Who will save Terrace Ave? (Point Reyes Light, 11.06.2008)

Seawall

Surfer’s Outlook sits on 90 feet of vertical sandstone. Every year it loses about six inches to natural erosion processes—wind-driven rain erodes the face of the cliff while waves undercut the base of the bluff.

Sitting atop this challenging geology is Terrace Avenue, one of two access roads to the Bolinas Mesa. Water and sewer mains run directly underneath. If Terrace collapses, it will be a huge threat to public health and safety.

For the time being, the only thing keeping the wave erosion at bay is a 120-foot seawall built by Marin County in 1967. And even that is falling apart.

“There’s the relentless erosion that takes place,” said Don Smith, a board member of the Bolinas Community Public Utility District (BCPUD). “Where the wall doesn’t exist or is broken, there is visible undercutting going on. The top of cliff is getting nibbled away by the rain, and it’s encroaching on the edge of the pavement.”

A large gap in the seawall developed at the end of last winter, when flotsam in the waves during a storm bashed the front of the wall. “After every winter storm, huge pieces of the bottom of the hill are bitten out by wave action,” Smith said. “This is the first winter where we have a break in the wall, and then beachgoers tore out broken pieces for the bonfire. It’s starting to look like firewood—that’s how bad it is.”

A Terrace Avenue Community Committee was appointed by BCPUD. “We said to the county, ‘Your facilities are failing here. Here’s some data, here’s the observation, here’s what we think can be done.’ They need to take that information and come up with a solution,” said Jennifer Blackman, general manager of the district. “Instead, they issued a memo basically saying that the community is right, the wall is failing, and if the seawall fails, the road will fail. But we’re not gonna do anything.”

In a September memorandum, Bob Beaumont, chief assistant director of the Department of Public Works, recommended that “the County take no measures to attempt to maintain, reinforce or replace the wall.” Beaumont acknowledged that “the existing vertical timbers are only 76% adequate to resist active soil pressure” and “the failure of this wall will ultimately hasten the loss of Terrace Avenue at this location.” Replacing the wall would cost about $500,000 and the permit process could take at least two years, according to the memo.

“It’s becoming an emergency situation due to the county’s decision to not do anything about prolonging the life of that wall,” Smith said. “We’re not ready to accept that decision.”

“We understand and appreciate that the county has competing demands on its resources,” said Blackman. “But we believe that, for our community, it’s hard to get a higher priority issue.”

If the seawall fails this winter, Terrace will be lost, along with the water and sewer mains underneath it.

“The county’s decision is not cost free,” Blackman said. “It immediately shifts the cost onto the community.” Engineers have estimated that it will take $365,000 to move the water line. And relocating the sewer main could be twice as expensive.

Approximately 650 households are supplied by this water district. “That is not very many people to spread the burden,” Smith said. “It doesn’t make any sense to me to just let the seawall go and create all these new problems. A small patch costing $10 to 20,000 can get us through another winter or two.”

Since Terrace is one of two roads that lead to the Bolinas Mesa, which houses hundreds of Bolinas residents, it becomes a public safety concern if Mesa Road is the only access road. Over the last five years, the tree-lined Mesa Road has been closed six or seven times.

“The fire department can’t go downtown and ambulances can’t come up,” said Anita Tyrell-Brown, the fire chief of Bolinas Fire Protection District. “We can generally clear a tree, but if there are powerlines involved, we have to wait for PG&E to come and make sure the power is out. If it’s a widespread outage, PG&E responds to large populations first. These lines service only a few homes, so it’s hard for them to prioritize it.”

“We end up being stymied for hours,” Blackman said.

“The wall definitely buys time to figure out a permanent solution,” Tyrell-Brown said. “At the very minimum, the seawall needs to be looked at and repaired.”

“What especially concerns me is that we’re now in November. We thought we would be doing a repair of the wall basically now,” Blackman said. “We’re losing the window of time we have to repair the seawall before the winter storms are really here.”

One couple’s cliff

Part of the seawall sits 90 feet below Robert and Diana Ekedahl’s house on Terrace Avenue.
After a landslide in January 2006, the Ekedahls, who have lived on the bayside bluff for nearly 40 years, applied for a permit to build piers that would prevent further encroachment.

“We waited until just recently. We thought the county would fix the base, and then we would fix the top. But when they didn’t, I proceeded with my project,” Robert said. “To the extent that my house is endangered, fixing the seawall was not as immediate. More immediate would be the slide area.”

Their request for a coastal permit was approved at the end of September. “When I made the formal request and applied for the permit, the county was very cooperative,” Robert said. Construction lasted just under three weeks.

“Fortunately, it was finished within hours of the storm on Friday night and Saturday,” he said. “It was pretty close,” Diana added.

Twelve piers were lowered into vertical holes 16-feet deep and 18 inches in diameter. Steel reinforcing bars were placed into the holes and then bent at the tops so that the rebars in each hole overlapped. The holes were then filled with concrete, and concrete was poured over the tops of the bent rebars to create a semi-horizontal grade beam to connect all 12 concrete posts. Except for one that leans against the retaining wall at Terrace, the concrete posts aren’t visible above ground.

For erosion control, the Ekedahls have placed waddles—long snakes of rolled-up straw—and plan to plant the native, deep-rooted violet flowered lupine on the slide area.

“The wooden wall can be fixed for a modest amount of money. The 90-foot vertical cliff is the big undertaking,” said Robert, who owns a portion of the cliff. “Fixing the seawall will only buy time for Surfer’s Outlook. I care about at least 25 percent of the county wooden wall, and ultimately, something has to be done about the seawall.”

“We’ve already spent many thousands of dollars protecting ourselves from the sea,” said Robert.

“Seems like we’ve been putting cement into the ocean forever,” Diana added. “Living on the ocean is a constant adventure, but it’s been worth it.”

The future?

If the seawall can keep the ocean from hitting the base of the cliff, it will slow the erosion and preserve the road. “The seawall has been effective in slowing the erosion rate. Had the seawall not been there, the road would have eroded away years ago,” said Ralph Camiccia, a Terrace Avenue Community Committee member with a background in geology. “It’s accelerated over the last few years, since the seawall has been breaking down. The sandstone looks like it’s fine, but it’s crumbling into the sea.”

Beaches replenish themselves by eroding the hill behind them. The particles in this sandstone aren’t that cohesive. When the undercutting starts, the integrity of the cliff is permanently compromised. “It’s gonna go sooner than later,” Camiccia said.

“It’s physically possible to fix the seawall. It requires the will of the county to do it,” Blackman said.

Two other things are needed—a new (or repaired) wall to block the waves at the base of cliff and some sort of armoring for the cliff surface.

One known technique can be seen on Highway 101 in San Rafael. The concrete that holds up the side of the mountain is textured, making it look like stone rather than a cement wall. Along coastal areas of Highway One, cliffs have been beamed and buttressed.

Either one of these projects would require environmental review and coastal permit. “It’s not an immediate solution. The seawall has been quite effective at slowing the rate of erosion from down below,” Blackman said. “We can stabilize the situation, then take a couple years to agree on a solution to preserve the road. Whatever the solution is, we need time to evaluate the options, to go through the permitting process. But we keep losing time.”

“If we have to relocate these lines, we want to do it on our time frame, in other words, not under emergency conditions where the bluff has failed,” Blackman said. “So we are moving forward with that, but it’s a really time consuming process. If we are approved for the loan, the soonest we could do it is next summer.”

“In the end, we all have to save ourselves. We can’t depend on the government as we used to. The federal government has set the example—it’s been an abysmal failure in the past decade, and it’s trickling down to the state, and regrettably, in this situation, to the county as well,” Smith said. “So then the responsibility, the burden of this situation keeps getting pushed down and down, until it ends up with the townspeople.”

“People do stuff when they have to,” Smith said. “I’m kinda hoping someone just patches it up.”

~ by Janet Fang on November 7, 2008.

One Response to “Who will save Terrace Ave? (Point Reyes Light, 11.06.2008)”

  1. I’m kinda hoping someone just leaves a $10,000 blank check in my mailbox.

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