News

Questions persist about basement construction

Concrete, millions of gallons of pumped water are key issues

Many questions remain unanswered about basement construction in Palo Alto, the Planning and Transportation Commission agreed Wednesday night.

Without a vote, the commission postponed potentially recommending restrictions until a later meeting.

Some commissioners and residents remain concerned about the massive amounts of water — as much as 12 million gallons — pumped out for the construction of some basements. Basements also require about 300 tons of concrete, a significant source of greenhouse-gas emissions.

"I can tell you that a lot of people in town are indignant," resident Ellen Wyman said. Her neighbors have had trees die, foundations shift and old basements begin flooding after the construction of new basements, she said.

"When that many people perceive it as a problem, it's a problem," Wyman said.

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Yet if the city makes it harder to build basements, homeowners will be more inclined to build out or up, Norman Beamer said.

"It will significantly decrease the value of the property," he said.

About three to seven residential basements are constructed per year in Palo Alto that require water pumping, Senior Public Works Project Manager Bob Morris said.

The city now restricts "dewatering" to April through October to prevent overstressing the storm-drain system, Morris said.

But the city hasn't found any pervasive problems for trees, foundations or the groundwater, Interim Planning and Transportation Director Curtis Williams said.

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"It's not a pervasive type of concern we hear from neighbors," Williams said.

And even if dewatering did affect a nearby residence the city couldn't do anything, Chief Building Official Larry Perlin said.

"It becomes really that one property owner is being harmed by the actions of another property owner. The two property owners have to resolve that amongst themselves," Perlin said.

The commission could require basements to be set back from property lines, limit the amount of water removed or the time pumping can continue, or it could require basement builders to add additional environmental features to their house to offset the effects of the concrete, a city report states.

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Questions persist about basement construction

Concrete, millions of gallons of pumped water are key issues

by / Palo Alto Weekly

Uploaded: Thu, Sep 25, 2008, 12:56 pm

Many questions remain unanswered about basement construction in Palo Alto, the Planning and Transportation Commission agreed Wednesday night.

Without a vote, the commission postponed potentially recommending restrictions until a later meeting.

Some commissioners and residents remain concerned about the massive amounts of water — as much as 12 million gallons — pumped out for the construction of some basements. Basements also require about 300 tons of concrete, a significant source of greenhouse-gas emissions.

"I can tell you that a lot of people in town are indignant," resident Ellen Wyman said. Her neighbors have had trees die, foundations shift and old basements begin flooding after the construction of new basements, she said.

"When that many people perceive it as a problem, it's a problem," Wyman said.

Yet if the city makes it harder to build basements, homeowners will be more inclined to build out or up, Norman Beamer said.

"It will significantly decrease the value of the property," he said.

About three to seven residential basements are constructed per year in Palo Alto that require water pumping, Senior Public Works Project Manager Bob Morris said.

The city now restricts "dewatering" to April through October to prevent overstressing the storm-drain system, Morris said.

But the city hasn't found any pervasive problems for trees, foundations or the groundwater, Interim Planning and Transportation Director Curtis Williams said.

"It's not a pervasive type of concern we hear from neighbors," Williams said.

And even if dewatering did affect a nearby residence the city couldn't do anything, Chief Building Official Larry Perlin said.

"It becomes really that one property owner is being harmed by the actions of another property owner. The two property owners have to resolve that amongst themselves," Perlin said.

The commission could require basements to be set back from property lines, limit the amount of water removed or the time pumping can continue, or it could require basement builders to add additional environmental features to their house to offset the effects of the concrete, a city report states.

Comments

Neal
Community Center
on Sep 25, 2008 at 1:06 pm
Neal, Community Center
on Sep 25, 2008 at 1:06 pm
Like this comment

Once again the law of unintended consequences raises its ugly head. The benefits of these mega basements outweigh the risks. I would never buy a house where there has been dewatering and I hope any seller is required to disclose this potential disaster.


More complainers
Stanford
on Sep 25, 2008 at 1:52 pm
More complainers, Stanford
on Sep 25, 2008 at 1:52 pm
Like this comment

If it is a problem for even one person in the city, then it needs to be addressed--as most people should know by now, just because you own your property does not mean that you have the right to do with it as you please (within the rules). Your neighbors will determine what can be built, since it may affect them. Remember the Palo Alto rule--what is yours is for the neighbors to determine what can be done with it.
It would be interesting to see how many people are indignant or is this just a ploy to get what you want from the city (i.e. as we all know, the squeaky wheel gets greased in PA--complain enough about a so-called problem and it will be resolved in your favor)


a observer
Another Palo Alto neighborhood
on Sep 25, 2008 at 3:41 pm
a observer, Another Palo Alto neighborhood
on Sep 25, 2008 at 3:41 pm
Like this comment

Basements should be banned and existing ones should be filled with sand in the FLOOD ZONE or area which gets flooded every few years from the San Franquito Creek.

The city was held responsible and millions in tax dollars were given to homeowners after the '98 flood. Yet no action has been taken to remove the bridge that restrict water flow in the creek/river. Isn't that amazing? Who is getting the "laundered tax money"?? The attorneys and a few connected homeowners.??

If basements are banned the city should start with it's own underground parking garages.
Any new underground garages should be banned. Like the proposed Police Bldg garage.

If construced and built correctly basements that are not subject for flooding should be allowed. It's only shallow water that is being pumped during construction and it is flowing thru the subsurface all the time, to the bay. There are underground rivers in much of Palo Alto. The Oregon Underpass has pumps running continously to keep it from flooding from the underground, shallow water in that area.


Too much water
Midtown
on Sep 25, 2008 at 4:53 pm
Too much water, Midtown
on Sep 25, 2008 at 4:53 pm
Like this comment

Crawl spaces yes, basements no. The danger of flooding your neighbors is too great. I live in the section of PA where the water table is less than 4 feet down. Flooding is a real problem.


Basement Dweller
Another Palo Alto neighborhood
on Sep 25, 2008 at 10:21 pm
Basement Dweller, Another Palo Alto neighborhood
on Sep 25, 2008 at 10:21 pm
Like this comment

I always have to chuckle when people complain about basement construction projects pumping groundwater. It is a lot of water, but it is nothing compared to the amount of water pumped out of the City Hall basement every day 24/7. All of that water goes directly into San Francisquito Creek and gives mosquitos a nice place to live. It dwarfs any of the small pumping projects around town.

Enjoy your debate. As usual it is just a lot of hot air.



Norman Beamer
Crescent Park
on Sep 26, 2008 at 7:46 am
Norman Beamer, Crescent Park
on Sep 26, 2008 at 7:46 am
Like this comment

This is one of the more exteme and unjustified attempts to impose unnecessary additional regulations on homeowners. Even FEMA has recognized that basements -- even in flood zones -- are appropriate if properly constructed. See 44 CFR 60.6(c). Although the sight of water gushing into a storm sewer from a site under construction looks alarming, it is actually just a drop in the bucket, to coin a phrase.


No Basement
Meadow Park
on Sep 26, 2008 at 8:05 am
No Basement, Meadow Park
on Sep 26, 2008 at 8:05 am
Like this comment

This issue really depends where you live in Palo Alto. If you live West of Middlefield and close to the Bay your water table is probably only 3 - 4 feet down. There is also a plume of undergound water South of Charleston which goes directly under the Campus for Jewish Life. That plume of water was the reason for the CJL building everything above ground and sealing off the underground water table.

Some areas East of Middlefield that are built on today were originally marshland at the edge of the bay.


Indignant
Another Palo Alto neighborhood
on Sep 26, 2008 at 12:33 pm
Indignant, Another Palo Alto neighborhood
on Sep 26, 2008 at 12:33 pm
Like this comment

What is most alarming is not only that people are putting the basements in, but they are knocking down perfectly lovely homes in order to construct McMansions. People's concept of how much space they actually NEED is being overshadowed by their concept of what they feel entitled to. I am happily raising my family of four in a 1000 square foot home.


More complainers
Stanford
on Sep 26, 2008 at 12:45 pm
More complainers, Stanford
on Sep 26, 2008 at 12:45 pm
Like this comment

Yes, indignant you are free to do what you want with your home--but don't homeowners have a right to build what they want, within the rules. Or do you have a sense of entitlement whereby you can dictate to others what kind of house they can live in? Please stop using derogatory terms like, McMansion, for homes that you do not approve of.


trudy
Crescent Park
on Sep 26, 2008 at 12:54 pm
trudy, Crescent Park
on Sep 26, 2008 at 12:54 pm
Like this comment

"millions in tax dollars were given to homeowners after the '98 flood.
Posted by a observer, a resident of Another Palo Alto neighborhood, 21 hours ago"

Really? My house was flooded, and I didn't get a dime, except from the flood insurance I had bought and paid for. And what I received from that was far less than I had paid in premiums.

I agree however, that it is typical idiocy that that bridge has not been removed, just as it was idiocy to let East Palo Alto go on with building that will raise the level of future floods in Palo Alto.


Why I left PA
Los Altos
on Sep 26, 2008 at 5:59 pm
Why I left PA, Los Altos
on Sep 26, 2008 at 5:59 pm
Like this comment

It’s the idiocy of this debate that exemplifies why I moved over to the next town after 23 years of living in Barron Park. Building a basement in a flood zone is lunacy and the resultant water/mold/smell/lawsuit problems that will likely ensue are welcome to the fool who buys / builds it.

Basements in areas without high water tables provides a method for the added space that many people want and "indignant" loathes (read jealousy) while controlling the mass and bulk of the home.

The beauty of this country is that the wise are free to make their decisions and the unwise are free to learn some lessons.


Homeowner
Professorville
on Sep 26, 2008 at 7:01 pm
Homeowner, Professorville
on Sep 26, 2008 at 7:01 pm
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Basements are already prohibited in flood zones and underground garages for single family homes have been prhobited in PA for many years. A geologic survey is required for basement permit, which will determine whether there is a problem with undergound water. Basements allow owners to retain the appearance of an older house, in lieu of demolition and re-building. The latter is simpler, cheaper and easier, believe me. We installed a basement under our 100-year house about 10 years ago in order to retain the historic appearance. We've had no water problems. Our neighbors had no problems and testified in favor of our project since it preserved the architectural integrity of the neighborhood.


I'm confused
Another Palo Alto neighborhood
on Sep 26, 2008 at 8:59 pm
I'm confused, Another Palo Alto neighborhood
on Sep 26, 2008 at 8:59 pm
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"'It becomes really that one property owner is being harmed by the actions of another property owner. The two property owners have to resolve that amongst themselves,' [Chief Building Official] Perlin said."

Really? So how is it that the City allows neighbors to comment on and influence neighbors' permit applications to build second stories and remove protected trees, but allows them no say on basements which can cause 10,000s of dollars of water damage to the neighbor's property.

The difference: second stories and trees can be seen, basements can't. The other difference: second stories and removals of inappropriately placed, harmful or dangerous trees can increase the neighborhood's value, re-directed underground water from new basements that harm neighbors' foundations apparently don't.


Super D
Community Center
on Sep 29, 2008 at 10:57 am
Super D, Community Center
on Sep 29, 2008 at 10:57 am
Like this comment

I say let them build their basements, the majority of which will eventually have leakage problems or flood. Then they can live with the byproducts of mold and mildew and enjoy the nostalgic root cellar smell. You'd have to be an idiot to build a basement in much of Palo Alto.


SaveTheGroundwater
Old Palo Alto
on Aug 30, 2010 at 10:55 pm
SaveTheGroundwater, Old Palo Alto
on Aug 30, 2010 at 10:55 pm
Like this comment

Two years later, the insanity persists. Two basement excavations in Old Palo Alto have active dewatering operations.

2021 Webster Street Web Link

481 Washington Ave Web Link

This is a waste of good water. The Webster property has two beautiful heritage oak trees. Washington has a towering redwood. Why does the Planning Commission allow this?


palo alto mom
Duveneck/St. Francis
on Aug 31, 2010 at 8:21 am
palo alto mom, Duveneck/St. Francis
on Aug 31, 2010 at 8:21 am
Like this comment

Common sense would tell you that if there is that much water in the ground when it hasn't rained in months, you should not be putting a basement in. Removing that much water can change the water table of the homes around you also, causing cracking and leaking in nearby foundations.


SaveTheGroundwater
Old Palo Alto
on Aug 31, 2010 at 9:24 am
SaveTheGroundwater, Old Palo Alto
on Aug 31, 2010 at 9:24 am
Like this comment

palo alto mom - You are so right!

The negative effects of dewatering operations are well documented. Basement construction in areas of high groundwater can damage neighboring structures and trees. Dewatering removes buoyancy from the soil. This increases the effective stress which can lead to subsidence and structural damage. The zone of influence of the drawdown wells extend well beyond the boundaries of the construction project, thereby jeopardizing structures on neighboring properties.

The expansive concrete walls of basements which are built in aquifers can interrupt the natural horizontal groundwater flow, causing a damming effect. Groundwater levels can rise on the upstream side of the structure and be lowered on the downstream side. Such barriers divert the groundwater flow around the sides of the structure and can cause flooding of adjacent properties. I understand that a number of homes in Palo Alto have seen flooding of their utility basements following the construction of basements on neighboring properties.

Our trees rely on groundwater from the unsaturated (vadose) zone, and the drawdown of the water table depletes that important source of water. Development, disruption, or contamination of ground water resources has consequences for hydrological systems and related environmental systems. The deliberate removal and discharge of groundwater is irresponsible, especially in a time of drought.


Helen Grant
Crescent Park
on Sep 23, 2011 at 10:00 am
Helen Grant, Crescent Park
on Sep 23, 2011 at 10:00 am
Like this comment

Is it a fact that no new underground garages can be built in a non flood zone area of Crescent Park?


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