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For more than a century, USGS scientists have conducted research in California’s Bay-Delta region. Informing natural-resource management decisions on the region’s issues, this research has been published in thousands of documents, some highlighted below.

Filter Total Items: 308

Quantifying the effects of tides, river flow, and barriers on movements of Chinook Salmon smolts at junctions in the Sacramento–San Joaquin River Delta using multistate models

Successful migration of Chinook Salmon (Oncorhynchus tshawytscha) smolts seaward in the Sacramento – San Joaquin River Delta (hereafter, Delta) requires navigating a network of numerous branching channels. Within the Delta, several key junctions route smolts either towards more direct paths to the ocean or towards the interior Delta, an area associated with decreased survival. Movements within the

Michael Dodrill, Russell Perry, Adam Pope, Xiaochun Wang

Influence of invasive submerged aquatic vegetation (E. densa) on currents and sediment transport in a freshwater tidal system

We present a field study combining measurements of vegetation density, vegetative drag, and reduction of suspended-sediment concentration (SSC) within patches of the invasive submerged aquatic plant Egeria densa. Our study was motivated by concern that sediment trapping by E. densa, which has proliferated in the Sacramento–San Joaquin Delta, is impacting marsh accretion and reducing turbidity. In

Jessica R. Lacy, Madeline R. Foster-Martinez, Rachel M. Allen, Judith Z. Drexler

Effects of tidally varying river flow on entrainment of juvenile salmon into Sutter and Steamboat Sloughs

Survival of juvenile salmonids in the Sacramento–San Joaquin Delta (Delta) varies by migration route, and thus the proportion of fish that use each route affects overall survival through the Delta. Understanding factors that drive routing at channel junctions along the Sacramento River is therefore critical to devising management strategies that maximize survival. Here, we examine entrainment of a
Jason G. Romine, Russell Perry, Paul Stumpner, Aaron R. Blake, Jon R. Burau

2011 Georgiana Slough non-physical barrier performance evaluation project report

The Sacramento River and its tributaries support populations of anadromous fish species including winter-run, spring-run, fall-run, and late fall–run Chinook salmon (Oncorhynchus tshawytscha); and steelhead (O. mykiss). Several of these species are listed as threatened or endangered under the California Endangered Species Act (CESA), federal Endangered Species Act (ESA), or both. These species spa
Jason G. Romine, Russell W. Perry, Theresa L. Liedtke

Shoreline retreat of the Corte Madera marshes, 1853 to 2016, Marin County, California

The greater San Francisco Bay estuary, prior to human intervention, encompassed about 2,200 km2 of tidal and salt marshes. Over time, these areas became increasingly diked, developed, and altered from their natural state. In addition, natural forces are always driving a continually shifting equilibrium.This study area, the Corte Madera marshes, is a tidal marsh or wetland located in southeastern M
Bradley A. Carkin, Robert E. Kayen, Florence L. Wong

Using the STARS Model to evaluate the effects of two proposed projects for the long-term operation of State Water Project Incidental Take Permit Application and CEQA compliance

The California Department of Water Resources (DWR) requested analysis of juvenile Chinook salmon survival in the Sacramento-San Joaquin River Delta (henceforth identified as “the Delta”) as part of an effects analysis that will be included in an Incidental Take Permit (ITP) Application. This application is in compliance with the California Endangered Species Act (CESA) and Environmental Impact Rep
Russell W. Perry, Amy C. Hansen, Scott D. Evans, Tobias J. Kock

Using the STARS model to evaluate the effects of the proposed action for the reinitiation of consultation on the coordinated long-term operation of the Central Valley and State Water Project

In 2016, the U.S. Bureau of Reclamation (USBR) and California Department of Water Resources requested a reinitiation of consultation under Section 7 of the Endangered Species Act on the coordinated long-term operations of the Central Valley and State Water Projects. This resulted in a Biological Assessment released by USBR in 2019. In its analysis of the Biological Assessment for its Biological Op
Russell W. Perry, Adam C. Pope, Vamsi K. Sridharan

Seasonal variation in sediment delivery across the bay-marsh interface of an estuarine salt marsh

Sediment transport across bay–marsh interfaces depends on wave energy, vegetation, and marsh-edge morphology, and varies over a range of timescales. We investigated these dynamics in a tidal salt marsh with a gently-sloped, vegetated edge adjacent to northern San Francisco Bay. Spartina foliosa (cordgrass) inhabits the lower marsh and Salicornia pacifica (pickleweed) predominates on the marsh plain
Jessica R. Lacy, Madeline R. Foster-Martinez, Rachel (Contractor) Allen, Matthew C. Ferner, John C. Callaway

Flow-mediated effects on travel time, routing, and survival of juvenile Chinook salmon in a spatially complex, tidally forced river delta

We evaluated the interacting influences of river flows and tides on travel time, routing, and survival of juvenile late-fall Chinook salmon (Oncorhynchus tshawytscha) migrating through the Sacramento–San Joaquin River Delta. To quantify these effects, we jointly modeled the travel time, survival, and migration routing in relation to individual time-varying covariates of acoustic-tagged salmon with
Russell W. Perry, Adam C. Pope, Jason G. Romine, Patricia L. Brandes, Jon R. Burau, Aaron R. Blake, Arnold J. Ammann, Cyril J. Michel

Survival, travel time, and utilization of Yolo Bypass, California, by outmigrating acoustic-tagged late-fall Chinook salmon

Juvenile Chinook salmon (Oncorhynchus tshawytscha) migrating through California's Sacramento-San Joaquin River Delta toward the Pacific Ocean face numerous challenges to their survival. The Yolo Bypass is a broad floodplain of the Sacramento River that floods in about 70 percent of years in response to large, uncontrolled runoff events. As one of the routes juvenile salmon may utilize, the Yolo By
Adam C. Pope, Russell W. Perry, Dalton J. Hance, Hal C. Hansel

Mercury on a landscape scale—Balancing regional export with wildlife health

The Cosumnes River watershed requires a 57–64 percent reduction in loads to meet the new Delta methylmercury (MeHg) total maximum daily load allocation, established by the Central Valley Regional Water Quality Control Board. Because there are no large point sources of MeHg in the watershed, the focus of MeHg load reductions will fall upon non-point sources, particularly the expansive wetlands cons
Mark C. Marvin-DiPasquale, Lisamarie Windham-Myers, Jacob A. Fleck, Joshua T. Ackerman, Collin A. Eagles-Smith, Harry McQuillen

Effects of the proposed California WaterFix North Delta Diversion on survival of juvenile Chinook salmon (Oncorhynchus tshawytscha) in the Sacramento-San Joaquin River Delta, northern California

The California Department of Water Resources and Bureau of Reclamation propose new water intake facilities on the Sacramento River in northern California that would convey some of the water for export to areas south of the Sacramento-San Joaquin River Delta (hereinafter referred to as the Delta) through tunnels rather than through the Delta. The collection of water intakes, tunnels, pumping facili
Russell W. Perry, Adam C. Pope