Impacts and Mitigation
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SECTION 3 Impacts and Mitigation This section summarizes the results of the Transportation Resources and Issues............ 3-3 environmental analyses conducted for this EA. Human Resources and Issues ....................... 3-13 The resource areas that were studied are consistent Socioeconomics ........................................ 3-15 with the National Environmental Policy Act Environmental Justice............................... 3-19 (NEPA) and implementing regulations, as well as Right-of-Way............................................ 3-25 CDOT and Federal Highway Administration Community Resources and Issues................ 3-31 (FHWA) guidelines. Detailed studies for these Neighborhoods.......................................... 3-33 resource areas were completed, and the resulting Parks and Recreation ................................ 3-37 information is contained in Technical Memoranda. Land Use................................................... 3-47 The Technical Memoranda are contained in the Visual Resources....................................... 3-51 Technical Appendices to this EA. Air Quality ................................................ 3-57 Noise ......................................................... 3-63 The project study area can generally be described Water Resources and Issues ......................... 3-73 as extending approximately one-half mile from Watersheds................................................ 3-75 either side of the centerline of I-25, as shown in Floodplains................................................ 3-79 Figure 1-2 in Section 1. However, the project Water Quality............................................ 3-85 study area does vary for different resource areas. Wetlands ................................................... 3-91 For instance, when observing economic Biological Resources and Issues ................... 3-93 conditions, it is useful to look at El Paso County in Wildlife ..................................................... 3-95 its entirety, or the whole region that I-25 serves. Threatened/Endangered Species ............. 3-101 As described in Section 2 of this EA, Vegetation............................................... 3-105 transportation alternatives were identified early in Noxious Weeds....................................... 3-107 the process in the I-25 Mode Feasibility Cultural Resources and Issues ................... 3-109 Alternatives Analysis. Many public workshops Historic Resources .................................. 3-111 were held to refine the ideas developed around the Archaeology............................................ 3-125 various alternatives. This process resulted in the Native American Consultation................ 3-127 development of a Concept Design that first avoids Paleontology ........................................... 3-129 impacts, then minimizes impacts that could not be U.S. Air Force Academy Issues .................. 3-131 avoided, and finally mitigates any potential Other Resources and Issues........................ 3-151 impacts. The end result is the Proposed Action, Hazardous Waste Sites............................ 3-153 which is discussed in detail in this section. The Indirect Effects........................................ 3-159 No-Action Alternative is also discussed for Summary of Impacts and Mitigation......... 3-165 comparison. Section 3 is organized as follows: (1) a discussion of each resource and the current conditions of that resource; (2) a description of the impacts of both the Proposed Action and the No-Action Alternatives; and (3) a description of the mitigation that is being committed to as a way to offset unavoidable impacts. Specific discussions can be found on the following pages. DEN/E072003002.DOC 3-1 Concept Development Process Various interchange types were presented to the In order to identify and quantify anticipated public for review and input, and multiple aspects impacts, it was necessary to understand the of each alternative were evaluated. Traffic configuration and the “footprint” of the operations, constructibility, cost, right-of-way improvements that comprise the Proposed Action. impacts, and environmental impacts were among This did not require detailed, final engineering the factors considered in the overall evaluation of plans and specifications, but did require each concept. conceptual-level plans that convert the planning- ENVIRONMENTAL APPROACH FOLLOWED level project description into a three-dimensional IN THE DESIGN CONCEPT PROCESS: template. This level of detail was needed to be able to understand the potential impacts of the 1. Avoidance of environmental impacts Proposed Action. 2. Minimization of any unavoidable impacts It was noted in the description of the Proposed Action that efforts were made to avoid 3. Mitigation of any remaining unavoidable impacts environmental impacts in the development of interchange reconstruction concepts. The same One interesting development in this process took approach was used in developing proposed alignments and elevations for the freeway place with respect to the proposed reconstruction mainline. For example, efforts were made to of the Fillmore Street Interchange. After the entire minimize right-of-way impacts and encroachment concept selection process for Fillmore had been completed in June 2001, CDOT officials were into parks and floodplains. concerned that the selected diamond interchange The engineers and designers who developed concept still had too great an impact on the interchange alternatives and mainline alignments surrounding residential area to the west. took environmental constraints into account A previously considered alternative called a single throughout the conceptual design process. The point urban interchange was revisited and refined, hierarchy of steps that was followed in this process then brought back to the public for consideration. was as follows: A definite tradeoff was involved: the urban interchange was inferior to the diamond 1. AVOIDANCE: impacts to environmental interchange in terms of expandability and driver resources were avoided wherever possible expectation, but offered the advantage of taking (example: mainline design speed on a curve fewer residential properties. At a subsequent was lowered to avoid impacting a floodplain). public meeting held in October 2002, CDOT 2. MINIMIZATION: in cases where complete proposed and the public embraced changing the avoidance of an environmental resource was concept to the urban interchange design. not feasible, design solutions were developed Avoidance of environmental impacts at the to minimize unavoidable impacts (example: concept selection stage was followed by efforts to roadside retaining walls were incorporated also minimize adverse impacts. In converting the into the conceptual design to minimize right- Proposed Action to a three-dimensional of-way impacts). conceptual design, the engineers modified 3. MITIGATION: after avoiding and minimizing horizontal and vertical alignments of the roadway environmental impacts as much as possible, where feasible to minimize the project’s impacts mitigation techniques were proposed to to adjacent properties. address any remaining, unavoidable impacts It is anticipated that additional opportunities for (example: materials from displacing a small impact minimization will be available in the portion of an historic stone wall will be used process of taking the conceptual plans to the more to restore other wall sections displace by an detailed level of actual engineering plans for earlier, unrelated project). construction. Therefore, the magnitude of For each interchange reconstruction project, remaining project impacts described in this section multiple public meetings were held, always in the is expected to be a “worst-case” scenario. immediate vicinity of the proposed project. Appropriate mitigation has been identified to address these impacts. 3-2 DEN/E072003002.DOC Transportation Resources and Issues This subsection addresses traffic, transit, and related intermodal issues. Trails are discussed in a later subsection, under the topic of “Parks and Recreation.” DEN/E072003002.DOC 3-3 Transportation Resources and Issues Existing traffic conditions in the I-25 corridor are An automated traffic recorder located just north of known from data collected by CDOT or local Bijou Street has chronicled the growth of I-25 governments. Projected future conditions are traffic over the years and also provides insights to based on the Destination 2025 Regional Long hourly, daily, weekly, and seasonal variation. For Range Transportation Plan, prepared by the example, the ten busiest days of traffic at this regional planning agency—the Pikes Peak Area location in the year 2002 were all Fridays in the Council of Governments (PPACG). Traffic spring or summer, with volumes ranging from forecasts for 2025 were derived based on outputs 116,000 to 121,500 vehicles (all lanes, northbound from TRANPLAN, which is PPACG’s regional plus southbound). Average weekday traffic is traffic forecasting model. Adopted PPACG lower than these peak daily counts, closer to economic data and roadway networks were used 110,000 vehicles daily. as model inputs. TABLE 3-1 Current Conditions Chronology of I-25 Interchange Projects Current conditions of traffic and transit as they Year Year Year Exit Interchange Built Added Reconstructed pertain to the I-25 corridor are described below. 161 SH 105 (Monument) 1959 2004 Traffic 158 Baptist 1963 * 156 North Gate/future 1959