Blue ribbon panel studies local flood control options

Water, water everywhere.

That could be a future scenario in La Conner – truly a case of too much of a good thing for its historic waterfront –if present weather and tidal conditions persist as forecast.

What to do about the prospect of projected heavier winter rainfall, rising sea levels, and more frequent storm surges brought together a panel of scientists, engineers, professors, and local officials for a two-day design forum last week coordinated by Town Administrator John Doyle.

The result was a flood of ideas going forward.

Remedies were both borrowed and original, short-term and long-range. Everything from storm surge resistance measures like seawalls and channel barriers to structural and economic adaptations such as floating shoreline structures and development of innovative revenue streams to pay for necessary renovations.

The local conference was modeled on a handful of similar design charrettes held in low-lying coastal areas in the U.S. and abroad.

It’s an idea whose time has come, according to Doyle and La Conner Mayor Ramon Hayes.

“These charrettes,” Hayes stressed, “should be taking place all over the state, country, and world.”

The hard data and casual observations indicate as much.

Doyle said he began to take notice of more frequent local flood events, with water spilling over the banks of Swinomish Channel onto parking areas and streets, more than a decade ago. That led to talks with Swinomish Tribal Community planners, who were successful in obtaining grant monies to address flooding and climate change issues.

The group meeting in La Conner walked the Channel Passage boardwalk and visited the area near the Sherman Street boat launch to view examples of how recent surface elevation modifications have helped curb flooding.

At least for now.

“Sea level has been rising significantly on the West Coast since 2011,” said Dr. Eric Grossman, a United States Geological Survey scientist.

He was careful to note that flood impacts vary from shoreline to shoreline. But generally, he said, minimal sea level increases result in more extended and extensive flooding.

The low-lying La Conner area and Swinomish Channel waterfront is especially vulnerable, Grossman said, given that the mouth of the north fork of the Skagit River is south of town.

“A little sea level rise will result in much more flooding for longer periods of time,” he said.

That, in turn, several con-ferees noted, will inevitably lead to higher flood insurance premiums in the years ahead.

By the 2080s, Grossman predicted, the 100-year Skagit River flood plain will be nearly 50 per cent larger than at present.

To put that in perspective, Doyle stressed that the term 100-year flood plain is based more on risk percentage than the turning of a century.

“It means there’s a one per cent probability each year of having that kind of flood event,” Doyle said.

Many factors are in play.

“If it rains more,” said Doyle, “you end up with rising sea levels, greater storm surges, and rising ground water levels.”

Steve Moddemeyer, of the Collins Woerman architectural firm in Seattle, said flood control planning must go beyond mere resistance strategies to embrace more proactive and enduring adaptive and transformative approaches. His case studies have included visits to Venice, the famous floating city in Italy, which has long dealt with high-water conditions.

His research in America and abroad has brought to light innovative approaches such as floating risers for pedestrians and the concept of amphibious buildings.

“The longer the recovery from a flood,” he said, “the less resilient you are. So you have to adapt to maintain who you want to be. And, of course, you have to think bigger to see the opportunities that present themselves when you choose to adapt.”

The charrette began with a tour of the 42-year-old La Conner Wastewater Treatment Plant, which has been adversely affected by the combination of increased daily water throughput and rising tides. Plant tanks have overflown when tides push back treated effluent piped to Swinomish Channel.

Treatment Plant Operator Kelly Wynn and work crews regularly survey conditions under First Street buildings where debris swept by tidal currents can damage piping and other infrastructure.

“Some of the plumbing,” Wynn explained, “just kind of hangs down there. So we report what we find to the building owners.”

The tone of the conference was serious and cerebral. But not without moments of levity.

“I’m glad for your interest in the plant,” Wynn deadpanned at one point. “People don’t generally want to come out here.”

Nor could Town Councilman John Leaver, who attended and took detailed notes during both days of the charrette, resist offering a one-liner after studying a series of dramatic flood scene photographs mounted inside Maple Hall.

“Looking around at all these flood pictures of La Conner,” he quipped, “it was a good move to buy a house on the hill.”