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With Baylands under flood threat, Palo Alto explores projects to address sea level rise

Residents invited to Wednesday webinar to learn, offer feedback on city's efforts

Pedestrians and cyclists pass by the Lucy Evans Baylands Nature Interpretive Center in Palo Alto on May 13. Photo by Magali Gauthier.

If current predictions hold, the entire Palo Alto Baylands could be submerged by the middle of the century because of sea level rise, a destructive predicament that would threaten both the sensitive habitat and the critical infrastructure in the nature preserve.

To prepare for rising tides, the city is moving ahead with the creation of a new Sea Level Adaptation Plan, a document that will consider upgrades to vulnerable infrastructure, a risk assessment of all structures near flood-prone areas and strategies that new developments would have to adopt as they adapt to a wetter reality. It is also pushing forward with plans on a levee project that would use treated wastewater from the nearby treatment plant to support a newly created nature habitat in the transition zone between the tidal area and the terrestrial uplands area.

Palo Alto officials plan to provide an update on both efforts this Wednesday, Sept. 9, when the city hosts a webinar on sea level rise. The event will go from 3 to 4 p.m. and will include staff presentations from the city and Santa Clara Valley Water District, which will discuss the agency's own long-term planning efforts around sea level rise.

According to Palo Alto's recently adopted sea level policy, the city also intends to undertake new partnerships with surrounding cities, including East Palo Alto and Mountain View, for joint planning efforts and projects such as levees to address the rising tides.

Palo Alto has already partnered with the San Francisco Estuary Partnership to create a concept plan for a "horizontal levee," a structure that aims to both boost the city's flood protection and protect habitat that would be threatened by sea level rise. Unlike traditional levees, which tend to be steeper and composed of rocks (known as rip rap), the proposed levee would be a gentle berm with "green" infrastructure that can support a brackish marsh in the transition zone close to the Palo Alto Airport and Baylands Golf Links golf course.

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Samantha Engelage, senior engineer in the city's Public Works Department, said the current flood-control levees near the Baylands don't meet standards set by the Federal Emergency Management Agency and at times experience overtopping, particularly when king tides coincide with storm events. In a February update to the city's Parks and Recreation Commission, Engelage said the levees need improvement "to secure Palo Alto and the key infrastructure that is in the Baylands," including the airport, the golf course and the Regional Water Quality Control Plant.

The project has already received two grants, from the Environmental Protection Agency and California State Coastal Conservancy, which funded the planning effort. Engelage noted that throughout the Bay Area, transition zones between marshlands and upland areas have been "decimated" by development. As such, regional agencies have made these transitional areas "a high restoration priority."

"The regional perspective is, 'How can we now take advantage of all this money and effort to address flood control, while also addressing this type of ecosystem that has been decimated throughout the area,'" Engelage told the commission at the Feb. 25 meeting.

As part of Palo Alto's recently adopted plan for sea level rise, the city will be conducting a "vulnerability assessment" that will identify critical infrastructure that could be at risk and estimate the economic impact of vulnerability for both public and private properties. The city also plans to create a multiyear implementation plan that could include zone changes near the Baylands, new permitting requirements for projects in at-risk areas and triggers for relocating facilities away from the area, according to Palo Alto's policy on sea level rise.

The policy, which the city adopted in March 2019, notes that if the Palo Alto Baylands is submerged by mid-century, as predicted, they would lose their ability to serve as buffers during flood events, to attenuate storm surge or to sequester carbon. Sea level rise would also have a disruptive and potentially devastating impact on local habitats, as well as on the recreational offerings throughout the preserve.

"The encroachment of Bay water may alter or eliminate habitat for endanger species that reside in Palo Alto Baylands and the millions of birds that use the Palo Alto segment of the Pacific Flyway for seasonal migration," the policy states. "The recreational and inspirational services of the Palo Alto shoreline could change if Baylands trails, playing fields, and golf course are surrendered to encroachment of San Francisco Bay."

To register for the Wednesday webinar, visit eventbrite.com.

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With Baylands under flood threat, Palo Alto explores projects to address sea level rise

Residents invited to Wednesday webinar to learn, offer feedback on city's efforts

by / Palo Alto Weekly

Uploaded: Mon, Sep 7, 2020, 8:35 am
Updated: Tue, Sep 8, 2020, 8:49 am

If current predictions hold, the entire Palo Alto Baylands could be submerged by the middle of the century because of sea level rise, a destructive predicament that would threaten both the sensitive habitat and the critical infrastructure in the nature preserve.

To prepare for rising tides, the city is moving ahead with the creation of a new Sea Level Adaptation Plan, a document that will consider upgrades to vulnerable infrastructure, a risk assessment of all structures near flood-prone areas and strategies that new developments would have to adopt as they adapt to a wetter reality. It is also pushing forward with plans on a levee project that would use treated wastewater from the nearby treatment plant to support a newly created nature habitat in the transition zone between the tidal area and the terrestrial uplands area.

Palo Alto officials plan to provide an update on both efforts this Wednesday, Sept. 9, when the city hosts a webinar on sea level rise. The event will go from 3 to 4 p.m. and will include staff presentations from the city and Santa Clara Valley Water District, which will discuss the agency's own long-term planning efforts around sea level rise.

According to Palo Alto's recently adopted sea level policy, the city also intends to undertake new partnerships with surrounding cities, including East Palo Alto and Mountain View, for joint planning efforts and projects such as levees to address the rising tides.

Palo Alto has already partnered with the San Francisco Estuary Partnership to create a concept plan for a "horizontal levee," a structure that aims to both boost the city's flood protection and protect habitat that would be threatened by sea level rise. Unlike traditional levees, which tend to be steeper and composed of rocks (known as rip rap), the proposed levee would be a gentle berm with "green" infrastructure that can support a brackish marsh in the transition zone close to the Palo Alto Airport and Baylands Golf Links golf course.

Samantha Engelage, senior engineer in the city's Public Works Department, said the current flood-control levees near the Baylands don't meet standards set by the Federal Emergency Management Agency and at times experience overtopping, particularly when king tides coincide with storm events. In a February update to the city's Parks and Recreation Commission, Engelage said the levees need improvement "to secure Palo Alto and the key infrastructure that is in the Baylands," including the airport, the golf course and the Regional Water Quality Control Plant.

The project has already received two grants, from the Environmental Protection Agency and California State Coastal Conservancy, which funded the planning effort. Engelage noted that throughout the Bay Area, transition zones between marshlands and upland areas have been "decimated" by development. As such, regional agencies have made these transitional areas "a high restoration priority."

"The regional perspective is, 'How can we now take advantage of all this money and effort to address flood control, while also addressing this type of ecosystem that has been decimated throughout the area,'" Engelage told the commission at the Feb. 25 meeting.

As part of Palo Alto's recently adopted plan for sea level rise, the city will be conducting a "vulnerability assessment" that will identify critical infrastructure that could be at risk and estimate the economic impact of vulnerability for both public and private properties. The city also plans to create a multiyear implementation plan that could include zone changes near the Baylands, new permitting requirements for projects in at-risk areas and triggers for relocating facilities away from the area, according to Palo Alto's policy on sea level rise.

The policy, which the city adopted in March 2019, notes that if the Palo Alto Baylands is submerged by mid-century, as predicted, they would lose their ability to serve as buffers during flood events, to attenuate storm surge or to sequester carbon. Sea level rise would also have a disruptive and potentially devastating impact on local habitats, as well as on the recreational offerings throughout the preserve.

"The encroachment of Bay water may alter or eliminate habitat for endanger species that reside in Palo Alto Baylands and the millions of birds that use the Palo Alto segment of the Pacific Flyway for seasonal migration," the policy states. "The recreational and inspirational services of the Palo Alto shoreline could change if Baylands trails, playing fields, and golf course are surrendered to encroachment of San Francisco Bay."

To register for the Wednesday webinar, visit eventbrite.com.

Comments

David Page
Registered user
Midtown
on Sep 7, 2020 at 10:00 am
David Page, Midtown
Registered user
on Sep 7, 2020 at 10:00 am
12 people like this

"Global warming, and the changes to climate and weather that it brings, is mainly caused by human activities that produce GreenHouse Gases (GHG's), like burning fossil fuels in our cars, buildings, and industries." Web Link

Is it necessary to jump to adaptation measures BEFORE we stop creating the pollution which is worsening the problem? If the Palo Alto doesn't want to take effective action to stop GHG emissions, can't the City at least do an educational campaign to help residents connect the dots between cars/airplanes/burgers/milkshakes...and floods/fires?
Web Link

For more info, look at:
Web Link

or follow the blog from Palo Alto online: A New Shade of Green:
Web Link



adapt and mitigate
Registered user
Fairmeadow
on Sep 8, 2020 at 7:52 am
adapt and mitigate, Fairmeadow
Registered user
on Sep 8, 2020 at 7:52 am
25 people like this

Unfortunately, we've raised temperatures enough already to lock in significant future sea level rise. We need to both cut net greenhouse gas emissions to zero in order to stop doing additional damage, and adapt to the damage we've already done. I don't expect raising levees to be a permanent solution, but it'll buy us another century of being able to live here


rita vrhel
Registered user
Crescent Park
on Sep 8, 2020 at 10:45 am
rita vrhel, Crescent Park
Registered user
on Sep 8, 2020 at 10:45 am
33 people like this

With Palo Alto identifying much of lower San Antonio Rd (below Middlefield) as a prime area for new housing, the prospect of Baylands flooding increases.

Each project like the almost completed Marriott Hotel will request a 1-2 level underground garage. As the water level is 5-7 feet below ground, massive amounts of dewatering may occur, if the correct construction and dewatering methods are not used. A rich vein of water was identified at 20 ft below ground when the Marriott was being planned.

Wisely the Marriott scrapped the 2nd floor of their underground garage, used cut off walls and did not tape into this rich water vein.

The entire area proposed for development is best evaluated as a whole rather than project by project. A piecemeal evaluation could result in underground construction which, in total, could act as a concrete dam impacting the natural flow of groundwater from the hills to the bay. This dam would also contribute to sheet flooding and many other well know but possibly not considered consequences.

Members of Save Palo Alto's Groundwater are very concerned abut unintended long term consequences if development of this area is not handled with care and adequate thought. Thank you


Bill Leikam - the Fox Guy
Registered user
Barron Park
on Sep 8, 2020 at 12:08 pm
Bill Leikam - the Fox Guy, Barron Park
Registered user
on Sep 8, 2020 at 12:08 pm
16 people like this

Within the article, "The encroachment of Bay water may alter or eliminate habitat for endanger(ed) species that reside in Palo Alto Baylands and the millions of birds that use the Palo Alto segment of the Pacific Flyway for seasonal migration," the policy states. True, but as far as I can tell at this time, what's not addressed is what's going to happen to all of the terrestrial wildlife like raccoons, gray foxes, opossums, etc. as the sea level rises? As a part of my study on the behavior of the gray fox, it is evident to me that as the waters rise, the wildlife will begin to shift into people's backyards. Residential areas will become the new corridors when the young disperse. This may increase conflict between wild critters and home owners. Looking ahead we need to conduct a massive educational campaign that will inform residents, not only in Palo Alto but elsewhere as well, on how to live side-by-side with wildlife; their "new" neighbors.


Bootstrap Argument - Groundwater Balderdash
Registered user
Palo Verde School
on Sep 9, 2020 at 8:47 am
Bootstrap Argument - Groundwater Balderdash , Palo Verde School
Registered user
on Sep 9, 2020 at 8:47 am
7 people like this

Taking strong exception to “Save Palo Alto Groundwater”’ take on the Marriott development project. Firstly, the “rich water vein” is nothing but highly contaminated surface water not connected with the lower water table that can be tapped for potable water. This thin layer of surface water is likely lightly contaminated due to human habitation in the area. The only thing “rich” about this water is probably TCE and/or pesticides. Secondly, the basement was abandoned for economic reasons, not as you would be led to believe, to save a precious rich vein of water.
Lastly, constructing a basement has next to zero long-term impacts to overall groundwater quantity and quality. The volume of the shallow basement is microscopic compared to the overall volume of below grade geology. Arguing to the contrary is simply the worst form of bad science.
Palo Alto and the Bay area need housing. There are no longer wide-open tracts of land suitable for single family home development. Our only choice is to build on smaller plots. To do this, we need to build vertically. With the current height limitations on peninsula development, the logical choice is to build down for garages and up for residence. The myth of “transit oriented development” has not panned out as we remain nearly one car for every adult resident. Even if we take CalTrain or BART, or Valley Transit, to work, we still want a car to get around on the weekends. These cars need to be parked somewhere and the best place turns out to be in a below grade garage.


Resident 1-Adobe Meadows
Registered user
Adobe-Meadow
on Sep 9, 2020 at 12:47 pm
Resident 1-Adobe Meadows, Adobe-Meadow
Registered user
on Sep 9, 2020 at 12:47 pm
7 people like this

Has anyone noticed that there is already a lot of building going on of both apartments and houses? Who or where is the status of the city building being tabulated? I keep seeing people say that we need housing as the bottom line for any argument out there. As though there is never any progress on this status.

It is time for the city to provide documentation on existing and planned/approved projects. I see new housing all over the place so do not accept the status of what people are saying which is probably 10 years old.
Maybe the Weekly can do a status of the mechanics as to how housing is documented. Also how the numbers are tabulated against what ever criteria is out there - goals that we have to meet.


jc
Registered user
College Terrace
on Sep 9, 2020 at 12:54 pm
jc, College Terrace
Registered user
on Sep 9, 2020 at 12:54 pm
7 people like this

What is not counted are the residential units we loose. For example, when two or three smaller cottages on a property are torn down to build one large home. Or the President Hotel, city hall continues to change the regulations specifically for AJ Capital to facilitate the building's conversion of what were 72 units of housing into hotel rooms.


Resident 1-Adobe Meadows
Registered user
Adobe-Meadow
on Sep 9, 2020 at 1:13 pm
Resident 1-Adobe Meadows, Adobe-Meadow
Registered user
on Sep 9, 2020 at 1:13 pm
4 people like this

When we were house shopping we got a map from the USGS that documents soil type, flood zone potential, earthquake impact based on soil /rock combination. Part of this is relative to location to major drainage from the hills. I suspect that information may have changed due to upgrades to the creek outflow options. SU is on more solid ground - lots of rock. My place is on former farm land. That farm land is adobe soil which is very changeable relative to high water years and drought years. That ends up in underground breakage of sewers and pipes. I am required to have flood insurance for the 100 year flood. I have never used it but it is expensive. It locks into FEMA. Now I think that I need earthquake insurance - we appear to be experiencing any and everything out there that can happen.


jc
Registered user
College Terrace
on Sep 9, 2020 at 1:20 pm
jc, College Terrace
Registered user
on Sep 9, 2020 at 1:20 pm
5 people like this

If you have ever driven on #280 and looked down at Stanford's linear accelerator (SLAC) built right across the San Andreas fault it's because the rock is so solid it hasn't fractured for millions of years!


Resident 1-Adobe Meadows
Registered user
Adobe-Meadow
on Sep 11, 2020 at 11:19 am
Resident 1-Adobe Meadows, Adobe-Meadow
Registered user
on Sep 11, 2020 at 11:19 am
6 people like this

I will say that I am in agreement with the Presidential being turned back into a hotel. It is on a major city street in a key location. That is the one place we do need a real hotel. The problem we all got into was turning it into living quarters.

That was the backward move to killing the downtown area. And yes it is being killed. Borders Books is gone replaced by what ever it is. Many restaurants are gone. Many cute stores are gone. It is like you built a shopping center and now everything has to happen at that location that represents a "city". Everyone does need a home but that is why we have residential areas. I used to go downtown all of the time and now have no interest in it. The one thing that is turning out well is all of the dining taking place outside. That is really going well. Yes - there is actual life out there and it is downtown - not the shopping center.


Resident 1-Adobe Meadows
Registered user
Adobe-Meadow
on Sep 11, 2020 at 11:25 am
Resident 1-Adobe Meadows, Adobe-Meadow
Registered user
on Sep 11, 2020 at 11:25 am
3 people like this

Like to note here that the main business location on East Embarcadero has changed hands. It is unclear what the new owners are going to with it. And the car sales on the corner will be rebuilt with a large new building. Any options for housing are dim for that specific location. And as you move down by the airport my guess is that the city is have to relook at the water and power distribution systems that are located in that area. Still need to define the Palo Alto Business Park on the San Antonio side - huge parking lot and buildings that appear to be unused.


Albert K Henning
Registered user
Duveneck/St. Francis
on Sep 14, 2020 at 10:08 am
Albert K Henning, Duveneck/St. Francis
Registered user
on Sep 14, 2020 at 10:08 am
5 people like this

@Resident 1-Adobe Meadows,

You wrote: "When we were house shopping we got a map from the USGS that documents soil type, flood zone potential, earthquake impact based on soil /rock combination. Part of this is relative to location to major drainage from the hills. I suspect that information may have changed due to upgrades to the creek outflow options. SU is on more solid ground - lots of rock. My place is on former farm land. That farm land is adobe soil which is very changeable relative to high water years and drought years. That ends up in underground breakage of sewers and pipes. I am required to have flood insurance for the 100 year flood. I have never used it but it is expensive. It locks into FEMA. Now I think that I need earthquake insurance - we appear to be experiencing any and everything out there that can happen."

We live in the flood plain. We were flooded in February 1998. We had 15" of water in our garage and back yard. 5" was clear water, from back-up of the storm sewers. The City and County have fixed the infrastructure relating to that problem, and I don't expect it to recur. 10" was muddy water, from overflow of San Francisquito Creek above the Chaucer bridge. Again, there have been substantial mitigations undertaken, including clearing obstructions along the creek bed and walls, and enlarging the outflow of the creek into the Bay, so that even at high tide there will be enough of a 'head' to effect flow, and not overflow. That said: rising Bay levels increase the risk from overflow flood.

As for cost of flood insurance: you should look at how your rate is calculated. There is a metric related to the ratio of first floor square footage enclosed by the foundation, and square inches of flow-through vent area into the crawl space. We found this ratio was mis-calculated for our home, and that we had been over-paying for flood insurance for nearly ten years. (This assumes you have a crawl space and not a slab.)

As for earthquake insurance: we have a two-story home. Both stories experienced the 1989 quake, without effect. Based upon USGS data, the time period between 1906-type quakes is between 150 and 300 years, over the past 1000 years. We are, on that basis, unlikely to experience an 8.0 level quake before 2056. Several 7.0 level quakes will precede the 8.0 event, as harbingers. On that basis, we have chosen not to pay for earthquake insurance.

This is our anecdotal experience, and chosen response to it. For what it is worth; your mileage may differ.


Anonymous
Registered user
Duveneck/St. Francis
on Sep 14, 2020 at 7:46 pm
Anonymous, Duveneck/St. Francis
Registered user
on Sep 14, 2020 at 7:46 pm
2 people like this

Yes, those who have not done so should get a qualified surveyor to do the altitude survey (sic), which may lead to a great reduction in flood insurance charges.


Resident 1-Adobe Meadows
Registered user
Adobe-Meadow
on Sep 15, 2020 at 12:24 am
Resident 1-Adobe Meadows, Adobe-Meadow
Registered user
on Sep 15, 2020 at 12:24 am
2 people like this

In the earthquake I was working in San Jose - Montague and Zanker. The buildings had a lot of obvious stress. Facilities had to re-think where weight bearing equipment was located. A lot of assumptions of where equipment was located had to be re-evaluated. Lots of computer equipment had to be further stabilized. At that time the general area was still fields of trees / crops. Driving home people were afraid of going under freeway cross-over bridges. That was a wake-up call for everyone. My house did not have obvious issues but the house directly across the street had hallway tiles that were moved and cracked. They ended up putting a lot of work into that house.

In the flooding you are referring to we had water shooting up from the drainage ditches. The high tide was forcing water backward from the bay colliding with water coming down from the hills. Adobe Creek has been rebuilt. I remember when it was shallow and water was at the top edge racing down. Some of our buildings on the circle were flooded. We had buildings on Charleston east of 101 that had flooding.

A lot of work has been accomplished to correct those issues but we did not have as many buildings back then. Now we are built out to the edges which is a game changer.


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