THE PROPOSED CROWN OF THE CONTINENT HYDROLOGIC OBSERVATORY
HARPER, JOEL T. (1); WOESSNER, WILLIAM W. (1); RUNNING, STEVEN W. (2)
(1) Department of Geology, University of Montana, Missoula, MT 59812; (2) College of Forestry
and Conservation, University of Montana, Missoula MT 59812
We are proposing a Crown of the Continent node within the NSF-sponsored Hydrologic
Observatory Network. This will be a large-scale field facility located in north-western Montana
that will generate multi-disciplinary characterization of the landscape necessary to advance the
environmental sciences (i.e., hydrology, biogeochemistry, ecology, geomorphology, limnology).
The Crown of the Continent Hydrologic Observatory (CCHO) is 280 km on a north-south axis and
180 km on an east-west axis. The CCHO will encompass a diverse hydrologic landscape
including high mountain areas, large pristine watersheds, inter-mountain valleys undergoing rapid
human development, a 95 km2 regulated reservoir and 510 km2 lake. The region has topographic
relief of over 2,339 m, and spans high alpine to arid climatic zones and a range of biomes. Rivers
flow from a triple divide to the Pacific Ocean, Gulf of Mexico, and Hudson Bay – hence the name
“Crown of the Continent”. The area spans the continental divide and has large gradients in all
factors that control hydrologic processes (e.g., climate, topography, vegetation, geology, and land
use factors). Consequently, CCHO is very well suited for basic research regarding the
fundamental understanding of large scale hydrologic processes, especially those of mountain
regions. Since the region spans the climatic transition from maritime-influenced to inter-mountain
to continental zones it shows significant interannual variability with strong signatures from ENSO
and PDO. In addition, the basin’s pristine areas and rich glacial-climate history offer unique
opportunities for isolating the impacts of long term climate change on hydrologic processes. As
part of the CCHO core data program, a large network of high elevation sensors will be installed
across the study area. Data from these sensors will enable unique investigations of mountain
climate processes such as precipitation and orographic processes, snow hydrology, and glacier
mass balance.