Wednesday, August 30, 2023

When too much water leads to water scarcity

 Like clockwork, every time we have a big rainstorm, I read news stories and hear people talk about all the "wasted" water running out to sea or out of the arid area. I understand the frustration, but want to highlight some of the complexities. 

For instance, Southern California received quite a bit of rainfall ~10 days ago as the remnants of Hurricane Hilary swept through. We received 2.5" according to my backyard rain gauge. I'll write more about that in a later post (already started drafting it). 

But, I thought it would be interesting to show what happened near Palm Springs, where Interstate 10 was washed out after the area received half of their annual average rainfall in 6 hours. Interstate 10 was shut down for miles due to flooding and mud

One of the surprising things to water neophytes is that less water is captured in torrential rainfall events than in more normal, smaller and slower rain events. 

This is why water professionals are so worried about climate change. Climate models forecast, and our recent experience verifies, that SoCal will get about the same average annual rainfall as in the past--but it will come in fewer and burstier storms like we experienced in August and January/February 2023. 

In arid climates, it makes more sense to store the water underground to minimize evaporative losses. Palm Springs exists due to a large aquifer and faults that allow the groundwater to seep to the surface. After unsustainable groundwater pumping, the Coachella Valley developed percolation ponds to spread imported river water to refill the aquifers. In this way, the aquifer has stabilized. 

This land works remarkably hard precisely because of it's geology. It has the surface to aquifer connection that allows it to function as a percolation pond. But it's also a transportation corridor because it has the surface water needed by overland travelers. 

Can you see the percolation ponds, wind turbines, solar farm, Interstate 10, and the railroad tracks in this aerial photo? That's five uses, not counting housing and related services. 

You can also see wind turbines in this photo from another percolation pond just to the south of this one. 

The transportation corridor is here because of water, but it's also at risk because of water. You can see the Site of the Original Palm Springs RR Depot in this aerial photo, along with Whitewater Canyon, which feeds the Whitewater River that eventually drains into the Salton Sea. 

It's more dramatic in the terrain contour map. 

The people are here because the water is here. 
The water is here because the mountains are here to squeeze the water out of the sky. 
The mountains are here because the faults are here. 
The water reaches the surface because the faults are here. 

It's all interconnected, but I'm digressing again. 

This is about why we couldn't capture most of the water from bursty rainstorms into the aquifer. 

Turbidity and Water

You know how lake beds have very fine soil impermeable (or only slightly permeable) to water? This allows them to hold the water. Watch Who Fills Your Taps as Kathy Kunysz explains how, when water comes pouring off the mountains, the larger gravel falls out first, and then the finer silt settles into clay layers (aquitards). If you don't keep the finer particles out of your spreading basin/percolation pond, they clog up and cease to function. 

If you don't have time to watch this 75 minute video, you can view the slides

In order to preserve the percolation pond, they had to redirect the muddy runoff AWAY from them, so they didn't capture most of the runoff. This happened in January 2023 and again in August 2023. 

If the rain comes too fast, and the water contains too many fine particles, then you can't capture it in percolation ponds. More and more of our rainfall is going to come from these bursty storms. 

The good news is that they water was diverted around the percolation ponds and sent downstream to feed the shrinking Salton Sea. If we preserve and restore coastal wetlands, that silty water can replenish the marshes, build up the coastline, and help protect us from sea level rise and storm surges. The bursty flows can scour out the waterways, remodeling/refreshing wildlife habitat. 

It's all good. 

Waste is in the eye of the beholder. If you look at it in terms of what's valuable to humans, you aren't seeing the whole picture. 

But, it also means we have to work harder and and spend more money to capture the same amount or less water, due to climate change. The people who told you that we couldn't do anything to stave off climate change because it was too expensive played the American public for chumps and we fell for it. 

Wednesday, August 23, 2023

The ghost of wells past

Remember when I wrote that I wasn't that worried about PFAS chemicals in my drinking water? I'm still not worried about it. But several things stood out when I looked at the 2022 Hermosa Redondo Water Quality Report

I expected to see small (but safe) amounts of Uranium from the imported drinking water purchased from Metropolitan Water District (via West Basin Municipal Water District). That's a blend of Colorado River and Sacramento-San Joaquin Delta water. For myriad reasons, water from the 4-corners states in the Colorado River Basin contains Uranium and Radium. 

But, why does my local groundwater contain more Uranium than the water imported from the states where we used to mine Uranium, and make and test bombs? I posted that question on the social media platform formerly called Twitter and had my answer in minutes. 

I found a map of active water wells from LA County Dept of Public Works. Unfortunately, I couldn't figure out how to download the map and combine it with other data so you'll just see a screenshot. Look at the 3 aqua balloon pins near the right of the map, just west of Inglewood Blvd. 

Now look at the map of Oil Wells (Inside LA County) from City of Los Angeles GeoHub

See the old oil wells that used to operate in the vicinity of the active water wells? 

EPA: Radioactive Waste Material From Oil and Gas Drilling

Rocks in and around certain oil- and gas-bearing formations may contain natural radioactivity. Drilling through these rocks or bringing them to the surface can generate waste materials that contain radioactivity.
I'm drinking a blend of local groundwater and imported river water with an average of 2.3 pCi/L and 1 pCi/L of Uranium respectively. 

The federal EPA Maximum Contaminant Load (MCL) for Uranium in drinking water is 20 pCi/L (one trillionth of a Curie per Liter; a Curie is a measurement of radioactivity). However, there are measurable increases in negative health outcomes for water above the EPA MCL Goal (MCLG) of 0.43 pCi/L. 

This is concerning but not panic inducing (at least for me.) Reverse Osmosis (RO) reduces contaminants in water, including Uranium and PFAS chemicals. RO also reduces the calcium salts responsible for Water Hardness. Anything above 300 ppm (parts per million) is considered hard water. Imported river water is semi-hard, at ~200 ppm, but the groundwater here is 380 ppm. 

I would be happy to pay for RO treatment of household water. The small extra expense would reduce wear and tear on my home's plumbing and my housecleaning time. It's a worthwhile tradeoff. 

[The EIR for West Basin's abandoned plans to build a desalination plant estimated that the RO-treated ocean water would have saved customers an average of $300/year in reduced plumbing and appliance replacement expenses. Coastal NIMBYs enjoying 100% imported river water blocked the plant despite support from inland communities using very hard groundwater like mine.]

Today's LATimes features an excellent profile about Adel Hagekhalil, general manager of Metropolitan Water District of Southern California. He talks about the existing three pipelines that bring water from the Delta, Owens Valley and the Colorado River. He advocated for developing our "Fourth Pipeline" of local water sources. 

I fully support that vision; it's an achievable goal. But let's not kid ourselves that it will be easier or cheaper. There are tradeoffs for everything, as I learned from the Water and Infrastructure Group lecture series I co-organize. Understanding Drinking Water Quality taught me the limits of conservation. Groundwater 101 and Measure W taught me the difficulty of developing *new* groundwater supplies. San Diego's Pure Water and LA County Sanitation Districts taught me the challenges of water recycling. 

I'm willing to pay a little bit more to stop dewatering faraway places, to honor our treaties with Tribes, for higher quality water, and for more reliable and secure water supplies. We have the technology to do all these things, but financing it is going to be the biggest hurdle. Middle and higher income users will be fine. 

But, I ask you to join me in overturning Proposition 218, which constrains our ability to buffer lower income people from the impact of higher utility bills. We need to figure out a way to spread the costs equitably, which includes overturning Prop 218 and securing State and Federal funds to help low-income users. 

Saturday, August 19, 2023


 I was going to title this post "Why I am not freaking out about PFOS/PFOA" but worried that it would be quoted out of context by people who don't read beyond headlines. The point is I am not worried about my personal exposure to PFOS/PFOA because I did a little research and am reassured that I live in an area where my water is safe. But that is not true for everyone. (PFOS & PFOA are a couple of flourinated compounds in the bigger class of PFAS.)

If you live in California, your water provider has to send you an annual Water Quality Report. It's no longer provided in hard copy with one of your monthly water bills. But the link to the report should be listed in one of your recent bills. For instance, read the California Water Service Rancho Dominguez District Hermosa-Redondo System Water Quality Report 2022

Cal Water is a regulated monopoly that tests for PFOS/PFOA and similar flourinated compounds even though they are not required to. From page 10 of my report for Hermosa & Redondo Beach:

In March 2023, EPA issued a proposed national primary drinking water regulation for certain PFAS. The proposed regulation calls for a maximum containment level for PFOS and PFOA of 4 ppt each. Four additional PFAS—PFNA, PFHxS, PFBS, and GenX— would have a combined hazard index limit of 1.0; the hazard index calculation would determine if the levels of these PFAS as a mixture pose a potential risk. 

Knowing that these were constituents of emerging concern, Cal Water proactively tested active sources in our systems for these PFAS years ago. Although not required, we believed it was the right thing to do. In any areas across the state where detections were above levels at which DDW recommends water suppliers take action (the response level), we took the affected sources out of service until treatment was or can be installed. 

None of our active water sources have levels of these six PFAS compounds over current California response levels.

Then on page 16, I can see that my local groundwater has no detectable PFAS and the imported river water (supplied by Metropolitan Water District) has a range of 0-2 ppt (parts per trillion) of PFAS and an annual average of 1 ppt. While adverse health effects can occur with any amount of PFAS above 0, my exposure is very, very small since I drink a blend of groundwater and Metropolitan water. 

 If you live in Hermosa Beach or North Redondo Beach, your water comes from a few wells near Artesia Blvd like this one behind state senator Ben Allen's field office. 

The water is piped to blending tanks behind the new (and fantastic) bakery, Tommy and Atticus

From there, the water is pushed out in distribution pipes to 90278 and 90254. 

What does it mean to take a water source out of service and treat it? 

It means that water from each well is tested and, if it is too high, they stop using that well and serve you cleaner water from another source (uncontaminated well or imported water purchased from MetropolitanWD). 

CalWater found PFOS/PFOA at a well in Montebello (east of DTLA) and took the well off-line in February 2020, and began construction of a facility to remove the contaminants in December 2020. In January 2022, they held a ribbon cutting for the updated facility and returned the well back to service

The technology is simple and well-known. Read the EPA's explainer, Reducing PFAS in Drinking Water with Treatment Technologies

Well water is passed through a bed of Granular Activated Charcoal (GAC), which adsorbs a whole bunch of stuff I don't want to drink (some dangerous, some merely unpleasantly smelly). A regularly refreshed bed of GAC can remove PFOS/PFOA to below detectable levels (ND = none detected). 

But what do you do when the GAC becomes saturated with contaminants?  In the case of a Brita Filter, I toss the old one in the trash, run the pitcher components through the dishwasher to disinfect them, and install a new filter. 

At the water treatment plant, they use a polymer resin to perform anion exchange to pull the adsorbed chemicals off the charcoal. The resin can be incinerated at a high temperature to destroy the PFAS. The charcoal can be reused for years. The resin is expensive and also relies on having access to a high temperature incinerator (which we have in Long Beach with SERRF.) This treatment process adds about $50/AF (acre-foot) to the cost of water, enough for 5-10 people for a year. For a large water system, this is affordable. 

However, PFAS is a problem around the world, including places that can afford charcoal but not the resin. That's why I found so many papers about how to remove PFAS from charcoal using heat so that they can reuse the charcoal. 

Thermal Stability and Decomposition of Perfluoroalkyl Substances on Spent Granular Activated Carbon

Recent advances on PFAS degradation via thermal and nonthermal methods

Thermal destruction of PFAS during full-scale reactivation of PFAS-laden granular activated carbon

I'm happy that all of these papers are open access (doesn't require $$ purchase) because the authors paid for open access. This kind of knowledge should be available to everyone. 

Anyway, back to the LA Times newspaper articles that freaked so many people out  and lacked context. 

Risk of tap water exposure to toxic PFAS chemicals higher in Southern California cites a USGS study that sampled 700 public and private wells around the country. They modeled the characteristics of the sampled wells and estimated that 45% of US wells are contaminated with at least one PFAS chemical.  SoCal wells are more likely to be contaminated due to urbanization (industrial facilities, domestic wastewater) and past foam retardant use (fighting wildfires and at airports). 

Since there is no requirement to test for PFAS, your water supplier may not test for it. So I may not be panicked about PFAS because I have been reading my annual water quality report, but most people never bother to read it. Many people don't even know who their water supplier is, but that's a whole other story.

If you are among the 10 million people in Los Angeles County, the LA Board of Supervisors recently voted to require all water suppliers to test for PFAS chemicals. This won't change my water, but might change yours. I presume that, if they find PFAS, they will be required to remove it before putting it into the domestic water supply. 

If you live in SoCal, your water supplier buys imported river water through Metropolitan Water District either directly, or from a subregional water wholesaler like West Basin MWD at a cost of $1,400-$1,800/AF. Well water costs about half as much as purchased imported river water, if your water supplier owns permits to pump groundwater. Building a GAC treatment facility at $50/AF is worthwhile because well-water is still a bargain compared to imported river water and we have a convenient and safe way to dispose of the PFAS removed from the water. 

I co-organize a monthly series for the League of Women Voters called WIG, the Water and Infrastructure Group. Upcoming discussion topics/speakers, recordings of past meetings/talks and other educational info can be found on the LWV Beach Cities Natural Resources Page

Hopefully, this will inoculate you against sensationalist newspaper headlines like Brita water filter company accused of false advertising. Have you ever installed a Brita filter wrong so that the water runs right through the gaps on the side of the filter? Do you always change your filter as often as the label on it?  I'm fallible. I'm using the Brita filter just to remove unpleasant odors. I expect it to reduce contaminants, but not to remove them altogether. I am running a home kitchen, not a water treatment facility. But I do expect my water company to supply safe water to my home. 

Read your annual water quality report. There are some smaller water systems that can't afford to fancy water treatment systems and are too remote to hook up to cleaner water supplies. Then there are big water systems like LADWP that politically can't raise water rates so they put off maintenance and upgrades. Look at how bad the LADWP water scores relative to other LA County water systems!  (Data and visualization from the CalEnviroScreen 4.0 Indicator Map of Drinking Water Contaminants.)

If I lived in the City of LA, I would be writing my council members and to the press every week. This is just so embarrassingly bad. (Fortunately, CA drinking water is very clean on a national scale, so you can be in the worst tenth (like LADWP at 90th percentile for CA) and still pass all federal EPA standards. But, for a large water system in an urban area, this kind of water system neglect is just inexcusable. 

Come to WIG on second Thursdays of each month at 7 pm on Zoom. Learn more about water and all sorts of other things that make our area run smoothly. Ask questions and get answers.