Fremont Pass Riparian Corridor Restoration Project

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Submitted by: Colorado Mountain College Natural Resource Management Institute

 Abandoned highway
Abandoned highway adjacent to the Arkansas River.

Project Partners:
Bureau of Land Management, U.S. Forest Service, Colorado Department of Transportation, Climax Molybdenum Corporation, Colorado, Mountain College Natural Resource Management Institute, Lake County, Commissioners and County Departments, Trout Unlimited, and Frontier Environmental Services.

As part of the enactment of Section 319 of the Clean Water Act, a national program was initiated that served to control non-point sources of water pollution, as well as means to help fund state and local implementation of non-point source management programs. Non-point source pollution occurs as water from rain and snowmelt moves over and through the ground collecting natural and human-made pollutants, and eventually enters lakes, rivers, streams, wetlands, estuaries, coastal waters and groundwater. This project was needed in order to stop erosion of materials from entering a very large wet meadow complex located along Highway 91 above Leadville, Colorado.

Under Section 319, States must develop management programs with identified best management practices (BPMs) suitable for reducing non-point source (NPS) pollution. To ensure the management programs are realized, Congress established Section 319 to award grants to states for implementation of non-point source management programs. This project is a grant award recipient of the 319 program in the State of Colorado.

The goal of the Fremont Pass Riparian Corridor Restoration Project was to stop erosion of sediments and road base from an abandoned roadway from entering the Arkansas headwaters and to heal raw cut banks between the abandoned roadway and new highway. The drainage from Highway 91 also needed correction. Failure to stop this bed load of material would introduce instability to an otherwise very stable stream/valley bottom at the headwaters of the Arkansas River.

Bank instability has been a common problem in the upper Arkansas resulting from historic dumping of mine waste into drainage ways. Although not mine spoil, excessive bed-load from the roadway will have similar impacts. Through 319 funding, best management practices were identified and applied to complete the project and to correct the drainage from Highway 91. Colorado Mountain College Natural Resource Management (CMC NRM) with the partnership of the Bureau of Land Management (BLM) provided the mechanism by which to complete the construction and monitoring associated with the project. The BLM has sponsored this project due, primarily, to a federal mandate to protect and restore riparian and wetland ecosystems on public lands.

 Sedimentation basin
Sedimentation basin with new vegetation.

The roadway was an old highway that paralleled Highway 91 for approximately two miles along the headwaters of the Arkansas River downstream from the Climax Mine. Due to lack of maintenance, banks between Highway 91 and the old highway had eroded due to excessive snow loads, runoff, and a steep gradient. The resulting sediment load had plugged culverts, and the re-routed water was eroding the road base along the old highway. The asphalt within the road base was breaking up and eroding severely. In addition, the un-drained moisture was further eating away the hill toe-slops creating areas of mass waste between Highway 91 and the old highway.

It was imperative to keep bed load from entering the Arkansas River so as to minimize impacts to water quality and fisheries habitat. The project area was located very near the top of a priority watershed within the Upper Arkansas River drainage basin. Material was being transported into downstream meadows, which are unconfined. The deposition was forming large bars at the top of the meadows. The introduction of sediments created instability in what was a very stable wet meadow/willow complex. Failure to stop sediment/road base fill material from entering the stream would have resulted in massive bank erosion downstream, which has been a persistent problem in other parts of the river below Leadville.

CMC NRM conducted public meetings, as well as construction activities, re-vegetation and sediment fence installation, and monitoring, which took place pre- and post-construction. CMC NRM acted as the liaison for all active parties involved by hosting and coordinating meetings and ensuring communication between all involved parties. Frontier Environmental Services completed the design/build engineered remedy for the project, including contouring of the old highway road bed, construction of the sedimentation basins and associated outfalls, as well as amendment of the old highway outfalls.

Best management practices were developed to reduce the non-point source water pollution affecting the watershed including:

  1. Breaching the roadway at locations of plugged culverts,
  2. Tilling in old road base with underlying material to create a water permeable layer to eliminate sheet flow,
  3. Ripping/seeding roadway, mulch and seeding eroding cut banks,
  4. Developing parking at locations to stop traffic and installing gates to limit vehicle traffic within the project foot print,
  5. Controlling water sources from the new highway which caused erosion above the old highway, and
  6. Contouring terrain within the old highway footprint where necessary to alleviate erosion.

All of the above BMPs were used, and additional ones were identified as the project progressed, including construction of sedimentation basins with metered releases, and enhancement of functional existing culvert systems.

Monitoring of the reclamation recovery as well as continued re-vegetation and project maintenance will continue. Students from Colorado Mountain College Natural Resource Management classes will collect the field data, complete electronic data entry and continue to revise the monitoring methods and results documentation that NRM has begun.

The project received a tremendous amount of public interest and participation. Several public hearings were announced in the news media, and the public was invited to voice opinion and concern. Tours of the project were held on a requested basis. The project served well for interpretation and education of BMPs of abandoned site rehabilitation techniques at high elevation. The area receives high traffic and provides a great opportunity to educate visitors from the Front Range as they enter the Leadville area. Interpretation topics in addition to site rehabilitation include: stream function, roadway/water interaction, proper road construction design in steep country, and the BMPs to use when constructing roads.

In addition to support from the Section 319 program, the project would not have been possible without support from Lake County. Their initial involvement was limited to coordination and approval of the old highway road closure. As the project progressed however, personnel, equipment and labor from the County Road and Bridge department was contributed. A large amount of services were also provided by the Colorado Department of Transportation including, labor, guidance, and equipment operations. Trout Unlimited was a partner in this effort and obtained rock contributed by the Climax Molybdenum Corporation and installed a gate at the south end of the project area.