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 portions 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.
After upstream development caused degradation within the stream corridor, the restoration of a tributary to Niver Creek (Tributary M) addressed an ongoing concern of system stability in order to protect public safety, nearby infrastructure, and local ecology. Leading the design, Otak collaborated closely with the City of Thornton, the Mile High Flood District (MHFD), and Stream Landscape Architecture + Planning in developing a design that would stabilize the area, reconnect the channel to it’s floodplain, and maintain connection to the retention area providing flood control for the community.
Stream Restoration to Preserve Resources and Public Safety
The restoration of Niver Creek Tributary M reestablishes the natural system as a healthy, high-functioning stream while also creating an opportunity to better utilize the area for the community in combination with enhancements to the Niver Creek Open Space. Reconnecting to its floodplain and realigning segments where necessary, the design allows the stream to spread out and slow down during high flows, reducing erosion and supporting a thriving riparian corridor. Meeting a key priority in preserving mature riparian trees perched along eroded banks, the design team quickly adapted an original restoration plan. That update would modify the floodplain grading while also balancing considerations such as backwater effects of a downstream earthen dam, permitting constraints, underlying geology, proposed bank heights, revegetation areas, and estimated construction costs. As part of this restoration process, a range of alternatives with geomorphic, hydraulic, and cost-benefit analysis produced an ultimate restoration project that realigned the channel around critical utility infrastructure, preserved mature vegetation, and reconnected the channel to its historical floodplain. These improvements represent an example of how flood mitigation can leverage its surrounding context to provide nature-based solutions also foster safe, recreational opportunities for the regional community.
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.
Ongoing work across numerous planning and design projects with the City of Burien has resulted in several regional stormwater facilities to serve redevelopment and growth. With several targeted and city-wide stormwater plans in place, the City of Burien is addressing drainage issues and investing in green infrastructure to support development while protecting local streams. In developing these plans and its subsequent projects, Otak also led community engagement in person and through interactive GIS StoryMaps to ensure an equitable process as well as community and staff buy-in.
Leveraging GIS Data for Ongoing, Equitable Stormwater Improvement
Starting with a master drainage plan for the North East Redevelopment Area (NERA), the City of Burien has expanded its stormwater approach and broader infrastructure development goals. Using hydrologic analysis and hydraulic modeling, the NERA plan included managing existing and future stormwater needs. The plan was implemented through years of design work, including all the way through construction management for regional stormwater facilities. Later, a Stormwater Management Action Plan (SMAP) was developed based on basin-level GIS analyses to protect and improve Miller Creek through green infrastructure and policy changes in the downtown catchment. The broader Burien stormwater master plan goes further to analyze city-wide drainage issues and design system improvements. These actions position the city to reduce flooding and improve water quality for the community.
With the goal of re-establishing its floodplain connectivity, the restoration of St. Vrain Creek enhances aquatic habitats, restores riparian health, and improves stream resiliency. The multi-objective design incorporates features to mitigate future flooding and moderate sediment loads from inundating the Town of Lyons.
Restoring a Floodplain for More Resilient Habitats and Community Flood Mitigation
Central to the design development was a thorough understanding of sediment dynamics and hydraulics. Sediment dynamics were assessed by modeling and comparing reach-scale capacities. The restoration involves approximately 3.2 miles of South St. Vrain Creek, extending from the canyon mouth to the Old St. Vrain Road bridge near the Town of Lyons. Channel hydraulics were assessed by 2D modeling of the study area using the Sedimentation and River Hydraulics 2D (SRH-2D) model, developed by the Bureau of Reclamation. The model informed the design with an understanding of the complex linkages between main channel and floodplain flow, including floodplain benches, overflow channels, and more than a dozen large wood structures throughout the reach. The project team worked with stakeholders to collect feedback and turn concerns into project goals. Otak led the channel restoration design, 2D hydraulic modeling, geomorphology, and sediment transport analyses for this CDBG-DR grant-funded restoration project.
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