APPENDIX P- AVOIDANCE, MINIMIZATION, AND MITIGATION PLAN, REV 2 I-64 Hampton Roads Bridge-Tunnel Expansion Project Hampton Roads Connector Partners 240 Corporate Blvd. 4th floor Norfolk, VA 23502 Hampton -Norfolk, Virginia December 19, 2019 DOCUMENT HISTORY Issue Date Description By Revision Revised for consistency with Revision 1 of the September 18, 2019 R. Wilk 1 Appendix G – Impact Tables December 19, 2019 Revised for re-submittal R. Wilk 2 TABLE OF CONTENTS P.1 Introduction ................................................................................................................................. 1 P.2 Avoidance and Minimization Overview ........................................................................................ 2 P.2.1 Immersed Tube Tunnel vs Bored Tunnel ............................................................................. 2 P.2.2 Construction ......................................................................................................................... 4 P.2.2.1 Temporary Construction Trestles .................................................................................. 4 P.2.2.2 Tunnel Construction ...................................................................................................... 5 P.2.2.3 Erosion and Sediment Control ...................................................................................... 6 P.2.2.4 Temporary Construction Access in Wetlands ................................................................ 7 P.2.2.5 Pile Driving / Underwater Noise Minimization ................................................................ 8 P.2.2.6 Dredging ....................................................................................................................... 9 P.2.2.7 Moorings ....................................................................................................................... 9 P.2.3 Avoidance and Minimization by Location ............................................................................ 11 P.2.3.1 Hampton ..................................................................................................................... 12 P.2.3.2 Bridge/Tunnel .............................................................................................................. 13 P.2.3.3 Norfolk ........................................................................................................................ 14 P.3 Conclusion ................................................................................................................................ 17 P.4 References ................................................................................................................................ 19 FIGURES Figure P-1: Chesapeake Bay Shellfish Grounds .................................................................................. 10 Figure P-2: Potential Mooring and Anchoring Areas ............................................................................ 11 Figure P-3: Settler’s Landing Road ...................................................................................................... 12 Figure P- 4: Bayville Avenue Exit ......................................................................................................... 15 Figure P- 5: 4th View Interchange ........................................................................................................ 16 TABLES Table P- 1. Impact Comparison for ITT and Bored Tunnel ..................................................................... 3 Table P- 2 Permanent WOUS Impact Reduction through Design ........................................................ 12 Page l P-i ATTACHMENTS Attachment P-1- HCA Attachment P-2- Mitigation Plan Attachment P-3- Benthic Report Page l P-ii P.1 INTRODUCTION The proposed Hampton Roads Bridge Tunnel Expansion (HRBT) Expansion Project will improve a section of Interstate 64 (I-64) that provides an important regional transportation link between the cities of Hampton and Norfolk, Virginia. The Project will address severe traffic congestion and will widen I-64 for approximately 9.9 miles along I-64 from Settlers Landing Road in Hampton, Virginia to the I-64/I-564 interchange in Norfolk, Virginia. The Project will create an eight lane facility with six consistent use lanes. The expanded facility will include four general purpose lanes, two new high-occupancy toll (HOT) lanes, and two new drivable (hard-running) shoulders to be used as HOT lanes during peak usage. Wetlands are regulated under section 404 of the Clean Water Act (CWA) which is administered by the U.S. Army Corps of Engineers (USACE) with oversight by the U.S. Environmental Protection Agency (EPA). The 404 permitting program indicates that no discharge into Waters of the US (WOUS) shall be permitted if first, a practicable alternative exists that is less damaging to the aquatic environment, or if the discharge would cause the nation’s waters to be significantly degraded. For a project to be permitted, it must be demonstrated that, to the extent practicable, steps have been taken to avoid impacts to wetlands and other aquatic resources, potential impacts have been minimized, and compensation will be provided for any remaining unavoidable impacts. Additional regulations are provided by the Commonwealth of Virginia through the state’s certification under Section 401, Virginia Water Protection Permit Program Regulation (9 VAC 25 - 210) and Virginia Marine Resources Commission’s (VMRC’s) wetlands mitigation guidelines (4 VAC 20 - 390). The Hampton Roads Connector Partners (HRCP) identifies the avoidance, minimization, and mitigation steps (see attached) the Project has taken to meet 404 requirements and Virginia regulations. Page l P-1 P.2 AVOIDANCE AND MINIMIZATION OVERVIEW P.2.1 IMMERSED TUBE TUNNEL VS BORED TUNNEL Two methods of tunnel construction were considered for the Hampton Roads Bridge-Tunnel (HRBT) Project design. An immersed tube tunnel (ITT) was placed for the existing tunnel and was proposed as an option during the planning and procurement stage for this Project. HRCP incorporated a bored tunnel construction method during the initial stages of design. A tunnel bored underneath the sediment- water interface will avoid substantial in-water impacts related to dredging and avoid direct navigation impacts to the federally- maintained channel. Less disturbance to the channel and open water reduces concerns to commercial ships and military vessels, which will minimize the impact on the economy, tourism, and national security as the tunnel is being constructed. The bored tunnel construction also reduces overall costs, shortens schedule, and improves worker safety (Table P-1). The use of a bored tunnel approach would substantially reduce the volume of dredging when compared to the ITT approach minimizing the need for ocean disposal. Approximately 1,200,000 cubic yards of dredging are required just for placement of the Immersed Tunnel Tube (ITT). Construction of the bored tunnel under the James River will have less disturbance to the main channel that marine life use as a travel corridor. An ITT approach would require building tunnel sections on land and sinking them in place in a dredged trench, then backfilling the trench and covering with stones to protect it from impacts once the sections are connected. This method is more likely to disturb wildlife due to the increased dredging and back-filling as compared to the bored tunnel construction. Construction of the bored tunnel underground results in a reduction of noise, dust, and visual impacts. Finally, the bored tunnel creates substantially less exposure to weather risks such as wind and wave action during construction as the deeper elevations of the tunnel are constructed under the surface of the James River. Page l P-2 Table P- 1. Impact Comparison for ITT and Bored Tunnel Immersed Tube Tunnel JPA Design Bored Difference between Resource (ITT) Tunnel Bored Tunnel and ITT Subaqueous Bottom, 60 acres 0 acres -60 acres EFH, Benthic Habitat Hampton Harbor Entrance Reach 12 acres 0 acres -12 acres Navigation Channel Dredging (in situ) 1,200,000 0 cubic yards -1,200,000 cubic yards Material Excavated by N/A 1,416,000 cubic yards +1,416,000 cubic yards TBM (below WOUS) 77 months – does not fit into the schedule of VDOT. 62 months until Project Schedule – Total -15 months We could not complete the substantial completion project on time. Construction Schedule – 61 months 36 months -25 months Tunnels only 24 months for placing of In-water Work between caissons + 12 months for the 2 islands (direct finishes, including N/A (apart from TBM -36 months impacts to the backfilling and armor delivery) navigation channel)* stones placement (see quantities below) 810,000 cubic yards of fill Rock placement for -810,000 cubic yards of and 200,000 cubic yards of tunnel protection (in fill armor stones to be placed addition to the material N/A on top of the new ITT needed for island -200,000 cubic yards of expansion) armor stone *An ITT is made out of concrete caissons fabricated in a drydock, floated to the project and sunk in place. HRCP calculated 19 caissons during the bid. Lowering them into place is a complicated and lengthy process. The main risk captured during the risks analysis is in case of emergency (a ship or submarine needs to leave immediately), Navy could ask to free the way in less than 2 hours. If HRCP is in the process of sinking a caisson in the middle of the navigation channel, it would be impossible to move in