back to blogging in 2016

After a long hiatus of being distracted by many other things, I am itching to get back to blogging. Look for more posts coming soon, probably once every two weeks or so.

As you’ve noticed (since my readers are of course the savviest folks around when it comes to water policy and water use🙂 ), the drought in California in the past three years has really shifted perspectives on the importance of water reuse, desalination, and managed aquifer recharge. On a professional front, as a remediation engineer, I’m seeing more and more places in Southern California with public pressure not only to clean up contaminated groundwater but to reuse it for potable water supply. It is certainly an exciting time to be an engineer interested in designing and building new projects to provide stability to the water supply in light of changing conditions!

wake up call on the Colorado River

I try to keep up with the latest news, but by no means could I use this blog to break news.  That said, developments in the past couple of days are must-reads for anyone interested in water resources.  The water in the southwest is just not there this year, folks, and it’s starting to dawn on people how precarious our water supplies can be.  The simple case is San Luis Reservoir, which supplies much of the South Bay – wealthy homes in Los Altos, Saratoga, and Cupertino, as well as industries in Silicon Valley.  The reservoir is at historic lows — 17% of full pool — because of one of the driest rainy seasons on record, combined with cutbacks in flows out of the Sacramento-San Joaquin Delta have cut off much of the typical inflows, while outflows, in the form of residential, industrial, and agricultural demand, continue unabated.  This year isn’t the year that water will have to be rationed within the San Jose area, according to officials, due to extra storage on-hand in groundwater and smaller reservoirs, but the Santa Clara Valley Water District should be pushing for conservation among its customers and a resolution to the long-term plans for the Bay-Delta, such as the tunnels, perhaps, to shore up their water reliability…

The reliability of the Colorado River’s flow has been debated since the first compact over-allocated the water rights based on wetter than average years.  We’re in a 14-year drought on the Colorado, and now 40 million people’s drinking water and some 15% of the nation’s produce depend on it.  Remarkable numbers, but that’s what happens when there’s only one “major” water source in a 7-state region, and it’s not even one of the top 25 rivers in the US in terms of discharge (at 1400 cubic ft per second on average, the Colorado is #28 of America’s 38 rivers over 500 miles long).  Lakes Powell and Mead, the largest two reservoirs in the US, help bridge the gap between high and low flows on the Colorado, but both are struggling to keep pace with the drawdown of the past 14 years.  Again, inflows are limited, and outflows just keep coming.

The Bureau of Reclamation, which operates both reservoirs, announced on Friday that less than 10% of the normal allocation would be available from Lake Powell this water year (starting October 1st), the lowest amount since the reservoirs were first filling in the 1960s.  This sets the stage for a legal “shortage” (also known as a “call”) to be declared in the next couple of years, which kicks in provisions to cut off water to Arizona, California, Nevada, and Mexico.  Arizona, last in line for water rights, loses supplies first, followed by Nevada and California.  Arizona will rely on its banked groundwater, stored in the “good years” of high runoff.  Las Vegas, which pulls supply from Lake Mead and discharges its treated wastewater into a tributary of the lake, will kick into gear a controversial plan to build a $7 billion pipeline to a groundwater resource in rural eastern Nevada, along the border with Utah.  And California’s farmers in the Imperial Valley, the largest consumers of Colorado River water, will have to be careful about taking only as much water as they’ve been allocated.

This can’t be a surprise to those who’ve been paying attention, from the Bureau of Reclamation’s farfetched feasibility study released last winter to the paper out of Scripps in 2008 that predicted a 50% chance that Lake Mead would be dry by 2021.  Savvy water managers across the southwest have been preparing policies and working out deals for what to do when the inevitable water shortage hits.  Thankfully this means resolution in a meeting room rather than in a court room.  But let’s hope that the public’s eye doesn’t forget this wake-up call if we have a particularly wet winter and seemingly resolve our troubles with plenty of water to go around.  We had a very wet year in 2011, which increased Lake Mead around 40-50 ft, and Lake Powell around 50 ft.  The problems did not go away; the “shortage” risk was merely delayed.

more than physics

People talk about water scarcity like it’s a physics problem: why don’t we tow icebergs from Alaska to alleviate the southwest’s water issues?  what about pumping water from the Great Lakes across the Rockies?  Sometimes that sort of grand thinking works, like the diversion of California’s water resources from the upper Sierra Nevada mountains southward to the Central Valley and Southern California.  But that’s only part of the equation.  One reason that California’s State Water Project and Central Valley Project are successful is that the source is virtually pristine snowmelt.  Move clean water from an area of relative abundance to an area of relative scarcity, add in a comment about humans adapting the environment to their needs, and voila, problem solved!

In my last post, I remarked on China’s limited water resources and their lack of wastewater treatment.  Well, not surprisingly, the Chinese government is trying their darndest to move water around to alleviate chronic water scarcity in the north (think Beijing) with relative abundant water from parts south (think the Yangtze River).  They’re apparently getting close on parts of this great diversion – the Danjiangkou Reservoir should be sending water northward next year.  The physics problem has been solved for a mere $81 billion!  Good job.

One small problem: the water to be transported is currently not fit for drinking.

A water pollution plan issued by the State Council, or China’s cabinet requires that the water quality for all five rivers that flow into the Danjiangkou meet a “grade III” standard by 2015.  But four of those rivers are now rated “grade V,” deemed for “agricultural use only” and the fifth river is considered “grade IV,” for “industrial use only,” reports China’s state-run news agency Xinhua.  “The target is very unlikely to be met as many pollution control projects lag behind schedule due to a fund shortage,” said Cheng Jiagang, vice mayor of Shiyan in Hubei province.

Oh.  What kind of fund shortage, when you just spent $81 billion on construction??

I’ve remarked previously on the lack of fame associated with building brand new shiny underground water infrastructure, and this appears to be a similar problem.  According to the above article, the local government needs about $500 million (just a fraction of that $81 billion price tag!) to build a wastewater treatment plant with nearly 700 miles of sewer pipelines.  So far, they’ve shuttered “329 factories in the last few years, but that has cut revenues by $130 million annually”.

Well, I hope they can find the money.  Until then…good luck to those intending to rely upon the diverted water.  Physics ain’t everything, folks.

a long way to go

Hello again, readers!  I’m finally rejoining the world of blogging, now that it’s been nearly 6 months since my last post.  In the meantime, I got married and changed my name — I’m now Claire Farnsworth Wildman, but otherwise blog content should remain unchanged.  I’m going to try to get into posting again once a week, and throw some links on my twitter feed when I can’t get to posting on interesting news.  Hopefully this will work!

~ Claire

So today’s post is a comment on China’s limited water supplies.  Bloomberg is noting that China’s coal mines are beginning to feel the crunch of limited water.  China has a fundamental problem that a bunch of development (agriculture and cities, and apparently many coal mines) is in the north, whereas the majority of their rainfall and streamflow is in the south.  This is not too different from the issues of the American southwest, where cities in dry areas keep expanding on the premise that they can access water from distant snowfall in the Rockies or Sierras via rivers and aqueducts.

The difference is that the US generally has pretty decent water resources (9,044 cubic meters = 2.4 million gallons per capita), but China’s are relatively sparse (2,093 cubic meters = 0.55 million gallons per capita), so moving water around won’t ultimately resolve all of their issues.

What struck me in the above article, though, was this: “…Veolia Water, which treated 1.2 billion tons of waste water in China last year…”  That sounds like use of numbers to imply large volumes of treated wastewater…but remember, China has 1.354 billion people as of January 2013.  So, one of the world’s largest water and wastewater treatment plant operators treated nearly 1 ton of wastewater per capita in China last year.  Let’s put that in perspective: an American city with low water use has about 150 gallons per day per capita, which we can assume goes to the wastewater treatment system.  This number is probably way too high for per capita water use for places without reliable drinking water supplies, but let’s use it for a back-of-the-envelope calculation:

150 gallons/day/person x 365 days/year x 8.34 lbs/gallon / (2000 lbs/ton) = 228 tons of wastewater per person in the US

Ok, again, very rough numbers.  Per capita water use is tricky to measure, but this website cites a 2006 UN Development Program report to suggest China averages something like 23 gallons/day/person (quoted as 86 liters/day/person).  Plug that in to the above equation, and you come up with 34 tons of wastewater per person in China, not including industrial wastewater.  Again, one of the world’s largest wastewater treatment companies was proud to hit the target of ~1 ton per person last year.  Whatever the per capita water use in China, it sounds like wastewater treatment has a long way to go…

drinking microbes is ok

Some work recently out of my former institute, Eawag, has been optimizing a novel method, flow cytometry, to measure microbes swimming/floating in water.  A couple of fluorescent DNA dyes are added to the water, then as a very narrow capillary stream flows by a laser, the cell numbers are counted.  Initial results have shown that there are a lot more microbial cells in water supplies than we might like to think.  Ambient water in the environment (e.g., a lake) generally has maybe 10^7 cells per milliliter (i.e., 10,000,000 cells per drop of water).  A soil or sediment has 1-2 orders of magnitude more cells per milliliter in general.  The flow cytometry results show that treated drinking water has roughly 10^5 cells per milliliter (i.e., 100,000 cells per drop of water).  That’s a lot of microbes in your water!  Time to freak out, set your hair on fire, and switch to bottled water!  The government is trying to kill you!!

Ok, it’s not that bad.  When water leaves a drinking water treatment plant, it is usually given a healthy dose of chlorine (“chlorine residual”) to keep microbial growth low in the piping network to your house.  Furthermore, there are tests for potentially dangerous bacteria, with standards to be met before the water is allowed to be delivered to you.  A common problem with standard tests is that they require the cells to grow on agar plates, even though many cells don’t grow under those conditions, and the results take up to 3 days.  Flow cytometry is available just minutes after sample collection.  The Eawag method has revealed that the standard test is a little misleading — no “bad” microbes doesn’t mean no microbes at all, and that’s ok.

What’s interesting is that the Swiss authorities have added this method to the list of acceptable tests for drinking water quality.  Who knows, maybe you’ll soon see this method coming to a water treatment plant near you!

Oh, and if you were going to switch to bottled water, just remember, it might have more microbes in it than tap water.  It will be ok.

Texas sacrifices water for energy

You know how fracking is so controversial, because applying high pressure to deep formations might cause hydrocarbons to migrate upwards and contaminate shallow drinking water aquifers?  Texas has got the next best thing.  This article calls it “fracking for uranium” which is just plain wrong.  Fracking relies on high pressure to break apart rocks holding oil and gas.  Uranium harvesting relies upon geochemistry to leach uranium out of rocks – no high pressure needed – and it has relatively low water requirements.  Unfortunately, it does have one other difference that makes it way more controversial: uranium harvesting is occurring within drinking water aquifers.

Here’s how it works.  Uranium is naturally present at trace levels in certain rock formations.  A company in Texas is injecting oxygenated water into underground aquifers that are normally anoxic.  This exposes the rock formations to different geochemistry and induces the uranium to dissolve into solution.  Extraction wells recover the uranium-laced groundwater and precipitate out the uranium.

I’m sure the process works, but at what cost?  Injection typically acts like a “bubble” that expands outward, with some mixing at the fringes.  In other settings, like aquifer storage and recovery, it has already been shown that it’s virtually impossible to completely recover the injected “bubble” due to the mixing at the fringes.  If you’re just talking about water storage, as in aquifer storage and recovery, that’s one thing.  But we’re talking about intentionally mobilizing a contaminant in a drinking water aquifer.  The mixing at the fringes means that uranium is going to stay in the groundwater, and potentially be pulled into someone else’s well eventually.

Maybe it doesn’t seem like a big deal now, especially if the aquifer in question isn’t heavily used.  But Texas is really running out of water.  The drought hit Texas hard this year, and their response has largely been to push for further conservation, rather than to expand long-term plans for water recycling or desalination (the only two realistic long-term options).  So even if energy is at stake, I’d be awfully hesitant to sign away aquifers for uranium leaching, given that there are many sources of energy, but Texas is running short of water sources.

learning from the past

Dear readers –

A friendly reminder to go get a flu shot, if you haven’t gotten one already.  I’d been only about a week over my cold/strep throat bonanza this winter when I picked up the flu.  What a pain.  I highly recommend avoiding the flu in any way possible.  Then, if you do get the flu, follow the CDC’s advice and don’t go out at all (not for shopping, not for the doctor, not for work) at least 24 hours after your fever is past.  The CDC’s advice is not for the sick person, but rather for the healthy people that the sick person could easily infect on short errands.

That said, I’m home today, recovering from yesterday’s fever, and writing about another group learning from past issues.  Remember the “Restore Hetch Hetchy” ballot measure in San Francisco?  It basically enabled the City of San Francisco to vote on whether the water supply of the City, the peninsula, and much of the South Bay would be dismantled.  The measure was voted down (77% said no!), but the water utilities around the Bay, who are tasked with maintaining supply, have decided not to wait for the Restore Hetch Hetchy folks to rally the City for Round 2.  Instead, they passed an amendment to their contract (that is, the San Francisco Public Utility Commission, SFPUC, and the Bay Area Water Supply and Conservation Agency, which is made up of the 26 water agencies that purchase Hetch Hetchy water) that requires any modifications to the Hetch Hetchy reservoir to be approved by all 26 agencies.

Now I don’t think that SFPUC and the Bay Area Water Supply and Conservation Agency are necessarily against modifying the Hetch Hetchy, but consider that the ballot measure would have allowed the City of San Francisco to dismantle a water supply in which 2/3rds of the customers (who pay for operations and maintenance) had no voice.  That seems pretty unfair.  The Restore Hetch Hetchy folks of course call this an “end-run around democracy”, but what was the ballot measure in that case?

happy 2013!

Dear readers,

Welcome to the new year! I unfortunately started the new year with a bout of strep throat that ran rampant through our office over the holidays, but I’m nearly 100% again, and ready to get back to writing!  I’ll start off the year with a quick follow-up to my last post of 2012, on the geochemistry of carbon capture and sequestration.

cheers!

Claire

My favorite journal, Environmental Science and Technology, has started off 2013 with a special issue entitled, “Environmental and Geochemical Aspects of Geologic Carbon Sequestration.”  ES&T has a running policy to open each year with a special issue, freely available to the public.  So take a look at the Table of Contents and read what the top environmental scientists and engineers have to say about long-term carbon storage in geological formations!  (Props to my undergrad advisor, Dan Giammar at Washington University in St. Louis, for co-editing this special issue.)

Of note, the opening letter from the co-editors has an overview of the technical geochemical issues of carbon storage.  They identify gaps such as “the rates and mechanisms of key geochemical reactions and their impacts on carbon storage performance, the multiphase reactive transport of CO2, and the management of environmental risks.”  I agree completely, and this issue is a great step in the right direction.

til 2013

Dear readers,

Due to the encroaching holiday craziness, including travel and work deadlines and a flurry of fascinating end-of-the-year reports about water, I’m going to have to sign off for the rest of 2012.  Of course I’m also hedging in case of the end of the world on Friday, as predicted by the Mayans.  Wouldn’t want to waste my time blogging right before the end of the world…

I hope that you all have a wonderful holiday season and safe travels.  In 2013, I hope to write up an analysis of the US Bureau of Reclamation’s recent report on water scarcity and the Colorado River, read the Pacific Institute’s reports on desalination and California’s water footprint, and eventually get back to that water balance of the Los Angeles basin.  If you get bored over the holidays without me, feel free to beat me to all of this!

take care,

Claire

getting carbon sequestration to work

One magic bullet that engineers like to talk about for global warming is carbon capture and sequestration (CCS) — pumping carbon dioxide into the right water-saturated geological formations just might form carbonate minerals, converting carbon dioxide gas (greenhouse gas!) to a greenhouse-neutral rock.  There are some hurdles, though, that haven’t quite been resolved.  Most of the current CCS projects inject the captured gas into oil formations to enhance oil recovery — this is means that some of the gas often comes back out with the oil.  It’s a different task to inject carbon dioxide to form minerals.

First, you have to have the right geochemistry in the water and in the rock.  Carbonates are actually really slow to precipitate, and in some cases in the lab, oversaturated solutions took months to precipitate out solids (chemistry note: thermodynamics is separate from kinetics).  Second, you have to get the pressurization right in the geological formation.  On the one hand, this means putting in the proper well casing and piping (the “walls” of the well hole) — see the BP oil spill for an example of improper well construction.  On the other hand, this means ensuring that the geological formation doesn’t open up cracks under pressure and leak that carbon dioxide back to the surface.  (This is the suspicion of what might go wrong in some fracking, for example: that certain formations might open preferential pathways for migration of gases and solutions upward into overlying aquifers of drinking water.  This is also an unknown, but not one that I’ll address here.)  Finally, there’s the risk that injecting pressurized fluids will lead to increased seismic activity.  This is currently being documented as it occurs, but we’re far from predicting when and where it might occur (other than “in locations where we injected stuff…after we injected the stuff” which isn’t that helpful for planning or engineering purposes).

Well, as usual, scientists are working on stuff that will eventually be useful.  A recent paper evaluated a new way to detect carbon dioxide leaking into shallow soils from deep formations.  Traditional technology has required an extensive collection of background data to understand how carbon dioxide might naturally move through a geological formation.  But the new method uses measurements of nitrogen, oxygen, carbon dioxide, and methane in soil gas to distinguish between naturally occurring processes and an extra influx of carbon dioxide from, say, a CCS injection site.

This is pretty sweet, because knowledge is going to save money on these projects, as well as give clearer answers that the traditional method could.  Plus, this will resolve a big question, at least in my mind, as to the viability of this technology.  We can deal with it if the kinetics of carbonate mineralization are slow underground, but if the carbon dioxide gas leaks back out, it isn’t really sequestered after all…