Palo Alto Weekly

Spectrum - January 4, 2013

On Deadline: Palo Alto area flooding problems go back decades, but is relief in sight?

by Jay Thorwaldson

Palo Alto and its neighbors Menlo Park and East Palo Alto have experienced flooding for decades — despite occasional efforts at flood relief.

But a new effort to increase the capacity of San Francisquito Creek — frequently referred to in news stories as "the flood-prone" creek — may reduce the risk of future floods, notwithstanding long-term concerns about global climate change, a rising sea (and bay) level and more volatile weather.

Most of the flooding threat stems from the flood-prone creek, although other sources of flooding have also added to people's wet-weather woes.

One chronic flooding-site is the Oregon Expressway underpass at Alma Street/Caltrain tracks. In one instance, the late William Clark, M.D., recounted how in the late 1950s he was racing at night to the home of a patient who was suffering a heart attack. He sped into the then-new underpass — and splashed into about 3 feet of icy-cold water. Clark waded away from his drowned car, but his patient died.

Recent flooding of the underpass indicates not much has changed. In heavy rains, it often floods, more seriously if there's a problem with the pumps.

Yet the primary concern for Palo Alto, Menlo Park and East Palo Alto officials and residents is the flood-prone San Francisquito Creek, the deep channel that separates Santa Clara and San Mateo counties. During much of the year, the creek is, well, a creek, sometimes virtually drying up to a trickle with some mossy ponds.

But during serious storms it becomes a deep brown torrent, on which some young persons — including one of my own sons, unbeknownst to me <0x21014> would secretly go whitewater rafting. A chilling risk.

The reason the creek surges from nearly empty to nearly overflowing is that upstream, as it wends through Portola Valley, it is fed by a series of relatively short and steep canyons, most with historically intriguing names. The first rains of the season get soaked into the predominantly redwood forests lining the canyons.

Yet when the second or third heavy rains hit the water quickly rushes down the canyons and combines into a torrent heading downstream, right toward Palo Alto and its lowland neighbors.

After major flooding of the mid-1950s, the two counties raised the levees and added low concrete walls, a significant improvement but far short of a permanent solution.

In the late 1960s, the surging creek jammed up at the infamous Pope-Chaucer Street Bridge, with its constricting arch. Then-City Manager George Morgan showed up at the bridge in the early morning hours and reportedly helped city crews wield long poles to shove floating trees through the arch.

Since then, the formation of the San Francisquito Creek Joint Powers Authority — usually referred to as "the creek JPA" — tackled two core problems that had for years stymied effective action. The first was competitive finger-pointing between the communities of Palo Alto, Menlo Park and East Palo Alto, along with the two counties. The second was a massive barrier: the bureaucracy of the Army Corps of Engineers that seemed to local officials to bog down action through delayed decisions and endless studies.

Tension between communities grew. At one point, during a heavy rain city crews from Menlo Park and Palo Alto gathered on opposite sides of the Pope-Chaucer bridge to assure that neither city did anything to increase risk of flooding to the other city.

The JPA's former executive cirector Cynthia D'Agosta, while successful in building a common effort relating to the creek, nevertheless struggled against the Corps' sluggishness and tight local budgets until she decided to leave to head the local environmental group Committee for Green Foothills. D'Agosta earlier launched a campaign to preserve three watersheds, and headed a joint-powers effort to bring together scores of agencies involved in the huge Los Angeles River basin.

Current JPA Executive Director Len Materman has shifted tactics, de-emphasizing the role of the Corps of Engineers in favor of local efforts and focusing on expanding downstream capacity of the creek to handle a so-called "100-year storm." That term means any storm that has a 1 percent chance of occurring in any given year. There is real concern that global warming could increase the 1 percent substantially, and rising sea levels would increase the odds of high-tide flooding of lower-lying residential area — including a huge area of south Palo Alto.

Lowlands of south Palo Alto were hit with a major flood in the Feb. 3, 1998, overflow of the creek, despite being distant from the creek itself. Water flows downhill, and failure of a large pumping system due to loss of power just backed water up into homes, sometimes up to 4 feet or more deep. The creek overflow also hit portions of the Crescent Park area and other homes as the water flowed through en route to south Palo Alto. Damage was ultimately estimated at more than $40 million.

Yet although the Pope-Chaucer bridge was target of most of the blame, the creek was at capacity for most of its lower length. Officials reported up to 17 overflow sites, most of them fairly minor. Ironically, the inadequacy of the bridge may have saved other homes downstream in Menlo Park and East Palo Alto from being flooded.

Some parts of East Palo Alto are particularly at risk. If a sudden levee failure were to occur, some neighborhoods would be quickly flooded with an estimated 8 to 10 feet of water. That's a fatal depth, trapping people in their homes and vehicles and creating what the Palo Alto Weekly once editorially called a potential "mini-New Orleans" catastrophe. The term reportedly helped shake loose some federal funds to expedite studies.

The state has already added to the creek's flow capacity under state Highway 101, and plans are afoot to redesign the Palo Alto Municipal Golf Course to allow some straightening and widening of the outflow channel to the bay. In a severe threat the golf course itself could serve as an overflow flood basin to relieve pressure upstream.

Big progress is slated for 2013. So at last this could be the year the creek is made substantially more flood-safe. Maybe.

Former Weekly Editor Jay Thorwaldson can be emailed at jthorwaldson@paweekly.com with a copy to jaythor@well.com. He also writes regular blogs at www.PaloAltoOnline.com (below Town Square).

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