Ten years ago Washington Department of Transportation officials began an early design and environmental review in regards to widening State Road 502 from two to four lanes between Interstate 5 and the city of Battle Ground to the east.
The city, which lies north of Portland and west of I-5, is a growing area that’s home to 18,000 people, a medical clinic, hotels and shopping. The combination of a growing community and a new interchange connecting 502 and I-5, built in 2007-09, is bringing more traffic to the area. Prior to that project, the highway ended before it reached I-5, with no direct access. With the new interchange in place, predictions over the next 20 years indicate that traffic on SR 502 is expected to increase from 20,000 to 33,000 daily drivers.
When presented with three design options — widen the existing roadway, shift to the north or shift to the south — the community lobbied for widening. “We started with multiple options for where to align the wider highway and had to consider impacts to the community, drivers and the environment,” said Abbi Russell, communications manager of WSDOT Southwest Region.
Design work on the 502 project continued through 2007, with a federally required environmental analysis undertaken in 2008-09, after which the final environmental permitting and design process was accompanied by an extensive Right-of-Way process, which became one of the project’s many challenges. “We have acquired about 150 of 170 properties or portions of properties needed to construct the project,” Russell said.
“Because we’re just widening, we only need a strip along many properties,” she continued. “We’re down to the last few.” Sadly, she said, property values have declined since the project began, resulting in some home owners in “upside-down mortgages” when WSDOT purchased their properties.
The long, drawn-out, difficult process of acquiring ROW delayed Phase 2, which was originally slated to begin in summer 2013 but was postponed a year so WSDOT could complete acquisition of more than 170 parcels needed for widening.
Phase 1 started construction in July 2012 and was completed four months later in November 2012 under direction of general contractors Tapani Underground Inc. of Battle Ground, Wash., and C&R Tractor and Landscaping of Longview, Wash.
Because this phase was mainly earthwork, no materials were needed. Russell said equipment such as loaders, graders, backhoes and dump trucks were used on the job.
One of six new stormwater facilities was built in Phase 1. “Due to the delay (of Phase 2), it’s had a chance for the vegetation to fill in, so it’s ready when construction is completed,” said Chris Tams, project engineer. “There was no stormwater treatment previously, so this is a significant improvement.”
A Draining Challenge
Drainage is a concern in the corridor. The highway bisects a peat bog (Manor Trough) and splits two watersheds (North Fork of the Lewis River and Salmon Creek). “The bog required heavy thinking about what to do with the soil,” Russell says.
Because the peat soil in Manor Trough is like a sponge that the road sinks into, Phase 2 will require some innovation. “We have two possible approaches to addressing the need for stability on this segment of highway,” Russell continued. They can choose to remove the peat and replace it with good fill, or install a geosynthetic pile-supported embankment to bolster the ground beneath the highway and keep it from sinking over time. The second option involves driving 1500-1600 piles that are 1,000 ft. (305 m) long by 90 ft. (27 m) wide down to confident material beneath the peat, then add fill.
“For every 10 feet of fill, we’re left with four after settling,” Tams elaborates on the problem. “We can either dig it out and put in 100,000 yards of good fill or we can install the geosynthetic pile-supported embankment. It’s ground improvement without digging and removing soil.”
WSDOT is letting the contractor decide which option to pursue. “It will be whichever is cheapest,” Tams said. Phase 2 contracts will be let to bid in fall/winter 2013-14. “There will be an A versus B bid in the contract.” If the embankment is chosen, he says it would be the first one in Washington, making for a unique aspect of the project. Although there might be opportunities to use this design elsewhere, it’s effective here due to the rare overall length of the bog and might not be suitable for other locations.
After indicating that WSDOT is “fine with either method,” Tams said they just want to make sure a contractor is on board by May. Western Washington has a short dry season, which makes it challenging to do earthwork, utility relocation and paving. They want no further delays.
North of the bog was a horse boarding stable that WSDOT bought and turned into a wetlands mitigation site. In all, WSDOT will construct 110 acres of wetland mitigation.
Something Old, Something New…
Another challenge to the project is balancing the needs and safety of today with the desire to preserve the history of the rural area, which is dotted with timber and old farms growing blueberries and hay. “This area has been inhabited for a very long time,” Russell said. Evidence of previous residents comes from remains of hearths of fire-cracked rock and flakes of stone from tool making.
“It’s a beautiful area with extensive archeological work,” Russell continued. While building the new interchange in 2007, crews discovered numerous historical sites along the corridor (farms and homesteads) as well as archeological concerns (prehistoric and historic).
Work shut down as WSDOT worked with regional tribes and the state historic office on plans for preservation and documentation. An archeologist was brought in to verify and record findings, some of which are commemorated on a plaque in a rest area.
Truly historic farms were then included on the historic register, Tams adds. Mitigation was done on some, and one is slated for a possible move because the setting is also historic. “We worked with the county preservation office on this,” Tams said.
Phase 2 Plans
Several decisions for Phase 2 have yet to be made, but the plan for the second portion of the project includes expanding the current road’s two 12-ft. (3.7 m) lanes with 4-ft. (1.2 m) shoulders to two 12-ft. lanes in each direction with 10-ft. (3 m) shoulders and a center median barrier to help reduce the severity of collisions along the corridor. “We’re currently considering high-performance barrier or something else to prevent crossover collisions,” Tams says.
The wide shoulders will provide space for pedestrians and bicyclists along both sides of SR 502 for the entire length of the corridor. Sidewalks and bike lanes also will be constructed in the unincorporated, commercial zone near Dollars Corner, a suburban center in Clark County located at the intersection of SR 502 and NE 72nd Avenue between I-5 and Battleground.
Other improvements include installing signals at four intersections where county roads intersect the corridor: Northeast 29th, 50th, 72nd and 92nd avenues. “It’s a safety issue,” Russell indicates.
In the name of safety, 72nd Avenue also will be widened to one lane in each direction plus two left turn lanes and one right turn lane off 502 to alleviate backups of north-south traffic during peak hours. It’s one of the significant improvements for Dollars Corner, Russell said.
The three-year project is budgeted at $88 million, with funding coming from a mixture of sources: $80 million from the 2005 gas tax; $7.7 million from the 2003 gas tax and $200,000 from pre-existing state funds.
Phase 2 construction is scheduled to begin in summer 2014. All phases of construction are expected to be complete by late 2016. The contract will be let to bid in early 2014. Once a contractor is chosen, final decisions will be made about the bog and other aspects of the job.
“We’re still looking at traffic control methods,” Tams said. “We’re leaning to keeping one lane in each direction open — we’re widening so much, the contractor can manage it. We could have lane restrictions during certain hours, use a flagger, have only one lane or do night work. The contractor will pick how to stage it. We leave a lot of innovation for the contractor.
Once work gets underway, Tams says crews will be laying rock, a base course, culvert and 100,000 tons (90,718 t) of asphalt.
When work is completed, WSDOT envisions safer, faster travel on SR 502 between I-5 and Battle Ground.