Category: Transportation

Anything related to transportation, including cars, traffic, other modes of transport, and so on.

Post #2126: Oh, the price of gold is rising out of sight, III

 

Gold blew through $3100 $3200 $3300 / ounce this morning.

 

As noted in prior posts, an increase in the price of gold is never a good thing.

By my reckoning, we’re now a couple of hundred dollars off the all-time high, in the real (inflation-adjusted) price of gold, in dollars.

My interpretation is that three months of Trumpism managed to do for Russia what 15 years of agitation by the BRICS countries could not.

By reneging on our international commitments, turning on our former allies, aligning ourselves with Russia, and giving an absolutely ignorant crew of knuckleheads complete control over tariffs …

… I do believe we’ve managed to destroy the dollar’s role as the key international currency AND cripple much of our industrial capacity.  In one fell swoop.

Restated, by setting large and rapidly changing tariffs, with no policy goal beyond making The Leader happy, we’ve slit our own throats.

It’s just going to take a few months for that to be completely obvious.

Putin’s ROI is beyond calculation.

Post #2121: EV charging drama.

 

A couple of years back, I took a look at the EV charging market around me, and concluded that it was just a mess.

(Tesla excluded.  This is really a rant about the non-Tesla car charging market in my area.)

Now FF to the present, and … it’s still a mess.

My only solid conclusion is that it’s worth signing up with a charger network or two.  Not out of brand loyalty, or for the nominal discount.  I’ve signed up with my local charging provider (EVGO) just to avoid having to use the totally-exposed-to-the-elements frequently malfunctioning outdoor credit card readers that seem to be standard on EV charging stations.

The lesson being that even if all the high-voltage stuff works right, if the charger can’t read your credit card, you’re still out of luck.

The bottom line is that the electrical energy that costs less than $4 at home, cost about $16 at my local EVGO fast charger.

OTOH, an hour at the fast-charger accomplished what would have taken about 20 hours of charging at home.

DC fast-charging is bad for your car’s battery, anyway.  The fact that it’s expensive is just further validation of charging at home whenever possible.

Probably better to know how it works before I need to use it.

I guess knowing-how-to-fast-charge fits in with flashlights and other preparedness gear.  If there comes a time when you need to use a fast-charger for your car, it’s probably best to know how it works, already, rather than wait to figure it out on-the-fly, when you really need it.

And so, even though I’m a 120V at-home charger 100% of the time, I got a notion to fast-charge my Chevy Bolt.  Just to make sure I could do the entire transaction.

I settled on the nice EVGO station next to the Safeway where I get my groceries.

Probably better to know what it costs, before I buy it.

Turns out, I have to drive to the EVGO car charger in order to have any idea what it costs to charge there.

Shouldn’t the economics/transaction part of this be relatively drama-free?

I mean, it’s not like the technical side of fast-charging is without issues.  Things can go awry as you try to fast charge EV A with Charger B under Conditions C.   If nothing else, the temperature of the battery matters.  So there’s plenty enough to worry about, there.

Anyway, I’m not at the point of finding the technical issues.  Because, stubbornly, I want to know how much the damned thing costs.  Roughly.  Before I pay.  And at this point, I’m betting the answer is, hey, we’ll bill you the right amount, don’t worry.

What’s your over/under bet on the transaction?

Here’s your chance to play The Price is Right, on the spot purchase of 25 KWH of electricity, using an EVGO fast-charger for my slow-charging Bolt, today, at my local EVGO station.

I’m guessing this little preparedness exercise is going to cost me like $30.

That, as a one-off customer in a slow-charging car.  Buying from a public charger with (so far) absolute lack of transparency about their rates.  Just from the smell of all that, I’m guessing my $4 at-home slow charge will cost me $30.

It’s now 1 PM on a sunny Saturday, and I’m off to fast-charge.

Don’t judge me.  Maybe this is how economists have fun.

Useless additional details follow.

Gentlemen may cry Price, Price — but there is no price.

I admit to being an economist.  And cheap.

Despite these handicaps, I don’t think I’m asking too much, of any vendor, of any good or service, that I get to see what the price is, before I agree to pay it.

Today’s challenge:  Can I determine how much it will cost to charge my Chevy Bolt at the local EVGO station, before I sign up for anything?

(Spoiler:  No.  That’s how it looks at the moment.)

Or, the more generalized version, how much (information and money) do I have to fork over and agree to, before they’ll tell me their rates?

Or, not to spoil the punch line, the even-more-generalized version, being, will they ever tell me their rates?

My point being that the lack of any price transparency, for what is a pretty simple deliverable, is really irksome.

There are plentiful technical issues, that I’ll try to get to some, at some point.

But, after nearly half a hour of digging, I finally came across a footnote in a section on a page, referred by a map, linked by the EVGO help section, which I only found because Google stumbled across it for me.

Pricing for EVgo DC fast charging is determined by charger location, your plan, and, for per-minute locations, the maximum power level your vehicle can accept. Real-time pricing is available in the app or at the charger.

Completely true, yet completely unhelpful.

The at-home benchmark

The at-home cost of this would be about $4, for 25 KWH plus charging losses.

I need like half-a-battery’s worth of charge.  Call it 25 KWH, for this Bolt. That 25 KWH recharge costs me well under $4 at my current rate of 12 cents or so, per KWH (Virginia Power).  Tossing on an additional 10% tax for energy losses in the charger and battery.

Given that the at-home cost is under $4, I just want a rough idea of how much it’ll cost to use this EVGO station.

I know it’ll cost more.  I realize it’s complicated, e.g., they’ll charge for the time occupied, and the electricity delivered, the former to ensure you don’t just park, walk away, and hog the spot.  So there’s a charging formula somewhere, not a simple flat rate per KWH.

But so far, I have been able to find anything remotely like pricing or cost information, anywhere.  Not even in comments (e.g., on the PlugShare app.)

So, off to I go.  To see if I can figure out their rates, if nothing else.  Worst comes to worst, I can sign up for their app on my phone, then see what they feel like charging me.

Like a normal American.

To be continued.

Results:  Success

Sure enough, the process was balky.  At least this first time.

It took a few tries to get the charger a) to talk to the car, and b) to take my credit card.  (I now see a big reason to sign up with EVGO is that they’ll have my credit card info and I can skip the @#$#W! exposed outdoor credit card readers.

Near as I can tell, the credit card readers on these machines are an afterthought.  Having run into this issue multiple times now, on EV chargers, and almost never on gas pumps, I have to wonder who thought that having a card reader totally exposed to the elements (e.g., no roof) was a good idea.

The total bill was about half what I expected it to cost, above. But that works out to $0.56/kwh, or about 4.5x as expensive as charging at home.  Charging the car 20x faster than I can from a 120V wall outlet.

None of the experience was hugely out of line with what I expected, except that the car was slow to charge.  (These chargers are capable of putting out 50 KW, but my car would only charge at 25 KW.  At that rate, a full charge would take a little over two hours).

I won’t be fast-charging again until I need to.

At that $0.56/KWH average rate, the electricity at this fast-charger was about twice as expensive as gasoline would have been, to get me the same number of miles, in an efficient hybrid car.  I went through that calculation in:

Post #1705: When is electricity the cheaper motor fuel?

By contrast, when charging at home, electricity is about half as expensive as gasoline, per mile.  That’s based on $3.36/gallon for gas, and $0.12/KWH for electricity.  That was true not only for my wife’s plug-in Prius Prime, but for almost all the dual-fuel (plug-in hybrid) passenger vehicles listed by the EPA.  Click the link for the post above to see the full list.

Post #2120: Oh, the price of gold is still rising out of sight

 

Gold blew through $3100 $3200 an ounce this morning.

 

As noted in prior posts, an increase in the price of gold is never a good thing.

Looking on the bright side, a good chunk of this last push was merely from dollar going down the toilet. 

That should happen because gold is an internationally-traded commodity.  It’s a global market.  When the value of the dollar falls, the value of gold, expressed in those dollars, rises.

I guess I need to start a countdown or something, as by my calculation, if gold tops $3519 (or so), that will be its all-time high in inflation-adjusted (CPI-adjusted) terms.

So, right now, gold is just (1- $3234 / $3519 =~) 8% below its all time high, in real (inflation-adjusted) terms.

I described the economic conditions under which gold set its previous high, in a recent post on this topic:

Post #2112: Oh, the price of gold is rising out of sight

Before that, my most recent prior post on this topic was from half a year ago:

Post #2017: The price of gold is up. That’s never good.

Post #2112: Oh, the price of gold is rising out of sight

 

Oh the price of gold is rising out of sight
And the dollar is in sorry shape tonight
What the dollar used to get us now won’t buy a head of lettuce
No the economic forecast isn’t right
But amidst the clouds I spot a shining ray
I can even glimpse a new and better way
And I’ve devised a plan of action worked it down to the last fraction
And I’m going into action here today.

From:  I’m changing my name to Chrysler, recorded by Arlo Guthrie.

Gold blew through $3100 an ounce this morning.

When the stock market is making new highs, everybody steps up to take credit for it.

But gold?  Nope. Nobody ever takes credit for a rising price of gold.  Given the cheapness and ubiquity of public lies these days, you’d think some prominent braggart would try.  But nobody ever tries to own a rise in the price of gold.   That’s because a rapidly rising price of gold is never good news.  And peaks in the price of gold tend to occur when the 💩 is in the process of hitting the 🚁.

What caught my eye about $3100 is that this has to be getting close to setting a new record for the price of gold in real (inflation-adjusted) terms.  (In the modern era, where the dollar price of gold has been allowed to float.  Post-1970, say.)

If I take the prior price peaks (red arrows I added to the chart above) and use the BLS inflation calculator to express them in 2025 dollars, I find that we’re now just 14% below the all-time high price of gold in real (inflation-adjusted) terms.

So, when Guthrie sang about the rising price of gold, in the context of the 1979 bail-out of Chrysler, following two Arab oil embargoes, the resulting energy crises, two long, deep U.S. recessions, and the near-destruction of the U.S. auto industry with its lack of energy-efficient cars, in a context of persistent double-digit rates of inflation … the price of gold, in real terms, was somewhat higher than it is today.

I’m trying to take some comfort in that.  Either things aren’t as bad now, as they were then.  Or they aren’t as bad, yet.

Either way: Eat, drink and be merry.

My most recent prior post on this topic was from half a year ago:

Post #2017: The price of gold is up. That’s never good.

Post #2111: Of arctic ice and rosemary.

 

You can fool all the people some of the time, and some of the people all of the time, but you cannot fool all the people all the time.

This saying is attributed to Abraham Lincoln.

This post is just a reminder that, in addition, you cannot fool the laws of physics any of the time.

Stuff’s melting.  Is anyone surprised?  Is anybody paying attention?

The full article is on the National Snow and Ice Data Center website:

https://nsidc.org/sea-ice-today/analyses/arctic-sea-ice-sets-record-low-maximum-2025

I don’t normally repeat the news, but I only just stumbled across the fact that Arctic sea ice hit a new low this year.  It peaks right about this time every year, and this year’s peak extent is the lowest in the roughly 50-year record.

No surprise, given the underlying trend.  The north polar ice cap has been shrinking slowly for about as long as there has been a satellite record of it.

The loss of reflective polar sea ice is an important positive feedback serving to accelerate the pace of global warming/climate change.  It lowers Earth’s albedo.  Dark open ocean absorbs more light energy than reflective white ice does.

If you don’t quite grasp why anyone should care about climate change, focus on a large net loss of arable North American land over the next century, as the climate changes.  Less food.  But with a growing world population.  And while that’s happening here, that’ll be happening across the world, as the (soil of the) the continental interiors warms and dries in response to climate change.

People also lose track of how long additional C02 emissions affect the climate.  The stuff coming out of your tailpipe will still be warming the earth centuries to millenia from now.

People forget about the two or three decade time lag in the global warming “pipeline”, due to the mass of the earth, relative to the small top-of-the-atmosphere energy imbalance.  Even if a miracle were to happen today, and atmospheric C02 were to stabilize, we’ve got three decades of warming “in the pipeline” as the earth’s surface temperate slowly adjusts to the energy imbalance that today’s level of C02 is creating.  That temperature increase is how nature restores the planet’s top-of-atmosphere energy balance.

And people forget how long energy-using devices last.  The majority of today’s new cars will still be on the road 15 years from now.  A new furnace?  Maybe 20 years.  A new house?  Maybe a century.  And for that entire century, a new house with natural gas heat will be pumping out tons of C02 per year.  Year in, year out.

Did the Biden Administration push the electrification of transport?  Sure did.  That’s because a world in which we drive gas vehicles, as we do now, but that still looks like our current world, is a pipe dream.  It’s not a feasible outcome.  The only way to hold onto a world whose climate is as benign as the climate in which civilization has flourished is to halt the buildup of C02 in the atmosphere.  Did the Biden administration push for more electrical transport than we seem to need right now?  Sure did.  Because “right now” isn’t the right time frame.  Twenty years down the road, as today’s new cars are finally heading off to the scrap yard  — twenty years of global warming in the future — look back and see how that modest push toward electrification looks then.

Global warming in your back yard:  The northward migration of the USDA plant hardiness zones.

Source:  Maps are from USDA.  I added the line marking the boundary between hardiness zones 5 and 6.

Maybe the easiest way to see climate change happening in your lifetime is to pay attention the good old USDA plant hardiness zones.  Every home gardener is at least passingly familiar with these, because these are a guide to what will and won’t overwinter in your climate.   The zones represent 10-degree-F increments in the coldest likely wintertime temperature, and are simply based on the coldest observed temperature in an area over the previous 30 years of weather data.  They get split into -a and -b halves, based on a 5F difference in coldest expected temperature.

In Zone 7b, for example, I should expect temperatures to go no lower than 5F.  This past winter it hit 5F here, and that killed a rosemary bush that I’d been growing for the better part of a decade.  Rosemary, I now find, is only hardy to USDA Zone 8.  Which I have now proven the hard way.

Turns out, these every-day use USDA plant hardiness zones are extremely sensitive to global warming.  I think that’s because they reflect the coldest wintertime temperature you should expect in an area.  That coldest temperature will occur in winter, at night.  And global warming has its strongest effects at night, and in winter.

So, even though global warming has done almost nothing to the U.S. so far, and certainly not much in terms of average US land temperature, the impact on minimum annual temperature — what determines the USDA hardiness zones — has been large enough to be easily visible.

On the maps above, the Zone 6 boundary moved north about 200 miles, in 33 years.  That’s ballpark for all of the zones, on average, over this period, but the movement north is fastest in the center of the continent, away from the coasts.

In Northern Virginia, over the same period, Vienna moved from just inside Zone 6, to just inside Zone 7.  Or, rather, the zones slid far enough north over three decades that one full zone slid past Vienna, VA in 33 years.

Same phenomenon.

But 6 miles a year is 600 miles a century.  Project that out, and a century from now, Iowa ends up with the climate that west Texas has now.  Just from that slow, 6-miles-a-year, northward migration of the climate zones under global warming.

Without too much exaggeration, let this continue, and today’s children will get to see the sagebrush desert of the U.S. Southwest take over the U.S. Midwest.  Let it go two centuries, and the current climate of Mexico will occur at the Canadian border.

With everything you think that would imply for U.S. food production.  Amber waves of grain?  That’ll be just another obsolete concept.

Merely from allowing the current observed rate of change to go unchecked.

As a society, we seem to have become too stupid to survive.

Conclusion

If civilization survives, the Republican Party’s head-in-the-sand policy toward climate change will go down as the stupidest, most costly, and most damaging thing ever done by a political party.  Wars included.

Except possibly for encouraging increased use of fossil fuels.  That would be even stupider than doing nothing, at this time.  But that also seems to be firmly embedded in the Republican agenda.

I can only hope that they are as effective at that as they were at helping U.S. coal miners.  The promise to do that being central to Trump’s prior win.

Source:  Federal Reserve Bank of St. Louis.

On global warming, I’ll have to listen to the Republican party parroting Russian disinformation for the rest of my life.  Fact-free spin and bullshit seems to be their preferred fuel these days.

But I will die with the certain knowledge that if civilization survives, the stupidity of encouraging faster global warming will be universally recognized.  By whatever portion of the population manages to survive the mass die-offs that will result from a world-wide reduction in arable land.

(As an afterthought, will the Arctic save us?  No.  Only if you live on a Mercator Projection.  And only if you think you can grow crops without topsoil, as the last ice age scraped most of Arctic North America down to bedrock, and deposited that topsoil in the U.S. Midwest.  (See Canadian Shield).  Some fraction of the population will likely survive there under even the most extreme warming scenarios.  But most citizens of the U.S., and the world, will have starved long before there’s any Arctic dividend to share.)

Post #2102: How high is that helicopter? Part 1.

 

Is there an easy way to determine the altitude of a low-flying aircraft?

After looking over my options, I’m going to try an antique optical rangefinder.

I bought it on Ebay.  I’m currently waiting for it to arrive.

Background

I was awakened last night by yet another low-flying helicopter, here in the DC ‘burbs.

The noise from these ranges from merely obtrusive, to loud enough to rattle the windows.  Below is a recording of one of the several that passed overhead today, taken from my back porch.  It doesn’t quite stop conversation, but you do have to raise your voice a bit.

This is normal for the DC area.  There are a lot of military and other government high officials stationed in this area.  These folks tend to get shuffled from place to place via helicopter.  Unfortunately, one of the well-used north-south routes passes directly over the Town of Vienna.

Is it really that loud, or is flying low?

In theory, nothing should be flying below 1000′, in my area.

But in the past, that has been an issue.  I recall that, many years ago, some Vienna Town Council members complained to various authorities about noise from low-flying aircraft, and got the “minimum 1000′ for the TOV” as part of the answer.

This got me thinking about measuring a passing helicopter’s height.

(Luckily, I am hardly the first person to have had an interest in this.  Luckily, I say in hindsight, because that way, my Google inquiries would not attract undue attention from the authorities.)

Turns out, there is no good way for an amateur on the ground to measure the height of an over-flying helicopter.  At least, none that I’ve come across.

But seriously, how hard can this be.

If nothing else, think of it as a way to rule out bad pilot behavior (low flight altitude) as an explanation for a loud helicopter fly-over.  (With the obvious alternative explanation being “that was a loud helicopter”.   Which, given that these may be military aircraft, is always a possibility.)

So, are those overflights loud because they are loud aircraft, or are they loud because they’re flying well below 1000 feet?

Optical rangefinders that won’t work

First, there are “laser rangefinders”, not intrinsically different from a laser tape measure, just more oomph and maybe some specialized optics.  But first, I ain’t pointin’ no laser at no aircraft, period.  Let alone a low-flying (likely military) helicopter.  Plus, the ones available for civilian use (e.g., laser tape measure, laser golf or boating rangefinder, rangefinders for hunting big game) probably won’t work for this use anyway, owing to the small visible target.   I get the impression these laser rangefinders (e.g., for golfers) can find the range to a hillside or location on an open lawn, but they aren’t designed to find something as optically small as a helicopter flying at 1000′.

I’m also brushing aside all the military “passive-optical” (coincidence and stereoscopic) rangefinders.   These are WWII-era and earlier tech with mirrors, prisms, and such.  If nothing else, aside from having to own one (they tend to be big, to get you the best separation of the two lenses), you’d have to have the forethought to have it handy, and set up, just as the helicopter was flying by.  Plus, those are all expensive military collectibles now.

 

A vintage civilian non-laser coincidence rangefinder, via Ebay

 

Source:  Ebay.

I can vaguely recall hand-held purely optical rangefinders, from the pre-laser era.  These are the vastly smaller, and likely less accurate, analogs of military coincidence rangefinders.  But they worked the same way, using two widely-separated lenses, then measuring how much you need to move the image from one eyepiece, until it coincides with the image from the other.

I bought one on Ebay.  Above, you see a RangeMatic 1000.

This allows you to measure distances to 1000 yards, with some modest degree of accuracy.  It looks like it should be more than adequate to allow me to identify helicopters flying at 500 feet, rather than at 1000 feet.  It looks like the difference between 150 yards and 300 yards is about an eighth of a turn of the dial.

This, if it works, will give me the line-of-sight distance to the helicopter.  That only tells me the height of the helicopter if it flies directly overhead.  I’m going to need to add some sort of mounting and an inclinometer.  The line-of-sight distance, plus the angle of elevation above the horizon, should allow me to infer the height of the helicopter over ground.  (In fact, that’s easy enough that I don’t even have to look it up.  Height above ground is the sine of the angle of elevation, times the straight-line distance to the object.

Thus ends this task, until my Ebay’ed optical rangefinder shows up in the mail a few days from now.

Estimating overflight height by apparent size.

The very crudest golfing range finders work by using the height of the pin (the stick-with-flag that marks the hole).  These pins are a standard size, and the simplest golf rangefinders simply place the apparent size of the pin on a scale — the smaller it is, the further you are away from it.

Other purely optical methods seem chancy.  In theory, if I could identify the model of helicopter, I could infer distance by measuring how how big the over-flying helicopter appears.

This is more work than I care do do.

Can I determine the height of a passing helicopter, purely from its sound?

Source:  Reference BBC.  Photo by Joe Pettet-Smith

First, an interesting historical side-note.  Listening for approaching aircraft is not a new idea.   As I understand it (likely from seeing it on YouTube), in parts of Great Britain, big, cast concrete parabolic sound reflectors still stand along the coastline.  These concentrate (and effectively, amplify) incoming sound waves.  These were used to detect the sound of incoming aircraft while they were still miles offshore, prior to the implementation of radar during WWII.  Reference BBC

This is one of those weird things that is clearly possible, from first principles.  Maybe not even terribly difficult, as a one-off proof of concept.  But for which you can buy no ready-made unit.

Sound travels about one foot per millisecond.  Two microphones, 100′ apart, would therefor experience about a 100-millisecond (or one-tenth-second) difference in when they “heard” a sound at ground level.

For this approach, I’d use some microphones, some recording gear, and the speed of sound, to triangulate where a near-surface sound is coming from, based on when (precisely) that sound shows up, at microphones placed at known locations perhaps 100′ apart.

The theory is easy:  https://en.wikipedia.org/wiki/Acoustic_location

Start with the concept of a gunfire locator or gunshot locator.  These (typically) use a widely-distributed set of microphones to detect and locate gunshots.  Once a gunshot is detected, these use “standard triangulation methods” to estimate the direct and distance to the gunshot.

(There are crowdsourced versions of these:  https://github.com/apispoint/soter, but that seems limited to categorizing a noise as a gunshot, not pinning down the location.)

Substitute helicopter noise for gunshot, and do the math in 3-D instead of assuming location on the ground, and that’s what I’m after.  Something that will give me a fairly precise location of a helicopter flying overhead.  From the noise of it alone.  So that I may then calculate the height above ground, from that location.

In two dimensions, you only need two microphones — think, two ears — to identify the direction that a sound is coming from.  Per Wikipedia, that’s all about the lag between the time the sound hits one ear, versus the other.  To quote:

Where:

  • is the time difference in seconds,
  • is the distance between the two sensors (ears) in meters,
  • is the angle between the baseline of the sensors (ears) and the incident sound, in degrees
  • c is the speed of sound

But that only works (pins down a unique direction) if you’re working in two dimensions.  And one pair of microphones provides no clue as to distance.  Just direction.

If you work through what you do need, to pin it down in three dimensions, a minimum rig would need four microphones, arranged like the corner of a cube.  This provides a pair of microphones in each of three dimensions.  The further apart the better, as these are going to be used to estimate a helicopter height of maybe 1000′.

The rest should be math.

But this solution involves a lot of hardware, no matter how I figure it.  Four microphones or recording devices, wires to connect them to a central station, and a four-track sound recorder.

This would be a difficult and expensive solution, so I’m not going to pursue it further unless the RangeMaster 1000 fails to do the job.

Conclusion

I’ll have to wait for my antique optical rangefinder to arrive before I can bring this to a conclusion.

My belief is that a simple hand-held “antique” optical rangefinder, plus something to measure the angle of elevation, should provide all the accuracy I need to distinguish helicopters flying at or about the 1000′ ceiling, from putative “low flying” helicopters at (say) 500 feet.

My guess is that these helicopters are merely loud, not low.  But I should be able to validate that with this simple bit of equipment.

Post #2100: Measuring road salt in drinking water, a summary.

 

This might make a good science fair project for somebody, so I’m giving this topic one final, compact write-up.

If you live in an urban area that draws its drinking water from a local river,  or other nearby flowing surface water …

… and you live in a climate where they salt the roads for winter storms,

… and the weather cooperates, in the form of some distinct road-cleaning rain or melt event following a winter storm,

… you can easily infer the presence of road salt, in your drinking water,

… with a cheap ($6) total-dissolved-solids (TDS) meter, a water glass, and some patience.

 

In my area — where the Potomac River is the main source of drinking water — it takes about ten days from the time the rain washes the salt off the roads and parking lots, until that salt shows up in the drinking water.  YMMV.

See posts 2085, 2086, 2088, 2089, 2090, 2091, and 2092 for background.

The required background, as a series of true statements.

We use a lot of road salt in the U.S.  Google’s AI tells me we use 20 million metric tons of it a year.  The same AI tells me we have about 230 million licensed drivers.  So I make that out to be just under 200 pounds of road salt, per licensed driver, per year.

The accepted EPA threshold for “salty taste” in the drinking water is 250 parts-per-million chloride ion.  Assuming I did the math right, 200 pounds of salt (60% chloride by weight) is enough to impart a salty taste to more than 50,000 gallons of water.   Or, enough to impart a salty taste to 0.7″ of rain, on your standard suburban quarter-acre lot.

That’s all by way of saying that, “outdoors” is a big place, but that’s still a lot of salt, even when spread outdoors.  Enough salt that you ought to be able to notice it, in the environment.

The negative effects of road salt use are well-known, including corrosion (of cars, bridges, rebar in concrete …) and pollution of surface and ground waters with the salty runoff.  In particular, nothing that lives in your local fresh-water environment really likes being subjected to a salty water.

There has been a prolonged push in the U.S. to use less road salt. Seems like that started in the late 1990s in New Hampshire, where they were discovering problems with water wells that had been, in effect, poisoned by prolonged use of salt on nearby roadways.

State DOTs and others do not use salt to melt the snow off the roads.  They plow the snow off the roads.  The salt is just there to achieve “disbondment”, that is, to prevent the packed snow and ice from freezing solidly to the pavement.  So that they can plow down to bare pavement.

The desire to use less road salt led to the now-common practice of brining the road surfaces prior to snowfalls, one of a set of techniques known as “anti-icing” (as opposed to after-the-fact de-icing).  If weather conditions are right (e.g., no rain prior to the snowfall), spraying the roads with a thin layer of salt water, then allowing that to dry, achieves “disbondment” of the initial snowfall with minimum use of salt.  Brining uses roughly one-quarter of the salt that would be required to achieve the same road-clearing result, if spread as rock salt.  (Source:  Brine Fact Sheet, 2016, American Public Works Association.)

That thin layer of salt creates a weak spot in the snow/ice layer that forms on the road.  That weak layer is what creates the “disbondment” of the ice and the underlying pavement.  That “disbondment” allows the plows to scrape the snow off the road, to get down to bare pavement.  Rock salt is also there for the disbondment, it just achieves it less efficiently.

Some of the sodium in salt tends to stay local.  This is what “burns” greenery near salted areas such as sidewalks.  But the chloride in salt travels along with the runoff, plausibly (around here) in the form of calcium chloride, formed as sodium was exchanged for calcium in the soil.

A “total dissolved solids” meter measures the electrical resistance of water, and so indirectly measures the concentrations of ions in the water.  Around here, in normal times, that would be mostly calcium and carbonate ions, as that’s the main dissolved mineral contributing to our roughly 10 grains of water hardness in this area.  But ions are ions, whether they be from calcium carbonate or sodium chloride.  And so, a total dissolved solids meter will react to salt in the water, as it would to any other ions in the water.

As a result, to the extent that road salt gets into my drinking water, this should generate a predictable rise in total dissolved solids, as measured in my tap water.  Each time the salt is flushed off the roads (by rain, say), I should see a rise in TDS in my tap water, with the appropriate lag.

In Fairfax County, it takes about a week for water to work its way from the filtration plants to the furthest taps in the system.  This is known, because Fairfax flushes the system annually (switching from chloramine to chlorine during that period), and it warns citizens about the resulting change in the smell and taste of the water, annually.  And in that warning is the factoid that it takes about a week.

All you need to track TDS in your drinking water is a cheap ($6 via Amazon) total-dissolved-solids meter, and patience.  The patience is required because, with a cheap meter, you’ll only get stable results if you allow the tap water to sit long enough to come up to room temperature.  (The underlying conductivity measurement is quite temperature-sensitive, and the cheap TDS meter that I bought takes forever to adjust to the water temperature.)

If you’re worried about your meter’s reading drifting over time, keep one water sample permanently, and use it for a reference.  Re-reading the TDS in that “reference” sample will show you that your meter’s reading is stable.  (Or, at least, that’s what it showed me.)

And, voilà:

As noted, these peaks in tap water TDS are ten days after some weather event that flushed a lot of road salt into the local creeks.  (Typically, a rainy day.)

Although the timing and magnitude are right, I have not proven that this is purely the effect of salt.  Maybe TDS goes up after every rainstorm, salt or no salt?  I think that’s unlikely, but I can’t rule it out until weather conditions are right, and we have a rainy day with no remaining salt on the roads.

Conclusion

I’m pretty sure the peaks in tap-water TDS, shown above are driven by road salt being washed off the roads.  Water filtration (short of reverse-osmosis) does not remove salt (or chloride) from the water.  And, because we drink river water, not well (ground) water or water stored in large reservoirs, that salt then shows up, in short order, in the water.

All of which tells me that these peaks look about right.

I’d like to have double-checked that it is salt, by being able to taste the saltiness in the water, but the increase in TDS was not large enough to cross the commonly-accepted threshold for salty taste (250 ppm chloride ion in the water).

Ultimately, all that’s left to show is to show that such TDS peaks don’t appear, 10 days after a rainy day, when there isn’t salt on the roads.  That way I can rule out that these TDS peaks are simply related to rainstorms.  Leaving salt (moved by rainstorm) as the only plausible explanation.

Again, the beauty as a science fair experiment is that all it takes is a cheap TDS meter, a water glass, and patience.

Post #2092: Salt rising — through 2/21/2025

 

The final post in this series is:

Post #2100: Measuring road salt in drinking water, a summary.

Original post follows:

In this post, I’m documenting the progress of my road-salt-in-my-drinking-water experiment.

Recall that:

  1. We had a half-inch of rain Friday 1/31/2025 that washed away the piles of road salt that remained from an earlier winter storm.
  2. It should take about a week for water to work its way from the Potomac River to my tap, per Fairfax County.
  3. Nothing filters salt out of the water, so the salt that got washed off the roads should show up in my tap any day now.
  4. After correcting for operator error, my tap water has shown a steady 210 ppm (parts-per-million) TDS (total dissolved solids) for the entire past week.

I am pleased (?) to report that last night’s water sample clocked in at 232 ppm.  And as of 2/8/2025, it had risen to 242 ppm.

Assuming that was not a fluke, I expect that was the beginning of the salt passing through my fresh water system.  The timing is right, in any case.

I’ll be tracking this for another few days, and will continue to document the results, here in this post.

Update 2/21/2025 sample.  The next salt spike appears in the drinking water right on time,following the ~2/13/2025 runoff of the most recent road salting.

 

Between the time of the rain, and now, my tapwater’s TDS increased by about 100 parts per million, against a relatively stable baseline of about 200 ppm baseline. The peak occurred about 10 days after the salt-clearing rainstorm.

But even if that entire increase is, in fact, due to chloride ion from road salt, we still won’t taste it in the drinking water.  The 100 ppm (presumed) chloride ion concentration in the drinking water is well below the threshold (250 ppm) above which (some?  many?) people will detect a “salty” taste to the water.  The bottom line is that, so far, this should not be a generally taste-able water saltiness event.

And that’s a good thing.

In addition, it is far from proven that the uptick in TDS of my tap water is even due to road salt.  E.g., maybe this happens after every significant rain.   But I’m betting that’s the road salt.  And even if it is driven by road salt, there has to be more in the TDS increase that just chloride ions.

It doesn’t matter.  Won’t taste this amount of salt in the water, no matter how you slice it.

In summary, there was a modest increase in my tap water’s TDS.  Timing is about right for this to reflect “salt in the tap water”, from road salt runoff of 1/31/2025.  But nothing has been proven, except that, even worst case, the ion concentration is not nearly enough to give the water a salty taste.

Edit:  As of 2/13/2025, we’re midway or better (?) through the “runoff” step of a new road salt runoff cycle.  Or, if not midway, we’ll get there and beyond today, with a predicted high in the low 50s.)  And so, we should see a smaller, smearier version of this most recent drinking water salt pulse … 2/21/2025.  It’s not clear that this simple rig, or any simple rig, would reliably let you “see” a pulse that small and ill-defined.  (And that’s assuming the measured TDS number for tap water is otherwise pretty steady from day to day.) 

OTOH, it’s no hardship to keep this going.  Just KISS.  All it takes is this cheap TDS meter, a drinking glass, and patience.

Use just one glass.  Test the water twice a day.  But you need to let that cold tap water stand a good long while, if you want a reliable reading out of a slow-read $6 meter.  So, let each sample sit half a day.  Covered.  AM and PM,  you use (and rinse) the meter, dump that water sample, run the tap and replace the water sample, and set it aside, covered. Then leave it alone.  Until it’s time to do all that again.  Repeat twice a day.

It’s idiot-proof.  And sometimes that’s a good thing.

Post #2091: Blah blah blah blah salt blah blah blah. Part 3: Operator error.

 

Edit 2/7/2025:  One week since a half-inch of rain washed away the remaining salt on the roads … and no sign of salt in the water yet.  TDS (total dissolved solids) readings for properly aged (i.e., room-temperature) water samples are steady at 210 ppm, plus or minus some single digits.

 

Recall that, as of my last post, my road-salt-in-drinking-water experiment was floundering.  My tap water was showing far more variation in measured total dissolved solids (TDS) than seemed reasonable.

Turns out, that’s because a) my tap water is cold, b) temperature strongly affects the conductivity of water, c) this $6 meter measures and adjusts for temperature,

d) extremely slowly.  And e) I’m not exactly a patient person.

I didn’t wait anywhere near long enough for the meter to adjust to my tap water temperature.  And going forward, I’m not going to stand around for a quarter-hour holding this meter in a glass of water, waiting for the temperature adjustment to reach equilibrium.

The solution is simple.  I have to let the glass of tap water sit for a couple of hours, and come up to room temperature.   Then measure TDS.  Once I do that, these “well-aged” water samples all provide consistent readings for parts-per-million total dissolved solids.

Properly measured, my tap water TDS has been around 210-215 ppm TDS for the past three days.  A little higher than the 170 ppm I expected based on “10 grains of hardness” of the water.  But definitely in the ballpark.  And seemingly stable.

Hey, maybe I’m not crazy.  It does, in fact, take about a week for water to pass through the Fairfax County drinking water system.

The presence of a stable, measurable baseline is important for this experiment.

And yet, as I go day after day without an increase in TDS, I begin to wonder whether I just imagined the salty-tasting tap water of winters past.

I expect road salt runoff to produce a big upswing in my tap water TDS, Wednesday-ish of this week, best guess.  That’s based on last Friday’s half-inch of rain washing (almost) all the remaining salt off the roads.  And my vague memory that the salt taste showed up on-order-of a week after road salting.

FWIW, I finally found confirmation that it takes about a week for water to move through my local water distribution network.  When Fairfax flushes the water mains, they change disinfectant chemicals.  Depending on where you are in the system, those chemicals may take up to a week to show up in your tap, and a week to go away (reference).

Depending on your usage patterns and location within the distribution system, it could take up to a week for your drinking water to transition from combined to free chlorine at the beginning of the flushing program, or from free chlorine to combined chlorine at the conclusion of the flushing program.

The upshot is that a) we may still be a few days away from salt showing up in my tap water, and b) while it has taken me a while to figure out how to use my $6 TDS meter, there’s no harm done.

So far, properly measured, the TDS in my tap water has remained steady at around 210-215 ppm.  If a flush of road salt passed through the system, that ought to stand out pretty sharply against that steady background rate.

 

The full story

  • This meter measures water’s electrical conductivity.
  • That conductivity is increased by ions in the water.
  • Such ions are generated when minerals and salts dissolve in water.
  • Thus, the meter can infer the amount of ions in the water, from the water’s conductivity.
  • It then translates that into something the user can understand, such as parts-per-million total dissolved solids (TDS) or salinity.   Depending on the end-use market that is being targeted.

Source:  Mettler Toledo white paper, “Reducing Measurement Error in Conductivity Readings”.  Annotations in red are mine.

 

  • But water temperature strongly affects conductivity.  A 9F decrease in water temperature creates a more-than-10% reduction in water conductivity.
  • Hence, this measurement typically requires temperature correction. The goal is to measure the water’s conductivity, adjusted to some standard water temperature.
  • And this $6 TDS meter includes that temperature correction via a built-in thermometer (and presumably a look-up table on a chip, or something).
  • But the meter is excruciatingly slow about doing that.

I finally got the bright idea of sticking this meter in a glass of ice water and see how long it took to display a temperature of 0 C. 

I gave up, it took so long.  I got tired of holding the meter in the ice water.  I’m guessing it would eventually get there, but it would take five or ten minutes to do so.

In any case, that adjustment is so slow that what I interpreted as the meter reading “setting down” to a final value, in just a few seconds, was nothing of the sort.

And that’s what tripped me up.  With incomplete temperature adjustment, cold water registers as “cleaner” water (lower TDS), owing to the lower conductivity of cold water.

Conclusion:  Never rule out operator error

On the on hand, I could blame the meter for being so slow to adjust to different temperatures.

On the other hand, it’s up to the meter operator to use it correctly.  Or spend the big bucks on one that works faster.

In any case, for $6, I got a very smart meter.  Smart enough to do the temperature correction for me.

But the hardware?  That’s still the best that $6 can buy.  It’s fine, as far as I can tell, but there’s no expectation that $6 bought me some kind of heirloom-quality super-tool.

And, as it turns out, what I got for $6 is a meter that works, but takes forever to settle to a final reading, owing to the glacial pace of adjustment of its internal temperature sensor.

Which I consider fair, for $6.  That it works at all is kind of a miracle.  That was unkind.  What I should have said is “more than fair”.

Now that I know that the temperature correction takes forever to register,  all I need to do is let my tap water samples warm up to room temperature.

And poof, what seemed like a ridiculously inconsistent meter turns out to be … pretty consistent.

Well worth the $6.

I probably need to buy some distilled water, for another buck or two.  Not to test the meter, but to rinse it after I’m done.  By device design and by common acclaim, I get the impression that I’m never supposed to let anything touch the electrodes but water.  Which precludes wiping the electrodes dry, in any fashion.  But, I think that if I just let the little electrodes air-dry, after tap water, I risk “poisoning” the electrode surfaces over time with calcium carbonate deposits, a.k.a., water spots. This, by analogy to premature dulling of un-dried razor blades by the thickness of water spots (Post #1699).

Distilled water, by contrast, leaves nothing behind when it evaporates.  So you don’t dry them, you rinse them with pure water and then allow them to air-dry.

Otherwise, the experiment is now on track.  I have documented a stable baseline of around 215-225 ppm dissolved solids in my (room-temperature) tap water.

I just need to give it a few days for the road salt to work its way from the Potomac River to my water faucet.