Photo Credit: Kimberli Miller, USGS National Wildlife Health Center.

Standing in the entrance of a Vermont cave in March 2008, it was clear from the dead bats in the snow, another flying in the frigid cold and one clinging to an icicle that something was wrong.

I’m a Wildlife Disease Specialist for the USGS National Wildlife Health Center in Madison, Wisconsin.  The Center’s mission is to safeguard wildlife and ecosystem health through dynamic partnerships and exceptional science.  I was at the cave with two Vermont Fish and Wildlife Department biologists to learn more about white-nose syndrome (WNS), a new disease that was killing bats in New York, Vermont, Massachusetts, and Connecticut by the thousands.

Bats are fascinating creatures that have evolved very specialized survival skills.  One of these is their ability to hibernate to conserve energy by reducing their heart rate, temperature and other body functions to very low levels for extended periods.  This allows bats to survive long winters using their stored body fat when their insect food source is unavailable.  Although bats may briefly rouse out of hibernation to drink water or move to a different part of the cave, they typically stay deep in their hibernaculum or winter “roost site” until spring.

So it was odd in winter 2007 when New York residents reported seeing bats flying during the day and finding them dead in the snow in their yards.  Biologists following up on the reports were surprised to find a nearby cave littered with dead bats and a fuzzy white growth on the nose and wings of some of the live bats.  The following winter, sick and dead bats were reported in multiple locations in New York as well as Vermont, Massachusetts, and Connecticut.  The disease has now spread as far west as Kentucky, as far south as North Carolina, and to four Canadian provinces.  It is estimated that over a million bats have died since 2007, making this the largest disease outbreak among mammals in modern times.  WNS has spread very rapidly, by bats themselves, and likely also by people moving between affected and unaffected sites.

WNS Occurrence by County. Map courtesy of Cal Butchkoski, Pennsylvania Game Commission.

Navigating the icy rocks into the Vermont cave, dead bats were so numerous; stepping on them was sometimes unavoidable.  A live little brown bat clinging to the rocks overhead didn’t have white nose fuzz but did have wing damage, which we now know, is one of the components of WNS.

Photo Credit: Kimberli Miller, USGS Nation Wildlife Health Center

Nationwide, scientists are collaborating to quickly learn as much as possible about this disease.  One of my Center’s laboratories first isolated a cold-loving fungus from sick bats that they later named Geomyces destructans.  Additional studies determined that it is the cause of WNS.  Other scientists studied the wing damage caused by the fungus and how the injury affects body temperature and hydration during hibernation.  The caving community has helped efforts to prevent the accidental spread of the fungus to new areas on equipment and supplies.  All involved hope to one-day find ways to slow or halt the spread of the disease and reduce bat deaths before WNS causes some bat species to become extinct.

 National Wildlife Health Center Investigates Educator Guide

“The National Wildlife Health Center is sort of what it says. We're a national center and we receive carcasses from refuges and state management areas all around the country, usually from state biologists, federal biologists, tribal biologists,” says disease investigation chief Dr. Scott Wright. Those carcasses shipped overnight to the center are most often samples taken from large animal die-offs. It’s the job of the center to determine the cause of death.

“Much like the CDC would do for human health, or the USDA would do for agricultural animals, for livestock and so forth, that's the role we play for wildlife,” says Wright.

At the heart of the center is a level 3 bio-safety lab where the animal samples are processed and examined through necropsy, the animal version of an autopsy. “Every case that comes in is a potential real challenge,” says veterinary pathologist Dr. David Green. “I sit down and look at all of these different lab results; the toxicology, the poison tests, the virus cultures, the bacterial cultures. And I have to put all of these pieces of information together to determine why was that animal sick, why did that animal die or why did 500 birds die at this site.”

It was 5000 red winged blackbirds dying in a small Arkansas town on New Year’s Eve 2010 that briefly thrust the work of the Center into the national spotlight. “Oh there were just all sorts of clever names applied to the event,” remembers Green. “'Aflockolypse' was, I think, the cleverest.”

Harbinger of the end times, covert military testing, magnetic disruption, all manner of strange theories were applied to the event. The intense interest surprised the NWHC staff, says Wright. “There were people calling me at my home at night, on weekends wanting to know what was going on.”

The cause of death, determined after numerous bird necropsies, was much more banal than the theories. “All of the tests and cultures that we did for infectious diseases and parasites and chemicals came back negative,” says Green. “Basically it came down to, we couldn't find anything other than physical injuries, what we call blunt force trauma in the birds.”

Those necropsy findings, combined with field reports of New Year’s fireworks, and the fact that blackbirds are terrible night flyers came together to paint a picture of startled birds flying into each other and stationary objects and succumbing to traumatic injury.

This most plausible explanation didn’t satisfy the most dedicated conspiracy-theorists according to Wright. “It really sort of floored us. We didn't expect that. We didn't expect to be not believed.”

That’s something that Dr. Wright, who is soon to retire from the Center, finds a troubling omen for the future of science and public understanding. “Science is not being believed,” he says. “That's not a good sign, because there's too much important stuff coming that we need to be stepping up and telling everybody, ‘This is what's going on.’ And they hopefully will believe us.”

^{The tiny ranching town of Parkfield is California's seismic playground for scientists. This instrument package sits in Turkey Flat. Photos by Andrew Alden.}

Besides earthquakes, there is a whole spectrum of energetic activity in the solid Earth. Thankfully, most of it doesn't disturb anyone's sleep. After a century of focus on jolts and jiggles, earthquake scientists have begun turning their attention to these more subtle signals. And California is one of the prime laboratories for this research.

Most big earthquakes happen in the mid-crust in a zone between 10 and 20 kilometers deep, where rocks are strongest. Above this zone, rocks are cold and brittle and tend to crack; below, they are hot and ductile and tend to stretch. Menlo Park seismologists looking at the deeper, ductile crust have put a new piece of the great puzzle into place this week.

Earthquakes of the classic type—cracks in the ground, alarums and mayhem in the human sphere—are only the best known type of seismic activity. They center around the brittle–ductile transition zone, but can be found from very near the surface down to almost 100 kilometers deep, if tectonic forces have put cold, brittle rock down there. (Deep earthquakes, which occur down to almost 700 kilometers, are a separate species.)

The new types of seismic events are small and slow murmurings within the deep crust. They involve motions that are gentler and at much lower frequencies than typical earthquakes. Think of them as less like the crisp cracking of a baguette crust and more like the quiet ripping of the bread inside.

Different varieties of these slow events have been discovered by different people in the last two decades. Their names include tremor, slow earthquakes, episodic slip events, transient creep and so on. They are hard to detect and difficult for seismologists to model. But that's what they used to say about ordinary earthquakes, and I'm sure that we will tame these creatures too. I suspect that they will eventually align in a kind of spectrum with names akin to the colors we designate in the blurry bands of the rainbow.

This week's news centers on the lively research topic of triggering: Do distant earthquakes set off local events as their seismic waves roll through? It seems obvious that they would, but science looks for proof before accepting even what seems obvious. Triggering was first accepted when the 1992 Landers earthquake in Southern California was shown to set off small quakes all the way out to Yellowstone, in Wyoming. The effects are subtle and of scientific rather than engineering interest.

The San Andreas fault is a laboratory for slow-event research; the area around Parkfield, east of Paso Robles, has been intensively instrumented since the 1970s. Recently, persistent clusters of tremor have been mapped there at depths below the earthquake zone. A paper by U.S. Geological Survey seismologist David Shelly and others published this week in Nature Geoscience notes that these ticklish spots of "ambient tremor" are sensitive to large, distant earthquakes in the right circumstances.

_{Frame from Supplementary Movie 3, Shelly et al., Nature Geoscience doi:10.1038/ngeo1141. North-south profile of San Andreas fault; shaded zone and star represent slip in and hypocenter of the 28 Sept 2008 Parkfield earthquake; blue dots are earthquake events, crosses are ambient tremor locations; depth grid is 10-km intervals.}

Here's an example grabbed from a Quicktime movie file showing these ambient tremor spots "lighting up" after passage of the surface waves from the February 27 2010 Chile earthquake (magnitude 8.8). Surface waves are the strongest, most damaging and slowest-moving vibrations of an earthquake; they are what makes the entire planet reverberate as long as weeks afterward. What interested the researchers about this triggered tremor is that it lasted long after the triggering waves had passed. Something was moving very slowly after the trigger left, something that continued to set off tremor until the stresses finally dissipated.

What moves slowest of all the new seismic slow events? It is creep, which I described in last week's post. Creep is known to be variable—some parts of a fault have it while others don't; its speed also varies in different locations. It's known to change speed, too. In fact, you might think of it as just an extremely slow earthquake with a frequency of years instead of seconds.

Shelly and his coauthors therefore suggest a new kind of triggered event to go along with triggered earthquakes and triggered tremor: triggered creep.

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^{Suburbia is warped in downtown Hayward, where fault creep is steadily distorting curbs, walls and pavement. All photos by Andrew Alden except where noted.}

In my first post on KQED Quest Science, I invited you to make friends with your local earthquake faults. The best place to do so, in my opinion, is in Hayward, where the Hayward fault runs right through downtown. You can start at the Hayward BART station and enjoy a good meal while you're in town.

What makes Hayward special is that the fault moves steadily there, even without earthquakes, in the process that geologists call aseismic slip, or fault creep. Very few faults are known to creep, but in the Bay Area we have three: the Hayward fault, the Calaveras fault in Hollister, and the San Andreas fault south of Gilroy.

I love my copy of U.S. Geological Survey Map MF-2196, "Recently Active Traces of the Hayward Fault," published in 1992 on a topographic map base. But the Survey's online database, updated twice since then, costs nothing and is projected on aerial photos. Here's how downtown Hayward looks in it; click the image for a larger version. North is to the left.

The BART station is at the bottom between A and D Streets. If you can, walk through the new City Hall on your way to Mission Boulevard; it's highly engineered for earthquake resistance, and the apron of stone around it hides a base-isolation system that lets the building shimmy like a surfer to ease the stress on it from a magnitude-7 event.

On Mission it's simply a matter of walking in either direction and going up each side street. The annotations have a simple code: C1 and C2 denote excellent and good creep evidence, respectively. Here are examples of the codes that follow them. First is "ec," for echelon cracks, like this set from Oakland's Lake Temescal where the fault has its own exhibit.

Before we go any farther I should point out that Hayward is not proud of its fault. Many homes and properties were built upon the fault trace before creep was first recognized in 1956. It's best not to stand and point. Geology teachers tell their classes the same thing.

The code "rc" stands for right-offset curb. These are easy to spot. I photographed this example a few years ago; since then the construction site has become a structure, but the curb still takes its rightward jog. The Hayward fault is classified as right-lateral, meaning that when you look across it, the other side moves to the right.

The curb on Sunset Street, near Prospect Street, is a clearer example.

The codes "rb" and "rw" mean offset buildings and walls, respectively. You'll see a lot of damaged brick buildings, or recent repairs, in line with the bent curbs. The code "jo" means open joints or cracks in concrete. This example shows a steadily opening gap that has been patched.

Localities marked "so" have had their offsets surveyed. The most commonly visited site is the corner of Rose and Prospect Streets, the yellow circle on the map. The corner curb has had a constant stream of visitors since it was built in 1971. This is how it looked in 2001.

_{Photo courtesy misspudding of Flickr under Creative Common license}

You can see from my photo taken in 2007 that it has moved further since then. The street here has a good set of echelon cracks too.

Prospect Street got its name because it runs along a low ridge with a nice view west. The ridge is a pressure ridge, thrown up during thousands of years of creep and earthquakes. That's one natural sign of fault activity. Another is offset streams, which are just like offset curbs only much larger. You'll see one on the map where a stream flows down from the top (east), turns sharply to its right, then jogs leftward on the other side of the fault. It's marked "G1, rs" meaning excellent geomorphic evidence consisting of a right-offset stream.

Another natural fault sign appears about 2 miles south on Mission at Holy Sepulchre Cemetery, where you can look up on the hillside just to the south and see another natural sign of the fault: a line of springs. It really stands out in the dry season.

This is just a beginning of what geologists learn to see, but you can follow in their footsteps as far as you care by visiting the USGS's Northern California earthquake home.

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Loma Prieta earthquake, Marina Diistrict of San Francisco, 1989. Courtesy of California Watch.

What would a California earthquake early warning look like?

Probably something like this clip from Japanese TV, which shows a session in Japan's parliament when last months' 9.0 earthquake struck.

The Japanese earthquake early warning system had some bugs. For one thing, the sensors under-estimated the size of the massive earthquake. They also misjudged how much of the country would feel it.

Still, to researchers who work on earthquake warning systems, what happened in Japan was proof: The systems work.

Listen to the QUEST radio story Earthquake Warning

The Sendai area, which was hardest hit, received about ten seconds. In Tokyo, farther from the epicenter, residents had 30 to 60 seconds before the worst of the shaking took place.

Here in California, we have no such system, which means if an earthquake were to hit here residents would have no warning at all.

"This has been sort of percolating along in the seismological community for a long, long time," says Douglas Given, a geophysicist with the United States Geological Survey. "But it’s only since about 2007 that we started working on it seriously here in the US."

The groundwork for a system is already in place. It’s a network of about 400 seismic monitoring sites, scattered across California.

One of them is near UC Berkeley, in a vault dug into the side of a hill. The vault was built during the cold war, to try and detect the vibrations of other countries’ nuclear tests. Today it houses instruments so sensitive that they can pick up shaking on the other side of the planet.

A couple years ago, I got a tour from Richard Allen, the assistant director of UC Berkeley's Seismological Laboratory. (You can see photos of the vault in the slide show, below.)

"The way the early warning system works," explained Allen, "is it makes use of the fact that the energy that radiates during an earthquake, there’s two types of energy."

The first are called P waves. They travel fast but are relatively weak. Then come S waves, which are sluggish but do a lot more damage. Once you know how fast the S waves are traveling, you can calculate when they’ll reach other parts of the state, and quickly send out a warning before the S waves arrive.

But here in California, that might not be a lot of time.

"Unfortunately," says Allen, "our faults go right beneath the metropolitan regions. If you’re right above the quake, even with an early warning system, you probably won’t get any warning."

But the farther away the epicenter, the more warning you get. Allen says if we’d had an early-warning system back in 1989, during the Loma Prieta quake, Oakland residents could have had 15 seconds of warning.

That’s enough time to close the toll plaza on the Bay Bridge, or to open up fire station doors, so they don’t jam shut during the earthquake. David Oppenheimer, a seismologist with the USGS in Menlo Park, says there’s a lot you can do with just few seconds.

"You really need to think about automatic applications," he says, "elevators stopping at the next floor, doors opening, alarms in schools saying duck and cover with a voice telling you what to do."

And of, course, consider major surgery.

"One example that I always like to give because people cringe is what if someone's performing cataract surgery on you, and obviously you'd like the surgeon to remove the scalpel away from your face."

In Japan, the alarm system automatically triggered a slow down of the country’s bullet trains. That’s probably why none of them derailed.

John McPartland who represents BART District 5, made the case last week at a meeting in Berkeley of earthquake early warning advocates.

"If we don’t have this warning system," he said, "and we’ve got trains that are traveling at 60-70 miles per hour, and we end up derailing 20 to 30 trains, that’s going to end up [causing] one heck of a doggone toll in injuries and misery."

So far, arguments like these have fallen on deaf ears in Congress.

Each year, the program gets about 500 thousand dollars, barely enough to continue basic research. Now, that line item has been cut entirely from the President’s latest budget proposal.

Unless Congress reinstates the funding, the early warning program will stay where it is, says Given, "held together with duct tape and bailing wire. It’s not a reliable system, or a complete system."

Getting the system up to speed would cost $80 million, over five years. Given and others who work on the program say it's been a tough sell.

Japan, after all, didn’t start building its warning system until after the devastating Kobe quake in 1995. Same thing in Mexico, says Given. "After the 1985 Mexico City earthquake, there was suddenly — for some strange reason, maybe 8K fatalities? — a public will to move forward with the system."

It would be wise, he says, not to repeat that pattern here in the States.

"It’s our hope that we can get sufficient interest and build a system without first having to have a killer earthquake."

According to the USGS, the chance of a magnitude 6.7 or larger earthquake shaking California over the next 30 years is greater than 99 percent.

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_{The Hayward fault crosses Oakland's Temescal Regional Park. Photo courtesy Andrew Alden}

Earthquakes will never be as predictable as the weather, I think it's safe to say, but if you get to know your nearest faults then earthquakes will be less of a surprise. When our local faults rupture, you will be less likely to panic and more likely to get through the event unscathed. So when I urge you to friend a fault, it's not to infect you with a scientific hobby but to bring you a lasting practical benefit.

A fault is a crack that has had movement along it. Geologists find them everywhere, and geologic maps are festooned with them. Almost all of them are inactive, though, and they're generally obscure even to practiced eyes. You can see what I mean on the U.S. Geological Survey's zoomable geologic map of the Bay Area.

_{US Geological Survey image}

Here's a part of it showing the area around Fremont. We can't be expected to worry about every heavy line, can we? Thankfully, no; and not the colors and symbols either. That's geology stuff: bedrock and contacts between stratigraphic units. But the two heaviest lines are important. On the left is the Hayward Fault and on the right is the Calaveras fault, both capable of major shocks.

_{US Geological Survey image}

Another USGS map called the Quaternary map focuses on just the active faults—well, the sort-of active ones that have moved during the Quaternary Period. You need to know only two things about the Quaternary: it's pronounced "qua-TERN-ary" and for our purposes it includes the last 1.8 million years of geologic time. Now a fault that hasn't moved in a million years, like a volcano that hasn't erupted in a million years, is not much of a threat. The color codes on the faults match the time of the latest fault movement, angry red being historic time (namely, 1868).

There are two good ways to visit our local faults. One is visiting them in parks (see the list below), and the other is the freelance approach of tracking them through the neighborhood. For that, the best tool is the State of California's Alquist-Priolo Earthquake Zone Maps, which have just been placed online by the California Geological Survey. Mandated by the Alquist-Priolo Act of 1972, these maps display the locations of faults that have ruptured during Holocene time, which is geologese for the last 11,000 years. Unlike Quaternary faults, activity on these Holocene faults is a pretty sure thing. And the maps display the detailed fault traces as mapped by geologists, superimposed on a high-quality topographic map.

With these, you can drive or stroll an area and assess the land for yourself. In places like downtown Hayward, the signs are plain and plentiful. In many others, you'll wonder what the heck those geologists were seeing. (The answer is that they were looking at historical aerial photos and data, finding subtle clues on the ground, and doing a lot of connecting dots.) You'll have a head-scratching good time, and you won't see your landscape the same way again.

Visit the San Andreas fault:
Fort Ross—Take Fort Ross Road east about 0.5 mile and spot the painted line across the road; an interpretive trail is nearby.
Olema—Take the Earthquake Trail near the Bear Valley Visitor Center in Point Reyes National Seashore.
Los Trancos Ridge—This ridgetop park above Palo Alto has an earthquake trail along the fault.
Sanborn County Park—South of Cupertino in the Santa Cruz Mountains is this park with the 2.5-mile San Andreas trail along the fault trace.
San Juan Bautista—The fault runs just yards east of the mission here.

Visit the Hayward fault:
Berkeley—Tour the fault in "Bear territory" including the infamous football stadium built across the fault in 1923.
Oakland—Lake Temescal park displays the fault in several places.
Hayward—The historic downtown and old City Hall straddle the fault, and signs of steady (aseismic) creep are abundant here.

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Severe flooding in Sacramento during 1861-1862 storms.

Earth's 4.5 billion year history is riddled with the evidence of landscape-altering events that would be considered rare and catastrophic from a human perspective. Some of the 'normal' events that shape the Earth's surface occur at intervals longer than the lifespan of a human. For example, let's say that an abrupt event (an earthquake, flood, or tsunami) occurs, on average, once every 500 years. Such an event would have occurred more than 5,000 times since our species has walked the Earth.

We have our grandparents and great-grandparents (and written/photographed history for that matter) to remind of us events that did happen. But there's nothing quite like direct experience. The stories of natural disasters that occurred many generations ago seem far away and detached from our current world.

How do we deal with this? One tool to remind ourselves of what is possible when it comes to 'rare' natural events is science. Under the right circumstances and analyzed with the proper tools the geologic record holds clues to how often such events might occur (frequency) and how significant there effects might have been (magnitude). Combining this type of work with sophisticated modeling of the processes at work can provide insight into what to expect.

Following on the very successful ShakeOut Scenario of 2008, the U.S. Geological Survey's Multi-Hazards Demonstration Project (MHDP) is working on another large-scale disaster awareness project. But instead of an earthquake, this one is about large storms.

The project is nicknamed ARkStorm, which refers to storms related to atmospheric rivers (the 'AR') that occur on average once every 500 to 1,000 years ('k' refers to 1,000). The image below is from a USGS publication released last week about the ARkStorm scenario (Open File Report 2010-1312) and shows an example of an atmospheric river in the Pacific in 2004. In this example, this relatively narrow arm of high water vapor content extends across the ocean basin to the town of Cazedero, California.

A storm scenario similar to what is described in the ARkStorm report happened in California in the winter of 1861-1862. A series of powerful storms lasting a month flooded much of the Central Valley — people described it as an inland sea. The ARkStorm scenario has happened before and is scientifically realistic.

Similar to earthquakes, it's not so much a matter of if a storm scenario like this will occur but when. The point of an initiative like ARkStorm is about raising the collective awareness of what is possible. I think Californians are, for the most part, aware of the seismic hazards we face. Adding a super-storm to the list is not meant to be sensational or scary — it's meant to communicate the inevitable so we are prepared.

To learn more about how different agencies and authorities will be participating in ARkStorm, check out this short video put together by the USGS:

Thanks to Bay Area geologist and About.com 'guide' Andrew Alden for mentioning this story last week on his blog.

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Bay Bridge and San Francisco / Flickr

The magnitude 7.0 earthquake that occurred a couple weeks ago near Christchurch, New Zealand is yet another reminder for those of us living in the Bay Area about the inevitable seismic danger we face. While many details of the New Zealand earthquake are different than what we face in the Bay Area, there are a few aspects that are comparable.

The fault that ruptured on the South Island of New Zealand was dominated by strike-slip motion, which is similar to the San Andreas, Hayward, and related faults in the Bay Area*. And, unlike the devastating earthquake that struck Haiti in January, the state of building construction in the Bay Area and Christchurch is, in general, much better.

But there are a lot of older structures in the Bay Area that could be quite dangerous in a powerful earthquake. Individuals need to be prepared. A few months ago, my wife and I declared a weekend ahead of time to be "seismic hazard preparedness weekend" (I even wrote that on the calendar). The USGS has incredible resources when it comes to Bay Area earthquake awareness, education, and preparedness. We downloaded their packet Putting Down Roots in Earthquake Country for putting together our kits.

We spent a good day and a half preparing kits with food, water, and other emergency supplies for our home, our car, and for both of our workplaces. I have to admit, it really felt good to get it done and feel like we could brave 3-4 days without power, water, and communications. We have plans for what to do if we are at work as well. Don't put it off. Declare next weekend or the one after that your own seismic hazard preparedness weekend. Put it on the calendar and make it real.

The last thing I'll mention about this has to do with mental preparedness. That is, you can buy all the supplies, have the plans all worked out, prepare your house, and so on — but you also need to be mentally prepared. A relatively large earthquake will happen, eventually. You can't stop it and deciding not to think about it won't decrease the chances. I'm not saying you need to worry every moment — worrying doesn't help either. It's good to come to terms with the high probability that you will be  affected by an earthquake and then take steps to reduce the risk to you and your family.

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* see this QUEST segment from 2008 about seismic hazards related to the Hayward Fault. You can search on our website for other related stories, including these:

Predicting the Next Big One
Earthquake Early Warning
Earthquakes: Breaking New Ground

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Generally speaking, these habitats are the marshes, sand beaches, mudflats and the shallow waters of our rivers and creeks whose soil is saturated with moisture either permanently or seasonally; such areas may also be covered partially or completely by shallow pools of water.

They are also nature’s best defense against climate change and subsequent sea-level rise, because of two important functions they perform: they help reduce the concentrations of greenhouse gases through their ability to sink carbon; and store and regulate water. In other words, they act as sponges absorbing any overflow of water.

The federal government came to understand how biologically productive wetlands are and in 1977 enacted the Clean Water Act, the primary federal law in the US governing water pollution and limiting wetlands destruction. The law also created requirements that if a wetland had to be drained, developers at least had to offset the loss by creating artificial wetlands.

Wetlands have historically been the victim of large-scale draining efforts for real estate development, flooding them for use as recreational lakes or agriculture. Ironically, wetlands absorb and protect the surrounding ecosystem from the polluted run-off coming from the agricultural lands that displaced them.

Since 2000, more than 300 wetland restoration projects have been commissioned, varying in size from the 0.7-acre large 12^th Street Reconstruction Project in Alameda County to more than 13,000 acres being restored as a part of the South Bay Salt Pond Restoration Project in San Mateo County. However, the collective size of the projects (58,889.5 acres across California) is dwarfed when you consider that the state has lost 95 percent of its wetland habitat in the past 125 years.

Worldwide, it is estimated that by 1993 half of the Earth’s wetlands had been drained, according to a report published in the New Scientist.

Below you’ll find a map detailing the restoration projects taking place in the San Francisco Bay Area that shows information of their size, location and construction status.

View Wetland Restoration Projects–Northern California in a larger map

Listen to The Changing Bay radio report online.

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