Crown of the
Continent Hydrologic Observatory:
proposed Hydrologic Observatory is 280 km on a north-south axis and 141 km on
an east-west axis. Topographically, the watershed extends from the 3,092 m Mt
Stimson to 753 m at its mouth near
1,560 km2 of the
annual discharge of the
basin, generate 5% of the annual flow. Portions of the
watershed regulated by dams include the South Fork of the
Metasedimentary rocks of the Precambrian Belt Super Group dominate the tectonic history of
region as the
million years ago. Subsequent extensional forces forced apart large parallel bocks
of bedrock with sediment- filled intermountain valleys. Most recently, continental and alpine
glaciations carved the landscape and deposited glacial sediments in the intermountain valleys.
landscape was also dominated by glacial lakes including glacial
and emptied leaving an unparalleled record of glacial lake sedimentation. The mountain
arÍtes, u-shaped valleys, and hummocky terrain of the intermountain valleys reflect the glacial
influence on the basin landscape.
Soil development and depth are dependent upon the type of deposition and physiographic
position. Soils of intermontaine
valleys are primarily formed in either fine textured lake bed sediments or
floodplain sediments over coarse alluvial gravels. Depth of development and
suitability for various crops is dependent upon the short growing season and
the availability of irrigation diversions. Soils of uplands are formed in
deep tertiary alluvial deposits or in Belt colluvium
or residuum. Soil development is limited by the rugged topography (surface
drainage), limited rainfall, and recent deposition or exposure. The upland
soils are vegetated by intermontane prairies or
climate is dominated by the Pacific coastal systems in the winter that are
occasionally overridden by the continental air masses originating north and
east of the area. The average winter temperature in Kalispell is 7C and
summer temperatures typically range from 20C to 27C. The large variation in
topography results in high mountain areas receiving 200 to 300 cm/y of
precipitation with snow packs reaching 6 m. In contrast the valleys receive
39 to 50 cm/y (FHEIS, 1983). The growing season is estimated at 120 to 130
days in the main
of glaciers in the
2004. Forecasts suggest all glaciers will be gone within 40 years. These studies are associated
with sets of long term climatic records collected by the park and USGS researchers.
vegetation below the 2,450 m treeline is dominated
by Englemann spruce, Whitebark
pine and subalpine fir (Figure 2). At lower
The basin contains 12 hydrologic landscape regions (USGS). It is dominated by semi arid mountains with impermeable bedrock (15, 17,18). Other major landscapes include sub-humid plans with impermeable soils and permeable bedrock (3), humid plains with permeable soils and impermeable bedrock (9), and semiarid plains with impermeable soils and bedrock (8). Valley floors are classified as arid to semiarid plans and plateaus with permeable soils and bedrock (5, 10, 12, 13, and14). A portion of the mountain region is classified as humid mountains with permeable soils and impermeable bedrock (20).
The basin contains over 500 lakes ranging from glacial tarns to the 510 km2 oligotrophic
(Figure 1). It occupies an extensional half-graben that is bounded on the east by the
margin of the Cordilleran Ice Sheet during the most recent (Pinedale) glaciation. Sediments
within the lake contain a very well preserved record of deglaciation associated with retreat of
the Cordilleran Ice Sheet.
Water management practices include water diversions for irrigation, power generation, flood control, flows for endangered, threatened and listed species, and recreation. Federal, state, tribal and local units are involved in water management. Management actions include local needs and national mandates.
Stream flows are snow-melt dominated and underpinned by groundwater baseflow. The site headwaters contain 37 glaciers and thousands of square kilometers of watersheds in which fire and disease are the only disturbances.† In contrast, the HO also contains watersheds at multiple scales that were dominated by glaciers within the last 100 years but are now glacier free, impacted by timber harvests and fires of varying ages to varying degrees, modified by water management practices including irrigation diversion and dams, and altered by development for homes, cities and agriculture.
For several thousand years this system has been dominated by snow-melt runoff and moderated by large quantities of water stored in Glacial ice. However, the timing and magnitude of droughts and summer flows have changed dramatically. With the information that can be gleaned from sediment cores and landscape records at different scales, this HO will provide scientists with opportunities to establish baseline watershed conditions and data on natural hydrologic variability. Such a context frames the current and further observations and assists with translating measured changes into links with the varied HO ecosystems.
The HO watersheds are some of the only pristine watersheds
left in the contiguous