By Anne Gelhuas, Judy Peterson and Khalida Sarwari
While Monday’s storm wasn’t precipitated by El Niño, it was a harbinger of the pummeling doses of rainfall that meteorologists say will come this winter if the tropical weather front moves in as anticipated.
The storm system that hit the Bay Area on Nov. 2 came from the Gulf of Alaska and dropped more than an inch of rain in Santa Clara County. Of the numerous rainfall reporting stations in the region, the gauge at Los Gatos Creek at Interstate 280 had recorded 1.95 inches as of 6:15 a.m., according to the weather service.
Some local roadways were shut down due to flooding, including the underpass at The Alameda and Stockton Street near the SAP Center in San Jose.
To help keep flooding to a minimum during what is expected to be a wet winter, the Santa Clara Valley Water District, PG&E and local cities have been busy repairing eroded creek banks, removing debris from clogged channels, cutting branches away from power poles and building makeshift retaining walls where needed, among other precautions.
The water district has been shoring up creeks for months, agency spokesman Marty Grimes said. Many of the flood control projects that have been in the pipeline for decades such as Calabazas Creek finally have been completed and others such as upper Guadalupe Creek are ongoing, he said.
The Calabazas project, which will protect roughly 400 creekside parcels in Saratoga, Cupertino and San Jose from rising waters, wrapped up on Oct. 24. The work included razing and replacing a Union Pacific Railroad bridge in Saratoga with a wider one and repairing a dozen eroded spots along the creek.
The effort should prevent $11 million worth of damage that officials say could otherwise be inflicted by a 100-year flood, so named because a flood that large happens roughly once a century.
Significant flooding occurred in the project area in 1955, 1958, 1963, 1968 and 1998, Grimes said. During the 1955 flood, water poured into residential streets and homes in and around the area, including Sunnyvale, forcing the evacuation of more than 100 families.
Flood waters inundated many of the same homes in 1958. And in December 2002, the area around Bollinger Road was flooded.
AN OUNCE OF PREVENTION
In San Jose’s Blossom Valley, construction of the Reach 12 segment of the Upper Guadalupe River Flood Protection Project is nearly complete, Grimes said.
That entailed planting native vegetation and trees along the existing channel and creating a meandering low-flow channel. Crews also made it easier to maintain the main channel by adding access roads and ramps.
While the project is referred to as a flood protection measure, Grimes said the benefits are broader, such as providing a better habitat for fish and better access to the creek for work crews.
“It’s the ongoing ability to get to vegetation and remove trees, so it does help the ability to prevent flood risk if you can more easily get down to the creek and remove an obstruction,” Grimes said.
Every summer, the district does maintenance work in its creeks, from repairing creek banks where erosion has occurred to removing sediment to maintain free-flowing water capacity.
The district also regularly surveys creeks for fallen trees, trash and debris, focusing on hotspots where debris tends to accumulate and clog up channels, resulting in floods, Grimes said.
“We have a routine that our staff goes through; when we see that there’s a storm in the forecast, our crews will be out checking out all these hotspots,” Grimes said.
Some of the hotspots now have cameras installed, allowing staff to monitor them remotely.
ACTING LOCALLY
Local cities also are taking measures to shore up hotspots within their own borders. In Los Gatos, for example, public works employees began preparing for the prospect of winter storms in September, and director Matt Morley says it’s one of his department’s highest priorities.
“We’ve reviewed our storm drain system to ensure the catch basins are clear,” Morley said. “We also look at the creeks and drainage ditches that bring water from the hillsides into the storm system; over the summer these fill up with trash, dead brush and all kinds of other debris.”
Morley said the debris can get caught at pinch points, such as openings to pipes. “This can create a dam, which may lead to flooding,” he said.
After the first rain of the season, public works crews will check the storm drains again to see if any “surprises” have washed down from higher elevations.
In addition, crews have been removing dead trees from town property, most of which succumbed to the drought, Morley said. “Proactive removal will keep the trees from falling over and causing damage. Where it makes sense, we leave the stump and root structure for soil stability purposes and will replace the trees in the spring,” he added.
SLIP-SLIDING AWAY
Residents of unincorporated areas of Los Gatos have reason to be concerned about soil stability in heavy storms. Experts warned that the flash floods in Southern California last month, which caused mudslides in the Tehachapi Mountains, were a wake-up call for people who live in or commute through the Santa Cruz Mountains, East Bay hills and other slide-prone regions of the Bay Area.
The winter of 1982-83 was dominated by strong El Niño patterns that brought massive rainstorms, triggering a mudslide that killed 10 people in the Love Creek area of Ben Lomond.
To help prevent future slides, people who live on or near hillsides should keep an eye out before the rains arrive for signs of instability, whether cracks in slopes, trees that are leaning or vegetation that’s moving. Concerned homeowners can have a soils engineer conduct an inspection or contact their local building department.
California Department of Transportation spokesman Bob Haus said Caltrans will be patrolling areas that are susceptible to mud and rock slides and erecting makeshift retaining walls where necessary; and inspecting drains, culverts and pump houses to make sure they are clear of debris.
In the town itself, Los Gatos has finished several capital improvement projects that address storm water issues. For example, work on a crumbling retaining wall on Jackson Street was completed a few weeks ago. “That road was slowly falling into the creek and likely would not have made it through the winter,” Morley said. “We also have several other improvements finishing up that relieve the pressure at some of our hotspots.”
Similar preparations are under way in Campbell, where city officials are working with West Valley Sanitation to inspect and clear every storm drain inlet within city limits, focusing on hotspots as well as locations along the city’s parks and trails.
In anticipation of El Niño, Campbell has also increased its efforts this year to remove dead or weak trees that may fail during a storm.
FLOOD ALERT
Valleywide, the water district is working to install a flood alert system designed to detect changes in water levels. The system, which works by sending a notification to district employees at least two hours before a creek is expected to overflow, has already been installed at San Francisquito Creek in Palo Alto.
In preparation for the big storms, the water district also has stockpiled nearly 500,000 sandbags, with plans to purchase more if necessary, said Gary Kremen, chairman of the district’s board of directors. For a full list of the 17 sandbag pickup sites within the water district, visit valleywater.org/sandbags.
Both the water district and PG&E have partnered with local, state and federal agencies to put together contingency plans in case of flooding and power outages and to inform the public about how to prepare for the big storms, mostly through fliers and websites.
PG&E prepares for winter storms throughout the year by cutting tree limbs away from power lines, a leading cause of power outages, utility spokesman Matt Nauman said, adding that crews annually inspect every one of the company’s 134,000 miles of power lines.
“We also have about 650 contract tree crews who are at work every day to keep vegetation out of the way of power lines,” he said. “Because of the drought, we did some extra patrols this year and extra tree work to make sure the trees and limbs stay away from the power lines.”
In addition, PG&E has created an emergency preparedness department that’s tasked with getting the company up to speed on natural disasters and emergencies.
“This year we held the largest drill in the history of PG&E,” he said. “That was held in multiple locations and was a two-day drill that involved 750 employees and 24 different emergency centers.”
POWERING THROUGH IT
While it’s too early to predict where power outages will occur, the company has the equipment ready if and when they do. These items include transformers, power lines and poles, Nauman said.
“Until [El Niño] materializes, you can’t know for sure,” he said. “We do have a meteorology department, and they use some advanced forecasting and modeling tools. … That really allows us to anticipate where storms will be most severe and outages will occur.”
Nauman warned residents to avoid downed power lines at all costs; it’s especially important to keep children and pets away from them, he said.
“The key message is that downed power lines can be dangerous,” Nauman said. “Stay away from them; don’t touch them; if you see one, call 911.”
There are other precautions residents can take even now, Grimes said. One of the most important is to have a family emergency plan that involves a discussion about escape routes and potential meeting sites in the event of flooding or other disasters.
Keeping an emergency kit at home with flashlights and nonperishable food is also important, as well as pre-filled sandbags. Kremen advises residents to sign up for emergency alert services.
And if roads do get flooded, motorists shouldn’t drive on them. “People think they can just power their cars through a flooded road; that’s very dangerous,” he said.
A LITTLE INSURANCE
The water district is reminding residents who live in flood-prone areas to consider getting flood insurance for their home, as regular homeowner’s insurance doesn’t cover flooding, and to keep in mind that it generally takes 30 days for the policy to kick in, Grimes said.
“We ask folks who live near a creek or walk the trails that they help us out by letting us know if they see a potential problem,” said Grimes, adding that they can they do so by using a reporting system on the district’s website at valleywater.org or calling 408.630.2378.
Even with all this preparation, Kremen said, people in flood zones are still at the mercy of El Niño. Hopefully the warm front brings stormwater that runs off into streams and creeks instead of being absorbed into extremely dry ground, causing flooding.
“We need the right kind of rain,” Kremen said.
Visit pg&e.com/beprepared to find more El Niño-related safety tips from PG&E.
SVCN reporters Julia Baum, Jasmine Levya and Matt Wilson and Bay Area News Group reporters Mark Gomez, Rick Hurd and Aaron Kinney contributed to this report.
Link: Bracing for El Nino
