05 February 2007

A's Waterworld

Matier and Ross pointed out in today's column that Pacific Commons is in some danger due to global warming. Should sea levels rise 1 meter over the next 100 years, it would appear that the low-lying project area would become waterfront property or at worst underwater. So which is it?

previous Chron article included a handy-dandy map showing which parts of the Bay shoreline would be inundated. While the map shows that the project area is not within the 1 meter zone, it's somewhat outdated because it doesn't include the work done to create the Pacific Commons wetlands preserve. In order to maintain tidal flow throughout the area, a causeway was built for Cummings Parkway, which runs through the western part of the project area. The causeway is some 3-4 meters above the preserve.

The preserve area (light gray) is physically lower than the project site by 1-2 meters (check this space later for GPS measurements). What you'd have is the project site above the preserve, evolving from a usually dry tidal marsh to an estuary-type area. So the ballpark and the nearby housing should be relatively safe, right?

I'm not going to make any predictions. It would be nice if the subject matter were covered in the EIR. One thing's for certain: Someone's going to need flood insurance.

I'm including murf's comments in this post. murf knows this particular field quite well, so his opinion is worth a lot more than mine, or a couple of columnists:

It won't be covered in the EIR except to say that future considerations should be made, dependent on observed sea level fluctuations. That's all that can or should be said about it right now.

An aside on potential sea level rise: 1 meter is a pretty generous (sensationalized) estimate. More recent estimates put the potential rise at 7 to 23 inches by 2100.

An important factor re: how sea level impacts are predicted. Anytime you see a number, be it 7 inches or 2 meters, it's a prediction for the average global change in sea level. Change, we know, is most severe at the equator with diminishing severity as you go north and south away from the equator. This is because there is a major factor beyond ice cap melt that is considered in the models: thermal expansion. Water at the equator, currently and predicted in the models, fluctuates with greater variance than in the northern and southern hemispheres. Unless ocean currents are reversed (very unlikely) the California coast will still receive current from cold regions near Alaska, which predictably could mitigate some of the thermal expansion expected in warmer waters. The one thing we know for certain is that we don't know everything about how the oceans are going to react. We've got a good idea, though. As for Pacific Commons, it lies within the Study Area of the South Bay Shoreline Study of the U.S. Army Corps of Engineers and a host of local sponsors. This project is in year 2 of a 7 year study to determine appropriate steps to protect the area for the next 100 years against tidal super-elevation and potential sea level changes. (New Orleans opened a lot of eyes.) Assuming the Federal Government can pass appropriations bills in the next 100 years, PC should be safe.

It's good to know that the Feds are learning from Katrina and could apply lessons to our situation.

The big chokepoint

The Merc's Mr. Roadshow, Gary Richards, has an update on the big chokepoint in South Fremont/Warm Springs, the 880/Mission interchange:

Q Gary, you've written so much about the construction on Highway 87, which I drive through every day and that is greatly appreciated. But I also drive up to Interstate 880 through the Mission Boulevard squeeze and need to know: When is this work going to end? Opening the merge lanes has helped, but I need to see more signs of progress.
Tom Enriquez, San Jose

A Oh, do I have good news for you. Progress is right around the bend on this $178 million project. The ramps from westbound Mission to south and north I-880 could open by spring or summer, a major milestone. And there is more you need to know:
• The Kato Road ramps will be closed and the new overpass open in another month, perhaps.
• The ramp from south I-880 to east Mission: spring 2008.
• The ramp from north I-880 to east Mission: fall 2008.
• Completion of the Warren Avenue interchange: Late 2008.
• Opening of carpool lanes on I-880: fall 2008.

The opening of the merge lanes from Mission to 237 has already made life a lot easier for those on 880 South during the PM commute. The incremental improvements, culminating with the carpool lane additions, should make 880 South quite smooth. As for 880 North, the widening and siphoning should alleviate some of the problems for the through traffic but there's no completely solution as the volume is too heavy to fulfill everyone's needs.