CEOP HYDROLOGY REFERENCE SITES: Wolf Creek, Yukon Territory,
Canada 60o 32’ N 135o 07’ W (drainage area ~195 km2)
Site summary: The Wolf Creek Research Basin (drainage area about 195 km2) lies in southern
mountainous headwaters of the Yukon River Basin in the subarctic region of northwestern
Canada (Figure 1). The sub-arctic continental climate is characterized by a large seasonal
variation in temperature, low relative humidity and relatively low precipitation. Mean annual
temperature is in the order of -3oC with summer and winter monthly ranges of 5o-15o, and -100-20o C. respectively. Summer and winter extremes of 25o and -40o C are not uncommon. Mean
annual precipitation is 300 to 400 mm per year with approximately 40 percent falling as snow.
With a general northeasterly aspect, elevations range from 800 to 2250 m with the median
elevation at 1325 m.
Forest
WOLF CREEK ECOSYSTEMS
FOREST
Subalpine
Showing the
Murrumbidgee
watershed
Alpine
Study Site
ALPINE
SUBALPINE
Granger
Figure 1:
Study
Site
Location Plan
Wolf Creek is situated within the Boreal Cordillera ecozone (Environment Canada, 1995) and
consists of three principle ecosystems, boreal forest, sub-alpine taiga (shrub-tundra) and alpine
tundra with proportions of 22, 58 and 20% respectively of the total basin area. Permafrost is
present in locations on north facing slopes and there is sporadic permafrost throughout the basin,
with prevalence increasing with elevation. Study plots are located within each of the ecosystems
at elevations of 750, 1250 and 1615 m respectively. The forest site is relatively level with gently
undulating terrain consisting of an alternating hummock and hollow landscape. The canopy is
dense, consisting primarily of white spruce to heights of approximately 20 m, with some poplar
trees to approximately 15 m. The subalpine taiga site is located on an east facing moderate
hillslope of approximately 15 degrees. The hillslope itself consists of undulating terrain with
numerous hummocks and depressions. The site is vegetated with shrub alder and willow to
heights of approximately 2 m. The alpine tundra site occupies a windswept ridge top plateau.
Approximately 50% of the site is relatively level, with the balance sloping at approximately 15
degrees to the south. Vegetation is sparse consisting of mosses, some grasses and lichens with
occasional patches of scrub willow no more than 0.2 m high.
. Various research projects (University of Saskatchewan, Environment Canada) provide and
maintain micrometeorological and hydrological instrumentation.
Drainage area to outlet: ~195 km2
Basin outlet latitude-longitude: 60o 32’ N 135o 07’ W
Stream gauge/water level recorder period of record: Four stream gages capture the relative
contribution of flow from each ecozone and the basin outlet. These gages have been in operation
from 1993-present. Streams are gauged throughout the year using drillholes in the ice. Special
twice-daily rating curves are developed for specific stream gauging sites in spring where snow
dams and channel ice change the depth discharge relationship very rapidly.
Precipitation gauges: Nipher shielded snowfall gauges are located at each tower site along with
tipping bucket and standard AES raingauges and are monitored year round. Snow particle
detectors provide high resolution snowfall rates for each of these sites. At the spruce site
precipitation is measured above and beneath the forest canopy.
Micrometeorological data:
Radiation (incoming and reflected shortwave and net), sub-canopy net radiation, air temperature
(multiple heights), relative humidity (multiple heights), pressure, wind speed, wind direction,
snow particle flux, soil temperatures (multiple depths), volumetric soil moisture content (multiple
depths), snowpack temperature, snow depth are observed as 30 min. averages year-round from
1993 to present at all tower sites.
Turbulent flux measurements:
Short term measurements have been made using Campbell CSAT3 and KH20 or C7500 eddy
correlation systems during intensive observation periods of several months each that include
summer, late winter, spring. Data have been collected sporadically starting from 1994 to present.
Soil moisture:
Soil moisture data are collected at the tower stations and a few times on grids of 360 points near
stations.
Other measurements:
Alpine tundra site: Snow course observations are taken twice over the winter (November and
February) and once just before spring melt (April). They consist of 25 depth points spaced 5 m
apart with a snow density every 5th depth (25 m apart).
Buckbrush Taiga: Snow course measurements are taken at 25 depth points spaced 5 m apart with
snow density measurements taken at every fifth depth point (25 m apart). This course extends
along the valley side, at 154° magnetic from the nipher snow gauge, and is monitored monthly
through the winter.
White Spruce forest: Snow course measurements are taken at 25 depth points spaced 5 m apart
with a snow density every 5th depth as at the alpine tundra and taiga locations. This course
extends through the forest sampling between trees and under branches on a consistent line and is
monitored monthly.
Granger Sub-basin: scaling subbasin experiment with intensive measurements of flux and state
on hillslopes using snow and soil moisture measurements, met stations and flux towers from 1999
to present.
Contact:
John Pomeroy: pomeroy@usask.ca)