Rethinking Management of the Colorado River through Lake Powell, Grand Canyon, and Lake Mead

Utah State University | November 15th, 2024

Reversal in estuarine sand supply driven by Holocene sea level rise: A model for sand transport in large structural estuaries, San Francisco Bay, California, USA

Elsevier | July 26th, 2024

Coastal sand supply is a critical component of shoreline stability in the face of modern threats to coastal zones such as sea level rise or anthropogenic sediment extract

Coastal sand supply is a critical component of shoreline stability in the face of modern threats to coastal zones such as sea level rise or anthropogenic sediment extraction. Understanding the natural and anthropogenically perturbed dynamics of coastal systems has become a pressing challenge for coastal communities, such as the San Francisco Bay area in the United Sates, a large structurally controlled estuary system where stakeholders seek to balance the extraction of coastal sand resources for economic use and ensure sufficient sand supply for sustaining natural coastal environments. Developing accurate and comprehensive models of sand inputs and transport pathways in different types of coastal systems is imperative to balancing these competing needs. While estuarine sediment transport has been well-studied in many systems globally, structurally controlled estuaries in tectonically active settings have received relatively less attention. The prevailing hypothesis for sediment transport through San Francisco Bay describes active input and transport of sand from a large integrated regional catchment, through multiple subembayments, and out to Pacific coast beaches; a model contrary to prevailing understanding of highstand estuarine sediment transport in most settings. We test this model by applying comprehensive sand provenance analysis to surface and near-surface sand deposits in and around San Francisco Bay coupled with sand residence time data from optically stimulated luminescence (OSL) dating. New provenance results include sand petrography modal abundances, bulk geochemistry, and U-Pb detrital zircon geochronology from 27 Holocene samples throughout the San Francisco Bay region. Collectively, these new results highlight marked sediment provenance and residence time differences between San Francisco Bay structural subembayments. In particular, distinct compositional differences and OSL ages exist between sand in the bayhead region of the estuary (OSL ages ca. 4 ka; Sacramento River/local provenance) and sand from the more distal bay regions and the Pacific coast (OSL ages ca. 1 ka; integrated Sierra Nevada provenance). These provenance differences better support a revised sand input and transport model with disconnected depocenters across three structurally restricted subembayments from bayhead to the Pacific coast. New data suggest that at present the bayhead region receives limited supply from the Sacramento-San Joaquin Delta drainage with subsidiary supply from local circum-bay drainages. Sand deposited in the region from the Pacific coast through the inlet (Golden Gate) and into the estuary consists of a combination of tidal winnowing and reworking of “relic” sand from lowstand periods combined with sand eroded from Pacific coast sea cliffs, and sand supply from local Coast Range drainages. These results suggest that sand is likely not transported directly to the Pacific coast from the Sacramento-San Joaquin Delta under modern conditions. Moreover, it is likely that structural constrictions between the main estuary and outer coast and between estuary subembayments cause abrupt cessation of sediment input from the main regional drainage during marine flooding, a feature likely common to large structurally controlled estuaries globally. This revised model for San Francisco Bay sand transport illustrates the need for research targeted at interpreting natural sand transport pathways in coastal systems where coarse sediment supply is a sustainability concern.

RipZET: Documentation of Tool Demonstration in Marin County

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

The San Francisco Estuary Institute and Aquatic Science Center (SFEI‐ASC) has developed the Riparian Zone Estimation Tool (RipZET) to help the California community of

The San Francisco Estuary Institute and Aquatic Science Center (SFEI‐ASC) has developed the Riparian Zone Estimation Tool (RipZET) to help the California community of riparian interests visualize and characterize riparian areas as habitat unto themselves as well as their capacity to function as buffers for protecting the ecosystem services of the state’s streams, lakes and wetlands. RipZET is a tool used with Geographic Information System (GIS) and spreadsheet software to estimate “functional riparian width,” or the width associated with different riparian functions (e.g., large woody debris input, shading, floodwater storage), which varies with channel type and watershed location. The concept of functional riparian width is central to the riparian definition recommended by the National Research Council (NRC 2002) and is integral in many recently developed riparian design and management guidelines around the country.

Sacramento Valley Salmon Resiliency Strategy June 2017

California Natural Resources Agency (CNRA) | June 2nd, 2017

The Sacramento Valley Salmon Resiliency Strategy (Strategy) is a science-based document that has been prepared by the State of California (State) to address specific near

The Sacramento Valley Salmon Resiliency Strategy (Strategy) is a science-based document that has been prepared by the State of California (State) to address specific near- and long-term needs of Sacramento River winter-run Chinook salmon (winter-run), Central Valley spring-run Chinook salmon (spring-run), and California Central Valley steelhead (steelhead). The Strategy mirrors the approach taken with the Delta Smelt Resiliency Strategy developed by the State in 2016: science-driven, focused, and designed to provide resource agencies, the public, Congress, and the California State Legislature with information critical to collaborative approaches to species resiliency. The Strategy relies heavily on the National Marine Fisheries Service Final Recovery Plan for winter-run, spring-run, and steelhead (NMFS 2014), and is guided by conceptual models of factors driving winter-run population dynamics at key life stages developed by the salmon and sturgeon assessment of indicators by life-stage (SAIL) teams (Johnson et al. 2016; Heublein et al. 2017). The actions are also supported, where indicated, by other salmonid recovery planning documents and efforts. The Strategy is an aggressive approach to improving species viability and resiliency by implementing specific habitat restoration actions. The State will take leadership roles in each action, although in all cases federal and local agency leadership, coordination, and partnerships are required for success. Recent successful restoration efforts led by local agencies and landowners demonstrate the importance and value of these collaborative partnerships. State agencies that could implement this Strategy include the California Natural Resources Agency, the Department of Water Resources (DWR) and the Department of Fish and Wildlife (DFW). The U.S. Bureau of Reclamation (Reclamation) will be a primary partner in many of the actions. In many cases, included actions will benefit an array of aquatic and terrestrial species. Coordination and alignment across various resource management agencies will ensure achievement of maximum public benefit. All of the actions will comply with applicable laws including the U.S. Endangered Species Act (ESA), California Endangered Species Act, California Environmental Quality Act, National Environmental Policy Act, and the federal Clean Water Act.

Sacramento-San Joaquin Delta Historical Ecology Investigation: Exploring Pattern and Process

San Francisco Estuary Institute (SFEI) | September 12th, 2012

In 2012, SFEI researchers (in collaboration with the CA Department of Fish and Wildlife) completed a historical ecology study of the Sacramento-San Joaquin Delta. The

In 2012, SFEI researchers (in collaboration with the CA Department of Fish and Wildlife) completed a historical ecology study of the Sacramento-San Joaquin Delta. The project improves understanding of what the Delta looked like and how it functioned prior to the significant modification that has occurred over the last 160 years. This historical reconstruction documents patterns of variation and extent of habitat types throughout the Delta for improved understanding of species support functions and controlling physical processes within the native landscape. Knowing how different parts of the vast historical Delta looked and functioned provides needed information for future restoration strategies.

Salton Sea Management Program and Community Needs

California Natural Resources Agency (CNRA) | January 31st, 2024

In the Southeastern corner of the state, straddling Imperial and Riverside counties, the Salton Sea (the Sea) is California’s largest inland lake and home to many Calif

In the Southeastern corner of the state, straddling Imperial and Riverside counties, the Salton Sea (the Sea) is California’s largest inland lake and home to many California Native American tribes and communities. Once a resort destination, the Sea has since become a growing environmental issue. The Sea has been shrinking, largely due to water transfers out of Imperial Valley that reduce inflows to the Sea. Drought and changes to Colorado River water availability exacerbate this trend. Although it continues to provide a vital stop along the Pacific Flyway for migratory birds, the water has become increasingly saline. As the Sea shrinks, it exposes the lakebed that has the potential to release dust, contributing to worsening air quality in a region already struggling with poor air quality from high wind events, idling vehicles, high off-road activity, commercial truck traffic, and agricultural burning. Compounding this, communities in the Eastern Coachella Valley and Imperial Valley have for decades also faced social and economic challenges. While these vibrant communities have rich cultural and natural resources, they suffer from decades of underinvestment. Residents have highlighted that local communities struggle with poor air quality, health issues, low broadband access, unreliable electricity, limited access to recreational opportunities, inadequate transportation systems, and underfunded public health infrastructure and services. These challenges make it difficult to overcome the growing environmental challenges related to the Sea.

Salton Sea Management Program Phase 1: 10-Year Plan Imperial and Riverside Counties, California Draft Environmental Assessment

U.S. Army Corps of Engineers (USACE) | June 21st, 2022

This Environmental Assessment (EA) was prepared pursuant to the National Environmental Policy Act (NEPA) and analyzes and discloses the effects of the implementation of t

This Environmental Assessment (EA) was prepared pursuant to the National Environmental Policy Act (NEPA) and analyzes and discloses the effects of the implementation of the Salton Sea Management Program’s (SSMP’s) Phase 1: 10-Year Plan (SSMP 10-Year Plan or Applicant’s Proposed Project) being proposed by CNRA (California Natural Resource Agency), California Department of Water Resources (DWR), and the California Department of Fish and Wildlife (CDFW), collectively known as the SSMP team. The SSMP team is seeking Department of the Army (DA) authorization from the United States Army Corps of Engineers (Corps), Los Angeles District, pursuant to Section 404 of the Clean Water Act (CWA; 33 USC §1344). The SSMP 10-Year Plan proposes to implement a total of 29,800 acres of aquatic habitat restoration and dust suppression projects around the perimeter of the Salton Sea. At least 50 percent of the project acreage will be created as habitat for fish and wildlife that depend on the Salton Sea ecosystem and the remainder will be projects to suppress dust.

Salton Sea Monitoring Implementation Program (MIP) Annual Work Plan 2024

California Natural Resources Agency (CNRA) | February 29th, 2024

The California Natural Resources Agency (CNRA), the California Department of Water Resources (DWR), and the California Department of Fish and Wildlife (CDFW) are implemen

The California Natural Resources Agency (CNRA), the California Department of Water Resources (DWR), and the California Department of Fish and Wildlife (CDFW) are implementing the Salton Sea Management Program (SSMP) to address air quality and ecological threats at the Salton Sea. The SSMP has a plan for action over the 10-year period from 2018 to 2028 (Phase 1: 10-Year Plan), which aims to improve conditions around the Salton Sea by constructing projects that create habitat and reduce dust from the exposed lakebed on 30,000 acres. Since the state is not a significant landowner in the area, collaboration with land-owning entities is essential and a top priority for the SSMP. The SSMP team also recognizes the crucial role of partnerships in meeting restoration goals through collecting data, facilitating project implementation, and helping obtain funding sources. The Salton Sea Monitoring Implementation Plan (MIP) is a regional-scale monitoring plan for the Salton Sea ecosystem (CNRA 2022). The MIP, which was developed with input from implementing partners (agencies, non-governmental activities to measure conditions of water, air quality, land cover, biological resources, and socioeconomics. The MIP prioritized indicators and metrics and summarized methods and sampling regimes. These indicators were prioritized based on their informativeness and relationship to key resources and drivers of the Salton Sea ecosystem, feasibility of measurement, and relevance for management actions. Some indicators were recommended only for focused study to inform a specific management-articulated information need or specifically identified data gap.

San Francisquito Creek Baylands Landscape Change Metrics Analysis

San Francisco Estuary Institute (SFEI) | June 21st, 2016

The goal of this study is to develop a high level overview of the physical and ecological changes to lower San Francisquito Creek and the surrounding tidal marshes and mu

The goal of this study is to develop a high level overview of the physical and ecological changes to lower San Francisquito Creek and the surrounding tidal marshes and mudflats (referred to here as “baylands”) since the beginning of intensive European-American settlement. Building upon a previous reconnaissance-level historical ecology study (Hermstad et al. 2009), this study analyzes the changes in key landscape features (or landscape metrics) within lower San Francisquito Creek and baylands through comparisons of reconstructed historical (mid-1800s) and contemporary (2011/2012) conditions. The results from this study are intended to provide baseline information that can be used to help with developing restoration and flood control redesign alternatives and appropriate habitat restoration targets. This study is one component of the Flood Control 2.0 project, a regional effort funded by the U.S. EPA to help design flood control channels at the Bay interface that support tidal habitats while maintaining the required level of flood protection. Emerging strategies for flood protection focus on reconnecting channels to floodplains and tidal marshes and using available dredged sediment as a resource to increase marsh elevations and help keep pace with sea level rise. Lower San Francisquito Creek is one of three implementation projects that have partnered with Flood Control 2.0 to assess the benefits of an integrated approach for flood control and habitat management at the Bay interface.

San Joaquin River Restoration Program

San Joaquin River Restoration Program | December 13th, 2007