Supplemental Environmental Impact Statement

Compared to the No-Build Alternative, the Modified LPA is expected to benefit transportation in 2045 by:​

• Reducing crashes​

• Increasing people moving through the corridor while reducing the number of vehicles on the road

• Improving access to public transit

• Providing safer and more accessible crossings for people who walk, bike and roll.

• Decreasing travel times and reducing the number of hours of congestion experienced at the bridge

Expected congestion reduction at the Columbia River Bridges in 2045

Number of hours in a weekday that congestion (speeds under 45 mph) is expected to occur northbound (NB) and southbound (SB) at the new Columbia River bridges in the year 2045. Southbound and northbound hours of daily congestion decrease under both Modified LPA options as compared to the No-Build. ​

Vehicle travel times 

Travel times are calculated as trips between the I-5/I-205 interchange near Salmon Creek and the I-5/I-405 interchange in North Portland during weekday two-hour peak in the year 2045. Southbound (AM) and northbound (PM) travel times decrease under both Modified LPA options as compared to the No-Build. ​

Transit travel times

Average travel times (including 10-minute walk access on either end of trip) by transit between downtown Vancouver and Pioneer Courthouse Square in downtown Portland in the year 2045 on weekdays. ​

Intersection Operations

The Program studied 80 intersections as part of the No-Build Alternative and 86 as part of the Modified LPA and design options due to interchange and access changes under the Modified LPA which would remove some intersections, add others, and modify some as well.

See Chapter 3.1 

Navigation

The Modified LPA is expected to have the following benefits and impacts to marine navigation on the Columbia River:​

Benefits:

• Reduces the number of in-water piers.​
• Increases horizontal navigation clearance to 400 feet. ​
• Switches the locations of the primary navigation channel and the barge channel.​
• Reduces the number of directional changes vessels need to make when transiting both the new Columbia River bridges and the BNSF Railway Bridge.​
• Increases seismic resiliency by reducing the risk of bridge failure or collapse.

Impacts to marine navigation:

• Reduces the available distance to align with the openings of the Columbia River bridges and the BNSF Railway Bridge.​
• Fixed-span bridge reduces the vertical navigation clearance to 116 feet. ​

Neutral changes to marine navigation:​

• Shifts the Upper Vancouver Turning Basin to the west by approximately 350 feet. ​
• Movable-span bridge maintains the vertical navigation clearance at 178 feet.​​

See Chapter 3.2, Page 3.2-14, Table 3.2-6

Aviation

The Modified LPA is expected to have less intrusion into Pearson Field protected airspace than what exists today.

See Chapter 3.22 ​

Acquisitions and Displacements

The document identifies properties which may be impacted by construction and require a full, partial, or temporary acquisition. Below is a summary with more information provided in Chapter 3.3.​

Acquisitions: 47.0 acres ​

• Two auxiliary lanes: additional 0.1 acre​
• I-5 westward shift: additional 0.9 acre​
• Single-level fixed-span/movable-span: additional 0.2 acre​
• Waterfront Park & Rides​
  • Site 2: Columbia Street/SR14: additional 0.1 acre​
  • Site 3: Columbia Street/Phil Arnold Way (Waterfront Gateway Site): additional 1.5 acres​
• Evergreen Park & Ride​
  • Site 1: Library Square: additional 3.16 acres​

Displacements: 43 residential units, 36 businesses, 1 public use site ​

• I-5 westward shift​
  • 3 additional businesses
  • 33 additional residential units
• Waterfront Park & Rides​
  • Site 3: 1 additional business​

See Chapter 3.3, Page 3.3-8, Tables 3.3-2 & Table 3.3-3 

Economics

The Modified LPA is expected to benefit and impact economics in the following ways:

​Benefits to economic activity:​

• Improved freight mobility​

• Improved access to economic opportunities for all demographics due to faster travel times

Impacts to economic activity:​

• Reduced property tax revenue compared to No-Build due to displacement of residential units and businesses​

• 616 jobs impacted due to 36 businesses displaced

  • I-5 westward shift: Three additional businesses displaced with 142 additional employees impacted​

  • Waterfront Station Park & Ride Site 3: One additional business displacement; 53 additional employees impacted​

• Option to remove C Street Ramps would impact local businesses near Mill Plain Boulevard and downtown Vancouver due to traffic delay and increased travel time

See Chapter 3.4, Page 3.4-17, Table 3.4-6​

​Environmental Justice

Executive Order 12898, Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations (February 11, 1994) requires federal agencies to analyze the “disproportionately high and adverse” environmental effects resulting from federal actions on minority and low-income populations.

Impacts and benefits to EJ populations similar to those for the general population:​

• Increased access to high-capacity transit and active transportation, and reductions in vehicle travel time​
  • Single-level fixed-span bridge: Active transportation users would have more exposure to noise but would experience a shorter distance to walk/bike/roll across the bridge and may feel safer due to the extra security provided by visibility from passing vehicles.​
  • Single-level movable-span: There may be travel delays for transit and active transportation users due to bridge openings.​
• Increased job access to due to faster travel times​
• Improved air quality​
• Increased traffic and noise impacts from construction​

Impacts that would be disproportionately high and adverse:​

• Costs associated with tolling​
• Residential and business displacements in high-priority and meaningfully greater EJ areas​
  • I-5 Westward Shift: Additional residential and business displacements in EJ areas​
• Potential impacts to cultural resources​

See Chapter 3.20, Page 3.20-21, Table 3.20-11​

Climate Change​

The Modified LPA would have the following benefits and impacts to climate change compared to the No-Build:​

• Increased mode share of low- and zero-emission modes (transit, active transportation).​
• Lower energy consumption and GHG emissions in 2045 due in part to mode shift promoted by expansion of transit services and improvement of active transportation facilities, but also consistent with national trends and regulations.​
• Improvements in climate resilience with materials and design.

See Chapter 3.19, Page 3.19-14, Table 3.19-4 ​

Water Quality and Ecosystems

Water Quality

• The Modified LPA would have a substantial beneficial effect on water quality because it would include stormwater treatment facilities to remove pollutants in runoff from all roadway surfaces within the Program footprint. ​
  • Includes inlets, catch basins and gravity pipe drainage systems that would collect and convey runoff from the new bridges, transit guideway, and road improvements to stormwater treatment facilities. ​
• The Modified LPA would treat 190 acres of stormwater which currently is untreated.

Habitat​

• Under the Modified LPA, bridge removal and replacement would result in direct permanent impacts to sensitive aquatic habitats in the Columbia River and North Portland Harbor. ​
• While a specific restoration plan has not yet been developed, these areas would be restored consistent with federal, state, and local regulatory requirements, providing new habitat function.​

See Chapter 3.14 and Chapter 3.16