The geology of the watershed is composed of a diverse collection of Paleozoic and Mesozoic sedimentary rocks intruded by Tertiary igneous laccoliths and ore-rich stocks. Cretaceous Mancos Shale forms the primary bedrock of the study site. The Mancos is a marine black shale with spatially variable composition, including regions of elevated metal, metalloid, and pyrite content and varying degrees of alteration stemming from igneous dikes and sills cross-cutting the catchment. The watershed hosts multiple metal-rich ore deposits (including those mined at the former Standard Mine, a U.S. EPA Superfund site within the Coal Creek drainage) and the combination of structurally and economically important features has resulted in extensive geological mapping, with geologic data needed for model parameterization existing over the entire study domain. Supplementing this information is a newly acquired, high-resolution Light Detection and Ranging (LiDAR) dataset covering much of the study area and enabling a digital elevation model (DEM) of the watershed having a spatial resolution of <0.5 m.
The more ‘pristine’ upper East River drainage above the confluence with Brush Creek covers an area of ca. 180 km2 and is the site of the Rocky Mountain Biological Laboratory (RMBL), which provides an extensive experimental and observational database of relevance to the catchment’s ecohydrological functioning. Of note, RMBL enables data sharing related to meteorology, phenology, experimental warming, plant water utilization, and coupled vegetation-microbiology studies of direct relevance to the Berkeley Lab SFA research program. Constraints on the annual atmospheric deposition of nitrogen species and other aerosols at the site are provided through the presence of the U.S. Environmental Protection Agency’s Gothic, Colorado Clean Air Status and Trends Network (CASTNET) station collecting data under the National Atmospheric Deposition Program (NADP). RMBL facilities include laboratory and greenhouse space, soil warming plots, dining and housing, and field logistical coordination that enables execution of SFA science objectives.
Excursions in river discharge are driven primarily by snowmelt in late Spring/early Summer, with mid- to late-summer monsoonal rainfall inducing rapid but punctuated increases in flow. Berkeley Lab and its collaborators have established a network of 17 stream gauging stations for all major tributaries within the study area, with rating curves established for each. Each station also constitutes a stream water sampling location, with daily and weekly/bi-weekly samples collected beginning in May 2014. The U.S. Geological Survey maintains three additional gauging stations of relevance: Coal Creek; Slate River; and East River at Almont. In partnership with RMBL, Berkeley Lab has expanded and upgraded a meteorological network composed of six stations spanning an elevation gradient from 3500-2400 m. This network of stations supplements the data records available from the Butte and Schofield Snow Telemetry (SNOTEL) and Crested Butte Cooperative Observer Network (COOP) stations. Many other datasets are currently and will soon be available to support science at the site.
