Sustainable floodplains through large-scale reconnection to rivers

American Association for the Advancement of Science (AAAS) | December 11th, 2009

Flooding is the most damaging natural disaster worldwide, and the flood-vulnerable population is expected to grow in coming decades. Flood risks will likely increase beca

Flooding is the most damaging natural disaster worldwide, and the flood-vulnerable population is expected to grow in coming decades. Flood risks will likely increase because of both climate change and shifting land uses, such as filling of wetlands and expansion of impervious surfaces, that lead to more rapid precipitation runoff into rivers. In the United States, annual river flood losses continue to rise, punctuated by major events in the Midwest (1993, $30 billion in total costs; 2008, $15 billion) and California's Central Valley (1995 and 1997; $4 billion each event). Meanwhile, pressure to develop new housing in floodprone areas near rivers (floodplains) continues , even as levee-system maintenance is chronically underfunded.

The effects of aquatic area abundance, buffer, and hydrology on depressional wetland condition based on CRAM

San Francisco Estuary Institute (SFEI) | April 1st, 2016

The hidden influence of terrestrial groundwater on salt marsh function and resilience

Nature Portfolio (Springer Nature) | February 3rd, 2025

Salt marshes are hotspots of nutrient processing and carbon sequestration. So far, studies addressing spatiotemporal variability in and drivers of salt marsh biogeochemic

Salt marshes are hotspots of nutrient processing and carbon sequestration. So far, studies addressing spatiotemporal variability in and drivers of salt marsh biogeochemical function, carbon storage and resilience have focused on ocean-driven surface hydrologic influences, neglecting effects of terrestrial hydrology through subsurface connections. Here we evaluate drivers of salt marsh redox potential, a proxy for biogeochemical state, through wavelet analyses and information theory using data from seven marshes. The results point to terrestrial groundwater level as a dominant control on redox variability across all sites. Because redox is a key driver of biogeochemical processes, and specifically oxidation of organic matter that sequesters carbon and maintains marsh elevation, these terrestrial influences are critical to understanding marsh function and evolution. The newly identified links between onshore groundwater levels and marsh redox conditions shift the traditional paradigm and suggest that terrestrial hydrology is a primary control on salt marsh carbon sequestration potential and resilience.

The impact of vegetation on meandering rivers

Nature Portfolio (Springer Nature) | January 25th, 2022

The Palaeozoic evolution of land plants revolutionized river geomorphology. However, the relationships between biotic forcing and channel dynamics are still debated and,

The Palaeozoic evolution of land plants revolutionized river geomorphology. However, the relationships between biotic forcing and channel dynamics are still debated and, as such, the impacts of anthropogenic stressors such as climate change, reduced biodiversity and aridification on modern meandering rivers and their biogeochemical fluxes remain poorly understood. In this Review, we propose a unifying framework based on field and modelling data that describes the stability and dynamics of meandering rivers in both the presence and the absence of land plants. Based on evidence from the pre-vegetation rock record and from modern systems, we emphasize that meandering streams can indeed arise in the absence of land plants. However, plant evolution provided widespread settings suitable for stable meandering systems through retention of floodplain mud, sediment baffling and mechanical strengthening of channel banks. Altogether, these processes slowed the characteristic rates of meander growth and floodplain-soil reworking by up to an order of magnitude. Continued anthropogenic removal of riparian and watershed vegetation due to increased urbanization, deforestation, aridification and pollution could revert streams to pre-vegetation functioning, thereby increasing their channel and sediment mobility. Future research can use this framework to constrain the pace of ancient landscape processes on Earth and Mars, in addition to modern terrestrial rivers impacted by humans.

The value of marsh restoration for flood risk reduction in an urban estuary

Nature Portfolio (Springer Nature) | March 21st, 2024

Toward Natural Infrastructure to Manage Shoreline Change in California

California Natural Resources Agency (CNRA) | August 27th, 2018

Flooding and erosion caused by rising sea levels and powerful storms threaten property throughout coastal California. To protect against these climate-change related thr

Flooding and erosion caused by rising sea levels and powerful storms threaten property throughout coastal California. To protect against these climate-change related threats, landowners will certainly take action, and the default industry standard response has been to try to “hold the line” against the encroaching sea by constructing seawalls, dikes, levees and other forms of coastal armoring. While armoring may in some cases provide acceptable short-term protection, armoring also tends to accelerate shoreline erosion, exacerbating hazards to people and leading to the eventual loss of critical wildlife habitat and public beaches. Natural Shoreline Infrastructure can be as effective as armoring, while having the added benefits of preserving coastal habitat and public access. Recognizing this, California agencies have mandated that decision-makers prioritize its use in planning and investment decisions. Yet, planners have encountered many stumbling blocks as they have tried to incorporate these approaches into coastal resilience plans. Major obstacles include: a lack of a common definition and shared terminology; lack of expertise; lack of precedent; and the absence of siting guidance and technical design standards. Here, we set out to enable planners to adopt Natural Shoreline Infrastructure by filling in the missing information. With the input of dozens of coastal managers who served on our Technical Advisory Committee, we developed a definition and collected a list of case studies where Natural Shoreline Infrastructure has already been successfully deployed in California. Drawing from these and other projects, we collected into one place the first detailed technical guidance for implementation, including siting criteria and design thresholds. These criteria inform decisions about where and when to use six types of Natural Shoreline Infrastructure (e.g. sand dunes, seagrass beds). Using Monterey Bay and Ventura County projects as examples, we demonstrate how to use the technical guidance in tandem with spatial data to match a particular shoreline environment with appropriate Natural Shoreline Infrastructure options, creating “blueprints” for action. The information in this report is intended to facilitate the use of Natural Shoreline Infrastructure along California’s coast, improving the resilience of communities and habitats in the face of climate change.

Translating Science-Based Restoration Strategies into Spatially-Explicit Restoration Opportunities in the Delta (2018 Bay-Delta Science Conference Presentation)

San Francisco Estuary Institute (SFEI) | July 2nd, 2018

In a previous report titled “A Delta Renewed” we offered a collection of guidelines for science-based ecological restoration in the Sacramento-San Joaquin Delta that

In a previous report titled “A Delta Renewed” we offered a collection of guidelines for science-based ecological restoration in the Sacramento-San Joaquin Delta that emphasized restoring or emulating natural processes, anticipating future changes associated with climate change, establishing appropriate configurations of habitat types at the landscape scale, and utilizing a variety multi-benefit management strategies. In this talk, we present on our recent work to support regional restoration planning efforts by developing a repeatable process for using these guidelines to identify spatially-explicit restoration opportunities. The process is largely GIS-based and utilizes spatial data on existing land cover and conservation status, habitat configuration (including patch sizes and distances), surface elevations (including depth of subsidence), and future changes in tidal elevations associated with sea-level rise.  By distilling generalized guidelines into spatially-explicit opportunities, we hope to provide a practical tool for incorporating science into planning. To that end, these new methods are currently being piloted through planning efforts focused on the Central Delta Corridor and the McCormack Williamson Tract, and are also being used to assist with the quantification of ecological restoration potential in the Delta Plan Ecosystem Amendment.

Valuing Urban Nature – Implications for Flood Resilience

Stanford University | June 3rd, 2019

Sea-level rise and extreme weather events such as torrential rain storms are having devastating consequences in the United States and globally. Researchers, prac

Sea-level rise and extreme weather events such as torrential rain storms are having devastating consequences in the United States and globally. Researchers, practitioners, and policymakers are increasingly calling for the use of natural and nature-based approaches to protect urban areas from flooding which has increased in frequency and intensity as a result. Natural features can help stabilize shorelines and protect communities from river flooding while, providing other co- benefits for people and ecosystems. In a new study, scientists at the Natural Capital Project developed a framework for valuating urban nature and examined different factors cities must consider when making infrastructure and other investment choices. This brief is part of a series based on that research which looks at nature’s abilityto provide resilience to flooding and the various co-benefits associated with nature-based solutions.

Yolo Bypass Salmonid Habitat Restoration and Fish Passage Final Environmental Impact Statement / Environmental Impact Report (Executive Summary)

U.S. Bureau of Reclamation (USBR) | May 1st, 2019

The Yolo Bypass Salmonid Habitat Restoration and Fish Passage Project (Project) Environmental Impact Statement/Environmental Impact Report (EIS/EIR) addresses methods to

The Yolo Bypass Salmonid Habitat Restoration and Fish Passage Project (Project) Environmental Impact Statement/Environmental Impact Report (EIS/EIR) addresses methods to improve fish passage and increase floodplain fisheries rearing habitat in the Yolo Bypass to benefit Sacramento River winter-run Chinook salmon, Central Valley spring-run Chinook salmon, Central Valley steelhead, and Southern Distinct Population Segment of North American green sturgeon. The Project actions would implement Reasonable and Prudent Alternative actions I.6.1 and I.7, as described in the 2009 National Oceanic and Atmospheric Administration National Marine Fisheries Service Biological Opinion and Conference Opinion on the Long-Term Operations of the Central Valley Project and State Water Project and the 2012 Yolo Bypass Salmonid Habitat Restoration and Fish Passage Implementation Plan.  This EIS/EIR has been prepared according to requirements of the National Environmental Policy Act and the California Environmental Quality Act. Direct, indirect, and cumulative impacts resulting from the project alternatives on the environment of the region are evaluated.  Full document files: Chapters 1-8 Chapters 9-12 Chapters 13-26 Appendices and drafts