As a multiple-benefit diversion project, the reconstruction of Godfrey Ditch aims to reduce sediment transport disruptions, improve maintenance requirements, limit damage potential in future floods, enhance aquatic and riparian habitats, and enable fish and safe recreational boating passage—all while delivering the full decree of water. Based on an initial study of interactions between water and sediment within a 20-mile segment of the Middle South Platte River, engineers and geomorphologists reconfigured the Godfrey diversion in order to restore longitudinal sediment continuity, thus improving disparities in sediment transport through the reach.
Geomorphic Study Informs the Design-Build of a Diversion Structure Replacement
Located on the Middle South Platte River in Weld County, Colorado, the replacement of the Godfrey Ditch Diversion structure is a design-build project completed in partnership with Naranjo Civil Constructors and in close coordination with CPRW and the Godfrey Ditch Board. After a comprehensive alternatives analysis with project stakeholders, the selected alternative involving moving the point of diversion upstream 350 feet to a more stable location and replacing the nine-foot failing structure with a three-foot-tall bladder dam structure, fish passage ramp, and increased efficiencies in ditch infrastructure. In leading the geomorphic study and throughout the project, the Otak team coordinated closely with DOLA (to ensure the proposed design meets the goals of the funding grant), landowners (to coordinate concerns regarding an adjacent parcel with a stringent water court decree), the Godfrey Ditch Board (to address their concerns regarding sediment minimization/maintenance and to ensure they will be able to divert their full decree), and local/state/federal agencies (to ensure permit requirements were being met).
The City of Portland aimed to enhance conditions along Crystal Springs Creek, a major tributary to Johnson Creek, to benefit native fish and wildlife and improve water quality. Those enhancements were done through stream restoration and replacement of undersized culverts that were barriers to fish migration.
Finding Efficiency in the Culvert Replacement Process
The creek is largely spring fed, which results in cool and uniform streamflow throughout the year that provides significant habitat for salmon, birds, and other wildlife. It was originally expected that there would be a need to prepare a Conditional Letter of Map Revision (CLOMR) based on hydraulic modeling and mapping by the US Geological Survey. Through initial work on the project however, it was determined that a no-rise condition could be demonstrated and a CLOMR would not be necessary. Otak then worked with the City to prepare a Letter of Map revision after the last culvert replacement project was constructed. The work included hydraulic modeling, floodplain mapping, and assisting the City with individual property and public notifications. Now that half of Crystal Springs has been restored, salmon find colder, cleaner water and more abundant food and shelter.
Kitsap County wanted to build more than just a bridge. Bucklin Hill Road was an increasingly busy two-lane arterial in Silverdale that crossed the Clear Creek estuary. For many years, the County sought to widen the road and replace its two 72-inch culverts with a bridge to improve fish passage and restore the natural estuary habitat. In leading the design, Otak also prepared environmental documentation and coordinated significant permitting.
Eliminating Traffic Congestion and Fish Barriers
A decades-long goal was achieved in designing a 240-foot four-lane bridge and widened road that improves traffic and creates fish passage for the region’s endangered salmon populations. Using an integrated approach, the design team worked with County staff, local businesses, and Silverdale residents to make the bridge part of the community, implementing new lighting, scenic overlooks, bike lanes and trail connections. The design raises the road to allow clearance for the estuary and in doing so also provides much better grades along the corridor for pedestrians, including at curb ramps. Construction accounted for staging issues related to working in a tidal zone, road closures and traffic impacts, and the relocation of nine utilities, including a major telecommunications line in completing this vital connection for the community.
Salmon returned to the Hunter Point Road culvert after a 100-year absence, thanks to the investment of Thurston County, Washington, in rehabilitating the culvert and the stream. See for yourself here.
The culvert was in a deep ravine and had a large drop at the downstream end, which blocked fish passage. Thurston County received state grants for culvert replacements, and Hunter Point Road was their highest-priority fish passage project. The project involved a new bridge and complete stream reconstruction, which was completed in fall 2018. Complications included high road embankments, a single access road (dead end), a stream confluence immediately upstream of the crossing, and the need to provide habitat function to the stream beneath the bridge structure. After consulting with the tribes and the Washington Department of Fish and Wildlife, the team elected to include large woody debris in a variety of configurations along with specific stream bed geometries and materials.
During construction, the fish salvage team relocated approximately 500 fish from the downstream reach, indicating the high potential of future use upstream of the project. Otak structural engineers designed an 80-foot-span bridge to replace the existing four-foot-diameter culvert. Shortly after construction was complete, in November 2018, videos captured the return of spawning salmon—after almost a century-long absence. This was truly a historic moment, and a tribute to the funding agencies and Thurston County for funding this project and hiring Otak to bring it to fruition.
Otak’s team (Doug Sarkkinen—project manager; Elizabeth Sheehy—structural; and Nathan Dasler, Ryan Makie, Frank Sottosanto, and Mike Rafferty—water resources) is looking forward to seeing continued fish in the system, the new channel settling in, and the vegetation establish.
Otak, in partnership with the Oregon Department of Transportation (ODOT) and Quincy Engineering, provided design and construction management for this $25 million roadway improvement in the heart of Tillamook. The project made significant improvements to both US101 and OR6 and the intersection between the two highways, and it included reconstruction of the US101 bridge over Hoquarton Slough.
Otak designed the one-way couplet through downtown Tillamook and provided stormwater treatment and landscape architecture services throughout the project. With construction starting in summer 2016, we provided construction management and inspection to oversee work progress. The project was substantially completed in October 2018, a success story for both ODOT and the City of Tillamook.
On October 31, 2018, the City and ODOT held a ribbon-cutting ceremony in the 2nd Street plaza, a festival street that will be used for farmers markets and other outdoor festivities to bring the community together. Members of the local community shared stories, along with ODOT and state representatives such as Senator Betsy Johnson and Congressman Kurt Schrader.
This project provides great value to the Tillamook community through improved traffic flow, pedestrian connectivity, and safety improvements, and it continues downtown revitalization with the new streetscape and aesthetics.
The Otak team is excited for ODOT, the City of Tillamook and its citizens, and the road users who will experience this great project!
On a recent Saturday, nearly 20 Otak employees and their friends joined in planting the riparian buffer of the Otak-designed Zackuse Creek Fish Passage and Stream Restoration Project.
The City of Sammamish partnered with King County to upgrade three undersized culvert pipes to fish-passable box culverts in the first 400 feet of stream above the confluence with Lake Sammamish. Otak designed the third fish-passable culvert, under a major arterial, and realigned and restored over 400 feet of the creek upstream of the culvert and within private property.
Improvements included creating a more sinuous, stable channel with step pools, boulder bands, and woody debris appropriate for Kokanee spawning. Many key stakeholders were involved from the early stages of planning through design and permitting, including assisting during public outreach. This level of public involvement was greatly reflected in the diverse group of 100 people who came to help replant the area near Zackuse Creek, including the Snoqualmie Tribe (who organized the revegetation work party), families from the neighborhood, City staff, and other community members.
In addition to design, Otak also provided construction support on the project. It was a special opportunity for many on the design team, to put the final touches on a project they had been creating and visualizing through a computer over the previous two years! And such a treat to do so on a sunny day with friends and coworkers! “It felt like Earth Day,” said Kaela Mansfield, water resources engineer. “The Snoqualmie Tribe did a great job of advertising the event.”
Congratulations to Otak’s team: Greg Laird, project manager; Ryan Hawkins, construction management/inspection; Kaela Mansfield and Mike Rafferty, water resources; Eva Ho, Touta Phengsavath, and Dave Cole, civil and utility support; Bob Doherty, culvert/structures; Kevin O’Brien, permitting efforts; Ben Schneider and Lindsay Martin, planting restoration design; and Jeff Gray and Kevin O’Brien, permitting support.
Five Otak employees from our Redmond office (left to right: Kevin Kraxberger, Joe Schober, Ellen Webster, Dave Cole, and Kaela Mansfield) went flyfishing on Saturday, October 13, at Rocky Ford in eastern Washington. The event was sponsored by Flycaster Brewing in Kirkland, Washington. They enjoyed a BBQ lunch and Flycaster beer on a sunny day, fishing for rainbow trout just downstream of the state-run Rocky Ford hatchery, which sits on a natural spring in the Columbia Plateau. Part of the group stayed the night in Ephrata and golfed in the morning at Moses Lake.
At Otak, our employees enjoy spending time together after hours…just as much as we enjoy working together! And yes, they went home with some fish!
The first phase of construction is wrapping up this month on the salmon-safe clean water retrofit that Otak designed at Mt. Hood Community College. This project, led by the Sandy River Watershed Council, will improve water quality and salmon habitat in Gresham’s Beaver Creek by treating 1.9 million gallons of polluted runoff per year. Older parking lots like this college campus were built without the stormwater treatment that is typically required in new development today.
Otak’s water and natural resources engineers designed the retrofit project to treat as much runoff as possible while keeping costs down, minimizing loss of parking spaces, and protecting the mature trees that shade the parking lots. Stormwater swales and planters fit into slivers of available space, with drywells added to increase infiltration. A large raingarden creates the focal point of the retrofit, providing a visible opportunity to educate campus visitors about stormwater and watershed health. New signs designed by students will help spread the word about the project’s environmental benefits, and the City of Gresham installed devices to monitor water quality and flow rates before and after construction.
The project is funded by East Multnomah Soil and Water Conservation District, Metro regional government, the City of Gresham, Spirit Mountain Community Fund, and the Oregon Department of Environmental Quality. In 2016 the partners came together to identify retrofit projects on the college campus that would maximize environmental benefits and public education opportunities. These parking lots got top priority and are expected to be the first of many future improvements. Mt. Hood Community College is the first Salmon Safe certified community college in the country, and the stormwater retrofits will help the college maintain its certification.
On October 27, volunteers will plant the portions of the project that were built by the nonprofit group Depave. Contractors for the project are Britton Excavating and Grow Construction. The second phase of the project is expected to be built next summer, pending funding.
Close collaboration with the Columbia River Estuary Study Taskforce aimed to restore estuary function and wildlife habitat to the Buckmire Slough near Vancouver Lake, Washington. The slough had poor water quality conditions and two large berms blocking fish passage.
An Improved Floodplain Habitat with Fish-Friendly Features
The removal of four in-stream barriers restores full estuarine tidal processes and improves juvenile salmon access to the slough and wetland habitat. Installing two new bridges led to an improved floodplain habitat while placed logs and other low-lying features support native vegetation (e.g., Sedges and Wapato) and prevent juvenile fish from getting stranded. The design includes fish-friendly features, ecological features to support native Wapato, and large wood habitat structures. In developing the design, the Otak team used hydraulic modeling to assess water quality, fish passage conditions, and scour potential at the bridge sites.
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