City Council Takes Steps to Reduce (but not Eliminate) Waste of Groundwater from Basement Construction

First, thank you to the nearly 100 supporters who came to City Hall on March 7th and to all those who wrote letters of support.  Not a single person spoke in opposition to our proposals, including three persons from the construction industry, thereby demonstrating strong community support for our position.  The Palo Alto City Council unanimously passed a motion to implement enhancements to the 2016 Dewatering Guidelines.  These will take effect for the 2017 dewatering season, with an exclusion for those properties that have already received their building permits.

Special thanks to Councilwomen Lydia Kou and Karen Holman who proposed an amendment, which passed, to  significantly reduce grandfathering by requiring projects that have preliminary conditions of approval but have not yet received building permits be included in the 2017 enhancements.

Check out Palo Alto Online’s coverage and this terrific video made by 8-year old Cate A. and presented at the March 7th meeting:

There is still work to do for 2018.  The current regulations help, but are still far from requiring no discharge of groundwater to the storm drains while avoiding increases in flood risks.  Read more for the details of Council actions and our comments.

Continue reading

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REMINDER: Council Meeting Tues. 3/7, 6 PM

REMINDER: Palo Alto’s City Council will hold a special meeting on Tuesday, March 7th, 6 pm at City Hall, 285 Hamilton, Palo Alto to discuss and determine dewatering regulations for 2017 and 2018.    Please join us and let the City Council know that this issue matters to you.

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Palo Alto Online Coverage for the Council Meeting, Tuesday March 7th

Palo Alto Online has just posted two articles on dewatering:

Doug Moran’s excellent blog, which provides an in-depth discussion of the issues and complexities surrounding groundwater pumping, along with links to references to earlier coverage in the footnotes section and, Palo Alto Weekly writer Gennady Sheyner’s overview of the upcoming Council Meeting on Tuesday, March 7, 6 PM in the Council Chambers at City Hall, 285 Hamilton.

At least since 2004, residents have been asking the City to protect our groundwater and our natural and built environment from the effects of dewatering.  It is time to show the City that we are seriously concerned about this issue. With climate change, the paradigm has changed:  it is no longer surface water, wastewater, groundwater, etc.  It is all ONE water and all water is important.  Please attend the City Council meeting on March 7th and/or write and let Council members (  know that you care about our groundwater, a valuable community resource.  It’s especially important that Council direct Staff to investigate simplifying the ordinance in 2018 to simply put an end to discharge of groundwater to the storm drains.  There are proven, better ways to build basements in areas of high groundwater.  Let’s make the following statement true:

We’ll be wearing blue.  Join us!  We hope to see you on the 7th!


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Please Join Us! Dewatering Regulations March 7th, 6 PM, City Hall

Palo Alto’s City Council will hold a special meeting on Tuesday, March 7th, 6 pm at City Hall, 285 Hamilton, to discuss and determine dewatering regulations for 2017 and 2018.    Please join us and let the City Council know that this issue matters to you.

City Staff is proposing to incorporate the 2016 dewatering guidelines as an ordinance in 2017, and to return to Council with a proposal for additional enhancements to the ordinance in 2018.  Continue reading

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Building basements without wasting water

City Council will review Staff’s recommendations for 2017 dewatering regulations on March 7th, 2017. Please join us for a special City Council meeting on Tuesday, March 7th at 6 pm (the City has changed the date several times; we will reconfirm date and  time when the agenda is final) at City Hall, 250 Hamilton and let City Council and Staff know that groundwater (all water) is important to you, and that proven alternative construction methods can be used to preserve this water. California is a land of recurrent drought. It is time for better stewardship of our groundwater – it supports our buildings and infrastructure, it’s our hedge against drought, part of our emergency water supply, and our children’s birthright.

In order to build a basement, the groundwater level needs to be lower than the basement’s foundation. When this level, the water table, is above the proposed basement’s foundation, it needs to be drawn down within the construction area; this is achieved by pumping the water out. In broad area dewatering (BAD), the method currently used, the groundwater level is drawn down not only at the construction site but hundreds of feet away from it (see diagram).

This is the equivalent of a localized drought for nearby neighbors and their properties. Depending on distance from dewatering site, type of soil, location, dewatering duration and other factors, broad area dewatering can affect nearby buildings, infrastructure and canopy. And, millions of gallons of groundwater are wasted. Last year’s average was 17.5 million gallons of groundwater per basement. For comparison, the amount of water required for fracking a well is between 2 and 10 million gallons.

Due to our collective efforts to bring this issue to the City’s attention, Staff is proposing for 2017 a pilot program that encourages using alternative construction methods for building basements in areas with high water tables. It is voluntary because Staff wants to see if there are any unintended consequences before recommending it be mandatory.

In alternative construction methods, also called local area dewatering (LAD), the use of cofferdams, sheet piles, cut-off or secant walls, etc., essentially limits the amount of groundwater that is pumped out for the underground construction (see diagram). The smaller amount of water pumped out via these methods is expected to be less than 10% of the amount pumped when broad area dewatering is used, and can then be percolated back to the aquifer or used beneficially such as for dust suppression, street cleaning, irrigation, etc. Local area dewatering not only limits the amount of water that is wasted but greatly reduces the risk of damage to neighboring properties, canopy and nearby infrastructure.

Why would anyone choose broad area dewatering when local area dewatering has much lower impacts on the built and natural environment? Under current regulations, the dewatering applicant doesn’t pay for either the groundwater that is pumped out or for the use of the storm drains, where this groundwater is placed. For applicants, this has made broad area dewatering economically more attractive than local area dewatering. Meanwhile, the costs are externalized to us, the taxpayers.

The wasting of this water is, however, not sustainable. It is time to protect our groundwater and its many benefits to our environment and us. Incentivizing local area dewatering and/or de-incentivizing broad area discharge can achieve this goal. Please show up on Mar. 7th and say that we want zero waste of our groundwater, a valuable community resource.

Thanks for your support!

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