Restoring the Whilamut Natural Area

From ODOT- Long before it was named the Whilamut Natural Area, the Kalapuya tribe inhabited this 70-acre site on the north bank of the Willamette River west of Interstate 5. The Kalapuya gathered food, traveled on the river and hunted local game. Later the site served as farmland, supplied sand and gravel for the original I-5 bridge and was used as a Lane County landfill from 1964 to 1974.

Transformation of the site continues today. The City of Eugene and volunteers serving on the Citizen Planning Committee oversee efforts to restore the area to its natural state. Removal of non-native plant species such as blackberries, Scotch broom and tall fescue allows native species to survive and thrive. Planting of native grasses and wildflowers creates new upland prairies for wildlife habitat. Western meadowlark, vesper sparrow, woodpeckers, lizards, gopher snakes, frogs and turtles are expected to return and thrive.

A new forest canopy of black cottonwood and Oregon ash will protect plants needing shade while providing wildlife habitat and a cool zone along the river for juvenile Chinook salmon.

As the restoration proceeds, bicyclists, walkers and runners use the variety of hard and soft paths to travel east, west, north and south. Some stop to enjoy the river or just sit and experience the natural surroundings.

Future generations will appreciate the opportunity to see cycles of nature and flourishing native plants and wildlife.

Waterways Surrounding the Bridges

From ODOT-

Do you know that besides the Willamette River, there are 13 other bodies of water surrounding our project?



Both natural and manmade waterways flow here. The Whilamut Natural Area is home to the Canoe Canal, also known as Patterson Slough, and two protected wetlands. The Canoe Canal water originates from a diversion structure built in 1974 east of the bridge and reconnects to the river near the Ferry Street Bridge. The wetlands retain rainwater throughout much of the year, providing natural filtration and supporting a diverse plant environment.



On the south bank of the river, an interconnected network of waterways includes eight wetlands and two creeks. Three of the largest are Laurel Valley Creek, Augusta Creek and the Glenwood Slough. Water from the Laurel Hill Valley neighborhood winds through this network and flows into the river west of the bridges. Located along Interstate 5, the Franklin Boulevard off-ramp and the railroad tracks, this network captures and naturally treats rain runoff.



Before construction began, we developed plans to avoid or minimize impacts to all of these bodies of water. As part of the Willamette River Bridge project, we will improve this system through stream restoration and new bioswales that capture and treat more of the runoff before it enters the river.

Keeping the river environment healthy

From ODOT-

When the original Willamette River Bridge was constructed between 1959 and 1961, workers built diversion dams and filled portions of the river to provide access to the work-site and to capture debris from the construction. Today, with much more knowledge, we understand the environmental impacts on the river from construction and have plans in place to limit them.



Traveling on Franklin Boulevard or on nearby pedestrian paths, you will see the machinery tearing down the temporary detour bridge. However, you may not notice what our contractor built to protect the river and use as a work platform, just as they did for the southbound bridge work in 2009.



Directly under the detour bridge, 10 feet above the river’s ordinary high-water level and covering almost 120,000 square feet, is the work bridge. To build the work bridge we first drove steel piles into the river, connected them with large steel beams and then added a work surface of large timbers and plywood. The surface is sealed with an impermeable plastic layer, capturing any runoff and carrying it through pipes to an offsite treatment system before the water is released.



Workers will place sand on the work bridge to cushion large pieces that fall during demolition, but will remove it afterward to keep it from clogging the drainage system.



The work bridge is strong enough to support heavy equipment used in demolition and construction, large enough to capture falling debris from demolition of the temporary bridge and secure enough to build the wooden forms, or falsework, needed to create the new bridge arches.



We are pleased our efforts to protect the river are successful, while at the same time allowing for efficient construction of the new bridge.

Temporary fish ladder to help with migration

From ODOT-

In cooperation with the Oregon Department of Fish and Wildlife, our contractor installed a temporary fish ladder near the new Willamette River Bridge.

You may wonder what a fish ladder has to do with the new bridge. Let me explain.

A protected wetland fed by waters from Augusta Creek, Glenwood Slough and other local streams sits on the south bank of the Willamette River near the bridge. Currently, water from the wetland flows through a pipe under Franklin Boulevard to the river. Unfortunately, juvenile fish can’t get safely into the river because the pipe outlet is too high above the river. This also prevents mature fish from returning upstream to spawn.

Recently, biologists identified cutthroat trout upstream from the pipe outlet. We have built a fish ladder—a series of steps that helps fish swim around barriers—as a temporary solution to support the local fish population.

Our bridge project includes restoring the wetlands and stream system on the south bank of the Willamette River to enhance the natural setting and support fish and wildlife habitat. When the bridges are complete, we will restore the streams in the project area, remove culverts, create spawning ponds and reconstruct a historic stream channel outlet to allow for fish passage without needing a fish ladder.

Until then, the temporary fish ladder will allow cutthroat trout living in the waterways on the south bank of the Willamette River to move freely.

Treating what nature provides

From ODOT-

On the Willamette River Bridge project, planning for the rainy season and the impacts of water runoff is very important.



The new wider southbound bridge has a larger surface area that will collect more rainwater than the old bridge did. The rainwater runoff becomes contaminated when it mixes with pollutants from vehicles, such as grease, brake dust, automotive fluids and deicing chemicals. Without containment and treatment, the runoff would flow directly into the river and nearby natural areas.



Instead, we have started collecting runoff and discharging it into a system of bioswales for treatment. Bioswales are landscape elements designed to remove silt and pollution from surface runoff. They are gently sloped areas planted with native vegetation. Runoff captured from the bridge is filtered by the vegetation or held in a grassy bowl until particles settle out. The treated water either soaks into the ground or is released into the surrounding watershed, such as the river or nearby creeks.



We have built multiple bioswales to treat rainwater runoff on or near the project site, saving the cost of collecting and piping it for discharge further away.



Building bioswales is just one of the ways ODOT is reducing the environmental footprint of the new Willamette River Bridge.

Protecting the Environment

From ODOT - The construction area for the Willamette River Bridge project has multiple environmentally and historically sensitive areas, including the Whilamut Natural Area, Mill Race Ruins, the river itself and its banks. We have taken many measures to protect these areas. Before construction, an inventory of the site documented wetlands, plant and animal species, and areas of historical importance. Fencing and markings have been placed identifying areas to be left undisturbed. During the design phase, bridge piers and other project features were located to avoid impacts as much as practical. Sometimes it was impossible to avoid impacting the protected resources. In these cases, we inventoried items carefully and submitted plans detailing the impacts and strategy for restoration and mitigation which were then approved by local, state and federal regulators before construction began. Environmental monitors conduct inspections to verify that we are meeting the permit requirements and identify any future needs. I am happy to report that we continue to receive positive comments and reviews. Once construction is complete, we will provide new vegetation and habitat, and improve the surrounding areas. Balancing the project need to protect and enhance environmentally and historically sensitive areas during construction requires a strong partnership between the community, ODOT, other State and Federal Agencies, local jurisdictions, and our contractors. We have a path forward. I believe when we are through we will be leaving the area better than we found it.

The Rain is Here

From ODOT-
Hi, Karl Wieseke here from ODOT’s Springfield area office.

As ODOT’s construction project manager on WRB, I see firsthand how the weather affects our construction activities.

The rainy fall and winter months present new challenges to ODOT’s commitment to minimizing impacts to the environment by ongoing construction activities.

Over the past several weeks, ODOT and our contractor, Hamilton Construction and their subcontractors, have prepared the work site to minimize the impacts of rain and to keep construction on schedule and within permit requirements.

· We have seeded bare slopes and open spaces, or covered them with straw to absorb and better control runoff.

· Hamilton Construction crews inspected the work bridge and made necessary adjustments to ensure that it captures and treats all the runoff before it reaches the Willamette River.

· We have cleaned out drift logs stuck around and under the work bridge to avoid potential problems from rising river levels brought on by winter rains.

· We have also checked equipment for appropriate protection to capture any possible oil or lubricant leaks mixing with rainwater.

Together, ODOT and Hamilton Construction are determined that when the bridge work is done, the work area, riverbanks and adjacent parklands will be in better condition than before we started work.

Tree wall shields park users of freeway noise

From ODOT-

Original plans for the Willamette River Bridge included removal of existing trees west of Interstate 5 and north of the bridge. Early on, local community stakeholders identified the importance of preserving these trees, which shield park users from the noise of the freeway.

We took the stakeholder's interest seriously. The best solution turned out to be a tree wall along the west side of the southbound I-5 lanes just before the bridge. The wall preserves the trees and provides an edge for the widened southbound lanes without increasing the width of the embankment impacting the trees.

For more information on additional environmental measures we're taking with the I-5 Willamette River Bridge, check out this article from HubDOT, written by ODOT environmental program manager Geoff Crook: Bringing new life to the Willamette River Bridge.

Below is a picture of the now completed wall being constructed.