Atmospheric and Terrestrial Desalination Challenges for California
“Water Plant’s Long Journey” in the June 21 Wall Street Journal reports on a twenty years delayed Carlsbad, California desalination facility. For debaters researching marine natural resources, it should be no surprise that the most valuable marine resource is water itself. Reverse osmosis processes can push salt water through a membrane so fine the salt can’t fit through. (San Diego County Water Authority desalination description here.)
The Carlsbad plant is projected to cost a billion dollars when completed and provide fifty million gallons a day of desalinated water. But the process requires 300 million gallons a day of salt water and returns more heavily salted water (brine) to the ocean.
Desalination is costly and critics argue that less expensive alternatives are available “such as collecting storm water for reuse” and even smaller low-flow toilets (I leave it to someone else to blog about tiny toilets).
Storm water, especially in California, is particularly interesting. Storms are part of nature’s desalination process, and can play a large role in marine ecosystems. Heavy downpours can flood drainage systems and sweep raw sewage into waterways. Private firms can be fined, sued, and shut down for polluting rivers, bays, and ocean coasts. But when storm drainage systems owned and managed by cities and counties dump raw sewage into marine ecosystems they are generally given a permit or token fine. The EPA notes that forty years after passing the Clean Water Act:
Many of the sewer systems in New York State and New Jersey and some in Puerto Rico are combined systems that carry sewage from homes and businesses as well as rainwater collected from street drains. When they overflow during heavy rains, the rainwater mixes with sewage and results in raw sewage being directly discharged into water bodies. (EPA sewage report, 2011, pdf here.) …
This EPA report is titled: “Keeping Raw Sewage & Contaminated Stormwater Out of the Public’s Water,” though it might better be titled: “Keeping Raw Sewage & Contaminated Stormwater Flowing Into the Public’s Water.” Older sewer systems were designed to carry rainwater as well as sewage. They worked reasonably week except when heavy rains flood the system:
Combined sewer systems, on the other hand, are designed to transport sewage, industrial wastewater and rainwater runoff in the same pipes to wastewater treatment plants. They are remnants of the country’s early infrastructure and are typically found in older cities. Combined sewer systems serve about 40 million people in roughly 772 communities nationwide. Most communities with combined sewer systems are located in the Northeast and Great Lakes regions, and the Pacific Northwest.
The chart at right from the EPA’s Keeping Raw Sewage… report lists types of pollution and consequences from combined sewer overflows (CSOs) (p. 5). It is important to understand that discharging raw sewage into marine ecosystems is permitted by state and federal environmental protection agencies. Don’t believe me? Well, from the report:
Industrial, municipal and other facilities must obtain permits if discharges from their combined sewer systems go directly to surface waters. In New York and New Jersey, the permit program is administered by state environmental agencies and is an essential tool for the control of CSOs.
In Puerto Rico, permits are issued by EPA.
• Total number of CSO facilities and discharge points from which untreated wastewater is discharged into receiving waters:
- New York State has 76 CSO permit holders with 966 outfalls;
- New Jersey has 30 CSO permit holders with 254 outfalls;
- In Puerto Rico, EPA has recently identified four potential outfalls.
Turns out all municipalities need is a permit to dump raw sewage. So for debaters, one possible affirmative case would reform EPA’s current permitting policy. Maybe EPA has in mind reducing permitted pollution discharges over the next forty years. But why wait?
Maybe the new National Ocean Council will make progress. But new sewage systems cost money, and local governments are unlikely to invest when they can as easily keep dumping their sewage out to sea.
From Eastern Sewage to Western Storms…
However, moving our discussion back to the left coast, let’s look again at storm drainage issues in California. Most California municipalities have upgraded their storm drainage to separate them from sewer systems. Some older sewer lines still leak pollution into waterways, according to this California Coastkeeper Alliance post.
Large-scale storms can still cause pollution outflows, but given the scale of past California events, water pollution may be the least of problems when the next superstorm hits. This post began with a quote from critics of the Carlsbad desalination plant, who said alternatives “such as collecting storm water for reuse” should be considered.
Consider that much of California has two water problems. The first is not enough rain and snow for agricultural, suburban, and city use in much of the state. But the second is too much water falling too fast, falling from the last stage of nature’s desalination process. Across the Pacific, sunlight turns salt water to water vapor that rises to form clouds that from time to time (and when they can’t find their way to Washington and Oregon) end up over California, falling as rain.
Sometimes this rain falls way too fast and for too long. Even heavy downpours
for a few day can cause destructive flooding across central or southern California. What if storms instead lasted for a month or two of torrential rains?
“California Megaflood: Lesson from a Forgotten Catastrophe” in Scientific America (January 19, 2013) explains how the next atmospheric river will turn much of the state into a marine ecosystem.
The last one hit in December, 1861-62, when it rained for 45 days. Over sixty inches of rain fell in the Los Angeles area.
Large brown lakes formed on the normally dry plains between Los Angeles and the Pacific Ocean, even covering vast areas of the Mojave Desert. In and around Anaheim, , flooding of the Santa Ana River created an inland sea four feet deep, stretching up to four miles from the river and lasting four weeks.
Snow melt and rain falling in California’s Central Valley:
This enormous pulse of water from the rain flowed down the slopes and across the landscape, overwhelming streams and rivers, creating a huge inland sea in California’s enormous Central Valley—a region at least 300 miles long and 20 miles wide.
You can read more about the “ARKstorm” here, and can watch a USC animation on what to expect (“USC: California superstorm would be costliest US disaster”).
These California superstorms are thought to be caused by “atmospheric rivers,” which are discussed here (sometimes called the “Pineapple Express”).
Atmospheric rivers are relatively long, narrow regions in the atmosphere – like rivers in the sky – that transport most of the water vapor outside of the tropics. These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow.
So when is the next atmospheric river expected to drench and flood California?
|“Atmospheric River Research Gathers Steam” Scripps Institution of Oceanography|
No one knows. Historical records suggest about every two hundred years. (“Beware the ARkStorm.“)
The vaporized water carried by the wind in these narrow regions is equivalent to the amount of liquid water carried by seven to 15 Mississippi Rivers combined. (Source)
Atmospheric rivers can come in many sizes and durations. Infrastructure built to retain water and reduce floods from future California storms and superstorms also provides an alternative source of water during long California droughts, like the five-year drought that led to the building of the Carlsbad desalination plant.
So…what policy proposals might best offer incentives for California firms, government agencies, and individual property owners to invest in infrastructure that would help contain the rains when next an Mississippi-size atmospheric river flows down across the state?