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Weathering El Nino

Pleasanton and Tri-Valley agencies prep for intense winter storms

Amid much hopeful and anxious waiting, winter rains have come to Pleasanton. With more strong, howling winds and raging gales expected to arrive in the coming weeks and months, the inevitable question arises: Is Pleasanton ready for El Nino?

The Bay Area is well aware of the effects a strong El Nino event had on the region in 1998. A landslide in Fremont threatened homes, washouts in Pacifica tumbled houses into the sea and rivers across the state spilled over their banks and sent residents scrambling for higher ground.

In Pleasanton, localized flooding caused traffic backups, and eroding dirt caused the pavement of a bike lane above Shadow Cliffs Regional Park to crumble. But all in all, the city was spared the worst of the disastrous flooding and washouts.

Experts say the Tri-Valley has learned a great deal from the damage the Bay Area endured during that torrential winter. Since then, emergency management and flood control experts have put measures into place to prevent certain emergencies from occurring and to react quickly when damage and flooding does occur.

The El Nino system sent some rain to the Bay Area in December, but some experts believe the large storms will start hitting this month or next -- much like they did during the 1997-98 El Nino. Others say it's impossible to completely predict "the big one" until it's on its way.

"Nobody knows when the big El Nino storms will hit," National Oceanic and Atmospheric Administration meteorologist Steve Anderson said.

During the last El Nino, the Pleasanton-Livermore area got 24.6 inches of rain from November to May -- 12 inches of which dumped during January and February, according to NOAA data.

Kathleen Yurchak, Pleasanton's director of operations services, said the city is working on multiple fronts to make sure the city is as prepared as possible.

"If anything, I feel like we're more prepared this year than we have been in a while," she said.

Then again, agencies' staff acknowledge nature is unpredictable.

"The best we can do is prepare for heavy rain, and then wait to see what Mother Nature brings us," said Dan Gallagher, operations manager for Dublin San Ramon Services District (DSRSD).

Getting ready for the big one

A century ago, Pleasanton was subject to the whim of nature. A heavy rainfall would almost always mean flooding, particularly near Shadow Cliffs and in the area that is now Hacienda Business Park.

But developments in civil engineering have ensured the businesses near Hacienda have adequate drainage, and natural areas like Shadow Cliffs have water channels that keep runoff moving through the city to San Francisco Bay.

Pleasanton has a few areas that officials are keeping an eye on for potential damage and danger as the El Nino approaches.

In the western area of town, Dublin Canyon and Foothill roads are expected to get cascading runoff from Pleasanton Ridge that can make driving difficult, according to Leo Lopez, city environmental compliance manager.

That rainfall can cause a problem in and of itself, but it also means tree branches, dirt and trash might wash onto the road.

"Dublin Canyon poses a particular safety hazard for us because aside from getting a lot of runoff on the road and creating a traffic hazard, clearing those areas is dangerous for us because folks are driving at high speeds," he said.

In the central part of town, flooding is mostly caused when the above-ground channels are blocked with debris or when below-ground pipes are clogged.

City workers also often monitor areas along smaller waterways such as Kottinger Creek near Kottinger Community Park, as well as specific grates and outlet pipes that are known by experts to cause problems if left unchecked -- some of which are located on the southeast part of town.

When it rains, water is funneled away from Pleasanton in two ways: It flows into above-ground channels or it flows into storm drains and is carried off by underground pipes to the Bay.

The infrastructure can do its job and keep water moving, but a plug in the system means water will back up into streets and homes, Gallagher said.

Zone 7 Water Agency, a regional water wholesaler, is also tasked with providing flood management and mitigation to the areas under its jurisdiction, including Pleasanton.

Carol Mahoney, Zone 7's manager of integrated water resources, said staff regularly check the streambeds of above-ground channels, even if they're bone-dry, to make sure there isn't anything that could potentially block the water's path. If a tree or man-made debris gets in the way of a large flow of water, it can back up and overflow onto the nearby streets.

"In the major channels, what's happened is someone's dumped a couch and that's blocking a culvert," she said.

Pleasanton has about five major man-made channels that direct water through the city, such as Arroyo Mocho that flows along Ken Mercer Sports Park, Arroyo del Valle that runs through downtown and Chabot Canal that runs through Hacienda Business Park.

Each is a dirt channel, and they all flow west to combine with the Arroyo de la Laguna, which flows south parallel to Interstate 680 before emptying into Alameda Creek and then into the San Francisco Bay.

One of Pleasanton's unique challenges is the dirt that makes up these waterbeds is essentially fine silt -- easily moved soil with little gravel to keep it in place. Such soil can cave in easier than Livermore's gravel-based soil. Zone 7 staff are tasked with repairing the channels in areas where it has given way, which can also back up storm-flow and cause flooding.

For underground stormwater pipes, the biggest preventative measure is clearing away tree roots that have burrowed inside, in addition to contending with trash, grass clippings, leaves, dead animals and sediment. The years-long drought has been tough on trees, and they've pushed out their roots to any water source possible. While tree roots are a bigger problem in wastewater pipes, experts clean out those and stormwater pipes as needed.

"Trees are desperate for water," Gallagher said.

At the same time, the smaller floods are often caused when leaves wash off people's roofs and yards and plug up drains.

"If people have the opportunity to go out and clear those leaves before the storm hits, that is a huge benefit," Mahoney said.

In Livermore, Cal Water has cleared pipes, established contingency plans for flood-related problems and set up an emergency response team to fight floods in town, said Frank Vallejo, Cal Water Livermore district manager.

Pleasanton's Operation Services Center will run flood operations but have several levels of plans in place in case the El Nino packs a large punch.

At agencies across the Tri-Valley, staff members are setting up portable generators, stocking up on supplies and talking with county, state and federal disaster management agencies -- just in case.

"We are even equipped with portable beds and things like that in case we face a big emergency," Vallejo said.

One of the biggest concerns is for people's safety as rains approach. Some local arroyos are known to funnel water through quickly, creating a stream that could sweep someone off the bank.

Livermore-Pleasanton Fire Department (LPFD) has started practicing for swift-water rescues, particularly along the arroyos in the western edge of town, acting deputy fire chief Joe Testa said.

The LPFD advises residents to never drive into a flooded road, even if the water is still, since you can't be sure about the depth of the water. Testa said people should also never enter flowing stream water.

Even if the whitewater looks like fun, it is dangerous, he said.

"Some of the water rescue emergencies that we have had in the past have included kids attempting to use inflatable rafts in the arroyos during times of peak flows and people becoming stranded in the water on an island or in a vehicle," he said.

So, is the drought over?

With this winter potentially bringing the most water the state has seen in recent years, experts say the El Nino would not fix California's drought, and residents should still keep conserving water.

But the El Nino would help.

For example, it is expected to bring snow to the Sierra Nevada Mountains, the runoff from which provides water to many areas of California, including Pleasanton.

Experts from various agencies said this snowfall is entirely the key to helping alleviate the region's drought. No snow, no relief.

While some El Nino rainwater will be captured in nearby reservoirs, the Tri-Valley has few options for capturing rainwater for later use, aside from lakes.

One of the biggest reservoirs in this area is Lake Del Valle. The lake itself is five miles long, and some of the water that is caught there will be used for drinking water for Zone 7's wholesale buyers -- the cities of Pleasanton and Livermore, Cal Water's Livermore division and DSRSD.

In general, some rainwater will trickle through the dirt and gravel to reach the local underground aquifer, especially water that rages through above-ground channels.

However, the water doesn't have the time it needs to sink into the soil -- after all, it needs to be moved away from streets and homes to avoid flooding. That aquifer is relied upon by Zone 7, municipalities and private residents with their own wells to provide water in dry years.

Public and private water retailers in the Tri-Valley do not have their own reservoirs because it's not a part of their operational mission. Zone 7 has the ability to artificially recharge the underground aquifer with treated water, but there's no easy way -- given current infrastructure -- to funnel rain into a safe storage area where it can later be treated and used to replenish groundwater supply.

"Catching water and providing water are two completely different things. We don't have any storage reservoirs or any lakes or anything to hold water in," Gallagher said. "Unfortunately, there just isn't anything we can use to capture rainwater and to put it back into the ground."

So the fact remains that much of the rain that falls won't find its way into drinking glasses this summer. Most of it will be dumped into the San Francisco Bay or the Pacific Ocean.

What you should do

Pleasanton residents' efforts are essential to helping prevent flooding in town, experts say. Plus, most of the measures are simple.

City staff encourage residents to clean leaves off their yards and roofs and bag them for disposal. By doing so, residents will ensure these leaves won't be washed into storm drains when it rains, which can easily clog the drains and cause flooding.

Residents are also encouraged to store sandbags before the El Nino hits. Sandbags can be used along garage doors and entryways to keep water from getting into a home, causing damage.

Additionally, make sure drainage directs toward the street's storm drain system, and remove any dead trees and brush from one's property. Residents can use a rake, broom or shovel to unplug a storm drain grate if flooding has started to occur.

In the event of flooding or downed power lines, contact Pleasanton's operations service center at 931-5500 or the Pleasanton Police Department in the event of an urgent safety matter at 931-5100 or 9-1-1 in case of an emergency.

Resources

* To keep up-to-date on whether streams have flooded in your area, visit Storm Central to see water levels in local channels: https://stormcentral.waterlog.com/public/Zone7.

* Alameda County also has a website to keep residents up-to-date on flooding, road closures and storm safety information: https://www.acgov.org/pwa/info/elnino.htm.

* Now might be the time to talk with your insurance agent about whether flood insurance is necessary -- particularly if your home is in an area expected to get higher water levels. Visit www.floodsmart.gov to get information from the National Flood Insurance Program.

* The city of Pleasanton is handing out free sandbags throughout winter. To get your sandbags, take a shovel to one of the following locations for free sand and free bags:

- Operation Services Center, 3333 Busch Road

- Senior Center, 5353 Sunol Blvd.

- Ken Mercer Sports Park, 5800 Parkside Dr.

Those locations will be open from 7:30 a.m. to 3:30 p.m., and supplies will only be restocked during working hours.

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