Study their behaviors. Observe their territorial boundaries. Leave their habitat as you found it. Report any signs of intelligence.

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Sunday, October 07, 2012

My Candidate Ballot Statement For Purissima Election

You own a share of Purissima's two main assets: $20M of pipes/tanks, and the right to buy 800K units/year of water from SFPUC. For each household, that's $10K and 780 gallons/day. I defend those property rights, including the right to use the water you buy as you wish (without harming the rest of us). I defend close local control of the district while seeking savings via alternative arrangements for water supply and district operations.

SFPUC is raising water costs to pay for overdue seismic upgrades. These upgrades mean we can cancel an expensive project to make Quarry Lake an emergency water source. That insurance is not worth the price. I also voted against subsidies for candidate statements and a museum water exhibit.

A Sacramento law was going to make the Hills adopt 33 pages of default irrigation rules. I proposed an alternative that added a simple water budget to the town's permitting process, leaving property owners free to decide how to meet their budget. The town adopted my alternative.

For more (including Purissima budgets and audits), see

Purissima Candidate Answers For Town Crier

How long have you lived in Los Altos Hills?  6 years

What is your background experience in local government and community leadership?

In addition to my four years on the Purissima Hills board, I served on the town council's Water Conservation Advisory Committee.  I've also been a classroom volunteer in a local public elementary school.  I've been active in the county Libertarian Party, and have helped the Silicon Valley Taxpayers Association draft ballot arguments against tax increases.

How does your professional experience compliment your work on the Purissima Hills Water District board?

In my software engineering career in Silicon Valley, I've experienced first-hand the importance of customer service and controlling expenses. Analytical and problem-solving skills have also proved useful in my board service. However, the main qualification for a candidate is having a policy compass of governance principles, along with the diligence to apply those principles.

To a new resident of Los Altos Hills or someone from outside of our area, how would you describe what the Purissima Hills Water District does?

The District provides potable water and firefighting levels of water pressure to every address within its boundaries.

Why are you running for re-election to the Purissima Hills Water district?

To help ensure that the District runs efficiently and respects the property rights of the ratepayer-owners of the district.

There are four candidates for three open seats.  Why should voters choose you?

Voters should choose me if they agree with my principles and priorities.   My principles are rooted in property rights.  You as a ratepayer own a share of Purissima's two main assets: $20M of pipes/tanks, and the right to buy 1.62M gallons/day of water from SFPUC (the San Francisco Public Utilities Commission). For each household, that's $10K and 780 gallons/day. I defend those property rights, including the right to use the water you buy as you wish (as long as it doesn't harm the rest of us). Ideally, I would like you to be able to sell the water you don't use to community members who want to buy more than their share, so that you could profit from your conservation efforts.

My priorities are to maintain reliable and cost-effective water supply while exploring alternative arrangements for  water sourcing and district operations.

What are the greatest challenges associated with water supply locally?

Purissima's entire supply currently comes from SFPUC's Hetch Hetchy system. We've spent years pursuing other potential sources: well water, Quarry Lake water, recycled water from Palo Alto to our North, and county water from Cal Water to our South. None of these options has yet proved workable, though we are still talking to Cal Water.

In recent years Purissima was using nearly 125% of its SFPUC allocation, even as the overall Hetch Hetchy system  was approaching its capacity limits.  However, as SFPUC has raised wholesale rates to pay for long-deferred seismic upgrades, the rising prices have caused system demand to fall sharply, and there is no longer any imminent prospect of Purissima being limited to just its allocation. Nevertheless, we've tried to buy additional allocation from other agencies that are SFPUC customers, but none is for sale at a reasonable price.

We also consider conservation to be a valid water "source", and so we continue our conservation programs and tiered pricing.  We've successfully cut our usage to 105% of SFPUC allocation.

Can you highlight your accomplishments on the PHWD Board?

A Sacramento law was going to make the Hills adopt 33 pages of default irrigation rules. I proposed an alternative that added a simple water budget to the town's permitting process, leaving property owners free to decide how to meet their budget. The town adopted my alternative.

Another accomplishment has been to question an expensive project to make Quarry Lake an emergency water source. When you look hard at the range of scenarios in which that water could actually be useful, it seems that this insurance is just not worth the price.

Why do you deserve to be re-elected to the board?

Re-election should not be considered a reward for past performance.  Voters should vote for whomever they expect will best implement the voter's principles and priorities. Of course, past performance can be a useful predictor of those principles and priorities.

What goals would you like the PHWD board to set for the next four years?  Are there any long-term goals?

Our goals over the next four years should be to 1) continue our capital spending program to improve seismic reliability and operational efficiency, and 2) explore alternative arrangements for water supply and district operations.

For the long-term, I would like to see Purissima extract itself from the unsound CalPERS retirement system, or at least remain vigilant about keeping our retiree obligations explicit, cost-contained, and fully funded. I would also like Purissima ratepayer-owners to have explicit ownership of their shares of the system -- i.e. the infrastructure buy-in share and the right-to-buy share of Purissima's SFPUC allocation.  Ratepayers who buy less than their share could potentially turn a net profit on their water bill.  This would promote conservation, and would get the District out of the business of setting conservation prices.

Saturday, October 06, 2012

Info About Purissima Hills

Saturday, September 08, 2012

A Battleship Would Not Float In A Bathtub

Update on 2020-07-31: I was wrong. My mistake was in thinking that Archimedes' Principle required there to be a direct mechanical balance between the weight of the floating object and the weight of the water that is being held above what was the level of the water before the object was inserted. I had thought that when an object is inserted into the water, it will sink to the point where it has displaced upward an amount of the existing water equal to its weight. And that happens to be true any time there is more water than the object can displace.

But fluid mechanics makes no distinction between the existing water and the battleship. The battleship can be modeled as a weightless transparent arbitrarily-thin battleship-shaped water bowl that is filled with water to the battleship's waterline. Seen this way, it's obviously not just the water outside the ship-shaped bowl that is contributing to the final water volume in the tub. Each virtual column of water within the footprint of the ship has to be in balance with every other virtual column of water in the tub. For the ship to settle below its waterline (i.e. for the ship to sink to the bottom and maintain a cavity above it), it would require that a taller column of water outside the ship's footprint is balanced by a shorter column of water inside the ship's footprint. That's impossible. So the ship will stop sinking when the water in the bathtub -- no matter how small its original volume -- rises to the level of the ship's waterline.

Archimedes' principle states that "the upward buoyant force that is exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces."  It does not mean "the fluid that the body has displaced".  It means "the fluid that the body is taking the place of" i.e. "the fluid that would fill the cavity created by the body". It doesn't matter if there isn't enough of the original fluid at hand, because the body itself acts like a very large particle of the fluid.

Credit for enlightening me goes to the explanations at, especially the diagram at

Original post from 2012-09-08:

The world thinks (e.g. here, here, here, here, here) that a battleship could float in form-fitting tub of water after it displaced all but a tiny fraction of the water in the tub.  These writers cite Archimedes' Principle that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid the body displaces. They ignore Archimedes' assumption that the body of water has enough water and enough unused volume to combine together to balance the weight of the immersed body.

A floating ship is hydraulically balanced against the mass of the top layer of water that the ship has displaced upward in the body of water on which the ship floats.  A ship can only float if the body of water can contain that top layer of water and that water has a mass equal to that of the ship. If that water escapes or is otherwise not present, the equilibrium fails and the ship sinks.

Another way to think about it is to ask whether the battleship in the empty bathtub could be floated simply by pouring in the water to fill the bathtub around it. Battleship floaters claim this would work with an arbitrarily small amount of water.  But there is no free lunch -- you can't do the enormous work of lifting a massive ship merely by balancing it against a small mass of water.

Some floaters point to canal locks (e.g. the Miraflores in Panama) that can float a ship with just a foot of clearance on the sides (and allegedly the bottom).  However, they ignore the clearance at the front and back. After a ship enters a canal lock, you can bet that there is a new top layer of water (relative to the prior water level) whose mass is equal to that of the ship.

Floaters tell naive skeptics that when an object is floated in a full tub, the system doesn't remember that some water overflowed when the object was added, and that it floats just as well when it is taken out and then added back to the tub -- which now will not overflow at all.  However, what the floaters don't notice is that the no-overflow system has just enough room at the top to hold the mass of water that balances the object.

Some floaters point out that large machines like telescopes are often "afloat" on a thin film of oil. However, these lubricants are kept pressurized in a sealed system, and the pool of oil is not open to the atmosphere. It's a safe bet that such a telescope cannot be levitated (i.e. lifted) by a thin film of oil unless there is some balancing mass of oil (or some other way of pressurizing the oil).

It seems the physics folks who promote the bathtub battleship meme need to talk to some hydraulic engineers.

Friday, August 17, 2012

Argument Against SCVWD Parcel Tax

I drafted for the Silicon Valley Taxpayers Association the following ballot argument against Measure B. The Registrar of Voters instead chose an opposing ballot argument that didn't mention the county grand jury criticisms of SCVWD, and that instead based its opposition only on environmentalism.

The only part of the county not in one of five "flood control zones" is the remote area beyond Mount Hamilton. So you pay for "flood control", no matter how high or dry.

SCVWD says the tax has "helped reduce the flood threat" for only 16,000 parcels. Flood protection should be paid for by the 1% who buy flood-prone property, not by the 99% who don't. The tax is also to "ensure safe, reliable water supply". However, SCVWD already directly bills those who buy its water or pump from its aquifers. Improvements to water reliability or quality should be reflected in water price, in order to promote conservation and efficient use. Instead, SCVWD sells water to farmers at a 90% discount.

Grand jury reports have criticized SCVWD over high salaries and wasteful spending. In "Gold Street Education Center -- $1.38M For What?", a grand jury said "educational efforts should no longer be masqueraded as Environmental Enhancements". It noted the center was built adjacent to a trailer park owned a SCVWD director's family.

In "SCVWD Awash In Cash As County and Cities Drown In Red Ink", jurors said that in 2000 the district "polled the public on price points and found $39 would be what voters would accept. Program funding was NOT based on the cost of needed projects." SCVWD has already spent $27,000 in Measure B polling.

Last time, district employees were fined $24,000 for failing to report 75% of pro-tax contributions.

Last time, tax proponents told us that this parcel tax "will end in 15 years".

What are tax proponents telling us this time that will prove to be false in hindsight? What will the next grand jury report tell us about mismanagement at this district?