Effects of vegetation on methylmercury concentrations and loads in a mercury contaminated floodplain

Science of The Total Environment (Elsevier) | August 3rd, 2023

The Yolo Bypass (YB) is a large flood conveyance system designed to protect the city of Sacramento, California, USA from flooding when the Sacramento River approaches flo

The Yolo Bypass (YB) is a large flood conveyance system designed to protect the city of Sacramento, California, USA from flooding when the Sacramento River approaches flood stage. The Sacramento River watershed and YB are a source of methylmercury (MeHg) to downstream habitat as a result of historic mercury (Hg) and gold mining practices. In the dry season, the YB is extensively farmed and grazed. However, depending on the water year, the floodplain may remain inundated for months. Our experiments focused on the role of pasture land and decomposing vegetation as a source of MeHg during extensive periods of floodplain flooding. Decomposing vegetation, rather than sediment, was identified as the principal source of filter passing MeHg (fMeHg) within the floodplain. The decomposing vegetation provided a substrate for microbial methylation of inorganic Hg contained within the plants. In replicated flooded mesocosm experiments, MeHg concentrations increased from 2.78 to 31.0 ng g− 1 dw and 3.41 to 56.8 ng g− 1 dw in decomposing vegetation. In field collections, the concentrations of MeHg in vegetation increased from preflood levels of 2.78 to 45.4 ng g− 1dw after 17 weeks of flooding. The importance of vegetation was shown in laboratory experiments where there was a positive correlation between the amount of fMeHg in water and the amount of vegetation added. These results also provide Hg concentration data for an important functional type of vegetation, grasses, and fill a data gap that contributed to uncertainties with regards to the role of vegetation in Hg cycling.

Elevation and Opportunity in the Delta: Restoring the Right Thing in the Right Place

San Francisco Estuary Institute (SFEI) | May 31st, 2022

A future Sacramento-San Joaquin Delta and Suisun Marsh (“Delta” herein) that supports healthy ecosystems and native species, while also meeting flood risk reduction,

A future Sacramento-San Joaquin Delta and Suisun Marsh (“Delta” herein) that supports healthy ecosystems and native species, while also meeting flood risk reduction, water supply, water quality, carbon sequestration, economic, and cultural objectives, requires that appropriate restoration and management actions be taken in the right place at the right time. Geographic setting affects the potential opportunities available—not all actions are suitable everywhere. Physical factors determining what types of activities are appropriate now and in the future include a site’s elevation, degree of tidal and fluvial influence, salinity, soil type, and local effects of climate change, which all vary spatially across the Delta. While there has been considerable progress over the last several decades, continued acceleration of the pace and scale of enhancement actions appropriate to landscape position is needed. Understanding the physical template is necessary for developing strategies that move beyond opportunistic restoration, support resilience over time, and have the potential to connect and magnify benefits across the larger landscape.

Emergency Drought Barriers

Delta Stewardship Council (Delta Council) | April 26th, 2022

Emergency Response To Flood Threats in California

California Department of Water Resources (DWR) | April 8th, 2011

An explanatory memo on the Flood Operations Branch, Department of Water Resources, Division of Flood Management During the flood season, a number of public agencies co

An explanatory memo on the Flood Operations Branch, Department of Water Resources, Division of Flood Management During the flood season, a number of public agencies combine their efforts to provide high water warnings and minimize flood damage in California. The Department of Water Resources (DWR) is responsible for coordinating local, State and federal flood operations. The State-Federal Flood Operations Center, located on El Camino Avenue in Sacramento, is the focal point of this effort. State, federal and local flood operations on the North Coast streams are coordinated through the DWR Eureka Flood Center in Humboldt County.

Empirical and Experimental Analyses of Secondary Louver Efficiency at the Tracy Fish Collection Facility: March 1996 to November 1997

U.S. Bureau of Reclamation (USBR) | January 30th, 2004

Enhancing the Vision for Managing California’s Environmental Information

Delta Stewardship Council (Delta Council) | July 1st, 2015

The Environmental Data Summit, convened under the auspices of the Delta Stewardship Council’s Delta Science Program in June 2014, witnessed remarkable participation fro

The Environmental Data Summit, convened under the auspices of the Delta Stewardship Council’s Delta Science Program in June 2014, witnessed remarkable participation from experts across California, the nation, and even the world. Summit attendees from the public, private, federal, and non-profit sectors shared their views regarding the urgent needs and proposed solutions for California’s data-sharing and data-integration challenges, especially pertaining to the subject of environmental resource management in the era of “big data.” After all, this is a time when our data sources are growing in number, size, and complexity. Yet our ability to manage and analyze such data in service of effective decision-making lags far behind our demonstrated needs. In its review of the sustainability of water and environmental management in the California Bay-Delta, the National Research Council (NRC) found that “only a synthetic, integrated, analytical approach to understanding the effects of suites of environmental factors (stressors) on the ecosystem and its components is likely to provide important insights that can lead to enhancement of the Delta and its species” (National Research Council 2012). The present “silos of data” have resulted in separate and compartmentalized science, impeding our ability to make informed decisions. While resolving data integration challenges will not, by itself, produce better science or better natural resource outcomes, progress in this area will provide a strong foundation for decision-making. Various mandates ranging from the California Water Action Plan to the President’s executive order demanding federal open data policies demonstrate the consensus on the merits of modern data sharing at the scale and function needed to meet today’s challenges. This white paper emerges from the Summit as an instrument to help identify such opportunities to enhance California’s cross-jurisdictional data management. As a resource to policymakers, agency leadership, data managers, and others, this paper articulates some key challenges as well as proven solutions that, with careful and thoughtful coordination, can be implemented to overcome those obstacles. Primarily featured are tools that complement the State’s current investments in technology, recognizing that success depends upon broad and motivated participation from all levels of the public agency domain. This document describes examples, practices, and recommendations that focus on California’s Delta as an opportune example likely to yield meaningful initial results in the face of pressing challenges.  Once proven in the Delta, however, this paper’s recommended innovations would conceivably be applied statewide in subsequent phases.

Environmental Baseline Biological Resources - Fauna, Total Water Management Study for the Central Valley, California

U.S. Bureau of Reclamation (USBR) | January 1st, 1975

Environmental Water Account: Need for Legislative Definition and Oversight

Legislative Analyst's Office (LAO) | January 29th, 2001

We recommend that the Legislature hold oversight hearings to evaluate CALFED's proposal for the Environmental Water Account, implemented to acquire water for endangered s

We recommend that the Legislature hold oversight hearings to evaluate CALFED's proposal for the Environmental Water Account, implemented to acquire water for endangered species protection and recovery in the Bay-Delta region. There are many policy and implementation issues that the Legislature should consider before CALFED proceeds with the new program, including the program's costs, benefits, impacts, governance, and funding. Funding should be governed by the "beneficiary pays" principle.

Envisioning Futures for the Sacramento-San Joaquin Delta

Public Policy Institute of California (PPIC) | January 25th, 2007

California’s Sacramento-San Joaquin Delta is widely perceived to be in crisis today: its levee system is fragile, many of its native species are declining rapidly, and

California’s Sacramento-San Joaquin Delta is widely perceived to be in crisis today: its levee system is fragile, many of its native species are declining rapidly, and it lacks strong governing institutions to deal with its problems. In its current state, the Delta is unsustainable for almost all stakeholders. This report provides a comprehensive, scientifically up-to-date analysis and outlines several alternative management strategies for the Delta.

Ephemeral floodplain habitats provide best growth conditions for juvenile Chinook salmon in a California river

Environmental Biology of Fishes (Springer) | June 6th, 2008

We reared juvenile Chinook salmon for two consecutive flood seasons within various habitats of the Cosumnes River and its floodplain to compare fish growth in river and

We reared juvenile Chinook salmon for two consecutive flood seasons within various habitats of the Cosumnes River and its floodplain to compare fish growth in river and floodplain habitats. Fish were placed in enclosures during times when wild salmon would naturally be rearing in floodplain habitats. We found significant differences in growth rates between salmon reared in floodplain and river enclosures. Salmon reared in seasonally inundated habitats with annual terrestrial vegetation experienced higher growth rates than those reared in a perennial pond on the floodplain. Growth of fish in the non-tidal river upstream of the floodplain varied with flow in the river. When flows were high, there was little growth and high mortality, but when the flows were low and clear, the fish grew rapidly. Fish displayed very poor growth in tidally influenced river habitat below the floodplain, a habitat type to which juveniles are commonly displaced during high flow events due to a lack of channel complexity in the main-stem river. Overall, ephemeral floodplain habitats supported higher growth rates for juvenile Chinook salmon than more permanent habitats in either the floodplain or river. Variable responses in both growth and mortality, however, indicate the importance of providing habitat complexity for juvenile salmon in floodplain reaches of streams, so fish can find optimal places for rearing under different flow conditions.