Impacts on Historical Resources

What is the philosophy in making tradeoffs between the Historical Resources and the widened transportation corridor footprint impact? Throughout the development of all alternatives, the philosophy has been to minimize the impact of the new transportation footprint and to avoid historic resources. We feel that this has been accomplished by the few resources affected. Intangible effects also of a concern are visual, noise, and construction disruption. Through the programmatic agreement to be developed with the consulting parties responsible for local historic interests and the process engaging local communities in developing locally acceptable design solutions, we hope that the project will result in positive, not negative, impacts on the communities.

Existing Wildlife and Water Quality Impacts

Existing I-70 has already caused environmental impacts that need to be addressed. Will these impacts be mitigated? Wildlife and water quality issues were identified early during Tier 1 in light of existing problems. I‑70 currently crosses many traditional wildlife movement and migration routes, creating a barrier or restricting wildlife movement and reducing access to critical habitat. These areas are termed wildlife linkage zones. CDOT and FHWA enlisted four other state and federal agencies — CDOW, Bureau of Land Management (BLM), US Forest Service (USFS), and US Fish and Wildlife Service (USFWS) — to participate in a program to address the barrier effect issues of the Corridor. This committee, named the “ALIVE Committee” (A Landscape Level Inventory of Valued Ecosystems), identified wildlife crossings or other mitigation at 14 critical wildlife linkage zones along the Corridor between C-470 and Glenwood Springs, where wildlife movements are impeded by the highway. Three water-resource-related programs were established to gather information on water resources within the Corridor. These programs included the Sediment Control Action Program for Black Gore Creek and Straight Creek, the Stream and Wetland Ecological Enhancement Program, and the Storm Water Quality Monitoring Program. Specific mitigation activities for wildlife and water quality will be further studied and identified during Tier 2.

Social and Economic Values Issues

If nothing is done, how much economic loss will there be in the mountain communities? Peak weekend recreation travel demand within the Corridor would be suppressed by more than 20 percent if no increases in travel capacity are made in Corridor, resulting in economic impacts on the mountain region. With the suppression of recreation trips, there would be a reduction in recreation spending and costs associated with transportation delays in the Corridor that could affect the annual gross regional product for the nine -county region (Eagle, Garfield, Gilpin, Grand, Lake, Park, Pitkin, Summit, and Clear Creek counties) by up to $10 billion by 2035 from expected levels.

How will the possible impacts of induced or suppressed growth be considered in selection of the preferred alternative? Decision-makers would be faced with tradeoffs during the process because Corridor growth is generally associated with Corridor economic growth, and efforts to limit growth/development might also limit economic growth. The Draft PEIS compares alternatives in terms of growth impacts and allows the public to examine and comment on alternatives based on growth impacts and economic and transportation mobility tradeoffs.

Water Quality and Winter Maintenance

Were impacts on water quality from winter maintenance activities (sand and deicer) considered? What will be done to control impacts from winter maintenance? The Draft PEIS compares alternatives based on historic levels of sand and deicer usage. CDOT is implementing Sediment Control Action Plans in existing problem areas of the Corridor. The Sediment Control Action Plans include sediment retention areas. Snow storage areas have been incorporated into the typical sections of the Highway alternatives. Tier 2 studies will include further study and detailed mitigation plans to protect Corridor water quality.

Clear Creek County - Special Concerns

Noise Impacts and Mitigation - In Clear Creek County, what kind of noise abatement program is feasible, especially in Idaho Springs? A number of noise mitigation strategies can be applied to reduce highway noise. The most commonly employed noise mitigation is the use of noise walls, which reduce noise by blocking the line of sight between a noise source (I-70 traffic) and a receptor (communities along the Corridor). Concerns for the use of sound walls in Clear Creek County include economic impact to businesses that may no longer be visible from I-70, aesthetics, reflection of noise to residents on the opposite side of the highway, and icing. There are no recommended or proposed noise mitigation measures at this time. These measures will be considered where applicable in future Tier 2 studies. Noise mitigation measures will be evaluated for properties during these studies that meet the impact criteria under the appropriate regulations (FHWA/FTA) based on the future proposed alternatives.

Inequity of Impacts and Benefits - In Clear Creek County, will there be more impacts than benefits if the action alternatives are implemented? Because all of the build alternatives are in Clear Creek County, there are more impacts on that county than the other counties along the Corridor. The Draft PEIS discloses impacts – both potentially adverse and beneficial. The consideration of the environmental sensitivity and community values purposes have shaped many of the alternatives evaluated. For example, the community’s desire for a narrow footprint helped to shape the alternatives and reduce impacts on streams and historic properties.

Property/Structure Impacts - Exactly how many property takes will there be in Clear Creek County under the action alternatives? Due to the conceptual stage of planning and design at the Tier 1 level, exact numbers of property takes would not be determined until Tier 2 level site-specific studies are conducted. Tier 1 level studies indicate that there is the potential to avoid all structures in the towns of Clear Creek County by minimizing the footprint of the alternatives, and construction zones at interchanges, where impacts on structures would most likely occur. Without mitigation, the following is an estimate of the number of structures in Clear Creek County that were identified within the footprint of conceptual alternatives: Minimal Action – 11, Rail –16, AGS and Bus in Guideway – 12, Six-Lane Highway – 13, Reversible HOV/HOT Lanes – 20, and Combination Six-Lane Highway with Transit alternatives – 20. One of these impacts is to a historic structure near Georgetown, which would be unavoidable.

Emergency Response and Gaming Access - A frontage road between Floyd Hill and Hidden Valley needs to be constructed for Clear Creek County residents and for emergency response. Besides I‑70, no access for local residents or emergency services occurs between Floyd Hill and the Hidden Valley interchange. The narrow valley and steep topography makes the development of local access difficult through this portion of Clear Creek Canyon. Depending on the outcome of the I‑70 PEIS, options of a frontage road could be examined as a part of the I‑70 Tier 2 process. Initial cost estimates for frontage road connections between East Idaho Springs and Hidden Valley, and Hidden Valley to US 6 have been included in the PEIS for each alternative.