The team working to told City Council Monday night that if residents want protection against a so-called "100-year" creek flood, it will cost $20-30 million more than a less burly alternative and will require strong Council support.
Otherwise, said Len Materman, Executive Director of the San Francisquito Creek Joint Power Authority (SFCJPA), a trimmed-down option could offer residents protection against a 50-year flood—an event slightly larger than the 1998 El Niño floods that caused San Francisquito Creek to overflow, forcing hundreds of evacuations and causing $28 million in damages in Palo Alto.
The difference between the two options, other than the price tag, is the level of design and construction work involved.
Preparing for a 50-year creek flood will require “discreet” in-stream and bridge improvements, said Materman. The 100-year option, however, may require building five to six-feet high flood walls along portions of the creek, a diversion culvert that runs under Woodland Avenue, water “detention” ponds upstream on Stanford land, or some combination therein.
One woman during a public comment period objected to the encroachment of the creek on her Crescent Drive and Woodland properties.
“My property is too narrow to absorb any encroachments,” she said. “It would encroach on my back yard, my husband’s office, my bridge, my Japanese garden. Please find another way.”
Materman agreed that flood walls would have a significant impact.
“The flood walls will have an impact on peoples back yards,” said Materman. “Not only will you have a visual impact on people who drive on Woodland Avenue or drive on University Avenue Bridge or drive on Pope/Chaucer Bridge, you’ll have floodwalls that are five to six feet high."
For this reason, he said, the Authority is actively seeking alternatives like the underground culvert and upstream water detention areas.
In order to build the 100-year creek plan, however, the Authority must first upgrade the coastal flood zone on the east side of Highway 101 so it can handle the volume of water coming down creek.
The total cost for protecting both the creek and the coastal floodplains against a 100-year flood is estimated to be $126-146 million and would protect 3,600 parcels, according to the presentation Monday night.
Those parcels currently pay into a FEMA flood insurance program that costs more than double the projected $650-700 it would cost annually to upgrade to the 100-year plan. What’s more, said Materman: insurance premiums will continue to rise in perpetuity, whereas servicing bond debt would end after 30 years.
Materman appealed to council to lend their support to local two bond measures being drafted by his agency and the Santa Clara Valley Water District that would bypass any dependency on federal funds.
“We can’t rely on the federal government to solve this problem. We have to take care of it ourselves,” he said.
The Army Corps of Engineers, said Materman, has been working on a feasibility study for seven years now, and would of course be invited to participate if and when they were able to, but that could still be decades from now.
Council members seemed generally supportive of the project, but honed in on questions around anticipated sea-level rise.
“What kind of assumptions are being made regarding sea level rise, particularly as it relates to coastal levees concept?” asked Council Member Karen Holman.
Materman said his agency follows the guidelines set forth by FEMA, which assume 26 inches of sea-level rise within the next 50 years.
Holman then asked about the creek upgrades, and if the 50-year option there is essentially an interim approach that would eventually be bolstered and connected to the coastal levees.
Materman said that the 100-year option on the creek requires first the completion of the 100-year coastal plan, and that one scenario could include pursuing a 50-year project upstream before taking it to the Army Corps and “essentially having them price it up” to the 100-year plan.
Council Member Larry Klein then asked Materman to describe the risk of sea-level rise.
Materman said that in 50 years, the daily high tide will equal the current 100-year tide, which would cause significant inundation west of Highway 101. This comment raised many an eyebrow on the council dais.
Joe Teresi, a senior engineer in the City’s Public Works department, at that point came to the microphone to drive the point home.
“The theory is that when FEMA looks at our levees, they’re looking at how we keep the bay out,” he said. “Based on current deficiencies, FEMA doesn’t think our levees exist.”
Materman said the State of California has awarded $8 million so far to start construction on the first phase of the project, which he said is a testament to the JPA Board’s decision to try to find funding outside of the federal sources.
“There was a fundamental paradigm shift on behalf of the JPA Board that said, we can’t rely on the federal government to solve this problem,” said Materman.
Moving forward, however, will still require ongoing support from council.
“We’ll need the council to support the golf course piece, we’ll need them to support the project piece, and ultimately if we go to the voters we’ll need the elected officials to make a clear statement that they’re behind it,” said Materman. “We’re trying to lay the groundwork for all those things to happen.”