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Replacing Canadian National Railroad’s Bonnet Carré Spillway Bridge – Permitting Strategies to Replace Historic Structures in a Complex Regulatory Environment

Thursday, August 27
12:30–1:15 PM PT
 | 3:30–4:15 PM ET

About the Session

uilding and replacing rail infrastructure in sensitive areas under today’s complex regulatory systems requires a team of professionals to achieve the purpose while minimizing impacts. The coastal zone of Louisiana includes diverse ecosystems with overlapping federal, state, and local regulations for permitting infrastructure. During the 1930s, the U.S. Army Corps of Engineers (USACE) constructed the Bonnet Carré Spillway to divert floodwaters from the Mississippi River to Lake Pontchartrain to protect New Orleans. To facilitate spillway construction and maintain operations to New Orleans and ports, CN built a 2-mile-long bridge between two USACE levees. The wooden trestle is beyond its design life and is affected by scour, debris, and termite damage. In 2016, CN’s team began coordinating studies, design, and approvals to replace the bridge. Complex interagency regulatory programs require a shift in how infrastructure projects are planned, designed, permitted and constructed. The days of developing an engineering approach before engaging environmental professionals, regulators, and field engineers are past. Today, regulators expect to review alternatives and provide input for avoiding and minimizing impacts during design. CN’s professionals (e.g., track, structures, operations, environment and real estate) combined with engineering, environmental and cultural resource consultants worked together to meet agency expectations while achieving approvals for a replacement bridge. Critical steps included 1) defining the need and purpose, and 2) evaluating alternatives that would achieve the project purpose and withstand regulatory reviews. Fourteen approvals and NEPA coordination were required. Previously, it was common to permit projects using 30% design and construction impact estimates. Today, agencies expect details of temporary and permanent impacts, progressive reviews, and 90%-100% designs prior to approval. This requires a shift in design and construction planning. This presentation reviews challenges, strategies employed, and lessons learned to successfully attain permits and approvals for sensitive locations in today’s complex regulatory environment.


  • Florida
  • Role of Government in Environmental Improvement
  • Planning and Permitting
  • Coastal Resiliency

About the Speaker

Kari Harris Photo

Kari Harris
Manager, Environmental Impact

Kari Harris is Manager, Environmental Impact for CN’s US operations. Ms. Harris has over 20 years of experience specializing in wetland and stormwater regulations. With extensive project experience across the Midwest, South and Northeast regions of the US, Ms. Harris has considerable understanding in navigating the regulatory framework of federal, state and local wetland permitting and the associated intricacies of design solutions that can translate to practical field applications. 

James Thomas Photo

James Thomas
Vice President
James Thomas manages the Environmental Regulatory Practice in HDR's South Central Region. He is a Professional Wetland Scientist with an emphasis on State/Federal permitting. James has 25 years of experience managing and/ or supporting infrastructure and restoration projects for clients across numerous business and governmental sectors. James also serves as HDR's CWA Permitting Practice lead with an emphasis on monitoring and analysis of regulatory changes.

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