Modeling Barriers and Levee-Break Effects on Delta-Wide Salinity

Delta Stewardship Council (Delta Council) | February 18th, 2016

Nature-based solutions extend the lifespan of a regional levee system under climate change

Nature Portfolio (Springer Nature) | May 9th, 2025

North Delta Water Management Program

California Department of Water Resources (DWR) | March 1st, 1988

Water management issues surrounding the Sacramento-San Joaquin Delta continue to challenge water resource planners in California. Many agree there are problems and urge

Water management issues surrounding the Sacramento-San Joaquin Delta continue to challenge water resource planners in California. Many agree there are problems and urge that they be corrected, but a consensus on how best to solve them has not yet been reached. Problems include frequent flooding due to unstable levees and constricted channels, flow patterns that are unfavorable for fish and water quality, and water level and circulation patterns that hinder irrigation. During the last several years, various water resources problems have been corrected through application of the public environmental documentation and regulatory permit process. This process has also shown the importance of Federal permit regulations in governing projects in the Delta estuary. To facilitate planning, the estuary has been divided into three study areas for evaluation of problems and needs unique to each area -- North, South, and West. This report discusses concepts for a North Delta Water Management Program. The long-term planning and environmental documentation process will includeother reports and will take about three years to complete. Planning flexibility afforded by the environmental documentation and regulatory permit process is expected to allow many of the concerns surrounding Delta water management to be resolved.

Novato Creek Baylands Historical Ecology Study

San Francisco Estuary Institute (SFEI) | July 31st, 2015

Over the past century and a half, lower Novato Creek and the surrounding tidal wetlands have been heavily modified for flood control and land reclamation purposes. Levees

Over the past century and a half, lower Novato Creek and the surrounding tidal wetlands have been heavily modified for flood control and land reclamation purposes. Levees were built in the tidal portion of the mainstem channel beginning in the late 1800s to convey flood flows out to San Pablo Bay more rapidly and to remove surrounding areas from inundation. Following levee construction, the wetlands surrounding the channel were drained and converted to agricultural, residential, and industrial areas. These changes have resulted in a considerable loss of wetland habitat, reduced sediment transport to marshes and the Bay, and an overall decreased resilience of the system to sea level rise. In addition to tidal wetland modification, land use changes upstream in the Novato Creek watershed have resulted in several challenges for flood control management. Dam construction and increased runoff in the upper watershed have resulted in elevated rates of channel incision, which have increased transport of fine sediment from the upper watershed to lower Novato Creek. Channelization of tributaries and construction of irrigation ditches have likely increased drainage density in the upper watershed, also potentially contributing to increased rates of channel incision and fine sediment production (Collins 1998). Downstream, sediment transport capacity has been reduced by construction of a railroad crossing and loss of tidal prism and channel capacity associated with the diking of the surrounding marsh. As a result of the increased fine sediment supply from the watershed and the loss of sediment transport capacity in lower Novato Creek, sediment aggradation occurs within the channel, which in turn reduces the flood capacity of the channel, necessitating periodic dredging (fig. 1; Collins 1998, PWA 2002).

Pared-Down Water Plan to Be Submitted in 1987

Los Angeles Times | June 17th, 1985

SACRAMENTO — Gov. George Deukmejian’s Administration is preparing to submit a new water package to the Legislature in 1987, a stripped-down version of the plan that f

SACRAMENTO — Gov. George Deukmejian’s Administration is preparing to submit a new water package to the Legislature in 1987, a stripped-down version of the plan that failed in 1984, according to David N. Kennedy, director of the state Department of Water Resources. The plan, contingent on Deukmejian’s reelection next year, would reverse the position the governor took after the stinging rebuke of a year ago, when he blamed Democratic lawmakers for the defeat. He said then that it would be up to the Legislature to produce an acceptable plan for supplying the state’s water needs. But now the Administration is once again gearing up to take the initiative on the water issue. The package would contain three key elements: - Authorization for $300 million in Sacramento-San Joaquin Delta projects needed to ship additional surplus water south. - A commitment to help maintain and restore deteriorating delta levees. - Environmental protections for San Francisco Bay.

Prioritization of State Investments in Delta Levees and Risk Reduction - Initial Statement of Reasons

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

Prioritization of State Investments in Delta Levees and Risk Reduction Amendment to Existing Regulation

Delta Stewardship Council (Delta Council) | September 21st, 2023

Productive wetlands restored for carbon sequestration quickly become net CO2 sinks with site-level factors driving uptake variability

PLOS | March 25th, 2021

Inundated wetlands can potentially sequester substantial amounts of soil carbon (C) over the long-term because of slow decomposition and high primary productivity, partic

Inundated wetlands can potentially sequester substantial amounts of soil carbon (C) over the long-term because of slow decomposition and high primary productivity, particularly in climates with long growing seasons. Restoring such wetlands may provide one of several effective negative emission technologies to remove atmospheric CO2 and mitigate climate change. However, there remains considerable uncertainty whether these heterogeneous ecotones are consistent net C sinks and to what degree restoration and management methods affect C sequestration. Since wetland C dynamics are largely driven by climate, it is difficult to draw comparisons across regions. With many restored wetlands having different functional outcomes, we need to better understand the importance of site-specific conditions and how they change over time. We report on 21 site-years of C fluxes using eddy covariance measurements from five restored fresh to brackish wetlands in a Mediterranean climate. The wetlands ranged from 3 to 23 years after restoration and showed that several factors related to restoration methods and site conditions altered the magnitude of C sequestration by affecting vegetation cover and structure. Vegetation established within two years of re-flooding but followed different trajectories depending on design aspects, such as bathymetry-determined water levels, planting methods, and soil nutrients. A minimum of 55% vegetation cover was needed to become a net C sink, which most wetlands achieved once vegetation was established. Established wetlands had a high C sequestration efficiency (i.e. the ratio of net to gross ecosystem productivity) comparable to upland ecosystems but varied between years undergoing boom-bust growth cycles and C uptake strength was susceptible to disturbance events. We highlight the large C sequestration potential of productive inundated marshes, aided by restoration design and management targeted to maximise vegetation extent and minimise disturbance. These findings have important implications for wetland restoration, policy, and management practitioners.

Promoting atmospheric-river and snowmelt fueled biogeomorphic processes by restoring river-floodplain connectivity in California’s Central Valley

Springer | April 30th, 2015

Potential biogeomorphic benefits from intentional levee breaks and weir overflow on the managed floodplain-river system of California’s Sacramento and San Joaquin River

Potential biogeomorphic benefits from intentional levee breaks and weir overflow on the managed floodplain-river system of California’s Sacramento and San Joaquin River watershed (Central Valley) are discussed here. Prior to the nineteenth century, the system was characterized by natural levees alongside complex multichanneled rivers and tributaries, and geomorphic processes such as channel migration and avulsion, typical in lowland floodplain-river systems globally, dominated. Today, the floodplain-river system has been heavily modified with infrastructure such as levee embankments that disconnect floodplains from channels and diminish key processes of floodplain-river ecology. Unintentional levee breaks in river systems where floodplains have been developed for agriculture or urban uses still occur regularly (in a quarter of twentieth century years) and are sometimes catastrophic. Floodplain inundation, erosion, and sedimentation, the dominant geomorphic processes that occur during unintentional levee breaks, are flood risks in such embanked river systems. Climate and flood variability still dictate the frequency of unintentional levee breaks despite many decades of engineering. Of particular consequence are the so-called atmospheric-river (AR) storms. Since 1951, 81 % of breaks have occurred as a result of AR storms and flooding, while most of the rest occurred during snowmelt floods. Intentional levee breaks or planned weir overflows that are designed for floodplain restoration can facilitate a return towards more natural and dynamic biogeomorphic processes. In areas where room for flood-driven geomorphic processes is available on floodplains, local sediment scour and deposition near a levee break promote topographic diversity that enhances vegetation establishment and floodplain habitat. This chapter summarizes our current understanding of climate processes and flood variability that govern unintentional levee breaks or weir overflow. We also review examples of alternative flood management approaches in the Central Valley that promote processes necessary to restore or sustain lowland floodplain biogeomorphology. Future climate-driven changes in flood regime, such as enhanced flooding during winter months or more frequent atmospheric rivers, could be accommodated by additional intentional levee breaks or planned weir overflow for restoration. Implementation of these alternatives could be used to improve restoration policy and management of floods in embanked river floodplains.

Prospect Island Tidal Habitat Restoration Project: Admin Final Restoration Plan

California Department of Water Resources (DWR) | June 12th, 2014

This Prospect Island Tidal Habitat Restoration Project (Project) Draft Restoration Plan (Plan) describes the proposed actions needed to restore up to 1,600 acre (ac) of

This Prospect Island Tidal Habitat Restoration Project (Project) Draft Restoration Plan (Plan) describes the proposed actions needed to restore up to 1,600 acre (ac) of diked lands to tidal wetlands. The Project site is located in Solano County, in the northern Sacramento-San Joaquin River Delta (Delta) (Figure 1-1). Prospect Island falls under two ownerships: the approximately 1,300-ac northern property is owned by the California Department of Water Resources (DWR), and the southern, approximately 300-ac portion is owned by the Port of West Sacramento (Port). There are three privately owned properties contiguous to the site: the Stringer property, a small peninsula connected to the southeast margin of the DWR property; the Hall property, a small peninsula connected to the southeast margin of the Port property; and the Fahn property, actively farmed land north of the Project boundary. A privately operated marina, Arrowhead Harbor, is located at the northeastern corner of the site. With the exception of discussion of site topography (Section 4.3.3), three areal extents are used for the purposes of this Restoration Plan and interrelated environmental analyses of the Project. The Tidal Restoration Footprint is the area internal to the levees that would be subject to tidal action following restoration. The Diked Lands Project Area represents all diked lands that would be restored and potentially used to construct the Project, and extends outward to the high tide line on the exterior side of the levees. The Construction Project Area represents the Diked Lands Project Area plus all potential exterior in-water work areas.