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Synoptic conditions associated with cool season post-fire debris flows in the Transverse Ranges of southern California

Natural Hazards (Springer) | April 22nd, 2017

Summary

The Transverse Ranges of southern California often experience fire followed by flood. This sequence sometimes causes post-fire debris flows (PFDFs) that threaten life a

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Syntheses of scientific knowledge for maintaining and improving functioning of the South Bay ecosystem and restoring tidal salt marsh and associated habitats

San Francisco Estuary Institute (SFEI) | October 1st, 2004

Summary

This synthesis focuses on the form and function of South Bay landscapes to address the following two issues – maintaining and improving functioning of the South Bay Eco

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Synthesis of data and studies relating to Delta Smelt biology in the San Francisco Estuary, emphasizing water year 2017

Interagency Ecological Program (IEP) | November 1st, 2021

Summary

In the San Francisco Estuary (SFE), the effects of freshwater flow on the aquatic ecosystem have been studied extensively over the years and remains a contentious managem

In the San Francisco Estuary (SFE), the effects of freshwater flow on the aquatic ecosystem have been studied extensively over the years and remains a contentious management issue. It is especially contentious with regards to the Delta Smelt (Hypomesus transpacificus), a species endemic to the SFE that has been listed as threatened under the Federal Endangered Species Act and endangered by the State of California. Early studies of Delta Smelt distribution within the SFE suggested that Delta Smelt habitat is determined largely by freshwater flow; however, the exact mechanisms and processes producing such benefits remained unclear. In the summer of 2017, the Flow Alteration Management, Analysis, and Synthesis Team (FLOAT-MAST) was established to analyze, synthesize, and summarize the data collected from the various flow-related monitoring and special studies occurring in 2017(see Table Intro 4). This report will focus on the 2017 summer-fall status of Delta Smelt and its habitat following a record wet year. There has been a long-term decline in the abundance of Delta Smelt associated with a decline in other pelagic fishes. Investigators concluded that the decline has likely been caused by the interactive effects of several causes, including changes in both physical and biotic habitats, many of which are tied to amount and timing of freshwater flow. For this report, we formulated a number of basic predictions about the likely effects of high flows in 2017 on Delta Smelt and their habitat (Table 3). We use a qualitative weight of evidence approach to evaluate whether these predictions were supported by available data. Data sources included a variety of long-term monitoring surveys conducted by Interagency Ecological Program (IEP) agencies, as well as model outputs. Delta Smelt population, health, and life history metrics rarely responded as predicted. Water temperature appears to have a stronger effect on Delta Smelt growth rate and some metrics of life history diversity than outflow or X2 position. Other life history diversity attributes varied but did not appear to be driven by outflow or temperature. Health status was difficult to interpret. Low prevalence of lesions and improved nutritional condition during the drought was contradicted by declining overall population levels. Because of the sparse catches of Delta Smelt in the post-POD years, we consider the data insufficient to reach firm conclusions about the predictions concerning range and distribution of Delta Smelt, especially in the fall. The prediction of high survival was not supported. The 2017 Delta Smelt year class began with poor recruitment in spring of 2017 and below average survival for spring to summer and summer to fall. Thus, low production and low survival led to low abundance of all life stages. During the fall to winter period survival improved, yet the resulting adults were low in number. Foraging success of the fish captured, as measured by stomach fullness, was high for juveniles and adults in 2017 relative to recent years associated with the higher densities of common zooplankton prey that occurred in 2017.

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Synthesis of Data from High-Frequency Nutrient and Associated Biogeochemical Monitoring for the Sacramento– San Joaquin Delta, Northern California

U.S. Geological Survey (USGS) | July 11th, 2017

Summary

This report is the second in a series of three reports that provide information about high-frequency (HF) nutrient and biogeochemical monitoring in the Sacramento–San J

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Synthesis of Studies in the Fall Low-Salinity Zone of the San Francisco Estuary, September–December 2011

U.S. Geological Survey (USGS) | July 14th, 2014

Summary

In fall 2011, a large-scale investigation (fall low-salinity habitat investigation) was implemented by the Bureau of Reclamation in cooperation with the Interagency Ecolo

In fall 2011, a large-scale investigation (fall low-salinity habitat investigation) was implemented by the Bureau of Reclamation in cooperation with the Interagency Ecological Program to explore hypotheses about the ecological role of low-salinity habitat in the San Francisco Estuary—specifically, hypotheses about the importance of fall low-salinity habitat to the biology of delta smelt Hypomesus transpacificus, a species endemic to the San Francisco Estuary and listed as threatened or endangered under federal and state endangered species legislation. The Interagency Ecological Program is a consortium of 10 agencies that work together to develop a better understanding of the ecology of the Estuary and the effects of the State Water Project and Federal Central Valley Project operations on the physical, chemical, and biological conditions of the San Francisco Estuary. The fall low-salinity habitat investigation constitutes one of the actions stipulated in the Reasonable and Prudent Alternative issued with the 2008 Biological Opinion of the U.S. Fish and Wildlife Service, which called for adaptive management of fall Sacramento-San Joaquin Delta outflow following “wet” and “above normal” water years to alleviate jeopardy to delta smelt and adverse modification of delta smelt critical habitat. The basic hypothesis of the adaptive management of fall low-salinity habitat is that greater outflows move the low-salinity zone (salinity 1–6), an important component of delta smelt habitat, westward and that moving the low-salinity zone westward of its position in the fall of recent years will benefit delta smelt, although the specific mechanisms providing such benefit are uncertain. An adaptive management plan was prepared to guide implementation of the adaptive management of fall low-salinity habitat and to reduce uncertainty. This report has three major objectives: •To provide a summary of the results from the first year of coordinated fall low-salinity habitat studies and monitoring. •To provide a synthesis of the results of the fall low-salinity habitat studies and other ongoing research and monitoring, to determine if the available information supports the hypotheses behind the adaptive management of fall low-salinity habitat as set forth in the adaptive management plan. •To begin to put the results from the fall low-salinity habitat studies into context within the larger body of knowledge regarding the San Francisco Estuary and, in particular, the upper San Francisco Estuary, including the Sacramento-San Joaquin Delta, Suisun Bay, and associated embayments.

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Synthesis Report: Integrating probability and targeted survey designs in regional stream condition assessments with examples from southern coastal California

California State Water Resources Control Board (SWRCB) | June 30th, 2010

Summary

Ambient water quality monitoring programs have traditionally relied on the use of targeted monitoring designs (in which sampling locations are assigned non-randomly) to a

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Synthesizing Conservation Motivations and Barriers: What Have We Learned from Qualitative Studies of Farmers’ Behaviors in the United States?

Society and Natural Resources (Routledge) | August 15th, 2019

Summary

Since 2011, qualitative studies examining adoption of conservation practices and programs (CPPs) have burgeoned. This article presents a systematic review of al

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Synthesizing Relationships Between Winter-Run Chinook Salmon Out-Migration Survival and Water Operations in the Sacramento–San Joaquin Delta

University of California, Davis (UC Davis) | December 19th, 2025

Summary

Sacramento River winter-run Chinook Salmon (Oncorhynchus tshawytscha) are an endangered population that faces numerous challenges across its life cycle, including juvenil

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Synthetic Streamflows

American Geophysical Union (AGU) | January 1st, 1971

Summary

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 1. This monograph contains virtually no mathematical derivations an

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System Reoperation (Resource Management Strategy)

California Department of Water Resources (DWR) | July 29th, 2016

Summary

System reoperation in the context of water resources means changing existing operation and management procedures for a water resources system consisting of supply and con

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Synoptic conditions associated with cool season post-fire debris flows in the Transverse Ranges of southern California

Syntheses of scientific knowledge for maintaining and improving functioning of the South Bay ecosystem and restoring tidal salt marsh and associated habitats

Synthesis of data and studies relating to Delta Smelt biology in the San Francisco Estuary, emphasizing water year 2017

Synthesis of Data from High-Frequency Nutrient and Associated Biogeochemical Monitoring for the Sacramento– San Joaquin Delta, Northern California

Synthesis of Studies in the Fall Low-Salinity Zone of the San Francisco Estuary, September–December 2011

Synthesis Report: Integrating probability and targeted survey designs in regional stream condition assessments with examples from southern coastal California

Synthesizing Conservation Motivations and Barriers: What Have We Learned from Qualitative Studies of Farmers’ Behaviors in the United States?

Synthesizing Relationships Between Winter-Run Chinook Salmon Out-Migration Survival and Water Operations in the Sacramento–San Joaquin Delta

Synthetic Streamflows

System Reoperation (Resource Management Strategy)

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