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Environmental & Mitigation

Environmental & Mitigation | Section 4(f) Regulations

Mitigation Measures being Proposed in the Final EIS (FEIS)

Community Mitigation Update, Notice to Elyria and Swansea Residents, Mitigation Measures being Proposed in the Final EIS (FEIS) - October 2015 (thumbnail) Since the start of the I-70 East project more than a decade ago, the Colorado Department of Transportation (CDOT) and the Federal Highway Administration (FHWA) have worked to involve the communities in the project area in the decision making process. Identifying mitigations to reduce the impacts of the project has been an important part of this effort.

The 2014 Supplemental Draft Environmental Impact Statement (EIS) included a number of proposed mitigation measures. This update describes proposed mitigation measures that have been revised and refined based on the comments received on the 2014 Supplemental Draft EIS and additional analyses. These proposed mitigation measures will be included in the Final EIS, which will be released for public review in January 2016. A Record of Decision (ROD) is expected in summer 2016 with construction beginning in 2017.

Community Mitigation Update (Oct. 2015)

Social, Environmental, and Economic Resources

The I-70 East EIS will consider possible effects that alternatives might have on a variety of social, environmental, and economic resources. These resources include: Photos: Social, Environmental, and Economic Resources - I-70 East Environmental Impact Statement (EIS)

bulletSocial and Economic Conditions

bulletEnvironmental Justice

bulletLand Use and Zoning

bulletLand Acquisition, Displacements, and Relocation of Existing Uses

bulletHistoric Properties

bulletVisual and Aesthetic Qualities

bulletParklands and Recreation

bulletAir Quality



bulletBiological Resources

bulletFloodplains and Drainage/Hydrology

bulletWetlands and Waters of the U.S.

bulletWater Quality

bulletGeology and Soils

bulletHazardous Materials



bulletCumulative and Secondary Impact Considerations

Read more about the Section 4(f) Regulations which establishes the requirements for consideration of park and recreation lands, wildlife and waterfowl refuges, and historic sites during transportation project development: Section 4(f) Regulations

Assessments of the potential effect on each of these resources due to project alternatives are being prepared as part of the EIS. Here is a sample of information you'll find in the SDEIS:

Environmental Justice

CDOT has stated that the Swansea-Elyria neighborhood is an environmental justice community. One of the defining principles of environmental justice is to avoid, minimize, or mitigate disproportionately high and adverse human health and environmental effects—such as air pollution—on minority and low-income populations. Several sources have suggested that the air pollution created by lowering and covering the highway through this section might violate these tenets. More information on this topic will be presented in the SDEIS.

Land Acquisition

A key advantage of the PCL Alternative is that it allows Swansea Elementary School to remain in its current location despite the northern shift of the highway. CDOT developed these mitigation measures when it became clear that a suitable replacement site does not exist within the neighborhood. The agency has committed to design a completely reconfigured play space located at the end of the school property farthest from the highway. In addition, CDOT has committed to provide new windows and an HVAC system for the school—which is above and beyond the mitigation that normally would be required.

Air Quality

Determining impacts on local and regional air quality is a critical component of CDOT's current environmental impact study. To receive transportation funding or approvals from the Federal Highway Administration, CDOT must determine whether emissions associated with the I-70 East project will cause the Denver metro area to violate national ambient air quality standards. If the project creates a new violation of these standards, or makes any violations already identified even worse, the project can't be built. This pass/fail test (known as an air quality conformity determination) is one of the most stringent environmental standards evaluated in the National Environmental Policy Act process. A "hot spot" analysis for particulate matter on either side of the covered highway also is part of CDOT's air quality analysis. Later, during the building period, the project will—at a minimum—use dust control measures, neighborhood notification, and air quality monitoring. CDOT is also investigating ways to improve the homes of those who will be living near the project during construction by providing retrofits to items such as doors, windows, and ventilation.

Water Quality

While some portions of the lowered highway may be below the top of the water table, this will not generate impacts to water quality. It will not force water into the South Platte River, which is located in this area, nor will CDOT allow groundwater to seep into the highway facility. Any groundwater removed during construction will be treated and disposed of in ways allowed by the Colorado Department of Public Health and Environment (CDPHE).