"...require “localized” techniques that require less pumping."

In other words, build a cofferdam around the footprint that extends to below the water table. That can be very expensive, but hey, if you can't afford it, just dig your hole in a dry area and avoid all those post-construction hydroheadaches too.

If you can't dig any holes more than 3' below the basement floor then installing plumbing becomes more challenging. I wonder if ejection pumps can for in that space. (Ours is certainly deeper.)

"Another requirement would limit pumping to 10 weeks (in addition to the two-week "startup period," during which time the builder would have to demonstrate compliance with water-quality standards)."
10-12 weeks of continuous pumping sounds like it'd cause a heck of a lot of wasted water and impact to the surrounding homes. And this is an improvement?!

[Post removed due to factual inaccuracies.]

What a colossal waste of water, there is no other way to describe what this dewatering process is. Selfish, and wasteful. In good time, the water should return, and your ego basements could turn into moldy mushroom farms.

I am glad that the city is finally taking action to mitigate how dewatering impacts neighbors. This is a huge improvement over statements from the city employee, who had 0 credentials as an expert at anything, who not so long ago, and quoted in this paper, dismissing dewatering as nothing to be concerned about.

This is all very complicated with fill stations, cutoff walls, water the neighbors trees, time limits and new techniques. Wouldn't it be easier to stop allowing basements to be built?

If you think groundwater pumping is insignificant, ask anyone who has been living in San Jose for a few years.

The city was sinking due to the draining of aquifers. Roads and buildings, especially homes, were damaged.

The SJ City Council made the decision to forbid groundwater pumping and the building of basements, residential or otherwise.

Since that decision only a few years ago, San Jose has regained most of the water in its aquifers and thus has stopped the sinking-- actually regaining some of the elevation it had lost.

Mtn View has begun to tax basements: the deeper the basement, the more square footage it holds, the bigger the tax.

New basement building has virtually stopped in Mtn View!

Drilling is excavation. An eighteen inch diameter hole, that is drilled sixteen feet in the ground produces about 2 cubic yards of dirt or more.According to this type of drilling,many holes will need to be dug. Sometimes the water table may be very deep. If one cannot excavate below three feet of basement floor which is about 14 feet total. I wondering how this will work. For example, the water table on Bryant and El Dorado is about 11 feet, this was during drought years, this year I have no doubt that it will be higher. Just wondering how all this will work?

Thank you for again spotlighting the dewatering issue. This is a not a small issue as over 140 million gallons of community groundwater was pumped and dumped in 2016 during the construction of 8 residential basements.

Yes, it's probably better not to build basements in areas of high water but that is a different decision. Probably won't happen. But the groundwater can be percolated back into the soil on the property.

The goal of "no dumping of any extracted groundwater into the storm drain by 2018" is do-able. Period. Easy for the City to monitor; no fines nor curtailment of property owner's rights. No dumping could also reduce neighbor's complaints of property damage - cracked windows and foundations caused by dewatering. A ban would likely cause innovative thinking and problem solving.

Not mentioned in this article is the property owners/developers "free" use of the storm drain when the groundwater is dumped.

Many problems; the REAL solution is not dumping the extracted groundwater into the storm drain. The property owner must be required to use 100% of the extracted groundwater rather than the current dismal 1%.

Please send your comments to the city council at city.council@cityofpaloalto.com. Or better still come to the March 7th meeting. Thank you.

This is the dumbest use of city resources ever.

[Portion removed.]

There is no engineering or agricultural evidence that temporary localised dewatering has any durable effect on the water table, local trees, or global warming.

In 30 years of shallow foundation construction (meaning less that 14 feet deep) we have never seen any adverse structural, hydraulic, or horticultural damage caused by correctly designed and executed dewatering.

I challenge ANYONE to identify (with something close to facts) a case where correctly performed shallow foundation construction has permanently damaged the water table, caused structural damage to adjacent properties, or killed trees.

This is a red herring for those who really do not want large homes with basements constructed in there neighbourhood.

I get it.

I did not like the 2 bedroom mid-century modern house across the street replaced with a Spanish revival pavilion with 5 bedrooms, 6 baths, and a one car garage either. When we challenged the CPA Planner over the pending approval, she stated that the house conformed to every PA requirement.

This is the real problem.

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From Web Link

In most areas of California, overlying land owners may extract percolating ground water and put it to beneficial use without approval from the State Board or a court. California does not have a permit process for regulation of ground water use. In several basins, however, groundwater use is subject to regulation in accordance with court decrees adjudicating the ground water rights within the basins.

The California Supreme Court decided in the 1903 case Katz v. Walkinshaw that the “reasonable use” provision that governs other types of water rights also applies to ground water. Prior to this time, the English system of unregulated ground water pumping had dominated but proved to be inappropriate to California’s semiarid climate. The Supreme Court case established the concept of overlying rights, in which the rights of others with land overlying the aquifer must be taken into account. Later court decisions established that ground water may be appropriated for use outside the basin, although appropriator’s rights are subordinate to those with overlying rights.



This part is especially important IMO:
"..the rights of others with land overlying the aquifer must be taken into account. Later court decisions established that ground water may be appropriated for use outside the basin, although appropriator’s rights are subordinate to those with overlying rights."

So, if my neighbor is pumping out water (and wasting it), they are infringing over my rights to the same water??!

"The city was sinking due to the draining of aquifers."

Shallow groundwater pumping has no impact on local aquifers, which are close to 1000 ft. down. Also, the local aquifer has shown very little impact by the drought.

"Residents want to know why they should conserve water (on their properties) when they see water gushing down their (storm) drains".

The answer is that water coming out of your sink and that fills your irrigation system comes from 167 miles away and is limited. This local groundwater is a nuisance when building, and is abundant. Neighbors freaking out about inconsequential groundwater and looking to put restrictive regulations on something that really impacts nobody are also a nuisance.

Let's not overcomplicate with needless science. The point is 'don't waste water...ever.'

Just include the basement in the floor area ration and maybe people will quit destroying every existing house in Palo Alto to make partially buried mega homes.

Put some of this on Doug Moran's blog post comment thread, but even on the "save our groundwater" website, there is a report from a firm that actually has credentials in this area:

"Because the deflection is temporary and very localized, and because groundwater levels at the sites recover rapidly once pumping has ceased, there appears to be no discernible long-term effect on the surface aquifer"

"Although the amount of water pumped from an excavation may appear substantial as it flows along a street to a storm drain inlet, it is small compared to the amount of groundwater directly beneath the Santa Clara Plain."

"Because dewatering for basement construction occurs only in the uppermost portion of the surface aquifer, there would be no effect on the deep aquifer."

There you go. Saving our groundwater is based on #fakescience. It's amazing how people with little or no knowledge can propagate this kind of nonsense in Palo Alto. For a self-proclaimed educated community, I'm really disappointed. It's like we live in Berkeley or something like that.

(in case you want to read the report yourself, since I'm guessing the Save Our Groundwater group will take it off their website)

Web Link

[Portion removed.]

Simplest solution is listed above - stop the FAR exception for basements and charge a dewatering fee based on actual metered outflows. Since there's no agreement in the science, why wouldn't we at least use logic as it relates to development? Exceptions to FAR are a relic of a bygone era, get rid of them. And if someone is just hell-bent on going underground in an area clearly not suited for that, then charge them for the privilege.

Doesn't have to be a complicated or half-measure solution. Or are we too scared to offend any developers at all?

Cmon CC, do the right thing.

To me the basement thing is not about water, it is about the character of our community. The FAR exemption means that every home in Palo Alto that does not have a basement is a tear down. It is destroying the reason we all want to live here.

@Me 2

No, we will not remove the 2004 EIP report. A number of us are scientists (physicists, chemists) and we have read it as well as all the other more recents reports and articles on our website. Historically, there have been some misconceptions about the shallow groundwater, including that there is no connection between the shallow and deeper aquifer (see the 2016 San Mateo Groundwater Workshop powerpoint link that shows otherwise, also on our website). Read our White Paper for a rebuttal of the 2004 EIP report. The 2004 EIP report has some deficiencies including no data and no references to other studies or peer-reviewed articles. But, it is part of the historical record and it is nothing we would try to hide or pretend doesn't exist.

[Portion removed.]

"A number of us are scientists (physicists, chemists) and we have read it as well as all the other more recents reports and articles on our website. "

What would physicists and chemists have to do with geology? That's like asking a neurologist about hemorrhoids. Sure, there's some overlap in training, but not really the experts we should be relying on.

[Portion removed.]

For anyone who doubts the affect of dewatering on neighboring properties, I have new and recent LARGE cracks in my foundation and walls due to the giant basement that was dug at 2724 Cowper St. To add insult to injury, the dewatering hose was run past two houses, directly in front of my house, to a nearby storm drain causing us inconvenience (muck, closed sidewalks, no available parking in front of my own home) for several months. Of course people building new homes have property rights, but so do neighbors when their properties are affected. These basements are not dug in a silo and ground water doesn't respect property lines. Dewatering can affect all neighboring properties. At this point, we have no recourse. The damage to our home is done.

why in this city we must do everything convoluted way when simplest solution staring us in the face. Tax the basements.

"What would physicists and chemists have to do with geology? That's like asking a neurologist about hemorrhoids."

Well, I'll ask a neurologist about that before I'll ask a physicist, and I'll ask a physicist about groundwater before I'll ask a neurologist. [Portion removed.]

After hearing news media on the subject of de-watering near the leaning/sinking Millennium Towers in San Francisco, I am worried since my property and home are close to a house that had water gushing at a high rate down a pipe to the storm drain for many weeks....cracks may be an issue...garage at Millennium Towers has cracks...seems odd to permit de-watering in a recognized flood zone where we wren told basements were not permitted to be built.
Guess we'll find out...our valuable property is being experimented on by someone else.