The water flowing past Big Break Regional Shoreline through the Sacramento and San Joaquin Rivers drains half of California's watershed, and creates the largest estuarine environment on Pacific shores.

We once again enlisted the help of our colleagues at the East Bay Regional Parks District on this feature. They've collaborated with us twice before, on science hikes in Briones Regional Park and Sibley Volcanic Regional Preserve.

We were welcomed at the gate by EBRPD Naturalist Mike Moran. Normally, we'd have rolled right on in to the parking lot, but the district has closed the parking area temporarily as part of a significant renovation, to include new trails and interpretive facilities. The lot should reopen sometime in November of this year (2010). Check the EBRPD website for closure updates if you are planning a visit. That said, don't be discouraged by the locked gate, even without the lot, the shoreline is still accessible through the foot path to the right of the main entrance.

Before we'd even unpacked our gear, Mike pointed out some raptors on the horizon, perhaps a quarter mile away. Some careful spotting through the binoculars revealed they were likely a pair of Swainson's Hawks. To my untrained eye, it might have appeared they were juvenile Red-tailed Hawks, but the different markings on the underside of the wings (e.g. lack of the black bars on the leading edge), plus the overall narrower profile of the wings themselves indicate otherwise. I've learned not to rely on the presence of a red tail, but Mike's keen eye helped me add this majestic buteo to my life list. What a way to start the day.

Other highlights? An amazing number of dragonflies and damselflies, including the Variegated Meadowhawk (Sympetrum corruptum). Stumbling upon a field of the understated but lovely yerba mansa plant (Anemopsis californica). Getting to see the marsh monkeyflower (Mimulus guttatus), a close cousin to the sticky monkeyflower (Mimulus aurantiacus) so common in the drier areas of our region. And lastly, an encounter not with an actual bird, animal or plant, but with something they had left behind– Otter scat.

And there's much more that I can tell you in this short post – please go check out the science hike and let us know what you think. Even better, through our partnership with EveryTrail, you may take it with you in print or via your smartphone and let us know how it goes.

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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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Reported by Alison Hawkes

As the sun comes up, lighting a ridge of windmills, I'm traipsing around the State Water Project grounds outside of Tracy trying to puzzle out this battle between farming and fish

The courts are packed with lawsuits on this issue. But one in particular caught my attention. It has to do with striped bass, a voracious predator in the system that was introduced in the 1870s and went on to become a popular sport fish.

Stripers are almost a naturalized citizen to the Delta, but farmers hope to blame the big fish for the plummeting numbers of endangered fish. If they win the case, which is now headed for trial, it could surely lessen the onus on water diversions from the Delta. That means the farmers could get more water, leaving the state to pay for costly mitigation measures to save the endangered fish species like Delta smelt and chinook salmon.

What is the evidence that stripers are wiping out these native species? At Clifton Court forebay, a large reservoir that feeds water to the pumps, stripers are a-plenty. Fishermen line the banks waiting for the gates to the forebay to rise so that the rushing water jostles the stripers out of their slumber. I met one fisherman down there who showed me a photo on his cellphone of a 15-incher he had recently caught. He brought it home for dinner.

It was also easy fishing for a team of state biologists who were on a motor boat in the forebay catching and tagging the stripers for further study. The big question the courts want answered is whether the stripers have a population level affect on the endangered fish species. Meaning, do stripers eat enough of these smaller fish to affect their numbers delta-wide. Here's where the science gets squishy.

In the lawsuit, the farmers and water users argue that stripers do have a population level effect.
They want to see fishing regulations on stripers lifted as a means to bring back endangered fish. But some biologists claim there's not enough research to show a population level impact. UC Davis fish biologist Peter Moyle says the best estimate done, involving a winter run chinook salmon, showed a 9 percent loss to stripers, which he says is “not a big number.” That was a National Marine Fisheries study. Remove the stripers, he says, and you could actually be upsetting a balance in the ecosystem. Stripers may be keeping other predators in check, like the tiny inland silverside, another non-native fish that has an appetite for delta smelt eggs.

Perhaps the best solution is to target striped bass fishing where we know they hang out – at places like Clifton Court Forebay and other structures created by the state and federal water projects. It's here where the endangered fish are most vulnerable, and where the stripers know they can find an easy meal.

Listen to Delta Predators radio story online.

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Every year, millions of fish make a strange and harrowing detour through the Skinner Fish Facility, part of the State Water Project's facilities in the Delta.

In my last post, I wrote about my visit to the Banks Pumping Plant, whose giant pumps slurp water from the Delta to help quench California's thirst. As the volumes of water are sucked up, both resident and migrating fish come along for the ride. The Skinner Facility, in operation since 1968, was built to protect fish from being killed at the pumps–an effort that sadly is not as successful as one would hope (more on that below).

I was amazed to learn there is a whole art and science to fish screens, which range from physical barriers–called positive barriers–like perforated plates or wire mesh, to behavioral barriers like sound, light, or other stimuli aimed at keeping fish away. Well-designed screens minimize both entrainment (fish being pulled into the pump or diversion) and impingement (fish being trapped or injured against the screen itself due to water velocity).

Both physical and behavioral barriers are used at the Skinner Facility. Fish being pulled toward the pumps first encounter a trash rack that diverts many bigger fish, along with floating debris. Next, fish encounter a large, v-shaped array of metal louvers. The louvers create turbulence that functions as a behavioral signal, encouraging the fish to swim away into bypass pipes that function, as our tour guide put it, like "a big vacuum system."

From the bypass pipes fish travel to another set of louvers and pipes, concentrating them into a smaller volume of water, and then into holding tanks in a nearby warehouse. Giant, suspended cone-shaped buckets are used to periodically sample the fish, which are identified, counted, and measured. Some 90 species turn up in the facility, including Chinook salmon, steelhead, white sturgeon, and delta smelt. (I asked our guide if delta smelt really do smell like cucumbers. He confirmed it. In fact, when a school of smelt comes through–an event that has become rare–the warehouse smells "like a salad.") When enough fish have been collected, they are loaded into trucks and driven back to the Delta.

Here's the rub. Many fish caught in the pull of the pumps are lost to predation before even reaching the screening facility. Then, the facility does not effectively screen fish smaller than about 1.5 inches, meaning that littler, less powerful species and juveniles are still vulnerable to the pumps. For the fish that make it to the holding tanks, the process is such a trauma–with big and little fish squashed together in the tanks, buckets, and trucks–it's no surprise there are casualties; in fact, the delicate delta smelt often do not survive. And even for fish that make it through the entire process and out the other end, there's a final, fatal hurdle: the trunks routinely dump salvaged fish at the same locations, where more predators have learned to cluster for a free lunch.

Scientists agree that the loss of fish at the huge state pumps–and other pumps and intake pipes throughout the Delta–is a major contributor to plummeting populations. How much water we use makes a difference: The higher the export rates, the more fish are entrained. There also is broad consensus that more state-of-the-art fish screening facilities are needed. That could come with a hefty price tag. But with our fish disappearing, can we afford not to invest in their survival?

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Harvey O. Banks Pumping Plant

In my last post I wrote about visiting a treatment plant to see where our water goes after we've washed the dishes. Now, on this tour of the Banks plant, I'm getting a glimpse "upstream" of the kitchen tap and learning more about where our water comes from.

The scale of the SWP is mind-boggling: More than two in three Californians rely on it for at least part of their drinking water. It is the largest publicly built and operated water project in the country, encompassing 17 pumping plants, more than 30 storage facilities, and over 660 miles of canals and pipelines. At the south end of the San Joaquin Valley at the Tehachapi Mountains, the huge Edmonston Pumping Plant raises the water 1,926 feet-the highest single lift in the world. (If you're driving to Southern California, check it out on the right side of I-5 just before the Grapevine). Moving all that water around and hoisting it over mountains doesn't come easy (water is heavy, after all): The SWP is the largest single user of electricity in the state.

The Banks plant is named for Harvey O. Banks, Director of Water Resources when voters approved funding for the SWP in 1960. The project was ostensibly conceived as a solution to the problem that most of California's water is north of the Delta, while most of its people are to the south and west. Big agricultural interests in the southern San Joaquin Valley also benefited-hugely-from "surplus" water shipped south. (And lest we Northern Californians start feeling smug, keep in mind we receive a greater percentage of our total water supply from the Delta than does Southern California.)

The Banks plant draws water from the Delta through intake gates into Clifton Court Forebay. From there, the water is pulled up a channel to the Skinner Fish Facility, where delta smelt, Chinook salmon, and some 90 other species of fish are, theoretically, screened out so they won't get sucked into the pumps (More on fish screening in my next post). But getting squashed in the pumps is not a fish's only worry: The pumping actually alters the habitat by impacting salinity and flow, disrupting natural rhythms that serve as vital cues for migration and spawning. The old joke that in California water flows uphill toward power and money is not far off the mark: The pull of the pumps is so powerful it causes rivers to flow backwards-literally uphill.

Crashing fish populations, poor water quality, the vulnerability of Delta levees and our water supply to earthquakes or other disasters-all have added to the growing realization that we can't keep quenching California's thirst through big straws stuck in the Delta. Obviously the SWP is not going to stop pumping anytime soon. But we do need to find ways to reduce our reliance on the Delta-through conservation, water recycling, and increased regional self-sufficiency-and to restore the functioning of an ecosystem so devastated by our radical retooling of our waterways.

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Recent news headlines have been full of Chinook salmon, but sadly the same cannot be said of Central Valley waterways. This fall, only about 90,000 Central Valley Chinook salmon returned to their home rivers and streams to spawn, down from more than 800,000 just a few years ago.

Like most salmon, Central Valley Chinook are anadromous, spending the bulk of their lives in the ocean but hatching and returning to reproduce in freshwater. The journey from the Valley through the Delta and San Francisco Bay to the Pacific, and back again, has always been a long and arduous one. In the past half century it has become even more difficult as the fish have increasingly faced an obstacle course of dams, pumps, and dewatered rivers and creekbeds.

Central Valley Chinook salmon populations include four runs-winter, spring, fall, and late fall-with each spawning not only at different times of the year but in different parts of the watershed. The dawning of the age of dams hit the winter and spring runs the hardest, cutting the fish off from their historic spawning grounds in the upper reaches of the watershed. Both runs are now listed under federal and state Endangered Species Acts.

The fall run, which spawns lower in the watershed, was less impacted by dam construction. In recent decades it has numbered more than 10x all the other runs combined and has been the mainstay of the California coastal salmon fishery. Now, even it appears to be in serious trouble: The count of 90,000 salmon this year was the second lowest on record and well below the minimum conservation target of 122,000 set by the Pacific Fishery Management Council. Also alarming is that the number of 2-year-old "jacks" returning was just 2,000, down from a typical count of 40,000. Since most spawners are 3-year-olds, these early returners are considered a good predictor of the size of next year's run.

Ocean conditions are one factor in the salmon decline, with rising water temperatures and more unpredictable upwellings-possibly resulting from global warming. But scientists are also pointing to overexploitation of our rivers and Delta-the "highway" for migrating salmon. The abrupt decline in the salmon population comes concurrently with the collapse of other fish species dependent on the Delta ecosystem, including delta smelt and longfin smelt. The salmon returning to spawn this year would have been juveniles headed to the ocean in 2005, the year Delta water exports hit a record high.

Between unfriendly ocean conditions and the degraded condition of the watershed, the salmon are facing a double whammy. But, as Bay Institute Senior Scientist Tina Swanson points out, "Apart from rolling back global warming, we can't really control ocean conditions. What we can do is drastically improve conditions within the watershed so that more adults can spawn successfully and more juveniles survive the journey to the ocean."

Ann Dickinson is Communications Manager for The Bay Institute (www.bay.org), a nonprofit research, education, and advocacy organization dedicated to protecting and restoring San Francisco Bay and its watershed, "from the Sierra to the sea."