Taking the Measure of Success at the South Bay Salt Ponds

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21
Mar

Taking the Measure of Success at the South Bay Salt Ponds

It is two decades now since some 23 square miles of South Bay salt evaporation ponds became public property. Eighty-eight old impoundments were to be remade into habitat for birds and other creatures—and into a superior flood-control buffer for communities beside the rising Bay. Progress since then has been slow, and fast. Slow, because relatively small swathes of territory have been visibly, obviously changed. Slow, because a whole set of basic questions had to be answered before the work could pick up speed. And fast, because those questions have now been answered, by and large, and the news is pretty good. As sea-level rise makes the project ever more urgent, the way seems open to a rapid transformation in the...
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Seining Luco pond. Photo: Brian Williamshen
21
Mar

Suisun’s Working Landscapes Support Fish

On a sunny spring day in 2014, two UC Davis PhD candidates in waders pulled a 30-foot seine through Luco Pond (also known as the Potrero Duck Club) in Suisun Marsh. Luco Pond is within the Nurse-Denverton Slough Complex where duck clubs use tidal gates to control water exchange. After 45 minutes of counting diminutive fish, Brian Williamshen and Melissa Riley were excited to tally more than 6,900 sticklebacks, a thorny-backed native fish in the Sacramento-San Joaquin River Delta. “There was definitely a moment of excitement,” Williamshen says. “But when we were at our 50th fish, and the little spines kept poking us in the fingers, our emotions shifted to like, oh man, we still have hundreds more to go!”...
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Shorebirds-on-1-restored-habitat_U.S.-Geological-Survey_William-Chan
21
Mar

Wetland Restoration is for the Birds

It’s high tide at Eden Landing Ecological Reserve, on San Francisco Bay due west of Union City, and Nathan Van Schmidt is counting birds on Pond E9 with both hands. Van Schmidt, science director for the San Francisco Bay Bird Observatory, has a clicker in his right hand to track American Avocet, and another in his left for Northern Shoveler. “Wetlands can support an incredible biomass of birds,” he says. “And Eden Landing is one of the birdiest places in the Bay.” The Observatory, a local nonprofit bird conservation organization, helps the South Bay Salt Pond Restoration Project to monitor how birds are doing on 82 managed ponds and restored tidal wetlands. This pond, with water levels maintained at about...
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blue whale feeding
31
Oct

Blue Whales Consume Microplastic Particles by the Billion

The age of humans, termed the Anthropocene, might just as well be considered the age of plastic. The dangerously durable material, made ubiquitous in products and packaging through the late 20th century, has inundated our planet’s environment. Today, miniscule plastic pieces are present in deep-ocean sediment, high-mountain snow and just about every place in between. Plastic waste has also entered the marine food web, and according to new research, baleen whales are ingesting staggering quantities.  Blue whales off the California coast may consume as many as a billion pieces, or up to several tons, of microplastic in the course of a summer feeding season, according to a paper published today in Nature Communications.  The authors of the paper, led by Cal State Fullerton...
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12
Oct

Science in Short: The Hullabaloo About HABS

Dead fish belly up in Lake Merritt and San Francisco Bay this past August sent scientists like Keith Bouma-Gregson scrambling to pinpoint the cause. A harmful bloom of marine algae had taken up residence in the Bay. Bouma-Gregson discusses his observations of the event in this podcast.
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12
Oct

Key Facility’s Fuzzy Future

There are 14 marine laboratories in California. Just one of them is on San Francisco Bay: the Estuary and Ocean Science Center (EOS), on the rugged eastern shore of the Tiburon Peninsula in Marin County. EOS has trained generations of leading figures in estuary science and management. It possesses a site and facilities that no possible alternative could match. The research community swears by it. And in two years it might close. In the 1970s, after decades as a U.S. Navy property, the 53-acre parcel was considered for inclusion in the Golden Gate National Recreation Area. Instead, in 1977, it passed—for one dollar—to San Francisco State University (SFSU). But the bargain has devolved into a burden, and today a budget...
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12
Oct

Drought Strains Stormwater Monitoring Endeavors

When it rains, it pours. This old saw passes for an apt description of the new precipitation regime that climate change has wrought for the Bay Area: larger winter storms, but fewer of them. The implications of this shift for ecosystems, infrastucture, and water storage are widespread, and often highly visible. But behind the scenes, it is also complicating efforts to monitor pollution inputs to the San Francisco Bay and other local water bodies from stormwater runoff. The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) has been collecting data in Bay water, sediment, and biota since 1993. RMP monitoring of stormwater flows after rain events, which began in 2006, has shown that runoff is a major...
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29
Sep

Of Mice and Marshes: Surveying Salties to Save Them

It’s five in the morning, and Don Edwards San Francisco Bay National Wildlife Refuge remains in the tight velvet grip of night. All is peaceful and quiet, despite the fact that the toll plaza of the Dumbarton Bridge is less than a quarter-mile away. By 5:15, car dome lights and slamming doors have transformed this lonely spot at the watery edge of Newark into a hub of activity. People are taking last sips of coffee, strapping headlamps to their foreheads, and swapping civilian footwear for rubber muck boots. The occasion that’s roused everyone from bed more than an hour before sunrise? The first survey of the salt marsh harvest mouse conducted across the rodent’s entire San Francisco Bay-centered range. In...
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31
Aug

Researchers are applying a novel genetic technique as part of the development of an annual estimate for the number of juvenile spring-run Chinook salmon entering the Delta.

The technique, spearheaded by geneticist Melinda Baerwald from the California Department of Water Resources, allows researchers to accurately distinguish young spring-run salmon from other runs by targeting DNA sequences specific to these fish.   In a paper published in San Francisco Estuary and Watershed Science, lead authors Baerwald and Peter A. Nelson explain some of the challenges of developing this estimate, called the spring-run juvenile production estimate. A key hurdle is differentiating spring-run fish from salmon that migrate during other seasons. Unlike juvenile salmon from the winter run, spring-run juveniles are hard to identify using the conventional length-at-date approach, which determines age and spawning migration season based on size.   “There’s nothing visually about a spring-run salmon that distinguishes it...
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31
Aug

Groundwater pumped from subsided islands back into Delta channels through 200 or more active outfalls can be laden with excess nitrogen transported from island soils, report the authors of a new study.

The Sacramento-San Joaquin Delta contains more than 50 peat islands. Most have subsided—some as much as three meters — as a result of drainage for farming, and must maintain artificial water tables below the land surface via managed pumping. According to researchers from the University of California at Santa Cruz and the US Geological Survey, these pump stations are an underappreciated source of nutrients in nearby waters, with potentially significant implications for habitat and water quality.   To get a sense of how much nitrogen is leaving the islands and when, the researchers measured monthly discharge along with nutrient and trace element concentrations in drainage from three Delta islands over the course of nearly a year and a half, then...
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31
Aug

Light and nutrients are the staples of every phytoplankton production recipe, but wind and tides in the Delta affect phytoplankton production too, say researchers.

Several projects in the lower Sacramento River and Delta have been exploring strategies for increasing the quantity and quality of food for migratory and resident fish. As part of a broader whole-ecosystem experiment that added nitrogen into the Sacramento River Deep Water Ship Channel, Leah K. Lenoch and colleagues at USGS and UC Davis looked into the channel’s hydrodynamics to explore whether the environmental conditions there hold promise for increasing the quantity of phytoplankton (the microscopic algae at the base of the food web). They knew that turbid and well-mixed waterways, including parts of the San Francisco Estuary and Delta, are not very productive because phytoplankton don’t get enough light and are at the mercy of invasive clams. However, where...
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19
Jun

Finding Her Way to Fish: Denise Colombano

The path into a career is not always a straightforward one. “I hated school. I mean, hated school,” says Denise Colombano, a postdoctoral fellow and Delta Science Fellow working on fisheries research at UC Berkeley. Today, Colombano feels that it is important to talk about her story as a way of encouraging inclusiveness and opportunity within her field — and in the sciences in general.  “I actually flunked ninth grade, and was attending a continuation school, when my science teacher asked if anyone was interested in skipping classes for the day.” Colombano jumped at the chance, and found herself at Martin Luther King Jr. Regional Shoreline in Oakland, helping the Audubon Society train schoolchildren in birdwatching. “We were supposed to...
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Over time, the median actual flow to San Francisco Bay in the ecologically critical winter and spring months has declined to less than half of the unimpaired runoff. This bar chart divides actual inflow (the amount that actually made it to the Bay) and unimpaired runoff (the inflow to the Bay that would occur if there were no dams or diversions) into quintiles from wettest to dry, and marks years drier than 2015 (roughly, the driest 2% of years) as “super-critically dry” years. Over the last 54 years, “super-critically dry” runoff conditions in the Bay’s watershed occurred naturally only once, in 1977, but the Estuary received runoff volumes in the super-critical range in 22 years, or 40% of the time. Overall, flow volumes characteristic of the driest 20% of years now occur more than half the time as a result of storage and diversion of runoff for consumptive uses. Source: The Bay Institute, based on data from California Department of Water Resources.
18
Jun

Defining Unimpaired Flows

For the second time in four years, a proposal for a voluntary agreement between agencies and water contractors on flows into and through the Delta from the San Joaquin and Sacramento rivers and their tributaries is wending its way through the State Water Resources Control Board. The proposal, which would replace the regime outlined in the Board’s most recent update to the Bay-Delta Plan, calls for substantially less water remaining in the system than the update, but comparing the two requires understanding some terminology, specifically the concept of “unimpaired flows.” In 2018 the State Board adopted Phase 1 of the Bay-Delta Plan update, calling for San Joaquin River inflows to the Delta of 40% of unimpaired flow; a framework for...
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Adrienne Ernst among the Phragmites. Photo: Michael Adamson
16
Jun

Living with a Novel Landscape: Suisun Evolves

Morning at Suisun Marsh is a living watercolor with a soundtrack. Miles of tule and pickleweed populate the foreground, split by canals glinting silver from the sun. In May, the hills undulate across the northern boundary in classic California gold. A red-tailed hawk’s iconic hoarse screech punctuates the insectine buzz as it takes off from a powerline. At 7:40 AM, it’s already 72 degrees and there’s no trace of a breeze. I’ve come to visit the Marsh from downtown Oakland seeking to learn from biologists, hunters, and land managers what’s at stake in the myriad battles with rising seas, worsening drought, and, especially, encroaching invasive species and what makes it such a singular, attractive landscape.  Indeed, the pastoral foreground is...
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Baldocchi at the end of one of the levees breached to restore tidal action at Dutch Slough. Photo: Janet Byron
16
Jun

Sniffing the Delta for Greenhouse Gases

Dutch Slough in Oakley, on the southern edge of the Sacramento-San Joaquin Delta, is less than a mile from where biometeorologist Dennis D. Baldocchi (above) grew up on his parents’ orchard and fished with pals in nearby Marsh Creek. In October 2021, the California Department of Water Resources breached the levees here, restoring nutrient-rich tidal flows to degraded ranchland. Early in the 20th century, Baldocchi’s father grew dry beans and sugar beets on the peat soils of the Delta’s Liberty Island, and his aunt’s family raised asparagus, sugar beets, and corn on Sherman Island. In 1952, his dad started growing almonds and walnuts at the junction of Sellers Avenue and Cypress Road in Oakley. “My family mined the Delta for...
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subisdence on 4 delta islands map
13
Apr

Asked to suggest an appropriate future for four Delta islands owned by the Metropolitan Water District, it’s difficult not to want the moon.

Why not richer rice fields, more wetlands, better boat launches, extended trails, even eco-tourism? ? A new survey for the Delta Islands Adaptation Project, funded by a Prop 1 Watershed Restoration Grant, wants the public’s opinion on the importance of 10 possible land-use objectives leading to the selection of one of the four islands for improvements. As your blinking cursor hovers over a satellite image of Bouldin, Bacon, Webb, and Holland Tracts, the survey lays out all that the experts know already: Holland is the least subsided; Bouldin the most accessible by road; Webb the best candidate for making more fish food, and more. “The Central Delta has some of the most critical landscapes in the state, and also some...
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chart by Hutton
13
Apr

An examination of 50 years of records reveals an apparent seasonal bias in estimates of freshwater flow from the Delta to the San Francisco Estuary.

The seasonal bias suggests flows were overestimated during the summer months and underestimated during the winter. Estimates of Delta outflow use a measurement called net Delta outflow index (NDOI), which is determined by taking the amount of Delta inflow, from sources such as the Calaveras, Sacramento, and San Joaquin rivers, and subtracting Delta exports, a direct measurement, and net Delta channel depletions. A team led by TetraTech’s Paul Hutton compared NDOI estimates against measured Delta outflow at four points, as well as against the Estuary’s historical salinity record. The study, which appears in the December 2021 issue of San Francisco Estuary and Watershed Science, focused on net Delta channel depletions, which are determined indirectly and involve considerations such as land...
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diagram of fish net trawl
13
Apr

Fish monitoring surveys in the San Francisco Estuary net different numbers of different fish species depending upon when and how they sample.

According to a new study published in San Francisco Estuary and Watershed Science, even surveys that target the same part of the water column can come up with significantly different catches. The study’s authors analyzed decades worth of data from the California Department of Fish and Wildlife (CDFW) Fall Midwater Trawl, which spans from San Pablo Bay to the upper Delta; CDFW’s San Francisco Bay Study midwater and otter trawls, covering the South Bay to the central Delta; and the UC Davis Suisun Marsh Fish Study, also an otter trawl. The two midwater trawls, which sample the middle of the water column, were found to be generally more successful at catching pelagic (open-water) fish like Delta smelt and American shad...
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field in delta with irrigation
13
Apr

Rain or shine, farmers in California use about the same amount of water every year, while residential water use varies considerably with precipitation.

A research team led by UC San Diego’s John Helly processed 15 years’ worth of water-use data from the state’s Department of Water Resources, reporting in the March 2022 issue of San Francisco Estuary and Watershed Science that while “the annually precipitated water supply in the Bay-Delta” varied by 30%, agricultural water use scarcely changed year to year. “The water management system maintained nearly constant agricultural water use even in periods of intense drought, with year-to-year variation of about 7%,” the authors wrote. Residential water use showed more variability, swinging by 20% from one year to the next–mainly, the authors theorize, as the result of voluntary and mandated water conservation during droughts. Though Helly says he had no expectations of...
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13
Apr

Science in Short: Daylighting Delta Data

Once you know how many fish are present in a particular part of a river, including additional details like the time of day and water temperature, what do you do with this information? For decades, Delta researchers have collected millions of similar data points from daily visits to the San Francisco Estuary, not all of which are available or immediately useful. How that information is then translated into a language relevant to water and conservation managers requires serious number, or data, crunching. Sam Bashevkin, senior environmental scientist at the Delta Science Program in the Delta Stewardship Council, is working to bring data science to the San Francisco Estuary and help to make sense of the overwhelming data troves generated by...
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