Petaluma River Bridge reaches milestone as expansion begins

This week marks a milestone in the $1.2 billion Highway 101 widening project as work begins on the expanded bridge over the Petaluma River, which with a price tag of $130 million, marks the most expensive piece of the 38-mile project. While traffic will be interrupted, mostly at night, the cliff swallows who make their nests on the bridge have been safely abated after Caltrans settled a lawsuit with environmental groups.

Cliff swallows have historically been known to build nests of mud under the Petaluma River bridge between late February and early August. Last year, contractors placed netting under the bridge to deter the swallows from interfering with the construction zones. But the plan backfired, and instead ensnared the birds.

Veronica Bowers, director of the Native Songbird Care and Conservation group based in Sebastopol, said by the first week of April 2013, there were already birds trapped and dead in the net. Dozens more would become tangled and suffer the same fate.

Bowers and other environmentalists sued, saying the project should stop while impacts on the swallow colony were studied. After a federal judge ruled against that request, Caltrans reached a settlement with the groups in January.

As a part of that settlement, Caltrans replaced all netting with new materials in early April. The first material, Coroplast, is essentially corrugated plastic sheets applied to the surface, creating a slick surface that the birds can't build on. The second material, BirdSlide, consists of triangular tubing made of long-lasting, UV-resistant plastic that fits into the angles of the bridge where the birds normally nest, blocking them from the area. Caltrans anticipates spending at least $4 million to protect migratory birds.

Bowers said she's made two site visits thus far to see the new hard-surface materials used in the construction zone.

Caltrans also agreed to not demolish bridges during the nesting season, to remove nests started by the swallows and to hire an environmental biologist to monitor the construction.

Bowers and other bird advocates are still concerned that the outermost areas Caltrans left open for the birds to nest are vulnerable to nest failure due to high winds and fog. She said massive nest failure occurred last summer in those areas after an early rainstorm.

"That kind of exposure to the elements is very damaging to a little mud structure," Bowers said. "So we're monitoring that weekly. At this point, that's all that can be done."

Another element of the settlement involved Caltrans meeting with conservation organizations, such as Bowers', throughout the year to review safety measures. Caltrans also provided $4,000 in funding for these groups to conduct an educational outreach campaign to protect the cliff swallows.

Bowers said this was necessary, as the swallows were moving to nearby residential areas due to a lack of available habitat. Environmental organizations began receiving an influx of calls from disgruntled, curious and pleasantly surprised residents, wondering how to handle their new tenants.

Bird advocates mailed out 7,000 brochures to homes surrounding the bridge area, informing residents about the benefits of swallows, their federally protected status and how to avoid harming them.

Ideally, Bowers said the swallows would be allowed to nest peacefully on the bridge during their nesting season — which can run from late February into early August and peaks between April and July. She hoped that Caltrans would wait to do work in those nesting areas until after the birds have left.

"Undisturbed, swallows can wrap up their breeding season by early August," Bowers said, "but when they're disturbed or delayed, that can extend through late August or early September."

Bowers said, historically, netting has proven to have negative impacts on small birds and swallows. She hopes Caltrans will proceed with better practices in the future.

"We hope they've had a positive experience with the new material they're using, and that they'll integrate it as part of their standard exclusionary material instead of using netting," she said.

With their new bird-friendly practices in place, Caltrans can continue work on the bridge, which aims to relieve traffic congestion through Petaluma by replacing the 60-year-old two-lane span with six lanes to accommodate a higher volume of cars. The highway widening project will complete 38 miles of carpool lanes from Windsor to Novato.

According to Caltrans, construction on the bridge will be completed in 2016, with future phases to continue as funding becomes available. Currently, the $1.2 billion project is $225 million short to finish the widening from Petaluma through the Novato Narrows. In addition to other funding streams, county officials have considered extending the life of Measure M, a quarter-center sales tax, which funded much of the widening project from Windsor to Petaluma.

(Contact Allison Jarrell at allison.jarrell@ar guscourier.com)