By

Nate Seltenrich
About the author

Nate Seltenrich is a freelance science and environmental journalist who covers infrastructure, restoration, and related topics for Estuary. He also contributes to the San Francisco Chronicle, Sonoma and Marin magazines, the journal Environmental Health Perspectives, and other local and national publications, on subjects ranging from public lands and renewable energy to the human health impacts of climate change. He lives in Petaluma with his wife, two boys, and four ducks. www.nate-reports.com

Articles by Nate Seltenrich

Nate
12
May

Nate Seltenrich

Among all the stories I’ve written for Estuary News, what makes two stand out in my mind? Location, location, location. The first, which ran in December 2017, involved a visit to one of my favorite Bay Area wildernesses, Henry W. Coe State Park. In my 20s and 30s I made many memorable backpacking and hiking trips throughout this vast, little-known park. The opportunity years later to return to a remote corner of the park with scientists studying wildlife in pristine Coyote Creek made for a very meaningful experience—and an interesting article, Coyote’s Cache of Intermittent Riches. The second, by contrast, represented my introduction to a whole new place: San Rafael’s waterfront Canal neighborhood. Through numerous visits to the area, both by foot...
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Techniques used to add sediment to the Montezuma Wetlands included hosing it from a sediment laden barge. Photo: Darren Graffuis
21
Mar

More Mud Please for Novato Baylands

Imagine a complex of tidal wetlands skirting San Pablo Bay unbroken from China Camp to Mare Island, providing vital wildlife habitat and protecting inland communities from storm surge and sea-level rise. With stretches of this shoreline formerly diked and drained (or in Hamilton Wetlands’ case, converted to a military airfield), reconnecting it may have once seemed unlikely. Yet today just two gaps remain, one of which is included in a restoration project that’s already underway: Bel Marin Keys. And it’s a doozy. The problem is one of scope—and more specifically of mud. The project site, currently partitioned into fields for agricultural use by a grid of berms and drainage ditches, is so large (1,900 acres), and the land so subsided...
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Top Photo: Bay Trail in Richmond. Photo: Ben Botkin
21
Mar

Boots on the Bayshore: Bay Trail

It’s largely taken for granted within the San Francisco Bay environmental community today that public trails through parks and preserves are both right and good: right, in the sense that they can offer equitable access to our region’s most treasured natural assets; and good, because they engender support for protection and restoration. But along the waterfront, trails weren’t always so welcome. “The local chapters of the Audubon Society and the Sierra Club were adamantly opposed,” recalls Tom Mikkelsen, who led implementation of the Bay Trail, an ambitious multi-use trail ringing the Bay, from its inception in 1988 until 2001. “Every time we came up with a project that was close to the edge of the Bay, they opposed it. And...
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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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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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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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15
Feb

Natives Who Can Rough It

Name a native fish. One that spends lots of time in the Delta. One that’s not a salmon, smelt, or sturgeon. One whose population isn’t plummeting, and in fact seems to be doing just fine. By now the list of possibilities has been shortened severely — though not exhausted. A number of native fish still ply Delta waters in stable numbers, but precisely because there are no restoration projects, monitoring programs, or conservation efforts designed to save them — or perhaps because they’re not game fish, or particularly large, or traditionally “charismatic” —  theirs are not household names. To the extent that they are recognized by the general public at all, some are even referred to, somewhat derisively, as “rough”...
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15
Dec

A large pulse of water sent through the Yolo Bypass in summer 2016 boosted phytoplankton biomass and food web conditions in Cache Slough and the lower Sacramento River, a new report confirms.

 “Our goal was to improve estuarine habitat by increasing net flows through the Cache Slough Complex to enhance downstream transport of lower trophic-level resources, an important driver for fish such as the endangered Delta Smelt,” write the authors—including esteemed (and recently retired) California Department of Water Resources lead scientist Ted Sommer—in the latest issue of San Francisco Estuary and Watershed Science. The pulse occurred over three weeks in July, a time when flows in the region above Cache Slough are often negative (meaning they go “upstream”) due to agricultural diversions and low freshwater inflow. Producing the pulse, which increased downstream flows from about negative-two cubic meters per second to a peak of 15 cubic meters per second in the Toe Drain...
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25
Oct

Invasive Species Breakdown

The invasion of the Delta continues, with new plants and animals threatening to upend ecosystems alongside established non-native species like largemouth bass and spartina. Preventative measures, early detection, and rapid response to novel threats are all key in protecting the Delta from further disruption. But the concepts of community involvement and reconciliation ecology also encourage land managers to consider non-natives with nuance. This means accounting for the cultural and ecological values of invasive species and, in some cases, learning to accept their presence on the landscape while still prioritizing natives. These were among the takeaways of the Estuary Summit’s lunchtime breakout discussion of invasive species in the Delta (one of seven breakout sessions, on topics ranging from water quality to...
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25
Oct

Saving Water Under the East Bay

It’s a matter of semantics as to whether the Bay Area ever really left the drought of 2014-2017 before staring down another, more severe one beginning last year. But a huge lesson for our entire state from that “first” water shortage still being learned today is that more attention must be paid to groundwater. That’s true even in the urban East Bay, where the East Bay Municipal Utilities District (EBMUD) and the City of Hayward are developing a plan to ensure continued sustainable use of freshwater sitting beneath the East Bay flats from Richmond to Hayward. In September 2014, Governor Jerry Brown signed into law three bills known as the Sustainable Groundwater Management Act. Among other things, the Act requires...
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Smelt cam photo
19
Aug

Monitoring Delta smelt with an underwater camera could be safer and more effective than with a traditional trawl.

Standard smelt surveys rely on the use of boat-driven nets, which trap fish by funneling them from the wide mouth of the net to the closed end (known as the cod end). To check their catch, researchers must pull the net and its contents from the water. But this additional handling can harm and even kill the same fish that wildlife agencies are trying to save with the support of robust, long-running monitoring efforts. There may be a better way: According to a new study in the June 2021 issue of San Francisco Estuary and Watershed Science, the use of an underwater camera—the “SmeltCam,” developed about a decade ago by U.S. Geological Survey (USGS) research fish biologist Frederick Feyrer—could provide...
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17
Jun

Three Ways to Feed the Marsh

Seal Beach is drowning. As a result of sea-level rise, subsidence, and limited sediment supply, much of the 920-acre National Wildlife Refuge in Orange County can no longer keep its head above water. Pacific cordgrass, normally exposed at low tides, is being completely inundated. Rare nesting habitat for the endangered light-footed clapper rail is disappearing at high tides. It’s a marsh manager’s worst nightmare, and a potential harbinger of things to come later this century for tidal wetlands up and down the state, including those in San Francisco Bay. The problem at Seal Beach has been building for decades, and by 2016 managers knew they had to act—fast. But options for saving the existing marsh were limited. So on an...
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07
Jun

Electrofishing is a powerful but underutilized tool for monitoring Delta fish, particularly species favoring “structured” habitats that are difficult to sample using more common methods like trawls and seines.

By analyzing fish catch data from past surveys, researchers Ryan McKenzie, of the US Fish and Wildlife Service, and Brian Mahardja, of the US Bureau of Reclamation, determined that electrofishing resulted in better detection rates for many native and non-native species than net-based surveys. Although electrofishing is currently restricted to freshwater areas of the Estuary and is more selective of larger fish and those with swim bladders, McKenzie and Mahardja recommend that resource managers employ the technique more widely to support long-term conservation planning. Electrofishing, or e-fishing as it’s sometimes known, uses a generator aboard a small boat to pass electricity through the water beneath and in front of the boat. “When the electricity moves through the water, it can...
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07
Jun

The robust monitoring programs established to track now-rare Delta smelt could benefit other native fishes, too.

Decades ago, resource managers first learned of declining Delta smelt numbers not through surveys targeting the once-abundant native fish, but rather as a byproduct of long-term monitoring programs for non-native striped bass. Now, the authors of a new study published in the March 2021 issue of San Francisco Estuary and Watershed Science advocate for the use of bycatch data from the recently established Enhanced Delta Smelt Monitoring (EDSM) program to better understand juvenile Chinook salmon distribution. “The scope of [this multi-million dollar Delta smelt survey] has not really been seen before in the Estuary,” says lead author Brian Mahardja, a biologist with the US Bureau of Reclamation, “that’s why there was a call to see what else we can gain...
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23
Mar

Fire Sparks Sewer Boon in Larkfield

Early on the morning of October 9, 2017, a firestorm roared with unforgiving speed across a swath of northeastern Santa Rosa. The unincorporated community of Larkfield lay directly in its path. One-hundred and sixty homes there burned to the ground. Three and a half years later, Larkfield is still being rebuilt—in some ways better than ever, thanks in part to an ambitious and innovative program by the Sonoma County Water Agency to bring sewer service to the modest, tight-knit community at the foot of the Mayacamas Mountains. New homes of all shapes, sizes, styles, and colors, each designed to suit the owner’s preference, are interspersed with dozens more in varying stages of construction. On a recent weekday afternoon, building and...
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01
Mar

North America’s largest and most ancient freshwater fish species, white sturgeon, hang out in some kinds of Estuary waterways more than others, scientists find.

 Researchers with the U.S. Geological Survey found that adult and sub-adult white sturgeon occupy deep open-water channels and shallow open-water shoals in equal measure, but don’t use shallow wetland channels. As a group, white sturgeon are characterized as amphidromous, meaning they regularly migrate between freshwater and the sea, in both directions, but not for the purpose of breeding. According to the study, which appears in the December 2020 issue of San Francisco Estuary and Watershed Science, adults in the local population use coastal habitats to some degree, but typically remain in the Estuary and lower Sacramento and San Joaquin rivers. There they congregate in deep areas with fine-sediment substrate, and are thought to move into shallow subtidal habitats to feed...
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22
Sep

Match Points in Stormwater Soup

Effluent from wastewater treatment plants is often seen as the primary source of emerging contaminants in San Francisco Bay. But a report published in July by the Regional Monitoring Program challenges that assumption by highlighting the importance of urban stormwater runoff as another major source.
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06
Jul

Sacramento pikeminnow and introduced striped bass in the middle Sacramento River eat a surprisingly similar diet, says a new study in San Francisco Estuary and Watershed Science.

Both species have been implicated in the decline of vulnerable native species in the river, particularly juvenile Chinook salmon, says lead author Dylan Stompe, a PhD student and researcher at the University of California at Davis. For eight months in 2017, Stompe and fellow researchers with the California State University at Chico and the California Department of Fish and Wildlife surveyed a 35 kilometer reach of the river outside Chico for the two predatory fish. They baited hooks with with sardines, worms, and chicken liver and fished from an anchored boat. When they brought a pikeminnow or striped bass on board, the researchers performed a gastric lavage, in which pulses of pressurized water are directed into the fish’s esophagus, causing...
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18
Jun

Squeezed by Geography

In most respects, Marin County is a privileged place. But its miles of Bay and ocean shoreline and many low-lying towns, positioned to afford easy coastal access and world-class scenery, represent a major liability in the era of sea-level rise. “Marin is the canary in the coal mine in some ways, because almost everything is in that narrow strip along the Bay,” says Roger Leventhal, a senior engineer with Marin County Public Works.
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16
Apr

A grassroots effort to move migrating newts across a Marin County road has drawn to a close, but organizers hope it leads to a more permanent solution.

For roughly half a mile, the two-lane road in a hilly rural area west of Petaluma travels alongside a large, natural body of water called Laguna Lake. On the other side is an oak woodland: the perfect place for California and rough-skinned newts, which spend the dry season in moist terrestrial habitat under leaf litter and wood debris or inside animal burrows. After seeing a number of native newts flattened along the road on rainy winter evenings, a small group of neighbors led by rancher Sally Gale formed the Chileno Valley Newt Brigade. Gale trained some 50 volunteers to monitor the road and physically transport newts across it on a nearly nightly basis throughout the winter migration. She also obtained...
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