For one of the fastest-growing areas of Snohomish County, plans for additional transit options and improvements to the arterial transportation system were considered a top priority. As a main route in the county’s southeast, the 180th corridor would be reconstructed with a multimodal design that addresses capacity needs while also enhancing multiple adjacent wetland habitats.
In meeting the county’s five-lane urban arterial design stands, improvements to the 180th Street corridor includes the widening of the road with two new lanes to improve capacity and reduce congestion. Sidewalks on both sides of the road and bike lanes are part of multimodal design. With much of the work occurring at the confluence of two fish-bearing streams, significant changes to that system were needed. Realigning a portion of Thompson Creek and the removal of a roadside ditch creates a more natural channel and habitat. A new stormwater conveyance system adds modular wetlands for stormwater treatment, and stormwater detention vaults for flow control. The removal of hydrologic barriers along with wetland enhancements through grading, soil amendments, and planting were part of fully-mitigating all impacts on site. Otak designed two culvert replacements, a restored stream channel, stormwater facilities, retaining walls, and utility relocation to support the County’s roadway improvement goals.
Adjacent to Little Boston Road, a 0.75-mile section of trail was designed and constructed as the principal nonmotorized connection to the Tribal Administrative Campus for the Port Gamble S’Klallam Tribe.
A Pedestrian Trail Designed for Tribal Administrative Access
The pedestrian trail consists of a ten-foot-wide paved trail with a number of amenities that also includes three pedestrian bridges, five stream crossings, and 7,600 square-feet of retaining walls. In limiting impact to to the area, the project included environmental mitigation as well as utility relocations, driveway and frontage restoration along 15 homeowner sites. As the prime consultant for design and construction Otak provided civil and structural engineering, landscape design, geotechnical investigation, environmental mitigation design, community engagement, construction document preparation, permitting, and construction management.
As a major east/west arterial, McGilchrist Street carries significant traffic volumes for the area surrounding Salem, Oregon. The corridor, which provides a vital connection to downtown access as well as I-5 via Highway 22, would undergo multiple phases across three segments of roadway improvements aimed at traffic, railway, bicyclist, and pedestrian use. In leading the roadway design, Otak prepared a corridor analysis and feasibility study, as well as the engineering design and stream analysis to accommodate multiple creek crossings.
Roadway Design Intersects Stream Analysis for an Improved Corridor and Fish Habitat
The roadway design of McGilchrist Street traverses existing railroad tracks along with crossings at Clark Creek as well as the East and West Forks of Pringle Creek. Widening throughout the corridor with additional turn lanes at major intersections featuring new traffic signals – including the realignment of the 22nd Street intersection to a four-leg intersection – aim to reduce traffic congestion while bike facilities including a 10-foot-wide protected cycle track and pedestrian crossings encourage active transportation. In facilitating multiple creek crossings as well as widening of an at-grade track crossing for a Union Pacific Railroad mainline, stream analysis also identified solutions to alleviate bank over-topping and chronic flooding from the creek channel onto adjacent properties and over the existing roadway. Two culverts – including three-sided culvert with a natural bottom to accommodate the road widening – along with large wood debris add to this approach while also improving fish passage and habitat.
An alternatives analysis process led to a selected concept for three roundabouts along the existing alignment of NE 171st Street in Woodinville, Washington. The design alleviates congestion created by zoning changes aimed at encouraging economic growth in the city’s downtown area. In leading the analysis, Otak also provided a variety of services including the full design and construction support that followed.
Converting an Arterial to Improve Capacity, Flooding, and Fish Passage
Zoning changes enacted within the downtown master planning area of Woodinville were expected to result in congested intersections at key entrances into the downtown core. Roundabouts at one existing intersection and plans for two others – at locations that would be constructed as the area became more densely developed – provided the basis for the identified best solution. The alignment for each intersecting roadway was determined while incorporating a roadway diet, from five lanes to two, between roundabouts to channelize the traffic safely and efficiently. These improvements came with several other benefits by substantially reducing paved areas, replacing two culverts to fish-passable standards, alleviating flooding, and adding stormwater quality improvements, and a multi-use trail.
As part of Washington State’s first bus rapid transit (BRT) line, the 11-mile Orange Line route connects potions of Snohomish County along with the cities of Lynnwood and Mill Creek. Otak led the design and permitting while also providing construction engineering support for this transit-oriented development.
Expanding Bus Rapid Transit Corridors and Facilities for Improved Public Transportation
The design of this corridor connects service to Edmonds College, Lynnwood city center, Alderwood Mall, Mill Creek, including four park-and-rides and three future Sound Transit Link light rail stations. Project elements include a new transit center for the western terminus at the Edmonds College, construction of 17 BRT stations along the new Orange Line corridor and one additional BRT station along the Blue Line Swift Bus route, retrofitting five Green Line stations to also function as Orange Line stations, reconstruction of the existing transit center at the McCollum Park Park-and-Ride, and roadway and signal improvements at approximately 14 intersections to improve transit speed and reliability. Otak team efforts include alternatives analysis, preliminary and final design, environmental permitting, PS&E preparation, and jurisdictional coordination and permitting for the proposed BRT stations and termini including all associated roadway, signal, and pedestrian improvements.
The relocation of fiberoptic cables crossing the Old Young’s Bay Bridge in Astoria, Oregon required a wide range of permitting. Otak provided a full array of permitting services for the development of this complete permit acquisition and strategy.
A Complete Permitting Strategy to Ensure Environmental Protection
Mitigation of construction impacts to stream and estuary functions also necessitated compliance with local City of Astoria shoreline requirements along with restoration and compensatory mitigation planning documents. Given the structural elements and surrounding natural environment, the permit strategy included cultural resources compliance for NHPA Section 106, ESA compliance documentation per a programmatic Biological Assessment, a Joint Permit Application in support of required cut and fill permit from Oregon’s Department of State Lands and the Corps Section 404 permits.
In the West Bull Mountain area of Washington County, Oregon, planning for future land use aimed at expansion. The goal of would be creating a highly livable “community of distinction” within the designated Urban Growth Boundary (UGB), including a custom stormwater strategy.
Outcomes-Based Concept Plan for a 500-Acre Expansion
An outcomes-based concept plan was developed for the 500-acre expansion area as well as an adjacent 212-acre rural area to be potentially added to the UGB. Innovative solutions were integrated into the planning to also account for complex engineering and transportation management elements. Otak would lead overall project management, planning, urban design, stormwater, natural resources, GIS, and public involvement services.
In revitalizing the central business district of Carnation, Washington, the reconstruction of four blocks was designed to improve a variety of areas from stormwater and utilities to traffic signage and pedestrian wayfinding. As the prime consultant completing these extensive streetscape improvements, Otak led the design, community engagement, and development of a comprehensive construction sequencing plan to minimize disruption to existing downtown businesses.
A Revitalized Streetscape Emphasizing Pedestrian Connectivity and Low Impact Development
This federally funded project applies a community-character design theme that draws on the area’s history to deliver new streetscape amenities as well as a host of functional streetscape improvements. Unique metal cut-out panels used as banners on street light poles and incorporated into street furniture highlight this theme. The design for core blocks downtown focused on pedestrian connectivity and gathering spaces while underground stormwater quality treatment vaults placed beneath sidewalks function as root-storage, allowing for street trees to be placed within the dense business-district environment. Integrated adjacent to the planter areas are stormwater bioretention facilities creating natural balance with landscape plantings. Use of a depressed-curb intersection design at Bird Street opens the cross-street pedestrian corridor for future festivals and other street events.
A combination of important roadway safety improvements and stream habitat enhancements provided the basis for repairs to Manley Road. With steep grades, sharp turns, and short sightlines, the existing roadway crosses Daybreak Creek at multiple locations where undersized culverts blocked fish passage to important upstream habitat. Otak worked as an extension of Clark County Public Works staff by providing stream, structural, and environmental permitting to ultimately benefit both driver safety and fish habitat for species including Endangered Species Act (ESA) protected salmonids.
In replacing the four undersized culverts, a multidisciplinary design process was established that included analysis of hydraulics, geomorphology, and habitat. Environmental permit approvals were also obtained while working in a stream with ESA protected species. Along with the design of replacement crossings was the opportunity for 750 feet of stream enhancements, all of which overcame unique challenges including: low cover at the crossings, steep channel slopes, dynamic lateral channel movement, and a failing roadway embankment. These enhancements improved the habitat conditions through bottomless culverts, detailed cascade-pool channel design, and bioengineered bank stabilization techniques. More than 3,000 plants were also added as part of the planting design. For an area prone to traffic accidents, roadway safety improvements adjusted the horizontal and vertical alignment of Manley Road while also addressing required stormwater management facilities.
As one of only a few locations on the island not having an adequate bypass route for emergency vehicles, Oakes Road was designed to provide a bypass in the event that this section of SR 525 becomes blocked. To offset unavoidable wetland, stream, and buffer impacts associated with the construction of the bypass, a compensatory wetland mitigation plan was designed to support local, state, and federal permitting.
Roadway Design with Unique Environmental Implications
A new, two-lane asphalt roadway, Oakes Road included features such as graded shoulders, drainage ditches and culverts; bioretention and infiltration LID facilities; retaining walls; onsite wetland and stream mitigation; utility relocations; channelization; and signing. The federally-funded project was also unique in that it traverses land parcels containing uncut forests and existing homes which ultimately required establishing an alignment that met objectives while also seeking to minimize property impacts and setbacks from existing structures and private wells. The goal of the mitigation site is to enhance an existing low-functioning wet pasture to a high-functioning wetland with a mosaic of wetland habitats using native plants. Otak led the planning and design of Oakes Road along with the wetland delineation and functional assessment, including coordination of environmental permitting, documentation, and plan installation.
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