Hydrology in the Central
Canadian Rocky Mountains:
Change and Natural
Processes
John Pomeroy
Canada Research Chair in Water Resources & Climate Change,
Centre for Hydrology, University of Saskatchewan, Saskatoon
and collaborators
Alain Pietroniro (Environment Canada),
Mike Demuth (Natural Resources Canada)
Richard Essery (University of Wales)
Masaki Hayashi (University of Calgary)
and students
Chad Ellis, Warren Helgason, Gro Lilbaek, Chris DeBeer
www.usask.ca/hydrology
Central Rocky Mountain Hydrology
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A ‘cold region’ hydrological system –snowmelt dominated.
Large variation from year to year
What is Changing:
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Precipitation ?
Forest cover - yes
Temperature - yes
Glacier size - yes
Groundwater ?
Dams, consumption, agriculture, industry – yes.
Structural change in the Rocky Mountain hydrological cycle??????
Crucial support for our society. The Rockies provide >80% of flow
of Saskatchewan River system that sustains the population and
economy of much of Alberta and Saskatchewan.
Ecosystems and the Earth System are intimately tied to hydrology –
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Basin vegetation, soils, topography, groundwater, beaver, ice
Snow ecology – winter season
Aquatic ecology - streams, ponds and lakes
Climate system – local climate feedbacks, freshwater to Hudson Bay
Biogeochemical cycling
Rocky Mountains, source of most
Canadian Prairie surface water
Rocky Mountain Snowpacks
450
Lake Louise, Alberta
400
350
SWE mm
300
250
200
150
100
Snow drought
50
0
1930
1940
1950
1960
1970
1980
1990
2000
2010
‘NATURAL’ FLOWS OF THE SOUTH
SASKATCHEWAN RIVER LEAVING ALBERTA
Mountain snow drought is evident in the
‘natural’ flows of the rivers draining the Rockies
18,000,000,000
Annual Flow m3
16,000,000,000
14,000,000,000
12,000,000,000
10,000,000,000
8,000,000,000
6,000,000,000
4,000,000,000
Drought
2,000,000,000
0
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
South Saskatchewan River is most
strongly affected by Gardiner Dam
900
South Saskatchewan River at Saskatoon
hydrometric station 05HG001
600
3
-1
discharge (m s )
1912 - 1958
1967 - 1993
300
0
J
F
M
A
M
J
J
month
A
S
O
N
D
Lake Diefenbaker Results from
Gardiner Dam
‘Natural’ and Actual Flow of South
Saskatchewan River leaving Alberta
18,000,000,000
Natural
Annual Flow m3
16,000,000,000
Actual
14,000,000,000
12,000,000,000
10,000,000,000
8,000,000,000
6,000,000,000
4,000,000,000
2,000,000,000
0
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
-Hydrology Change: Decline of natural flow by 1.2 billion m3 over 90 years (-12%)
-Consumption of 7%-42% of natural flows during last 15 years
-Combined: Decline of 1.1 billion m3 over 30 years (-15%) in actual flow,
-Combined: Decline of 4 billion m3 over 90 years (-40%) in actual flow,
-Note 70% of decline is due to consumption, 30% of decline is due to hydrology
Climate Change Model Results:
2039–2070 Average, Change from Current Natural
20% decline in natural flow of the South Saskatchewan River over 1912 to 2070
BUT GREAT UNCERTAINTY IN THESE PRELIMINARY RESULTS!
Al Pietroniro, Environment Canada
Red Deer at Bindloss
-13%
(-32% to 13%)
South Sask at
Diefenbaker
-8.5%
(-22% to 8%)
Bow River at mouth
-10%
Oldman at mouth
- 4%
(-19% to 1%)
(-13% to 8%)
Glacier Retreat in the Columbia Icefields
Mapped from
LANDSAT
satellite
Mike Demuth, Natural Resources Canada
How Important are Glaciers to
Hydrology?
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Recent Study of Lake O’Hara (5% glacier cover
on Opabin Plateau)
Flow to Lake O’Hara
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60% snowmelt
35% rainfall
5% glacier melt
Jaime Hood and Masaki Hayashi, Univ Calgary
Glacier Retreat – Recent Analysis
LANDSAT satellite, 1975 and 1998.
z The decline of the total glacier area of the
North Saskatchewan basin between 1998
(306 km2) and 1975 (394 km2) was 88 km2
(-22%)
z The decline of the total glacier area of the
South Saskatchewan basin between 1998
(76 km2) and 1975 (152 km2) was 76 km2
(-50%)
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Al Pietroniro, Environment Canada & Mike Demuth, Natural Resources Canada
Current Glacier
Contribution to River
Melt
Discharge
Fall
%
Annual
%
7.4
1.8
Fall
%
Annual
%
2.4
0.6
Glacier water no
longer significant
for Calgary
Al Pietroniro, Environment Canada & Mike Demuth, Natural Resources Canada
Al Pietroniro, Environment Canada & Mike Demuth, Natural Resources Canada
M
onthlyF
low(C
M
S
)
30
Pipestone River
20
10
0
8/1/80
12/1/83
M
onthlyF
low(C
M
S
)
4/1/87
8/1/90
Time (month)
50
Bow River at L. Louise
40
30
20
10
0
8/1/80
12/1/83
M
onthlyF
low(C
M
S
)
4/1/87
8/1/90
Time (month)
160
Bow River at Banff
120
80
40
0
8/1/80
12/1/83
4/1/87
8/1/90
Time (month)
1998 extent
1975 Extent
None
John Pomeroy, (Saskatchewan),
Sean Carey (Carleton),
Richard Essery (Wales),
Raoul Granger (NWRI/EC),
Masaki Hayashi (Calgary),
Rick Janowicz (Yukon Environment),
Phil Marsh (Saskatchewan/EC),
Scott Munro (Toronto),
Alain Pietroniro (Saskatchewan/EC),
William Quinton (Wilfrid Laurier),
Ken Snelgrove (Newfoundland),
Ric Soulis (Waterloo),
Chris Spence (Saskatchewan/EC),
Diana Verseghy (Waterloo/EC)
and 16 collaborators from
A Research Network of the
http://www.usask.ca/ip3
Environment Canada,
Alberta Environment,
Indian & Northern Affairs Canada,
Natural Resources Canada,
Univ Guelph, Univ Idaho,
Univ Saskatchewan, Univ Western Ontario,
Univ Waterloo,
USDA-ARS
IP3 – Goals and Theme Structure
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Theme 1 Processes: Advance our understanding of
cold regions hydrometeorological processes
Theme 2 Parameterisation Develop mathematical
parameterisation of cold regions processes for small to
medium scales
Theme 3 Prediction Evaluate and demonstrate
improved hydrological and atmospheric prediction at
regional and smaller scales in the cold regions of
Canada
Ultimately – contribute to multiscale assessment of
coupled climate system, weather and water resources in
cold regions
IP3
Research Basins
Havikpak Creek,
taiga woodland
Trail Valley Creek,
arctic tundra
Baker Creek,
Subarctic shield lakes
Wolf Creek,
subarctic tundra
cordillera
Scotty Creek,
permafrost wetlands
Peyto Creek,
glacierized alpine
Lake O’Hara,
wet alpine
Marmot Creek,
Dry subalpine
Marmot Creek Research Basin
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Kananaskis Valley, Alberta 1450-2886 m.a.s.l.
Alpine Ridge
Alpine Bowl
Subalpine
Montane
Clearcut
x x
Marmot Basin
Meadow
x x
+600 mm
precipitation
xxx
ey
vall
r
e
Riv
skis
x
a
n
a
70% snowfall
Ka n
~50% runoff
from snow
w
Bo
x
y
lle
va
r
e
Riv
Hay Meadow
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Chinook snow
sublimation, energy
balance and melt studies,
Open environment
snowmelt and
evaporation
Soil moisture,
precipitation, modelling
Wind flow in clearing
Typical of cleared valley
floor in Kananaskis
Vista View Clearcut
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Forest ‘regrowth’
High Elevation
snow melt, energy
balance and
evaporation
studies
Soil moisture
Cabin Creek
modelling station
Lodgepole Pine Forests
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North Slope 26o
Level 0o
South Slope 25o
East Slope 18o
Snowmelt
Canopy effects
Frozen soils
Runoff
Chemistry
Energy balance
Interception
Modelling
Upper Clearing & Upper Forest
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Mid elevation
modelling sites
Small clearing
Fir and spruce
forest
Precipitation, energy
balance, soil
moisture, snowmelt,
evaporation
Assess clearing
impact on snow
accumulation and
interception
New forest tower setup this winter
Fisera Ridge
Treeline transition
z Upper basin
snow cirque
z Blowing
snow
z Modelling
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Alpine Ridgetop
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Centennial Ridge
2475 m
High elevation
modelling
reference
Blowing snow
Snowmelt
Evaporation
Energy Balance
Soil moisture
Alpine Blowing Snow: Flow Separation
Sublimation of Blowing Snow
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Increases with fetch
Requires unsaturated
atmosphere
Possibly important at
alpine ridgetops,
where flow separation
results in ‘plume’ of
blowing snow
Limits alpine snow
redistribution distance
Simulation of Hillslope Snowdrift
3 km
Distributed Blowing Snow Model - Essery, Li & Pomeroy 1999 Hydrological Processes
Mountain Drift Simulation
Wind Î
Altimeter
1400
DEM
1380200
Observed
1360
SWE (mm)
Elevation (m)
1420
Simulated
150
1340
0
50
100
100
150
200
250
300
350
400
Horizontal distance (m)
50
0
0
100
200
Horizontal distance (m)
300
400
Snow Interception
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Leaf + stem area index
(surface to collect snow)
Air temperature (elasticity
of branch, adhesion and
cohesion of snow)
Wind speed (particle
trajectory, impact rate,
branch bending,
scouring)
Unloading from warm and
windy events
Intercepted Snow Sublimation
Pomeroy, Parviainen, Hedstrom, Gray 1998 Hydrological Processes
Forest Snow Interception Loss
Fir-Spruce Forest vs. Small Clearing
Suggests that 61% of snowfall was sublimated from intercepted snow
Snow Water Equivalent mm
140
Forest
120
Clearing
100
80
60
40
20
0
North
South
East
Marmot Creek, March 2006 Pomeroy, Essery, Rutter
West
Snowmelt
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Improved Methods to
Estimate Short and
Longwave Radiation
Terrain Effects on
Radiation
Terrain Effects on
Turbulent Transfer
Forest Canopies –
radiation effects
Combined Forest Canopy
and Slope Effects radiation
Incoming Longwave in Mountains
30
Percent increase in
longwave irradiance due
to terrain emission due to
sky view factor (Vf) and
surface temperature (Ts).
25
Ts (°C)
20
Air temperature is 0°C
and the clear sky
emissivity is 0.65
15
10
5
0
0.5
0.6
0.7
0.8
0.9
1
Sky View Factor Vf
Sicart et al. 2006 Hydrological Processes
Thermal IR Image
Sublimation from Mountain Snowpacks –
Measurements and Typical Model
Mountain snow is aerodynamically rougher than other snows
No evidence of large evaporation rates during chinook events
Hayy Meadow,
= 1.7371x + 4.9831
R2 =Creek
0.7532
Marmot
40
40
20
30
-80
-60
-40
-20
0
-20
-40
-60
20
Mud Lake
40
LE modeled
-100
LE_modeled
-120
20
y =0.3446x - 1.124
R2 =0.1026
0
-60
10
0
-50
-40
-30
-20
-10
-10
-20
-30
-80
-40
-100
-120
Qe_measured
-50
-60
QE_measured
0
10
20
30
40
Solar Transmission through
Sloping Forest Canopies
τ a function of
LAI,
Foliage inclination
Crown coverage
Slope,
Aspect,
Solar azimuth,
Solar elevation
South Face Forest
25
40
55
70
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
10
elevation angle
70
25
40
55
x
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
10
elevation angle
85
85
North Face Forest
50
100
150
200
250
azimuth angle
300
350
50
100
150
200
250
azimuth angle
300
350
Tall Shrubs
Marmot Creek level forest
Solar Radiation to Snow beneath Shrubs and Trees
1000
400
SW (W/m )
300
2
2
SW (W/m )
800
600
400
200
0
123
200
100
0
124
Day (2003)
125
74
75
Day (2005)
76
Fine Scale Modelling of Sub-alpine Solar Radiation
LIDAR and canopy delineation
Tree Shadow Simulation
Essery et al. (2007). In preparation for Journal of Hydrometeorology.
Stand Scale Modelling of Solar Radiation
Simulated skyview
Simulated skyview
Clear
Overcast
600
Measured
500
2
SW (W/m )
Modelled
400
300
200
100
0
84
85
Day (2003)
Essery et al. (2007). In preparation for Journal of Hydrometeorology.
86
Hot Canopy and Trunks Increase Forest
Longwave Radiation
14:20
11.40
17.00
JD86 Cloudy
JD87 Sunny
Temperature (TC) C
50
CLPX LSOS Open Canopy IOP1
40
Canopy North
30
Trunk
Snow Surface
20
Canopy South
10
0
-10
-20
-30
50
50.5
51
51.5
52
52.5
Julian Day 2002
53
53.5
Rowlands, Pomeroy, Hardy, Marks, Link, Essery 2002 Proc. Eastern Snow Conference
54
Cumulative Net Radiation MJ m-2
Net Radiation to Snowmelt on 25o Forest
Slopes, Marmot Creek Research Basin
South Facing Forest Slope
Level & North Facing Forest Slopes
Level Clearing
Ellis, Pomeroy, Essery, Link submission to Canadian Journal of Forest Research
Mountain Prediction
RCM Domain
GEM Domain North
1
GEM Dom ain South
1
Trail Valley Creek
(Arctic Tundra)
Havikpak Creek
(Taiga Woodland)
Mackenzie Basin
2
3
4
2
Wolf Creek
(Subarctic Tundra
Cordillrea)
3
Scotty Creek
(Permafrost Wetlands)
4
Baker Creek
(Subarctic Shield
Lakes)
Peace-Athabasca Sub Basin
(Mackenzie)
5
Saskatchewan Basin
Peyto Creek
(Glaciated Alpine)
Colum bia River
Basin
5
Lake O'Hara
(Wet Alpine)
Marmot Creek
(Subalpine Forest)
Conclusions
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Rocky Mountain hydrology is changing due to climate
and land use change, 12% reduction in the South
Saskatchewan River natural flow since 1912, snowmelt
change possible cause.
Climate change to 2070 will reduce flows by another
8.5% however there is great uncertainty in this value!
Glacier contribution to flow is small, even in ‘classic’
glacier basins
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0.6% of Bow River at Calgary
2.4% of North Saskatchewan River at Edmonton
Forest snow interception losses large in Rockies, forest
cover reduction may cause streamflow increase
Blowing snow redistribution – vegetation and
temperature sensitive
Snowmelt enhanced under south facing forests,
Major research initiative underway to develop a
predictive system for mountain hydrology and link this to
climate and weather prediction models
Thank You!
Marmot Creek Research is supported by:
-Kananaskis Field Stations, U of C
-Kananaskis Country, Canmore
-G8 Legacy Fund, Environment Canada
-IP3 Network, Canadian Foundation for Climate and
Atmospheric Science
-Natural Sciences and Engineering Research Council of
Canada
-Canada Research Chairs
-Canada Foundation for Innovation
-UK Natural Environment Research Council
-US National Oceanic and Atmospheric Administration,
Office of Global Programs