Flooding and mudslide concerns in the Bay Area

March 23, 2011 6:56:43 PM PDT
You just can't duck the rain since there is another big storm heading to the Bay Area and all of the rain may bring a flood of new troubles to already saturated hills, prone to rockslides.

A trail has been closed at Huckleberry Preserve in the East Bay Hills. A tree came down at Huckleberry and took a chunk of the trail with it. Officials are worried they will see more trees coming down in the next couple of days.

With the ground close to saturation in so many spots, there is growing concern about landslides and in the Oakland hills that saturation is starting to show.

On Wednesday morning, US Geological Survey said the saturation level in the Oakland Hills and throughout the Bay Area had reached 95 percent. It remains just over 90 percent. What USGS is really worried about in the next couple of days is the kind of slide that happens suddenly, without warning.

The signs are easy to see in the East Bay hills. In many locations, the ground has clearly had just about enough of the rain and some gradual slides had to be covered with tarps.

"It would certainly be safe to say that we're at the point where our instruments indicate the soil is close to saturation," said John Stock from USGS.

USGS monitors ground saturation in the Bay Area in two locations; one is at a monitoring station in the hills above Castro Valley and other is in the North Bay at Lucas Valley, where one hill there is already starting to slide.

"The thing we'll all be looking for is those intense bursts of rainfall, above half an inch per hour. And those are the ones if they're sustained for several hours, we will begin to see poor water pressures accumulate -- that is free water in the soil -- and that means there's a hazard of a shallow landslide," said Stock.

Along Oakland's Skyline Boulevard, a small rock slide took out part of a homeowner's front fencing.

Nearby, East Bay Regional Parks crews closed a hiking trail submerged in mud, they cleared trees that have fallen, and assessed those that could come down soon.

"Right now as you can see the storm door is open and saturations...it's kind of like a sponge. We've reached capacity," said Park Supervisor Jeff Hanley.

"The submersible pumps have been doing quite well for us," said Josh VanDermulen from Orinda Hardware.

At Orinda Hardware, there's been a run on pipes, pumps, and pretty much anything that could help homeowners manage all of the water.

"The land's just getting too much saturation, so the water's pooling up in spots it shouldn't be. Like yesterday, I had a gentleman came in to buy a submersible pump to save his basement," said VanDermulen.

A critical factor in the next couple of days is the heavy rains. More than half an inch per hour, for several hours, that's what has the USGS concerned. There is information online for homeowners who might think they're vulnerable.

There were four slides that occurred over the weekend in Oakland.


Load Comments