Pre-Mining Landscape
This valley once held beaver ponds, wet meadows, shrub thickets and open grasslands. Fires started by Native Americans supported herds of mountain bison and favored growth of grasses and wildflowers on the valley floor.
Archeological evidence from Vail Pass indicates the presence of Paleo-Indians dating back at least 6,800 years. Bands of Utes, the descendants of these early Americans, lived and hunted in this valley. They set fires to reduce tree cover on the valley floor and encourage the grasses preferred by mountain bison. Reduced tree cover eased travel for Utes and offered them greater security from surprise attack. After fires Ute women harvested tender new willow shoots to make baskets.
In 1839, explorer Thomas J. Farnham described the upper Blue River valley as having "swells covered with buffalo and wild flowering glens."
By studying the undisturbed sites near town, we can reconstruct what this view might have looked like before mining. As depicted in the artist's sketch above, beaver lodges formed islands of safety in the centers of shallow ponds. At the margins of ponds and wetlands, shrubby willows and alders formed thickets providing food and building materials for beavers.
On drier upland sites, colorful wildflowers dotted tufted bunchgrass meadows. Much as they appear today, the slopes above were dominated by lodgepole pines, a fire-adapted species. Spruces and fir stands formed dark bands at timberline and along drainages where late-lying snow and runoff kept soils wet and provided protection from fires.
The Mining Years
The 1800s brought mining that drastically altered the landscape. Forests disappeared and dredges turned the valley floor into huge piles of cobbles.
Granites, gneisses, and schists, the ancient rocks at the heart of the mountains surrounding Breckenridge, were first formed more than 600 million years ago (mya). Horizontal forces lifted and fractured these rocks during three separate episodes of mountain building. Solutions of minerals and water seeped through the fractured rocks, depositing gold, silver, lead, and zinc between 30-to-75 mya.
What goes up, must come down. Erosion wore away more than a vertical mile of the overlying rock, leaving the ancient core of the mountains exposed. Eroded materials washed down the Blue River. Finer sands and silts were carried to the Colorado River and on to the Sea of Cortez. Heavier or larger materials collected in the nearby valley floors and were not carried far beyond the confluence of the Blue River, Snake River, and Ten Mile Creek.
The cobble deposits below you descend 60-to-90 feet to bedrock. Flakes of the heavier gold settled in pockets deep within the stream channel, forming rich placer deposits between Breckenridge and the site of the Dillon Reservoir. Soon after gold was discovered in 1859, the landscape was dramatically altered.
Forests were immediately impacted by mining activities. Fires continued in the valley, either set accidentally by blowing embers or set intentionally to expose the rock and make prospecting easier. Although the yearly burning of the valley bottoms by the Utes impacted the area's vegetation, this action did not compare to the devastation that came with the mining years. More than all the fires combined, timber-cutting was responsible for denuding the forested hillsides.
Photographs from the late 1800s reveal that vast areas of trees in the surrounding mountains were cut. Timber provided building materials for cabins, sluice boxes, railroad ties, mine timbers, cribbing, miles of wooden pipes, and fuel for the enormous dredge boats.
For more than eighty years, miners employed a variety of techniques to reach the placer gold and, later, the mother lodes themselves. Each method left an imprint on the landscape. One of the last methods employed, dredging, was the most destructive. It literally turned the valley floors upside down. Dredges were huge floating mine structures build from as many as forty railroad-car loads of Pacific Northwest timber and other structural components.
Between 1898 and 1942, nine dredge boats operated in Summit County. The huge hulls floated on ponds of their own creation. They slowly moved up and down the valleys as they processed the cobble deposits all the way down to bedrock. With their voracious appetite for gold, dredge boats consumed the flowering meadows and wetlands that graced the valley of the Blue River. Larger dredges processed as much as 5,000 cubic yards per day. In a month a volume equal to a football field ninety feet deep was processed to recover $80,000 worth of gold.
Behind the dredges, heaps of dry, barren cobbles, piled two stories high, covered much of the valley floor. By 1942, when the last dredges shut down, most of the vegetation on the valley floor and the soil necessary to support plant growth was gone. It had been washed down the Blue River. Consequently, in places where the dredges had operated, the Blue River literally disappeared underground.
Ecological Restoration
In 1988 Breckenridge created a plan to restore the Blue River. Tons of cobble in the river channel were moved. Soil and thousands of plants from local development sites were relocated to the Riverwalk.
In the 1960s, the piles of cobble in town were leveled to create overflow parking lots for skiers. The once-beautiful Blue River was confined to a narrow ditch. Lacking fin silts and sand between the coarse cobbles, the river flowed deep within the porous deposits most of the year. It surfaced only during peak snow melt in the late spring and early summer.
In 1988 the town of Breckenridge purchased eleven acres of leveled dredge tailings in the heart of town to build the Riverwalk. The river was "restored" by reconfiguring 90,000 tons of cobble and burying a thick plastic liner about five feet under the new channel bottom. More than one quarter of the area was designated for ecological restoration. The dry dredge tailings were converted back to the "wild flowering glens" of the pre-mining landscape.
At 9,600 feet, Breckenridge experiences fewer than fifteen consecutive frost-feet days a year. However, local native plant populations are genetically adapted to survive this harsh climate. To restore these ecosystems in highly disturbed areas, restoration ecologists first sought to understand how native plant communities functioned. Remnants of several historical plant communities, called "target" areas, were identified and studied.
Then, some 11,000 tons of soil similar to that found in the target areas were salvaged from local sites scheduled for construction. This soil contained living microorganisms needed for healthy plant growth as well as the seeds of many local native species. More than 20,000 mature, native plants were also salvaged from these sites for installation on the Riverwalk.
Native seeds were collected from the target areas. Some were directly seeded into the prepared beds. Others were sent to a local grower to produce mature flowering specimens that were planted the following summer.
Yet, the Riverwalk restoration process continues. This site is like a patient in intensive care. It will require careful protection from infection (weeds) as it regains its strength and health (plant density, diversity, and function). This after care period is critical to project's success. A special Town of Breckenridge crew administers aftercare. We invite you to explore this exciting demonstration project. See for yourself the potential that ecological restoration holds for returning the beauty of the Blue River Valley.
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