Tules on Twitchell Island in the Delta. (Photo: Josh Cassidy/KQED)

With thousands of acres of rich farmland, the Delta has a long agricultural legacy. But farming there can be a risky business. Dozens of farms have been flooded over the past half century as aging levees have collapsed.

That became a reality for farmer Rudy Mussi on the morning of June 3, 2004. It was clear, sunny day. "You never expect a flood in the summer months," says Mussi.

Mussi was growing corn and asparagus on lower Jones Tract, an island in the Delta, 10 miles west of Stockton. That morning, he got a phone call. Water was flooding onto his farmland.

"Your heart stops for a second or two and then realism sets in. And you just start moving your equipment and get it to high ground," says Mussi.

How did a flood happen a on a sunny day? It's because of a basic rule of physics. Mussi farmed on an island below sea level, like a lot of the islands in the Delta. The Delta used to be a huge swath of wetlands, where two major rivers met San Francisco Bay. Today, earthen levees hold that water back – most of the time.

"Once a break occurs, you know, there's no way you're gonna stop that, not with 10 feet of water on the other side," Mussi says. Draining the island and repairing the levees around Jones Tract cost about $90 million.

The levee break on Jones Tract in 2004. (Photo: CA Department of Water Resources)

It wasn't an isolated incident. Over the last century, more than 150 levees have failed in the Delta.

Delta Infrastructure at Risk

"This is how we get ourselves in kind of an arms race between the water and the land," says Jeff Mount, professor with the Center for Watershed Sciences at the University of California-Davis.

Levee-building began in the 1850s, when settlers came to the Delta for the rich soil. More than a thousand miles of levees were built. "This network of levees through time had to get bigger and bigger for a very basic reason: the land has been steadily lowering," says Mount.

As farmers exposed the rich peat soil, it started decomposing. The land level dropped; "In some places they talked about four inches per year," says Mount. Today, it's less than an inch per year thanks to better farming practices.

Add up all those inches over the past century and some islands are now 30 feet below sea level. That puts a lot of stress on the levees. There are also other concerns: rising sea levels and extreme floods. "And then the big 800-pound gorilla in the room – we're due for a very large earthquake on the San Andreas system."

Add up all these risks and Mount says there's a two-thirds chance of a catastrophic levee failure in the next 50 years. That, of course, affects farmers and communities in the Delta, but it could also impact California's water supply.

"The raindrops that fall in Mount Shasta are consumed by people in San Diego. Water moves a great distance and this is one of the critical hubs in that system," says Mount.

Fixing the Delta's levees is estimated to cost billions. But on some islands, scientists are experimenting with a new fix.

Farming Carbon

Peat soil samples on Twitchell Island. (Photo: Josh Cassidy/KQED)

On a windy day on Twitchell Island in the Delta, ecologist Lisa Windham-Myers of the US Geological Survey pushes her way through a wetland filled with a tall, reed-like plant known as tule.

"The plant grows… some of these are 16 feet tall. They're just huge," she says. That growth is changing the ground we're standing on. Windham-Myers pulls out a sample of the dark peat soil.

The wetland produces soil at a rapid rate – four inches a year on average. That's huge, says USGS scientist Brian Bergamaschi, in a place where the land is sinking. "These islands are like bowls and the way we see projects like this is you want to fill up the middle of that bowl and help level out the whole island."

Planting wetlands like this one could raise the land level and water table on the inside of levees, relieving some of the pressure. But why would farmers want to replace cash crops with tule? Windham-Myers points to the soil.

"This is basically almost 100 percent carbon. These take up far more than a typical forest environment," she says. California is setting up a market for carbon, as part of the state's effort to cut global warming emissions. Early next year, companies that need to reduce their emissions could pay farmers to store carbon in wetlands like this.

USGS scientist Brian Bergamaschi talks with Delta farmer Al Medvitch. (Photo: Josh Cassidy/KQED)

Today, two farmers are here checking out the project: Steve Mello, a Delta farmer on Tyler Island and Al Medvitch, a farmer in the Montezuma Hills.

"The potential has been demonstrated well. You guys are standing in the middle of it. But in order to move from here to market, we need to develop a lot more techniques so people can come and verify that the carbon is stored," says Brian Bergamaschi, describing how wetland farming might work.

Both farmers seem open to the idea. But Mello says ultimately, it depends on the bottom line. "It would absolutely need to cash flow. While it could dovetail with levee stability, it would still need to generate enough to amortize your property value."

Still, Mello says assuming carbon prices are high enough, growing patches of wetlands could be a feasible way to improve the levees and to stay farming.

This month may be the moment of truth for six Bay Area communities. Each one is vying to be the new home of a high-profile national research center. But when it comes to development in the Bay Area, there are no easy answers.

Oakland, Alameda, and Berkeley, Emeryville, Albany, and Richmond are the six cities in the running for what you might call the 2012 Cadillac of Bay Area Development Projects: A new, second campus for the Lawrence Berkeley National Laboratory.

Will Travis – who, until recently, headed the Bay Conservation and Development Commission, a state agency that regulates building around the bay – says, sure, big development projects happen all the time in the Bay Area. But Lawrence Berkeley labs is what he calls "a platinum level, marquee" project.

Since it was founded in 1931, thirteen Nobel prizes have been won on work done here. Sixteen elements added to the periodic table. World-famous innovations in medical science, alternative energy and atomic research that helped win World War II.

"It reflects who we are as a society, a knowledge-based society," says Travis, "and this is the epitome of that."

With a staff of 4,000 and a budget of more than $800 million, the Lawrence Berkeley Lab has been overflowing its headquarters in the Berkeley Hills for some time. Research on biofuels and other fields has spilled over to satellite offices in Emeryville and Walnut Creek. The idea is to consolidate those operations into a second campus.

For several Bay Area cities, this seems like a dream opportunity.

On a blindingly sunny day in November, Alameda city development manager Jennifer Ott took me on a tour of Alameda's contender in the race: a 50-acre waterfront property in the Alameda Naval Air Station.

Gesturing to what now looks like a concrete wasteland – albeit with a spectacular Bay view – Ott described a bustling campus and waterfront promenade. Retail shops and restaurants, a jogging path.

She says when the Navy decommissioned the Air Station 15 years ago, the city lost thousands of jobs. The lab would be a chance to bring this area back to life.

So, Alameda is offering the site to the lab for free, which says a lot, especially when you consider that – as because it’s a national lab – the campus will contribute nothing in local property taxes

Ott says It’s still worth it.

"They will shop in our stores," says Ott, "eat in our restaurants. And we also believe that they will attract other private development to the area that will bring tax revenue into the city and jobs."

The need for jobs unites all six of the possible sites. But here’s something else many of them have in common: They're flat and by the water.

And that presents a problem that no one has much experience dealing with says Will Travis.

"The fact that these areas are low-lying and vulnerable to sea level rise isn't something that's been integrated into regulatory process yet."

San Francisco Bay waters are expected to rise steadily in coming years: 16 inches by 2050, up to 55 inches by the end of the century.

But the more imminent threat, says Travis, is storms.

"The scientists are telling us that we will have more extreme events more often. And we’re seeing it.

Travis believes that sea-level rise is something that can be designed around with stilts, or artificial hills, setbacks. His former agency, the BCDC is charged with writing those guidelines.

But at a certain point, says Heather Cooley, of the Oakland-based Pacific Institute, there will be places simply not worth developing. Places we will just abandon to the rising waters.

"We will need to have those sorts of conversations," says Cooley. But she adds that nobody in the Bay Area seems quite ready to have them yet.

Other hard conversations are taking place just north, near the Albany/Berkeley border at Golden Gate Fields.

On the day I visited, a thoroughbred named "I'm Tops" is getting a pedicure, his hooves filed down and shiny new aluminum shoes fitted with nails and a hammer.

"This is a dying art," said Peter Tunney, my guide and a member of the Stronach Group, the private racing firm that owns this racetrack and others.

Tunney has been in the racing business most of his adult life. But he said betting had declined in recent years. Sometime, the grandstands were only half-full.

Horse racing, said Tunney, "has become a television sport. We have all learned that we don’t need grandstands anymore."

If Lawrence Berkeley chooses this spot to put its new campus, the racetrack, built in 1941, would be torn down. The lab would either buy the property, or lease it from the Stronach Group.

Racing would continue, said Tunney, just somewhere smaller inland like Pleasanton.

"We're in the racing business. We’ll stay in the racing biz. We’re just following this through as a potential option."

If the lab chooses Albany, there will be some hurdles. Birders say the construction could damage precious habitat near the track.

And losing the track would cost the city of Albany about a million and a half tax dollars that it takes in from the track each year, money that funds its schools, among other things. By law, residents here would have the right to vote on whether to allow the lab or not, which could add time and risk to the process

There are no easy answers, says the BCDC's Will Travis. "And I think that’s what’s taking so long. We have a series of imperfect alternatives."

One final option is to build out the Richmond Field Station, off of I-580, and just north of the racetrack. The Field station, which Lawrence Berkeley Lab already owns, currently houses several scientific projects, including an earthquake simulator and UC Berkeley's Forest Products Lab.

A spokesman for the lab says a decision should be out within the month. They hope to have the new facilities up and running by 2016.

Click here for a larger version of the Nile Delta.

The Sacramento-San Joaquin Delta has this classic, triangular shape but with a major caveat — it’s inverted. That is, instead of the delta splitting into numerous channels in a downstream direction, it is characterized by numerous channels coming together in a downstream direction. The geologic history of the greater Bay Area helps explain this rather unique delta geometry. Unlike the Nile, Amazon, Mississippi, and other major river systems, the location where the Sacramento-San Joaquin rivers meet sea level is: (1) well inland of the coast and (2) strongly controlled by the topography of the region.

The Sacramento-San Joaquin Delta is known as a bay-head delta, which is when a delta forms at the head of a large estuary like the San Francisco Bay. When sea level was much lower during the last ice age the river met the sea at the position of the Farallon Islands. As sea level rose and the valleys that are now the Bay flooded, the river mouth moved inland to its current position. The complex topography of the Bay Area — a result of active faulting associated with the San Andreas, Hayward, and other faults — has forced the channels in the delta to come together at Carquinez Strait.

Future sea-level rise will affect the delta region, especially Suisun and Grizzly Bays, significantly. Even a relatively small rise will change the character of these wetland areas. Further east, near Antioch and Lodi, the delta is actively subsiding (sinking), which could exacerbate the negative effects of a rising sea level even more.

Images: (1) Nile River Delta; credit: Wikipedia, (2) Basemap from FlashEarth, annotation by me.

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Topographic image of the Bay Area and continental shelf and slope. The coastline during the peak of the last ice age was at the shelf edge near the Farrallon Islands.

Before reading this post, make sure to check out QUEST’s video segment from last week about sea-level rise in the San Francisco Bay, which provides a nice overview of the problem low-lying areas in the greater Bay Area will face in the coming decades. As good as it is, the QUEST piece is really just an introduction to the problem of current sea-level rise. Sea-level rise is happening and more than 100 million people could be affected globally over the next century even under somewhat conservative projections. This is an tremendously complex problem that will require research across numerous scientific disciplines and creative problem-solving from engineers and urban planners. Like many of the posts I write for QUEST, I’d like to zoom out in terms of the timescales we are used to thinking about and share a little information about geologically recent sea-level changes in the Bay Area.

Over the past few million years, the Earth has flipped back and forth about 20 times between periods of significant continental glaciation, or ice ages, and briefer periods of much less ice. The peak of the most recent ice age was approximately 18,000 years ago. During this time, referred to as the Last Glacial Maximum by Earth scientists, the continental ice sheets that covered much of northern North America and northern Europe reached their largest extent in area. When such vast continental ice sheets grow they “borrow” water from the Earth’s water budget and, as a result, global sea level is lowered. Only 18,000 years ago sea level was 120 meters (400 ft) lower than it is at present.

The map above is a simple sketch map of the paleogeography of the Bay Area at this time*. Think about this for a moment — if you were standing at Land’s End Park on the northwest corner of San Francisco you would not be at the land’s end! The coast would be about 20 miles offshore of the current coast, just beyond the uplands that are now poking out as the Farallon Islands. What is now the Bay was a network of flat valleys with the ancestral Sacramento-San Joaquin River and tributary streams making their way through the narrow notch in the hills at Golden Gate. As temperatures warmed and the continental ice sheets began to melt sea level started to rise. That’s a simplified picture of what the landscape may have looked like at different stands of sea level, but what about the rate at which the sea rose?

The Pacific Institute, a nonprofit research institute based in Oakland, published a thoroughly researched and very readable report on sea-level rise and its impact on the California coast, which is also featured in the QUEST report. Estimates of future sea-level rise as stated in their report are between 1.0 and 1.4 meters (40-55 inches) by the year 2100. To be conservative (and to simplify a bit) let’s assume this present rate of sea-level rise is 1 meter per 100 years. If we now look at a reconstruction of sea-level changes since the Last Glacial Maximum we see the rise in sea level was not constant — depending on the rate of warming along with other factors the rate of rise varied. As you can see in the graph below the rate of rise slowed significantly about 8,000 years ago. From 18,000 years ago to 8,000 years ago sea-level rose approximately 100 meters (330 ft), which is an average rate of 1 meter per 100 years. In other words, the Earth will soon be experiencing a rate of sea-level rise it hasn’t experienced in several thousand years.

The most important uncertainties regarding our understanding of current and near-term sea-level rise are magnitude and rate — that is, how much and how fast. By studying the relatively recent past (geologically speaking) we can learn something about the effects varying rates of sea-level rise might have on the Bay Area. For example, how did bayshore ecosystems respond to rapid sea-level rise thousands of years ago? How will tidal marsh ecosystems respond to slow versus rapid sea-level change? The map below from the San Francisco Estuary Institute shows the different types low-lying bay shoreline that will be affected by future sea-level rise.

These environments, some of which are entirely human-made, will respond differently to sea-level rise. Further study of past environments and ecosystems and how they were affected by sea-level rise since the last ice age will play an important role in the broader goal to mitigate the consequences of a rising San Francisco Bay.

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UPDATE (9/2/2010):

Also check out this great video piece from QUEST a couple years ago to help you visualize what the Bay Area landscape was like 20,000 years ago and the kinds of animals that lived here. Definitely worth a look.

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* Check out this fantastic slide show from UC Berkeley Earth scientist Lynn Ingram here (link opens a PDF). This is  a great resource for learning more about the information scientists are collecting from the Bay’s sedimentary record to answer some of the questions I pose above.

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There is no question that sea levels have been steadily rising, and will continue to rise at an increased rate in the future.  So the real question is not, “Will it rise?” but, "How MUCH will it rise, and what can we do about it?”

The sea is rising.  This, in itself, is not news.  The oceans of Earth have been slowly, steadily rising for hundreds of years.  But it’s about to get a lot higher a lot faster, and millions of people – and billions of dollars of infrastructure – are suddenly finding themselves at risk for flooding, storm surge damage, and possible relocation.  How could something that has been a known factor surprise us, unprepared?

Meet Sea Level Rise, the new poster child for climate change.  There is no question that sea levels have been steadily rising, and will continue to rise at an increased rate in the future.  So the real question is not, “Will it rise?” but, "How MUCH will it rise, and what can we do about it?”

As we were just starting research for this story, I attended the SF Bay Decision Maker’s Conference on Sea Level Change.  There was one idea that permeated the entire day’s discussions:

-         You can’t engineer for an unknown amount.

-         Developers are aware of sea level rise, but do not know how to approach the issue. “Tell how much it will rise, and by when, and we can plan for it.”

Of course, it’s just not that straightforward.  The science behind the estimates seems to be uncertain, providing ranges from as little as 12 inches by 2050, to as much as 80 inches by 2100. There is a consensus that the rate of sea level rise has increased in conjunction with the rise of global surface temperatures. The point of uncertainty is what the rate of sea level rise will be in the future. In 2007, German scientist Stefan Rahmstorf developed an empirical method for predicting future sea level rise using the relationship between sea level rise and global mean surface temperature. His estimates of global sea level rise by 2100 range from 10 inches (50 cm) to 55 inches (140 cm) respectively.  Research estimates done for the Governor of California state that sea level will increase between 12 and 17 inches (30 and 45 cm) by 2050 and between 20 and 55 inches (50 and 140 cm) by 2099.

Most estimates show a wide range, depending on how much glaciers and ice caps melt over the next 90 years. The truth is that scientists don’t know how much other environmental factors will contribute to, or slow down, the rate of sea level rise.  In addition, these are global estimates, which are averages and will not represent the exact numbers for specific locations. How much the sea level rises here in San Francisco Bay will not look the same as it will in Bangladesh.

The one thing scientists do agree on, however, is that sea level rise up to 2 meters (78 inches) is not out of the question, but certainly a high estimate. "Although increases of up to two metres this century can't be ruled out, this does not mean that they are inevitable or even likely."

And so we return to the question, “What should we do about it?”  The truth is, we just aren’t sure yet. What we do know are the factors that contribute to the acceleration of sea level rise.  Most scientists will tell you that, before we can fix the problem, we first need to stop the cause.  Otherwise, we’ll never get ahead our heads (and our buildings!) above the water line.

Peter Gleick, President of the Pacific Institute in Oakland, tells us “the good news is that there’s a lot that we could if we’re smart enough to do it in advance. There are a lot of things that we could do to reduce the risks of climate change and sea level rise around the Bay. The first thing we need to do is reduce the severity of climate change. And that’s an issue of reducing greenhouse gas emissions, that’s got to be done at the national level. We’re doing a little bit of it at the California level. It needs to be done at the global level. But whether or not the politicians get their act together and reduce greenhouse gas emissions, we’re still going to have to deal with some sea level rise. That’s built into the gases we’ve already put into the atmosphere…But where we get to at the end of the century is going to depend on actions that California or the United States or ultimately the whole globe takes to reduce the rate of greenhouse gas emissions, to reduce the rate of climate change.  If we don’t get our act together, if we don’t do things to reduce greenhouse gas emissions, we’re gonna reach a meter of sea level rise or more by the end of the century. And it’s gonna be growing even faster than it is now. But if for some reason we’re able to get a handle on emissions and the world is able to come together, we could slow that rate enormously, and limit the rate of sea level rise to hopefully only a few tens of centimeters. I don't think we’ll be that lucky, but that’s a possibility.”

Watch Going UP:Sea Level Rise in San Francisco Bay television story online.

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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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This is one of those environmental stories where one event, seemingly far in the past, can have a surprising ripple effect into the future. Most of us think of the Gold Rush and picture prospectors panning for gold in streams and rivers. But some miners used more industrial techniques like hydraulic mining. Using massive, pressurized hoses, they washed down entire mountainsides to get to the gold. (Check out this clip from the KQED special "Saving the Bay" for more).

As a result, millions of tons of sediment washed into rivers and streams in the Sierra foothills and made its way down to San Francisco Bay.  Amazingly, that process has taken decades, creating a murkier bay in the meantime.  Ten years ago, scientists at the US Geological Survey noticed the bay was clearing. While that can have many causes, scientists believe that the sediment pulse from the Gold Rush had finally worked its way out of the system.

It seems like the story would end there, but sediment has a complex role in the bay. Some ecosystems, especially wetlands, depend on sediment.  Salt marshes are built on every high tide by sediment that gets trapped in the plants.  These wetlands are also continually sinking as the soil settles, so this growth is key for keeping them at the right elevation. Less sediment in the bay means there's less for the wetlands, which could be an issue. But there's one thing that makes it worse: sea level rise. Some estimates say that the bay could rise by 55 inches by the end of the century.  That means sediment will have an increasingly important role in the future, one that state agencies are just starting to plan for.

Listen to The Changing Bay radio report online.

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Sea level rise scenarios for San Francisco International Airport.
Click the map to see a larger image.

The most recent estimate looks pretty dire. The Bay Conservation and Development Commission (BCDC), a state planning agency, says it expects San Francisco Bay to rise about 16 inches by 2050, and 55 inches by the end of the century.

The map on this page shows what San Francisco International Airport and the surrounding area would look like, if the bay rose a meter (roughly 36 inches). You can check other maps around the bay as well.

And the real danger of that big rise in bay waters happens during storm season. High tides and storm surges could send that higher water inland, flooding Highway 101 and neighborhoods along the bay. If the bay runs right up to the edge of development and we build sea walls to protect property, then that deep pool of water will have much higher waves, stronger currents and will pound the shoreline much harder than where there is now graduated wetlands. The effect, experts say, would be similar to what happens when you churn up water in a bathtub, and the wave energy quickly builds up and spills over the sides.

Part of the challenge in BCDC’s design competition is to come up with barriers that might absorb some of the power of those waves, instead of simply deflecting those waves with straight walls.

Listen to the Redesigning the Bay radio report online.

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