Boom: Removing 81 Dams Is Transforming This California Watershed
Removing one gigantic dam can have a massive effect on restoring a river ecosystem.
But bringing down more than 80 smaller dams? That can also cause a transformation.
This spring the Forest Service, aided by U.S. Marine Corps members, will blast apart 13 more dams in the Trabuco ranger district in Southern California's Cleveland National Forest.
It's the last phase of a groundbreaking project that began more than five years ago to remove a total of 81 dams from four streams in the mountains of Orange County.
"Nobody's really taken on a project this large and with this many partners and methods," says Forest Service fish biologist Julie Donnell, who's been working on the project.
The mammoth undertaking is designed to help boost populations of native aquatic species — most importantly Southern California steelhead (Oncorhynchus mykiss), which are federally listed as endangered.
It may also be a crucial learning tool due its sheer scope. Last year an estimated 90 dams were removed across the country, and nearly a quarter of those were in the Cleveland National Forest. That makes what's happening in California the place to watch as organizations plan for other multi-dam removal efforts around the country.
"Looking at what the Forest Service did is a really smart way for other agencies to begin to think about their infrastructure," says Serena McClain, the director of river restoration at the nonprofit American Rivers, which tracks dam-removal efforts. "The Forest Service is showing that the federal government can lead on this and demonstrate the possibility for the private sector and municipalities."
In addition to the work in the national forest itself, the ecological success of the project hinges on a downstream effort to remove two more barriers that prevent steelhead from reaching the forest as they migrate from the ocean.
The two projects have brought together a diverse, and unlikely, coalition of transportation departments, federal agencies, environmental nonprofits, local governments, and even the U.S. Marine Corps to help complete an ocean-to-headwaters restoration of more than 35 miles.
"This addresses one of the major threats to endangered southern steelhead," says Sandra Jacobson, the South Coast regional director of California Trout, which is leading the downstream effort. "Once you open up the rivers, it allows a tremendous change in the accessibility of steelhead to their historical habitat so that they can go in and reproduce."
A Group Effort
Large dam removals, like those on the Klamath River in California and Oregon, or the hotly debated Snake River dams in Washington, get lots of media attention. But smaller dam removals are quietly happening all across the country.
In the past 20 years around 1,100 dams have been removed in the United States — many of them aging, unsafe structures that had outlived their usefulness.
That's the story in the Cleveland National Forest, too.
Not a lot is known about the early history of the dams there, but most were likely built in the 1930s by the Civilian Conservation Corps, a public work program started to help Americans rebound from the Great Depression, says Kirsten Winter, a biologist in the Cleveland National Forest who has spearheaded the dam-removal project. It's not unusual for dams to be built in national forests, but this high a concentration of small dams may be a regional phenomenon in Southern California forests.
Most of these original dams would likely have washed away over time, but in the Cleveland National Forest, Orange County increased the size of the dams using native rock and mortar from the 1940s through the mid-1970s. Gates were lowered in the spring and raised in the fall to control the flow of the rivers. The impounded water was used mostly for fish stocking and recreation and was also available for fire suppression.
But eventually, Winter says, the dams aged, and the county got tired of maintaining them. Many washed out in storms. A few were removed in the 1980s by the county, and the gates were taken out of the remaining dams. Most fell back under Forest Service jurisdiction.
In recent years it became clear that some of the dams posed safety hazards and impeded fish migration. As part of a federal recovery effort to recover populations of endangered southern steelhead, a plan was developed to remove the 81 dams in the San Juan watershed on Upper San Juan Creek, Trabuco Creek, Holy Jim and Silverado Creek.
Projects of this scope require environmental assessments under the National Environmental Protection Act. Because the Forest Service had the forethought to take a watershed view of the project from the get-go they only needed to complete one environmental assessment for the removal of the whole kit and caboodle, which helped make the permitting process more efficient.
With that in place, the dam-removal work began in December 2014. The project has a $1.2 million price tag, but the majority of funding hasn't come from the Forest Service itself.
Before and after dam removal on San Juan Creek in the Cleveland National Forest. Julie Donnell / USFS
The project has generated a lot of interest and a diverse array of partners, including California Department of Transportation, Federal Highways Administration, Orange County Parks, Orange County Transportation Authority, the U.S. Fish and Wildlife Service, California Department of Fish and Wildlife, and the U.S. Marine Corps. The coalition has brought funds, organizational support, technical knowledge and a lot of energy to the process.
"People are really pretty enthused about removing dams," says Winter.
Despite all the partners, it's still been a learning experience, she adds, because the dams vary so much in size and accessibility. Some are just a few feet high and 10 feet wide. Others reach 14 feet in height and stretch up to 100 feet across.
To breach the dams and break apart the mortar, crews employed a wide range of techniques. For sites near roads, they bought in conventional excavators. Steeper canyons required the use of a nimble "spider" excavator. Explosives took down a few dams where appropriate, while other places required sledgehammers and jackhammers. An extra bit of muscle (organizational and otherwise) came from a partnership with Marines from nearby Camp Pendleton. Corps members have helped remove 31 dams since 2018.
The biggest benefactors of the dam removals in the Cleveland National Forest will be steelhead — a type of salmonid. Like salmon, steelhead are anadromous, spending their time in both freshwater streams and the ocean. But unlike salmon that return to their natal headwater streams to spawn and die, steelhead will often spawn more than once.
They're also a key indicator species, says Jacobson. "When they disappear, that means there are probably multiple issues within a watershed."
In the San Juan, dams are one of them.
Endangered Southern California steelhead spawning in Maria Ygnacio Creek in Santa Barbara County, Calif. Mark H. Capelli / WCR / CC BY-NC-ND 2.0
"Dams create a very artificial situation," says Winter. "It's not just that they hold water, but they retain sediment and then they create these weird splash pools below."
Without the dams, the streams are able to create a more natural gradient and pool structure. That's good for other native wildlife like the arroyo toad and the arroyo chub, both federally listed as endangered, as well as the California newt, a California Species of Special Concern.
While the process of removing the dams can be a bit messy, "we've seen no negative effects to the habitat or to species due to the dam removal," says Donnell.
One of the biggest concerns with any dam removal is ensuring that any trapped sediment released from behind the structures doesn't cause ecological problems as it moves downstream. But Donnell says they've timed the removals to account for that and the streams naturally carry large sediment loads during storm events.
"We're actually doing some of dams in phases rather than all at one time because of the sediment load that's being held behind them," she says.
In areas where dams have been removed, Donnell has already noticed an improvement. "The bedload and sediment transport have been able to naturally flow once again," she says. "And the channel is starting to adjust back to a natural state."
A Connected Watershed
As groundbreaking as the Cleveland National Forest's efforts are, the benefits for steelhead hinge on the downstream initiative.
Just five miles inland from Doheny State Beach, around the town of San Juan Capistrano, two barriers on Trabuco Creek block steelhead from 15 miles of upstream spawning habitat in the San Juan Creek watershed.
A quarter-mile-long concrete flood-control channel runs underneath five bridges, including the north- and southbound lanes of Interstate 5. The drop and the speed of water flowing through the hardened channel inhibits steelhead from making it through the gauntlet.
The second barrier sits a half-mile downstream, where another 20-foot drop under a bridge for the Metrolink regional railway poses an insurmountable roadblock for steelhead.
To solve both of these problems, California Trout is leading the multiagency design effort for a technical fish passage that will enable steelhead to navigate these obstacles using staggered weirs. At the I-5 obstacle, an additional fish transport channel will provide steelhead with an express lane to avoid the flood control channel and pass under the array of bridges.
The organization is working with fellow nonprofit Trout Unlimited, as well as Orange County's flood control district and public works office, the city of San Juan Capistrano, California Department of Transportation, and the Metrolink railroad association.
"We just received funding to complete the design," says Jacobson. The fish passages are expected to be completed around 2023 to 2025.
It's one part of a larger regional effort by the South Coast Steelhead Coalition, which consists of more than 35 organizations working to recover stable populations of the species in Southern California. Removing barriers to fish passage is a key element of the strategy, as are ensuring adequate water quantity and quality and removing nonnative species that compete for limited resources.
But there's one more objective: helping native rainbow trout. These resident trout are the same species as steelhead, but with a different life history — they don't migrate to the ocean. Since steelhead have been blocked from the upstream waters for nearly a century, resident trout populations have suffered from genetic isolation.
Only two resident trout populations remained in the region and one had to be emergency evacuated by a bucket brigade following the Holy Fire in 2018, which burned across the forest and threatened the water quality in the streams.
The removal of all the stream barriers — on and off the forest — will provide an opportunity for aquatic species to be more resilient. The wildfire is a perfect example of why that's needed, says Jacobson.
"It really gives the aquatic species the mobility they need to move around in response to drought, floods and wildfires," she says. "It's good for all sorts of species, too, not just fish."
With the dam removals in the Cleveland National Forest nearing completion, Donnell says she's hoping to soon begin presenting her data and methodologies so others can learn from the project.
"We've definitely heard from other forests and other districts wanting to know how we went about it, because this is new," she says.
McClain says American Rivers has been sharing the project's success story because it's a good example of how to think holistically about managing water and restoration opportunities for aquatic ecosystems.
San Juan Creek in the Cleveland National Forest shortly after a dam was removed. Julie Donnell / USFS
But it also makes sense fiscally. Why spend money maintaining dams we don't need?
"Even from a federal budget management perspective, we should be looking at where there may be projects on the federal books that are no longer serving a purpose," she says.
Thanks to the coordinated efforts in the San Juan watershed, southern steelhead will have a better chance of survival. But efforts to try and aid their recovery also have a larger benefit.
"We're not only restoring their environment, but also ours," Jacobson says. "We're actually improving the rivers overall."
And in the process, they may have established a model for mass dam removal across the country.
Reposted with permission from The Revelator.
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By Alexander Richard Braczkowski, Christopher O'Bryan, Duan Biggs, and Raymond Jansen
A Cute But Threatened Species<p><a href="https://www.worldwildlife.org/stories/what-is-a-pangolin" target="_blank">Pangolins</a> are the only mammals wholly-covered in scales, which they use to protect themselves from predators. They can also curl up into a tight ball.</p><p>They eat mainly ants, termites and larvae which they pick up with their sticky tongue. They can grow up to 1m in length from nose to tail and are sometimes referred to as scaly anteaters.</p><p>But <a href="https://www.sciencedirect.com/science/article/pii/B9780128155073000332" title="Chapter 33 - Conservation strategies and priority actions for pangolins" target="_blank">all eight</a> pangolin species are classified as "<a href="https://www.pangolins.org/tag/endangered-species/" target="_blank">threatened</a>" under International Union for Conservation of Nature <a href="https://www.iucnredlist.org/search?query=pangolin&searchType=species" target="_blank">criteria</a>.</p><p>There is an unprecedented demand for their scales, primarily from countries in Asia and <a href="https://conbio.onlinelibrary.wiley.com/doi/10.1111/conl.12389" title="Assessing Africa‐Wide Pangolin Exploitation by Scaling Local Data" target="_blank">Africa</a> where they are used in food, cultural remedies and <a href="https://www.nature.com/articles/141072b0" title="Chinese Medicine and the Pangolin" target="_blank">medicine</a>.</p><p>Between 2017 and 2019, seizures of pangolin scales <a href="https://www.nationalgeographic.com/animals/2020/02/pangolin-scale-trade-shipments-growing/" target="_blank">tripled in volume</a>. In 2019 alone, 97 tons of pangolin scales, equivalent to about 150,000 animals, were <a href="https://oxpeckers.org/2020/03/nigeria-steps-up-for-pangolins/" target="_blank">reportedly</a> intercepted leaving Africa.</p>
Reintroduction of an Extinct Species<p>Each year in South Africa the African Pangolin Working Group (<a href="https://africanpangolin.org/" target="_blank">APWG</a>) retrieves between 20 and 40 pangolins through intelligence operations with security forces.</p><p>These pangolins are often-traumatised and injured and are admitted to the <a href="http://www.johannesburgwildlifevet.com/our-hospital" target="_blank">Johannesburg Wildlife Veterinary Hospital</a> for extensive medical treatment and rehabilitation before they can be considered for release.</p><p>In 2019, seven rescued Temminck's pangolins were reintroduced into South Africa's <a href="https://www.andbeyond.com/destinations/africa/south-africa/kwazulu-natal/phinda-private-game-reserve/" target="_blank">Phinda Private Game Reserve</a> in the KwaZulu Natal Province.</p><p>Nine months on, five have survived. This reintroduction is a world first for a region that last saw a viable population of this species in the 1980s.</p><p>During the release, every individual pangolin followed a strict regime. They needed to become familiar with their new surroundings and be able to forage efficiently.</p>
A ‘Soft Release’ in to the Wild<p>The process on Phinda game reserve involved a more gentle ease into re-wilding a population in a region that had not seen pangolins for many decades.</p><p>The soft release had two phases:</p><ol><li>a pre-release observational period</li><li>an intensive monitoring period post release employing GPS satellite as well as VHF tracking tags.</li></ol>
Why Pangolin Reintroduction is Important<p>We know so little about this group of mammals that are vastly understudied and hold many secrets yet to be discovered by science but are on the verge of collapse.</p><p>The South African and Phinda story is one of hope for the Temminck's pangolin where they once again roam the savanna hills and plains of Zululand.</p><p>The process of relocating these trade animals back into the wild has taken many turns, failures and tribulations but, the recipe of the "soft release" is working.</p>
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By Jake Johnson
In a move that environmentalists warned could further imperil hundreds of endangered species and a protected habitat for the sake of profit, President Donald Trump on Friday signed a proclamation rolling back an Obama-era order and opening nearly 5,000 square miles off the coast of New England to commercial fishing.
Why You Should Wash Fresh Produce<p>Global pandemic or not, properly washing fresh fruits and vegetables is a good habit to practice to minimize the ingestion of potentially harmful residues and germs.</p><p>Fresh produce is handled by numerous people before you purchase it from the grocery store or the farmers market. It's best to assume that not every hand that has touched fresh produce has been clean.</p><p>With all of the people constantly bustling through these environments, it's also safe to assume that much of the <a href="https://www.healthline.com/nutrition/fresh-vs-frozen-fruit-and-vegetables" target="_blank">fresh produce</a> you purchase has been coughed on, sneezed on, and breathed on as well.</p><p>Adequately washing fresh fruits and vegetables before you eat them can significantly reduce residues that may be left on them during their journey to your kitchen.</p><p><strong>Summary</strong></p><p><strong></strong>Washing fresh fruits and vegetables is a proven way to remove germs and unwanted residues from their surfaces before eating them.</p>
Best Produce Cleaning Methods<p>While rinsing fresh produce with water has long been the traditional method of preparing fruits and veggies before consumption, the current pandemic has many people wondering whether that's enough to really clean them.</p><p>Some people have advocated the use of soap, <a href="https://www.healthline.com/nutrition/white-vinegar" target="_blank">vinegar</a>, lemon juice, or even commercial cleaners like bleach as an added measure.</p><p>However, health and food safety experts, including the Food and Drug Administration (FDA) and Centers for Disease Control (CDC), strongly urge consumers not to take this advice and stick with plain water.</p><p>Using such substances may pose further health dangers, and they're unnecessary to remove the most harmful residues from produce. <a href="https://www.healthline.com/health/chlorine-poisoning" target="_blank">Ingesting commercial cleaning chemicals</a> like bleach can be lethal and should never be used to clean food.</p><p>Furthermore, substances like lemon juice, vinegar, and produce washes have not been shown to be any more effective at cleaning produce than plain water — and may even leave additional deposits on food.</p><p>While some research has suggested that using neutral electrolyzed water or a baking soda bath can be even more effective at removing certain substances, the consensus continues to be that cool tap water is sufficient in most cases.</p><p><strong>Summary</strong></p><p><strong></strong>The best way to wash fresh produce before eating it is with cool water. Using other substances is largely unnecessary. Plus they're often not as effective as water and gentle friction. Commercial cleaners should never be used on food.</p>
How to Wash Fruits and Vegetables With Water<p>Washing fresh fruits and vegetables in cool water before eating them is a good practice when it comes to health hygiene and food safety.</p><p>Note that fresh produce should not be washed until right before you're ready to eat it. Washing fruits and vegetables before storing them may create an environment in which bacterial growth is more likely.</p><p>Before you begin washing fresh produce, <a href="https://www.healthline.com/health/how-long-should-you-wash-your-hands" target="_blank">wash your hands well</a> with soap and water. Be sure that any utensils, sinks, and surfaces you're using to prepare your produce are also thoroughly cleaned first.</p><p>Begin by cutting away any bruised or visibly rotten areas of fresh produce. If you're handling a fruit or vegetable that'll be peeled, such as an orange, wash it before peeling it to prevent any surface bacteria from entering the flesh.</p><p>The general methods to wash produce are as follows:</p><ul><li><strong>Firm produce.</strong> Fruits with firmer skins like apples, lemons, and pears, as well as <a href="https://www.healthline.com/nutrition/root-vegetables" target="_blank">root vegetables</a> like potatoes, carrots, and turnips, can benefit from being brushed with a clean, soft bristle to better remove residues from their pores.</li><li><strong>Leafy greens.</strong> Spinach, lettuce, Swiss chard, leeks, and cruciferous vegetables like Brussels sprouts and bok choy should have their outermost layer removed, then be submerged in a bowl of cool water, swished, drained, and rinsed with fresh water.</li><li><strong>Delicate produce.</strong> Berries, mushrooms, and other types of produce that are more likely to fall apart can be cleaned with a steady stream of water and gentle friction using your fingers to remove grit.</li></ul><p>Once you have thoroughly rinsed your produce, dry it using a clean paper or cloth towel. More fragile produce can be laid out on the towel and gently patted or rolled around to dry them without damaging them.</p><p>Before consuming your fruits and veggies, follow the simple steps above to minimize the amount of germs and substances that may be on them.</p><p><strong>Summary</strong></p><p><strong></strong>Most fresh fruits and veggies can gently be scrubbed under cold running water (using a clean soft brush for those with firmer skins) and then dried. It can help to soak, drain, and rinse produce that has more dirt-trapping layers.</p>
The Bottom Line<p>Practicing good food hygiene is an important health habit. Washing fresh produce helps minimize surface germs and residues that could make you sick.</p><p>Recent fears during the <a href="https://www.healthline.com/coronavirus" target="_blank">COVID-19 pandemic</a> have caused many people to wonder whether more aggressive washing methods, such as using soap or commercial cleaners on fresh produce, are better.</p><p>Health professionals agree that this isn't recommended or necessary — and could even be dangerous. Most fruits and vegetables can be sufficiently cleaned with cool water and light friction right before eating them.</p><p>Produce that has more layers and surface area can be more thoroughly washed by swishing it in a bowl of cool water to remove dirt particles.</p><p>Fresh fruits and vegetables offer a number of healthy nutrients and should continue to be eaten, as long as safe cleaning methods are practiced.</p>
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By Danielle Nierenberg
Following the murder of George Floyd by police in Minneapolis, people around the United States are protesting racism, police brutality, inequality, and violence in their own communities. No matter your political affiliation, the violence by multiple police departments in this country is unacceptable.
Mangroves play a vital role in capturing carbon from the atmosphere. Mangrove forests are tremendous assets in the fight to stem the climate crisis. They store more carbon than a rainforest of the same size.
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By Jacob L. Steenwyk and Antonis Rokas
From the mythical minotaur to the mule, creatures created from merging two or more distinct organisms – hybrids – have played defining roles in human history and culture. However, not all hybrids are as fantastic as the minotaur or as dependable as the mule; in fact, some of them cause human diseases.
When Looking Through a Microscope Isn’t Close Enough.<p>For the last few years, <a href="http://www.rokaslab.org/" target="_blank">our team at Vanderbilt University</a>, <a href="https://www.researchgate.net/lab/Gustavo-Goldman-Lab" target="_blank">Gustavo Goldman's team at São Paulo University in Brazil</a> and many other collaborators around the world have been collecting samples of fungi from patients infected with different species of <em>Aspergillus</em> molds. One of the species we are particularly interested in is <a href="https://doi.org/10.1006/rwgn.2001.0082" target="_blank"><em>Aspergillus nidulans</em>, a relatively common and generally harmless fungus</a>. Clinical laboratories typically identify the species of <em>Aspergillus</em> causing the infection by examining cultures of the fungi under the microscope. The problem with this approach is that very closely related species of <em>Aspergillus</em> tend to look very similar in their broad morphology or physical appearance when viewing them through a microscope.</p><p>Interested in examining the varying abilities of different <em>A. nidulans</em> strains to cause disease, we decided to analyze their total genetic content, or genomes. What we saw came as a total surprise. We had not collected <em>A. nidulans</em> but <em>Aspergillus latus</em>, a close relative of <em>A. nidulans</em> and, as we were to soon find out, <a href="https://doi.org/10.1016/j.cub.2020.04.071" target="_blank">a hybrid species that evolved through the fusion of the genomes</a> of two other <em>Aspergillus</em> species: <em>Aspergillus spinulosporus</em> and an unknown close relative of <em>Aspergillus quadrilineatus</em>. Thus, we realized not only that these patients harbored infections from an entirely different species than we thought they were, but also that this species was the first ever <em>Aspergillus</em> hybrid known to cause human infections.</p>
Several Different Fungal Hybrids Cause Human Disease.<p>Hybrid fungi that can cause infections in humans are well known to occur in several different lineages of single-celled fungi known as yeasts. Notable examples include multiple different species of <a href="https://doi.org/10.1002/yea.3242" target="_blank">yeast hybrids</a> that cause the human diseases <a href="https://rarediseases.info.nih.gov/diseases/6218/cryptococcosis" target="_blank">cryptococcosis</a> and <a href="https://www.cdc.gov/fungal/diseases/candidiasis/index.html" target="_blank">candidiasis</a>. Although pathogenic yeast hybrids are well known, our discovery that the <em>A. latus</em> pathogen is a hybrid is a first for molds that cause disease in humans.</p>
(Left) Candida yeasts live on parts of the human body. Imbalance of microbes on the body can allow these yeasts, some of which are hybrids, to grow and cause infection. (Right) Cryptococcus yeasts, including ones that are hybrids, can cause life-threatening infections in primarily immunocompromised people. Centers for Disease Control and Prevention<p><a href="https://doi.org/10.1371/journal.ppat.1008315" target="_blank">Why certain <em>Aspergillus</em> species are so deadly</a> while others are harmless remains unknown. This may in part be because <a href="https://doi.org/10.1016/j.fbr.2007.02.007" target="_blank">combinations of traits, rather than individual traits</a>, underlie organisms' ability to cause disease. So why then are hybrids frequently associated with human disease? Hybrids inherit genetic material from both parents, which may result in new combinations of traits. This may make them more similar to one parent in some of their characteristics, reflect both parents in others or may differ from both in the rest. It is precisely this mix and match of traits that hybrids have inherited from their parental species that <a href="https://www.nytimes.com/2010/09/14/science/14creatures.html" target="_blank">facilitates their evolutionary success</a>, including their ability to cause disease.</p>