Southeast Extension Environmental Assessment Extending Transit Service from the Lincoln Light Rail Transit Station to RidgeGate Parkway Prepared for: Federal Transit Administration Prepared by: Denver Regional Transportation District August 2014 Southeast Extension Environmental Assessment Table of Contents Page No. Executive Summary .............................................................................................................. ES-1 ES.1 Introduction ............................................................................................................ ES-1 ES.2 Description of Proposed Project ............................................................................ ES-1 ES.3 Purpose and Need ................................................................................................ ES-1 ES.4 Alternatives Considered ........................................................................................ ES-1 ES.4.1 No Action Alternative ................................................................................. ES-2 ES.4.5 Locally Preferred Alternative ..................................................................... ES-2 ES.5 Environmental Consequences and Mitigation ....................................................... ES-7 ES.5.1 Resources with No or Minimal Impacts ..................................................... ES-7 ES.5.2 Resources with Impacts ............................................................................ ES-8 ES.6 Transportation Systems ...................................................................................... ES-10 ES.7 Public Comment and Agency Coordination ......................................................... ES-11 ES.8 Impacts and Mitigation Summary ........................................................................ ES-12 Chapter 1.0 Purpose and Need ...............................................................................................1-1 1.1 Introduction ............................................................................................................... 1-1 1.2 Purpose of this Chapter ............................................................................................ 1-1 1.3 Project Location and Study Area .............................................................................. 1-1 1.4 Background and Project History ............................................................................... 1-3 1.5 Purpose for the Proposed Action ............................................................................. 1-3 1.6 Need for the Project ................................................................................................. 1-5 Chapter 2.0 Alternatives Considered .....................................................................................2-1 2.1 Introduction ............................................................................................................... 2-1 2.1.1 Funding ......................................................................................................... 2-1 2.2 Alternatives Development, Screening Process, and Criteria .................................... 2-1 2.2.1 Alternatives Developed and Evaluated ......................................................... 2-1 2.3 Screening Process and Criteria ................................................................................ 2-2 2.3.1 Level 1 Screening Results ............................................................................ 2-2 2.3.2 Level 2 Screening Results ............................................................................ 2-3 2.3.3 Design Modifications Following Level 2 Screening ...................................... 2-3 2.4 Identification of the Locally Preferred Alternative ..................................................... 2-4 2.5 Description of the Locally Preferred Alternative ....................................................... 2-4 TOC-i Southeast Extension Environmental Assessment 2.5.1 SkyRidge Station .......................................................................................... 2-5 2.5.2 Lone Tree City Center Station ...................................................................... 2-5 2.5.3 RidgeGate Station ........................................................................................ 2-5 Chapter 3.0 Affected Environment, Impact Evaluation, and Mitigation .............................. 3-1 3.1 Section 4(f) and 6(f) Analysis ................................................................................... 3-3 3.2 Land Acquisitions, Displacements, and Relocations of Existing Uses ..................... 3-3 3.2.1 Affected Environment ................................................................................... 3-3 3.2.2 Impacts ......................................................................................................... 3-4 3.2.3 Indirect Impacts ............................................................................................ 3-5 3.2.4 Construction Impacts .................................................................................... 3-5 3.2.5 Cumulative Impacts ...................................................................................... 3-5 3.2.6 Mitigation ...................................................................................................... 3-7 3.3 Noise and Vibration .................................................................................................. 3-8 3.3.1 Affected Environment ................................................................................... 3-8 3.3.2 Impacts ....................................................................................................... 3-11 3.3.3 Mitigation .................................................................................................... 3-14 3.4 Biological Resources .............................................................................................. 3-15 3.4.1 Affected Environment ................................................................................. 3-16 3.4.2 Impacts ....................................................................................................... 3-19 3.4.3 Mitigation .................................................................................................... 3-24 3.5 Waters of the U.S. and Wetlands ........................................................................... 3-26 3.5.1 Affected Environment ................................................................................. 3-26 3.5.2 Impacts ....................................................................................................... 3-29 3.5.3 Mitigation .................................................................................................... 3-30 3.6 Cultural Resources ................................................................................................. 3-31 3.6.1 Summary of Section 106 Consultation ....................................................... 3-31 3.6.2 Affected Environment ................................................................................. 3-32 3.6.3 Impacts ....................................................................................................... 3-36 3.6.4 Mitigation .................................................................................................... 3-37 Chapter 4.0 Transportation Systems .....................................................................................4-1 4.1 Transit Service ......................................................................................................... 4-1 4.1.1 Existing Transit Service ................................................................................ 4-1 4.2 No Action and Locally Preferred Alternative ............................................................. 4-4 4.2.1 No Action Alternative .................................................................................... 4-4 TOC-ii Southeast Extension Environmental Assessment 4.2.2 Locally Preferred Alternative ........................................................................ 4-4 4.3 Transit Impacts ......................................................................................................... 4-6 4.3.1 Ridership ...................................................................................................... 4-6 4.3.2 Station Boardings ......................................................................................... 4-6 4.3.3 Travel Time ................................................................................................... 4-7 4.4 Station Area and Surrounding Roadway Impacts and Mitigation ............................. 4-7 4.5 Pedestrian and Bicycle Facilities Impacts and Mitigation ......................................... 4-8 4.5.1 No Action Alternative .................................................................................... 4-8 4.5.2 Locally Preferred Alternative ........................................................................ 4-8 4.6 Construction Impacts and Mitigation ........................................................................ 4-9 4.6.1 Roadway Construction Impacts and Mitigation ............................................ 4-9 4.6.2 Pedestrian and Bicycle Impacts and Mitigation ............................................ 4-9 Chapter 5.0 Public Involvement and Agency Coordination .................................................5-1 5.1 Public and Agency Involvement