Simulated effects of delta outflow on the bay: 1998 compared to other years
No abstract.
Interagency Ecological Program Newsletter↗
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Pulsey, patchy water quality in the delta: Implications for meaningful monitoring
Valuable water quality and biological datasets have been gathered in the Sacramento-San Joaquin Delta for decades, most notably by the Interagency Ecological Program’s Environmental Monitoring Program (EMP). These extensive data have provided a means of analyzing and detecting long-term trends in water quality and ecosystem function (Jassby and others 2002; Kimmerer and Orsi 1996; Orsi and Mecum 1996) and may shape future restoration actions in the region. EMP water quality data—as well as data generated by the San Francisco Estuary Institute’s (SFEI) Regional Monitoring Program (RMP) and research groups like our own—have often focused on single, monthly or seasonal samples taken at several discrete points in space. Although such discrete data often push the practical limits of our equipment and human resources, higher resolution monitoring approaches can reveal limitations (in some cases severe) of these more coarse sampling schemes.
Interagency Ecological Program Newsletter↗
Spring 2000 Delta smelt salvage and Delta hydrodynamics and an introduction to the Delta Smelt Working Group's decision tree
No abstract available.
Interagency Ecological Program Newsletter↗
Environmental factors influencing the distribution and salvage of young delta smelt: a comparison of factors occurring in 1996 and 1999
The delta smelt (Hypomesus transpacificus) is listed as a threatened species under both the Federal Endangered Species Act (FESA) and the California Endangered Species Act. Through formal consultation under Section 7 of the FESA, USBR and DWR received a Biological Opinion from the USFWS, which allows for the incidental take of delta smelt arising through operation of the Central Valley Project and the State Water Project. The incidental take of delta smelt is estimated as part of the ongoing CVP and SWP fish salvage operations. Salvage levels of young delta smelt have exceeded incidental take levels every spring and summer since 1994, except in the high spring outflow years of 1995 and 1998 (Nobriga and others 1999). These high salvage levels have resulted in changes to project operations, often leading to the curtailment of water exports. An extended period of high salvage and export curtailment in 1999 raised substantial concerns and numerous questions that remain unanswered.
Interagency Ecological Program Newsletter↗
Fulfilling a paradoxical mandate: can the Environmental Water Account ensure the reliability of freshwater exports from the Sacramento-San Joaquin Delta and simultaneously protect delta smelt (Hypomesus transpacificus) from excessive entrainment?
The San Francisco Estuary (SFE) is often defined by its extremes. It is considered one of the most urbanized estuaries in the world (Conomos 1979, Nichols et al. 1986), and one of the most invaded estuaries in the United States, with hundreds of aquatic nonindigenous species established throughout the system (Cohen and Carlton 1995, Dill and Cordone 1997, Kimmerer and Orsi 1996). It is also one of the most managed estuaries, particularly in relation to freshwater inflow, water circulation, and water quality (Jassby and Powell 1994, CSWRCB 1995, Arthur et al. 1996, Kimmerer 2002). Despite this high level of disturbance, the SFE is one of the most valuable natural resources in the western United States (CALFED 2000). The SFE provides important habitat for numerous native plant and animal species, many of special concern, as well as several species with sport and commercial value (CALFED 2000). Conserving and restoring estuarine habitat and natural resources is a pressing and complex challenge for the responsible government agencies because human water needs continue to increase in concert with continuing urbanization of the watershed.
Interagency Ecological Program Newsletter↗
Primary food resources in the Sacramento-San Joaquin Delta
The Sacramento-San Joaquin River Delta, a complex mosaic of tidal freshwater habitats, is now a focus of ecosystem rehabilitation because of changes in critical functions associated with its geographic location at the landestuary interface. One of these functions is the production, transport, and transformation of organic matter that constitutes the “primary food supply,” that is, the food supply to the base of the food web. Interest in the primary food supply is motivated by evidence for sub-optimal food quantity or quality at trophic levels that support fish recruitment, including primary consumers such as clams, mysids, cladocerans, rotifers, and native copepods. We used the historical data set to examine the magnitudes of the most important organic matter sources for the Delta, the factors underlying their interannual and longer-term variability, and the implications of ecosystem rehabilitation actions for these sources. Here, we present a summary of the first phase of the analysis, including the quantitative importance of different organic matter sources and some of the hydrological controls on their year-to-year variability. The full report of this first phaseincluding data sources, the methods of calculation, and references, is in press elsewhere (Jassby and Cloern forthcoming). The historical data analysis is part of a larger project in which measurements of stable isotopes and biogeochemical markers, and experiments on organic matter biodegradation and zooplankton growth rates, are being used collectively to define the primary food resources and their quality.
California↗
Exposure of delta smelt to dissolved pesticides in 2000
Delta smelt abundance in San Francisco Estuary has been declining since 1983. The exposure of delta smelt to toxic pesticides during larval and juvenile life stages may be one possible factor of this decline (Bennett and Moyle 1996; Moyle and others 1996). Although pesticides have been detected in the Delta (MacCoy and others 1995; Kuivila and others 1999), minimal data on pesticide concentrations and the duration of occurrence in delta smelt habitat are documented. A three-year study (1998– 2000) was undertaken by the U.S. Geological Survey (USGS) to quantify the exposure of larval and juvenile delta smelt to dissolved pesticides. Moon and others (2000) reported on the exposure of delta smelt to dissolved pesticides in 1998 and 1999, and this article follows up on Moon’s work and reports the results from late spring and summer of 2000.
Interagency Ecological Program Newsletter↗
State of the network: Long-term, high-frequency flow and water quality data in the San Francisco Estuary, California
The USGS California Water Science Center is heavily involved in the measurement of flow and water quality parameters in the San Francisco Estuary, with support from many partner agencies. The California Department of Water Resources (DWR), through the Interagency Ecological Program (IEP) is one of those agencies. This article describes the resulting efforts and methodologies and provides examples of some of the uses of the data sets for science and management interests. The DWR/IEP-funded flow and water quality network provides high resolution data in both space and time, over a large portion of the San Francisco Estuary. This measurement network has evolved over the preceding decades, and proven invaluable for both management and science interests, with particular relevance to water supply and endangered species issues. Presented below are a summary of the measurement network, some of the methods being utilized, and some interesting conditions that became evident during the recent drought that spanned Water Years (WY) 2013-2016, and the wet WY2017 (water year spans Oct 1-Sept 30).
California↗
Sierra Nevada runoff into San Francisco Bay - Why has it come earlier recently?
By the time most of the Sierra Nevada snowpack has melted each summer, freshwater outflows from the Sacramento-San Joaquin Delta to San Francisco Bay are typically small, even after the wettest winters. These small delta outflows during the warm months (in comparison with the large flows of winter and spring) are overwhelmed by salty coastal waters, and the bay becomes more and more salty as summer progresses. Because longer lowflow seasons allow the bay to'become saltier, timing of the Sierra Nevada snowmelt and runoff, which are the source of the delta flows, has a profound influence on the salinity 0 the bay and, thus/ can affect its ecosystems (Peterson et al 1995).
Newsletter of the Interagency Ecological Program f↗
Red tide in Berkeley marina raises concern for toxic blooms in central Bay
No abstract available
California↗
Preliminary results from the hydrodynamic element of the 1994 entrapment zone study
This article discusses preliminary results from analyses of USGS hydrodynamic data collected as part of the 1994 Interagency Ecological Program entrapment zone study. The USGS took part in three 30-hour cruises and deployed instruments for measuring currents and salinity from April to June. This article primarily focuses on the analysis of data from five Acoustic Doppler Current ProUers (ADCPs) deployed in Carquinez Strait, Suisun Bay, and the Western Delta. From these analyses a revised conceptual model of the hydrodynamics of the entrapment/null zone has evolved. The ideas discussed in this newsletter article are essentially working hypotheses, which are presented here to stimulate discussion and further analyses. In this article we discuss the currently-held conceptual model of entrapment and present data that are inconsistent with this conceptual model. Finally, we suggest a revised conceptual model that is consistent with all of the hydrodynamic data collected to date and describe how the 1995 study incorporates our revised conceptual model into its design.
California↗