Excavation work for the Willamette Water Supply Program (WWSP) is set to begin in Orenco Woods Nature Park in summer 2023, but measures to protect wildlife and habitat have already begun.
You may have noticed vegetation in the area slated for construction was cleared in January. This was done to safeguard native birds and other animals during construction (read more about the benefits of early brush clearing). The well-timed removal of shrubs and thickets is just a small part of the Wildlife Protection and Adaptive Management Plan that was developed for the project.
The 46-page document created by Hillsboro Parks & Recreation Restoration Specialist & Wildlife Biologist Laura Trunk outlines steps and methods to protect the species that live in or pass through the park.
Choosing the Right Path
About 900 feet of water pipe will be buried under the northeastern edge of Orenco Woods Nature Park (See map for affected areas). By using this route, only about 2.3 acres of Orenco Woods Nature Park’s 44 acres will be directly touched by construction. This path was chosen to minimize environmental impacts and avoid large, mature trees.
“This route skirts Orenco Woods Nature Park’s critical wetlands, meadows, and oak savannah habitats,” explains Trunk, who also notes that woody debris from earlier brush clearing will enhance and improve the Park’s wildlife rich environments.
“We’re using the brush to create wildlife habitat that will provide much needed shelter for songbirds, small mammals, reptiles, and amphibians.”
The City of Hillsboro is dedicated to continued efforts to improve the wildlife habitat around the park, and staff are conducting restoration to enhance the open meadows for pollinators, monarch butterflies, and songbirds by adding native wildflowers.
Safer Animal Crossing
Over the last year of monitoring, biologists have determined that many large animals – like deer, coyote, racoons, skunks, and western gray squirrel – travel through Orenco Woods Nature Park at night.
The Wildlife Protection and Adaptive Management Plan lays out several protocols designed to keep these animals safe during their nocturnal journeys.
For instance, the riparian area around the TriMet rail bridge – probably the busiest, most popular route for animals passing through – is a designated “No Work Zone.” This designation will encourage wildlife to stick to this path and avoid active construction areas. Fencing will help keep animals within this corridor and out of busy roadways.
Lighting can distract wildlife. To keep animals moving, contractors will avoid work in sensitive areas at night. The construction staging area will be illuminated for security, but an expert-reviewed-and-approved lighting plan is in place to minimize light pollution and its effects on wildlife and people.
Animals are not totally predictable. Some may stray into a construction zone even with safeguards in place. To protect these critters, fencing will be installed around open trenches at the end of each workday.
Only 150 feet of open trench is allowed at any time. This limitation means that wildlife will not have to walk far to find safe passage. If the project’s Environmental Compliance Lead determines additional precautions are needed, taller fences could be installed or trenches could be covered with non-slip steel plates.
Rabbit Roundup
Many rabbit colonies live in Orenco Woods Nature Park, and there are plans to avoid disturbing them during construction. To set a baseline, the Environmental Compliance Lead has been tracking the colonies for more than a year. So far, no rabbits are residing in the construction zone, but observation will continue as colony locations change over time.
If rabbits do move into the construction area, humane deterrents will be used, such as removing vegetation or applying predator scents. If the colonies do not respond to deterrents, construction will stop until an expert can safely relocate the rabbits.
Protections for Reptiles and Amphibians
Along with mammals, like deer and coyote, Orenco Woods Nature Park is home to a wide variety reptiles and amphibians. The list includes northern red-legged frogs, Pacific treefrogs, long-toed salamanders, rough-skinned newts, and common garter snakes.
Silt fencing (permeable fabric stretched across posts) will be installed around the work area to inhibit small animals from entering the zone and getting stuck in a trench. Crews will monitor for any amphibians or reptiles that may make it past the silt fence, and then move them to safety before construction starts each day.
The northern red-legged frog is recognized as a sensitive species by the Oregon Department of Fish and Wildlife. Special efforts are taken to monitor and conserve habitat through the Oregon Conservation Strategy.
As part of the City of Hillsboro’s Environmental Sustainability Plan, the City tracks the health of amphibian populations in critical areas. For this project, these special efforts include prohibiting construction in and around Rock Creek and Beaverton Creek during the frog’s breeding season (December 1 to March 31).
Putting the “Adaptive” in the Adaptive Management Plan
The Wildlife Protection and Adaptive Management Plan is comprehensive, but construction is unpredictable and baseline conditions can change. Knowing this, the Plan describes a process for adapting to accommodate these unknowns. Any changes to the wildlife protection measures will be documented and shared publicly.
Find Out More
There are ways you can participate and help protect wildlife and habitat during construction. Start by avoiding the construction area once work begins. The Rock Creek Trailhead parking lot near Cornelius Pass Road will be closed, and segments of trail may be affected. Please look for signage and follow directions. You can also attend a meeting. The Willamette Water Supply Project will hold a public briefing every three months to talk about habitat and wildlife in Orenco Woods Nature Park. The Environmental Compliance Lead will be available to answer questions and address concerns.
- The Project’s monthly email updates are the single best way to keep up to date on construction activities. Sign up to receive email updates.
- Find information about upcoming meetings.
- Watch recordings of past events.
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