Reconciling fish and farms: Methods for managing California rice fields as salmon habitat

PLOS | February 24th, 2021

Rearing habitat for juvenile Chinook Salmon (Oncorhynchus tshawytscha) in California, the southernmost portion of their range, has drastically declined throughout the pa

Rearing habitat for juvenile Chinook Salmon (Oncorhynchus tshawytscha) in California, the southernmost portion of their range, has drastically declined throughout the past century. Recently, through cooperative agreements with diverse stakeholders, winter-flooded agricultural rice fields in California’s Central Valley have emerged as ecologically functioning floodplain rearing habitat for juvenile Chinook Salmon. From 2013 to 2016, we conducted a series of experiments examining methods to enhance habitat benefits for fall-run Chinook Salmon reared on winter-flooded rice fields in the Yolo Bypass, a modified floodplain managed for flood control, agriculture, and wildlife habitat in the Sacramento River Valley of California. Investigations included studying the effect of 1) post-harvest field substrate; 2) depth refugia; 3) duration of field drainage; and 4) duration of rearing occupancy on in-situ diet, growth and survival of juvenile salmon. Post-harvest substrate treatment had only a small effect on the lower trophic food web and an insignificant effect on growth rates or survival of rearing hatchery-origin, fall-run Chinook Salmon. Similarly, depth refugia, created by trenches dug to various depths, also had an insignificant effect on survival. Rapid field drainage yielded significantly higher survival compared to drainage methods drawn out over longer periods. A mortality of approximately one third was observed in the first week after fish were released in the floodplain. This initial mortality event was followed by high, stable survival rates for the remainder of the 6-week duration of floodplain rearing study. Across years, in-field survival ranged 7.4–61.6% and increased over the course of the experiments. Despite coinciding with the most extreme drought in California’s recorded history, which elevated water temperatures and reduced the regional extent of adjacent flooded habitats which concentrated avian predators, the adaptive research framework enabled incremental improvements in design to increase survival. Zooplankton (fish food) in the winter-flooded rice fields were 53-150x more abundant than those sampled concurrently in the adjacent Sacramento River channel. Correspondingly, observed somatic growth rates of juvenile hatchery-sourced fall-run Chinook Salmon stocked in rice fields were two to five times greater than concurrently and previously observed growth rates in the adjacent Sacramento River. The abundance of food resources and exceptionally high growth rates observed.

Relationship between wetland condition, stress, and buffer

San Francisco Estuary Institute (SFEI) | April 25th, 2016

Relationship between wetland size and CRAM condition scores for depressional wetlands

San Francisco Estuary Institute (SFEI) | March 28th, 2016

Restoration of Hetch Hetchy Valley and San Francisco’s Water Supply

Restore Hetch Hetchy | February 10th, 2016

Q: After restoration, where will San Francisco gets is water? A: From the Tuolumne River, just as it does now. This report addresses only the most commonly asked ques

Q: After restoration, where will San Francisco gets is water? A: From the Tuolumne River, just as it does now. This report addresses only the most commonly asked question by restoration skeptics: Where would the water come from? Restoration would also require increased water treatment costs and replacement of about 350 gigawatt-hours per year of hydropower production – issues not addressed herein.

Sacramento River Temperature Task Group Annual Report of Activities, October 1, 2015 through September 30, 2016

Delta Stewardship Council (Delta Council) | October 31st, 2016

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 Luis National Wildlife Refuge Complex Final Comprehensive Conservation Plan and Environmental Assessment

U.S. Fish and Wildlife Service (FWS) | July 31st, 2024

This Comprehensive Conservation Plan (CCP) will guide the management of the Merced National Wildlife Refuge (NWR), San Luis NWR and Grasslands Wildlife Management Area (W

This Comprehensive Conservation Plan (CCP) will guide the management of the Merced National Wildlife Refuge (NWR), San Luis NWR and Grasslands Wildlife Management Area (WMA) for the next 15 years. Located in Merced County, California (Figure 1-1), these three units are managed and administered by the San Luis National Wildlife Refuge Complex (the Complex). A fourth unit, the San Joaquin River NWR, is also managed and administered by the Complex but already has a CCP for its management, which was completed in 2006 and amended in 2022. For the sake of this document, the term Complex refers to the San Luis NWR, Merced NWR and Grasslands WMA only. The Complex comprises just four of the 568 refuges that currently make up the U.S. Fish and Wildlife Service (USFWS or the Service) National Wildlife Refuge System (NWRS or Refuge System). The mission of the NWRS is to conserve a network of lands and water for the conservation and management of fish, wildlife and plant resources of the United States for the benefit of present and future generations. As part of the Refuge System, the three units—Merced NWR, San Luis NWR and Grasslands WMA—addressed in this CCP provide important habitat for a unique assemblage of both wetland- (particularly waterfowl and other waterbirds) and upland-dependent wildlife species of California’s Central Valley. This CCP is divided into five chapters: Chapter 1, Introduction and Background; Chapter 2, Comprehensive Conservation Planning Process; Chapter 3, Refuge Resources; Chapter 4, Refuge Management Direction; and Chapter 5, Implementation. Click here for full appendices.

Select Water Quality Parameters During Wet and Dry Conditions in the Colorado River Delta

American Water Resources Association (AWRA) | August 27th, 2022