate Warming
 Warming in forest
 Warming in alpine
CRHM Modules
►
Prairie Blowing Snow Model (PBSM; Pomeroy & Li, 2000)
 Blowing snow transport
►
Saltation + suspension
 Blowing snow sublimation
►
f(particle size, radiation, turbulent & latent heat exchange, vapour
density)
 Vegetation partitions wind shear stress on snow surface
►
►
f(stalk characteristics, drag coefficients)
Snobal (Marks et al., 1998, 1999)
 Snowpack melt and sublimation/condensation
 Two layers
►
Canopy module (Ellis et al., 2010)
 Canopy radiation adjustment (Pomeroy et al., 2009)
 Snow interception, unloading, throughfall (Hedstrom & Pomeroy,
1998)
 Intercepted snow sublimation (Pomeroy et al., 1998)
 Enhanced longwave irradiance to surface from the canopy
Snow Interception Studies
Snow in Forest / Snow in Clearing
Effect of Forest Removal on Snow
Accumulation
1
0.9
Deforestation Effect
0.8
0.7
Sparsely Wooded
0.6
0.5
Medium Density, Young
0.4
0.3
Dense Mature Canopy
Measured
0.2
Parametric Model
0.1
0
0
1
2
3
Leaf Area Index
4
5
Net Radiation to Forests:
Slope Effects
South Face
Clearing
North & South
Face Forests
North Face
Clearing
Forest Disturbance Scenarios
►
40 scenarios tested, various areal removals of canopy due to:
 Pine Beetle,
 Fire,
 Logging
►
►
►
►
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Pine beetle only affects lodgepole pine
Trunk retention versus salvage logging for beetle and fire
Stump retention versus complete tree removal for logging
Selective logging on north versus south facing slopes
Forest removal results in

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reduced interception loss,
reduced ET,
changes to rooting zone,
changes to sub-canopy radiation,
changes to wind speed near the ground,
changes to blowing snow
Pine Beetle Impact on Snow Regime
Fire Impact on Snow Regime
Clear-cutting Impact on Snow Regime
Forest Cover Disturbance Impact on
Snowmelt Quantity
Forest Snow Regime on Slopes
200
level
30o north-sloping
30o south-sloping
SWE [kg m-2]
150
100
50
Open slopes highly
sensitive to irradiation
difference, forests are not
0
10/1/07
11/1/07
12/1/07
1/1/08
2/1/08
3/1/08
4/1/08
5/1/08
6/1/08
7/1/08
8/1/08
5/1/08
6/1/08
7/1/08
8/1/08
Date (M/D/YY)
100
SWE [kg m-2]
80
level
30o north-sloping
30o south-sloping
60
40
20
0
10/1/07
11/1/07
12/1/07
1/1/08
2/1/08
3/1/08
4/1/08
Date (M/D/YY)
Pine Beetle Impact on Streamflow
Fire Impact on Streamflow
Clear-cutting Impact on Streamflow
Forest Cover Disturbance Impact
on Seasonal Streamflow
Forest Cover Disturbance Impact
on Peak Streamflow
Blowing Snow: Fisera Ridge
► Flow
over ridgetop and into
forest
Blowing snow sublimation
Forest
SFbottom
SFtop
Ridge
top
NF
Alpine Hydrological Model
derived from Cold Regions Hydrological Model
► Model

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components
Snow wind redistribution, interception and melt
Actual evapotranspiration,
frozen soil infiltration,
unfrozen infiltration,
soil moisture balance,
routing
► Ability
to perturb the model via temperature
changes
 Affects precipitation phase
 Affects hydrological processes
Winter Warming Impact on
Alpine Ridge Snow Accumulation
200
reference simulation
150
+ 1°C
+ 2 °C
SWE (mm)
+ 3°C
100
+ 4 °C
50
0
30/11/06
30/12/06
29/01/07
28/02/07
30/03/07
29/04/07
29/05/07
Impact of Winter Warming on Date
of Snowpack Depletion
temperature increase (°C)
4
3.5
3
2.5
2
1.5
1
0.5
0
03-May
08-May
13-May
18-May
23-May
date of snowcover depletion
28-May
02-Jun
Change in Actual Evapotranspiration
250
ET Source Current
Water Equivalent mm
ET Drift Current
ET Source +4C
200
ET Drift +4C
150
100
50
0
06-Aug
25-Sep
14-Nov
03-Jan
22-Feb
12-Apr
01-Jun
21-Jul
09-Sep
29-Oct
Hydrology Change with
Temperature
800
700
mm water equivalent
600
Rainfall
Snowfall
500
Melt
Melt_runoff
400
Rain_runoff
Basinflow mm
300
BS Subl
BS Drift
200
100
0
0
1
2
Air Temperature Change
3
4
Change in Alpine Basin Discharge
2500000
2000000
Basin Outflow Current
Cubic Metres
Basin Outflow +4C
1500000
1000000
500000
0
06-Aug 25-Sep
14-Nov 03-Jan
22-Feb
12-Apr
01-Jun
21-Jul
09-Sep
29-Oct
Next Steps: Integrated Observing
& Predicting Systems
Current high altitude
observation network
in Canada is
inadequate, need a
network of stations,
remote sensing,
modelling, data
assimilation in order
to predict our cold
regions water
resources
adequately.
Canadian Rockies Hydrological Observatory
Initially the Upper Bow River Basin.

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10 high altitude hydrometeorological stations – research basins
5 high altitude stream gauge stations – research basins
Portable detailed measurement system
Data management, information assimilation and water modelling system
Glacier hydrology, treeline ecology, climate modelling, snow physics
Primitive Snow Observations
Sami in Lapland
Pomeroy & Guan in Alberta
Scottish Snow Surveyor
Acoustic Snow Measurement
Acoustic Gauge Testing
Acoustic gauge
Acoustic Results and Testing
Improved Snow Measurements
INARCH
INARCH: International Network for Alpine Research
Catchment Hydrology
Canada – Marmot Creek, Peyto Glacier Alberta and Wolf Creek,
Yukon;
Germany – Zugspitze; Switzerland – Dischma;
Spain – Izas, Pyrenees; USA – Reynolds Creek, Idaho.
Chile - Andes, China – Tibet
Conclusions
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Relationships between snow and vegetation are strongly influenced by
atmospheric energy and mass inputs which in turn are controlled by weather
and topography
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If windblown: less forest => less snow
No wind transport: less forest => more snow
South facing, level: less forest => faster snowmelt
North facing: less forest => slower snowmelt
Modelled impacts of forest cover reduction in Marmot Creek resulted in small
to moderate increases in streamflow despite much greater increases in snow
accumulation.
 Pine beetle infestation had a small effect on snowmelt quantities and
insignificant effect on streamflow due to the small and relatively dry area of
the basin covered with lodgepole pine.
 Fire and logging were much more effective than pine beetle in changing the
hydrology due to the higher elevations and larger area affected.
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Further warming and loss of snow and ice are likely to further reduce
streamflow and exacerbate high variability in water supply
Warming will increase importance of rainfall-runoff mechanisms and require
new water management approaches in downstream populated regions.
Improvement and expansion of observations and modelling outside of Marmot
Creek is essential.