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Instream Restoration Riparian Restoration Fish Passage
High Elevation Dam Removals in Rocky Mountain National Park   Rocky Mountain National Park, Colorado
Primary Project Type: Fish Passage
     Secondary Type:
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  Bluebird, Pear, and Sandbeach Dams were removed from high altitude wilderness in...  

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Primary Problem: Dams
     Secondary Problem:
Main Restoration Action(s): Channel reconstruction
Native Fish Focus: Greenback cutthroat
Is this project part of a watershed scale restoration? No
Project Dates: Summer 1988 to Summer 2002
  Initial Monitoring: 1989
Restoration Implementation: 1988-1990, 2002
Follow-up Monitoring: 1993, 1998, ongoing
Lead Agency:
     National Park Service
Project Partners:
Project Location: Bluebird, Pear, and Sandbeach Lakes are located at elevations above 10,000 feet in the southeast corner of Rocky Mountain National Park at the headwaters of Colorado’s Platte River system. Lawn Lake is located at an elevation above 10,000 feet in the northeast corner of the park at the headwaters of the Big Thompson River. Bluebird Lake is located at the head of Ouzel Creek, which travels approximately three miles before it joins the North Fork of the Saint Vrain River. Along the way, it travels through Ouzel Lake and Ouzel Falls. Pear Lake is located along Pear Creek, a tributary of Cony Creek, which discharges into the North Fork of the Saint Vrain River. Sandbeach Lake is located at the head of Sandbeach Creek, a tributary of the North Fork of the Saint Vrain River. It is one of the deepest lakes (50 feet) in Rocky Mountain National Park. Lawn Lake is located along the Roaring River, a tributary of Fall River that flows into the Big Thompson River. For a map of the project area, click here.
Project Description: Prior to the 1915 establishment of Rocky Mountain National Park, four high mountain reservoirs had already been built in the park, primarily for water storage for the city of Longmont, Colorado. In July 1982, Lawn Lake Dam failed, resulting in almost 22 million cubic feet of water rushing into the Roaring River. Damages downstream to the town of Estes Park were estimated to be $31 million, and there was a loss of three lives. An immediate inspection and analysis of other high mountain reservoirs revealed three other dams were leaking and/or severely deteriorated — the 60-foot-high, 200-foot-long Bluebird Dam; the 26-foot-high, 90-foot-long Sandbeach Dam; and the 26-foot-high, 140-foot-long Pear Lake Dam. Bluebird Dam was a concrete dam and the other dams were primarily dirt and rock. The Colorado State Engineer’s office directed the city of Longmont, owners of water storage rights in the dams, to breach or repair the dams. The water level behind the three dams was reduced immediately.

In 1987, Rocky Mountain National Park purchased the easement for the three dams, and planning for dam decommissioning began. The Lawn Lake Dam was in litigation until 2001, and restoration did not occur until 2002. Following the Environmental Assessment, the decision was made to remove the dams entirely. Dam removal was difficult due to their high elevation, and because the dams were four to seven miles into the backcountry. Careful dam removal was also necessary as the watershed was home to valuable spawning habitat for the greenback cutthroat trout (Oncorhynchus clarki stomia). It is one of three salmonids native to Colorado east of the Continental Divide listed as threatened under the Federal Endangered Species Act.
Project Goals: The goals of the restoration project were to remove the Bluebird, Sandbeach, Lawn and Pear Lake Dams; restore the wilderness area to natural conditions that included restoring pre-dam lake levels; minimize erosion into the lakes from steep hill slopes; and re-establish native plants.
Project Methods: The 26-foot-high earthen rock/stone masonry Sandbeach and Pear Lake Dam removals were accomplished in the summer of 1988 with a bulldozer and pneumatic hammers. Most of the removal of the 60-foot-high concrete Bluebird Dam occurred in the summer of 1989. To remove remnant dam and rubble material, work continued in the summer of 1990. Close monitoring and a high degree of caution had to be used during demolition of all four dams because of the location of the dams in wilderness backcountry, the sensitive nature of their high-altitude environment, and the presence of the threatened greenback cutthroat trout. Due to the proximity of greenback cutthroat trout in the outlet stream less than a mile below Bluebird Lake, an alternative method to dynamiting had to be used, as there was concern that concrete dust would increase the turbidity and pH of the stream. A Schaeff Walking Excavator with a hydraulic hammer on its arm was used to demolish the dam structure. The earthen rock/stone masonry Lawn Lake Dam was removed in the summer of 2002. Click here for more information on methods used.
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  Due to the proximity of greenback cutthroat trout in the outlet stream less than...  
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  The Erickson Sikorsky S-64 Sky Crane, one of only seven in commercial operation,...  
Monitoring Data and Collection Methods: Restoration monitoring plots 10 by 15 meters in size were randomly established on the dam sites of Bluebird, Pear and Sandbeach Lakes in the summer of 1989. Photo points were established along the shores of the three lakes in 1989. Vegetation plots were established along the lakeshore of Lawn Lake in 1983. Click here for more information on monitoring.
Was this project effective and how was this determined? After 80 years of disturbance from four dams impounding water in the backcountry of Rocky Mountain National Park, natural processes once again prevail. Lawn, Sandbeach and Pear Lakes and their outlet streams have reestablished populations of the native greenback cutthroat trout. Restoring the native trout to these lakes brings the the species one step closer to down-listing from threatened status. All four lakes are back to pre-impoundment water levels. Native flora and fauna are moving back into the disturbed areas, as fitting for a natural preserve such as Rocky Mountain National Park. There is now no evidence left behind of the four dams, other than the plaques describing the restoration efforts that took place. Research conducted on natural restoration in spruce/fir forests in Rocky Mountain National Park indicates it could take 100 to 200 years for the lakeshores to fully recover. The natural resources of an area disturbed by reservoir creation can recover if given the chance.
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  (Before) Bluebird Lake Dam in 1989. Over the course of two summers, crews worke...  
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  (After) Bluebird Lake site in 1993 (after removal of dam)....  
Confounding Effects/Additional Information:
Project Specs (all specs are estimates):
  Overall Estimated Cost: $1.9 million and $1.5 million to acquire water storage rights from the City of Longmont.
For more information on this project contact:
  Jeff Connor, Natural Resources Specialist, Rocky Mountain National Park, Estes Park, Colorado 80517, Email:
Joe Arnold, Rocky Mountain National Park, Estes Park, Colorado 80517, Email:
This information was collected by: Kristin Keith & Anne Martell
Project last updated on: 8/9/2007

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Updated: February 16, 2007
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