Glenn County | Hamilton City Flood Damage Reduction and Ecosystem Restoration Project

Nature Conservancy | January 14th, 2016

Although not designed explicitly as a groundwater recharge project, the Hamilton City Project is expected to benefit local groundwater supplies. Having an additio

Although not designed explicitly as a groundwater recharge project, the Hamilton City Project is expected to benefit local groundwater supplies. Having an additional 1,450 acres of floodplain reconnected to the Sacramento River during high flow events will allow transitory storage of flood flows and help recharge the groundwater basin.

Handbook for Assessing Value of State Flood Management Investments

California Department of Water Resources (DWR) | June 1st, 2014

Millions of people and over half a trillion dollars in assets are exposed to flood risk in California (DWR 2013a). This remains the case even as State, federal, a

Millions of people and over half a trillion dollars in assets are exposed to flood risk in California (DWR 2013a). This remains the case even as State, federal, and local flood management agencies have worked for decades to reduce the risk and consequences of flooding in the State. The people of California have shown that they understand the increasing flood risk due to population growth, environmental concerns, climate change, and land use practices, and they are willing to invest in flood risk management projects. This requires the public agencies responsible for California’s flood risk management to demonstrate the value of those investments both before and after they are implemented. This Handbook for Assessing Value of State Flood Management Investments (HAV) supports that effort.

Highlights Central Valley Flood Protection Plan 2022 Update

California Department of Water Resources (DWR) | January 23rd, 2023

The 2022 Central Valley Flood Protection Plan Update was adopted by the Central Valley Flood Protection Board on December 16th, 2022. Just days later, beginning on Decemb

The 2022 Central Valley Flood Protection Plan Update was adopted by the Central Valley Flood Protection Board on December 16th, 2022. Just days later, beginning on December 27th, 2022, a series of atmospheric rivers began to impact California. This succession of atmospheric rivers resulted in 34 trillion gallons of water falling across California in 24 days, and 21 forecast points in the Central Valley reaching flood or monitor stage. Governor Gavin Newsom declared a state of emergency on January 4th, 2023; federal emergency and disaster declarations followed soon thereafter. These events underscore the importance of the CVFPP as the State’s strategic blueprint for investment in flood risk reduction in the Central Valley, especially in an era of whiplash weather—from drought to flooding— driven by the impacts of climate change.

Historical Ecology and Landscape Change in the Central Laguna de Santa Rosa

San Francisco Estuary Institute (SFEI) | March 1st, 2017

This study synthesizes a diverse array of data to examine the ecological patterns, ecosystem functions, and hydrology that characterized a central portion of the Laguna d

This study synthesizes a diverse array of data to examine the ecological patterns, ecosystem functions, and hydrology that characterized a central portion of the Laguna de Santa Rosa during the mid-19th century, and to analyze landscape changes over the past 150 years. The primary purpose of this study was to help guide restoration actions and other measures aimed at reducing nutrient loads within this portion of the Laguna de Santa Rosa watershed.

How freeing rivers can help California ease flood risks and revive ecosystems

Los Angeles Times | February 20th, 2024

Natural floodplains — the lush green lands along rivers that historically flooded, retained water, and nourished life in the heart of the valley — were mostly drained

Natural floodplains — the lush green lands along rivers that historically flooded, retained water, and nourished life in the heart of the valley — were mostly drained and converted to farmland generations ago as the state’s waters were dammed and diverted. Today, an effort to bring back some of those floodplains is flourishing at the 2,100-acre Dos Rios Ranch Preserve near Modesto, where workers years ago planted native trees on retired farm fields and removed berms to create space for water to spread out again.

Human-induced and natural carbon storage in floodplains of the Central Valley of California

Science of the Total Environment (Elsevier) | February 15th, 2019

Active floodplains can putatively store large amounts of organic carbon (SOC) in subsoils originating from catchment erosion processes with subsequent floodplain depositi

Active floodplains can putatively store large amounts of organic carbon (SOC) in subsoils originating from catchment erosion processes with subsequent floodplain deposition. Our study focussed on the assessment of SOC pools associated with alluvial floodplain soils that are affected by human-induced changes in floodplain deposition and in situ SOC mineralisation due to land use change and drainage. We evaluated depth-dependent SOC contents based on 23 soil cores down to 3 m and 10 drillings down to 7 m in a floodplain area of the lower Cosumnes River. An estimate of 266 Mg C ha−1 or about 59% of the entire SOC stored within the 7 m profiles was found in the upper 2 m. Most profiles (n = 25) contained discrete buried A horizons at depths of approximately 0.8 m. These profiles had up to 130% higher SOC stocks. The mean δ13C of all deep soil profiles clearly indicated that arable land use has already altered the stable isotopic signature in the first meter of the profile. Radiocarbon dating showed that the 14C age in the buried horizon was younger than in overlaying soils indicating a substantial sedimentation phase for the overlaying soils. An additional analysis of total mercury contents in the soil profiles indicated that this sedimentation was associated with upstream hydraulic gold mining after the 1850s. In summary, deep alluvial soils in floodplains store large amounts of SOC not yet accounted for in global carbon models. Historic data give evidence that large amounts of sediment were transported into the floodplains of most rivers of the Central Valley and deposited over organically rich topsoil, which promoted the stabilization of SOC, and needs to be considered to improve our understanding of the human-induced interference with C cycling.

Humboldt County | Near-Stream Recharge: Reconnecting Surface and Groundwater

Nature Conservancy | January 1st, 2019

Baker Creek, a tributary to the Mattole River, is a key stream for the federally and state protected coho salmon, however portions of the river were running dry

Baker Creek, a tributary to the Mattole River, is a key stream for the federally and state protected coho salmon, however portions of the river were running dry due to drought, impeding salmon migration and deteriorating habitat. A partnership of federal and state agencies, consultants and NGOs are working to increase groundwater levels with both instream and offchannel projects to ensure year-round water in the creek and floodplain wetlands for salmon habitat. Salmon now returning to the stream, with Phase 1 of the project complete, 1,300 juvenile coho have been counted in Baker Creek after the previous five years saw zero juveniles. Stream restoration in Baker Creek in the Mattole River watershed is an excellent example of a multi- benefit project recharging groundwater, as well as providing the instream coho salmon habitat that has been disappearing.

Loss and Transformation of Coastal Wetlands due to Global Change in the Conterminous United States: Past, Present, and Future

Publisher not available | June 26th, 2026

Coastal wetlands are being transformed by global change, impacting the ecological and societal benefits provided by these ecosystems. Synthesizing knowledge of historical

Coastal wetlands are being transformed by global change, impacting the ecological and societal benefits provided by these ecosystems. Synthesizing knowledge of historical and expected future transformations in coastal wetlands can help inform forward-looking planning and stewardship efforts. Here, we review anticipated future ecological transformations in coastal wetlands of the conterminous United States and contrast them with past transformations. We examine trends at the national scale but focus in detail on the following six wetland-rich regions: (1) Everglades, (2) Mississippi River delta, (3) Chesapeake Bay, (4) San Francisco Estuary, (5) Puget Sound, and (6) Great Lakes. This review is among the first to integrate and compare coastal wetland transformations in the Great Lakes with their oceanic counterparts. Between 1850 and 1970, wetland losses across the nation were high because coastal wetlands were viewed as flooded wastelands needing to be drained, filled, or excavated to make room for other land uses. Over the last 50 years, growing public and scientific appreciation of the ecological and societal benefits provided by coastal wetlands has fostered tremendous gains in wetland restoration and legal protection. Looking to the future, climate change and accelerated sea-level rise have become critical threats to coastal wetlands and are emerging as major drivers of ecological loss and transformation. This review synthesizes regional knowledge regarding past, present, and future changes to help coastal scientists, environmental managers, and the public better anticipate and prepare for future coastal wetland transformations due to climate change, accelerated sea-level rise, land-use change, and other aspects of global change.

Marsh Sediment in Translation: A Review of Sediment Transport Across a Natural Tidal Salt Marsh in Northern San Francisco Bay

University of California, Davis (UC Davis) | March 15th, 2025

Deposition of inorganic sediment is essential for the sustainability of tidal salt marshes. Understanding variability in sediment sources and the processes of sediment de

Deposition of inorganic sediment is essential for the sustainability of tidal salt marshes. Understanding variability in sediment sources and the processes of sediment delivery to salt marshes are high priorities for decision-makers responsible for managing sediment and conserving and restoring marshes.

Methods Used to Update Ecosystem Restoration Maps Using New Digital Elevation Model and Tidal Data

Delta Stewardship Council (Delta Council) | June 29th, 2022