Executive Order N-7-23

State of California | May 17th, 2023

Executive Summary: An Evaluation of Compensatory Mitigation Projects Permitted Under Clean Water Act Section 401 by the California State Water Resources Control Board, 1991-2002

California State Water Resources Control Board (SWRCB) | August 1st, 2007

The purpose of this project, which was funded by the California State Water Resources Control Board (SWRCB), was to evaluate the compliance and wetland conditio

The purpose of this project, which was funded by the California State Water Resources Control Board (SWRCB), was to evaluate the compliance and wetland condition of compensatory wetland mitigation projects associated with Clean Water Act Section 401 Water Quality Certifications throughout California. This was done by selecting, reviewing and performing field evaluations for 143 permit files distributed across the 12 Water Board regions and sub-regions of the State. For each permit file we assessed the extent to which permittees complied with their mitigation conditions, including acreage requirements, whether the corresponding mitigation efforts resulted in optimal wetland condition, and if the habitat acreages gained through compensatory mitigation adequately replaced those lost through the permitted impacts. We found that permittees are largely following their permit conditions (although one-quarter to one-third of the time these are not met), but the resulting compensatory mitigation projects seldom result in wetlands with optimal condition.

Existing Accessible Modeling Tools Offer Limited Support to Evaluation of Impact Investment in Rangeland Ecosystem Services

Frontiers in Sustainable Food Systems (Frontiers) | September 24th, 2019

Privately owned rangelands in the western US support many ecosystem services and are threatened by financial incentives favoring conversion to housing development and m

Privately owned rangelands in the western US support many ecosystem services and are threatened by financial incentives favoring conversion to housing development and more intensive forms of agriculture. Recognizing this threat, the impact investment community has identified rangeland management as a potential investing strategy to produce financial returns while preserving or enhancing the ecosystem services provided by intact rangelands. This strategy is based primarily on the notion that a capital-intensive conversion from continuous to rotational grazing can financially sustain rangelands through a combination of increased productivity and potentially monetized ecosystem service flows. The potential for these gains is supported by compelling anecdotal evidence, yet a robust body of scientific literature based on rigorous field experiments has not supported those claims, nor produced transferrable estimates of the benefits provided by rotational grazing of livestock (particularly cattle in the western US). Therefore, to demonstrate investment viability and measure investment success, impact investors will likely need to address these well-documented disconnects through some combination of monitoring and process-based modeling. This study examines the extent to which existing modeling tools are up to this task, by assessing the ability of two process-based models to represent four specific rotational grazing benefits put forth by impact investors, using a ranch in northeastern Wyoming as a case study. Using the Soil Water Assessment Tool, we simulated high magnitude changes in the water balance from surface runoff to evapotranspiration, which may be a benefit or negative impact depending on context (Benefit 1). We simulated a decrease in soil water storage under rotational grazing, which directly contradicts the outcome assumed in investment literature (Benefit 2). Using the InVEST beta Rangeland Production Model (based on the Century ecosystem model), we simulated increased biomass productivity (Benefit 3) under rotational grazing, which enhanced animal performance under some management parameters but negatively impacted it in others (Benefit 4). We conclude that the impact investing community will likely find greater success through a shift to objective-oriented ranch management, rather than a specific focus on rotation, and will also need additional investment in science and monitoring to demonstrate benefits.

Exit here: Strategies for dealing with aging dams and reservoirs

Aquatic Sciences (Springer) | October 22nd, 2019

Aging infrastructure is prevalent throughout the world, but water control management structures, specifically dams, are of growing concern. Dams and their corresponding r

Aging infrastructure is prevalent throughout the world, but water control management structures, specifically dams, are of growing concern. Dams and their corresponding reservoirs have inherent, but separate, lifespans. The proportion of dams around the world that continue operation beyond their intended lifespans is growing at an alarming rate. Society will not only have to navigate the tradeoffs associated with the deterioration of services provided by reservoirs and dams, but also impending structural failures. Society is nearing a critical pinch point where we will have to decide how to deal with dams and reservoirs at scales that range from a single system to multiple systems in large watersheds. No comprehensive strategy exists to inform both the range of actions that can be applied to such infrastructure and how such actions would influence biophysical, socioeconomic, and geopolitical tradeoffs. The development of proactive exit strategies is a critical first step in ensuring controlled transitions for aging dams and reservoirs. Herein, we present an overview of actions and considerations for aging dams and reservoirs, followed by an initial framework for exit strategy development to launch a further discussion on how society could deal with this aging infrastructure.

Expansion and Intensification of the North American Monsoon During the Pliocene

American Geophysical Union (AGU) | November 10th, 2022

Expert review of the sediment screening guidelines for the beneficial reuse of dredged material in San Francisco Bay, Workshop Summary Report

Publisher not available | March 17th, 2020

Exploration of Tolerable Risk Guidelines for the USACE Levee Safety Program

U.S. Army Corps of Engineers (USACE) | January 10th, 2011

Risk assessment methodologies have been used around the world to provide decision makers with information on the likelihood of adverse outcomes and resulting consequences

Risk assessment methodologies have been used around the world to provide decision makers with information on the likelihood of adverse outcomes and resulting consequences. Governments are recently moving to broader flood risk management approaches that encompass structural measures and manage floodplain development while recognizing climate change, environmental functions and social factors. Such flood risk approaches consider the probability of a flood hazard occurring; the vulnerability of flood mitigation measures implemented to lessen flood consequences through preparation, response, recovery and mitigation; and the consequences that result from the mitigated flood event. Within that overarching flood risk management context, the U.S. Army Corps of Engineers (USACE) is considering risk management approaches for dams and levee systems in order to make better decisions, better prioritize and justify risk reduction measures, better communicate risks to decision makers and the public, and better understand and evaluate public safety risks in an environment of shared flood risk management responsibilities. USACE consideration of risk management approaches includes the potential use of a Tolerability of Risk (TOR) framework, originally developed in the United Kingdom and adapted elsewhere, as well as Tolerable Risk Guidelines (TRG). Tolerability of Risk was developed as a framework for reaching decisions with stakeholders that focuses on the most serious risks consistently, efficiently, and transparently. Tolerable Risk Guidelines categorize the nature of risks in ways that can assist in assessing their acceptability or non-acceptability, and in prioritizing actions for reducing risks. (Further information regarding TOR and TRG is available in the summary of Dr. Jean LeGuen’s presentation, in Section 3 of this report, and in his paper, included in Appendix D.) In March 2008, three Federal agencies - US Army Corps of Engineers (USACE), Department of Interior, Bureau of Reclamation (Reclamation), and Federal Energy Regulatory Commission (FERC) convened a workshop entitled “Workshop on Tolerable Risk Evaluation – A step towards developing tolerable risk guidelines for dams and levees”. With the formation of the USACE Levee Safety Program (USACE 2007), attention began to be directed toward adapting the newly developed risk-informed dam safety policies and methods for application to levee systems. The National Committee on Levee Safety (NCLS) authorized by the Levee Safety Act of 2007 published its draft recommendations in January 2009 (NCLS 2009) including Recommendation #5 that Tolerable Risk Guidelines (TRG) be developed for application in risk-informed, flood risk management (FRM) associated with levees. This March 2010 workshop constitutes one step in USACE engaging the flood risk management community to work collaboratively in developing policies, TRG, and methods to further levee safety for the nation. The workshop purpose was to examine the concepts and principles of tolerability of risk and tolerable risk guidelines and explore their application to, and use in, managing life, economic, and environmental risk associated with levee systems. The workshop scope encompassed national and international approaches to flood risk management, tolerability of risk, and tolerable risk guidelines as they would apply to the USACE levee safety program. The workshop was comprised of three parts: introductory plenary presentations that set a common base and vocabulary for subsequent discussions; three facilitated break-out sessions that deliberated on questions prepared in advance; and concluding panels and plenary sessions that would capture the sense of the participants in what was learned and how to proceed. Invited participants numbering about sixty were from USACE, FEMA, other Federal agencies, professional societies, NGO’s, and from The Netherlands, United Kingdom, Japan, and Spain.

Exploring scientific and management implications of upper trophic level food webs in the Delta

Delta Stewardship Council (Delta Council) | April 17th, 2024

The Sacramento-San Joaquin Delta (the Delta) has complex and evolving ecosystems characterized by multiple food webs that vary in time and space. Here, food webs are defi

The Sacramento-San Joaquin Delta (the Delta) has complex and evolving ecosystems characterized by multiple food webs that vary in time and space. Here, food webs are defined as the network of species interactions (competition, predation) and interactions with their environment that are related through the flow of energy through the ecosystem (e.g., Paine 1980). Physical modifications, in addition to the introduction of non-native species and the changing climate, have significantly altered the structure and energetic pathways of the food webs for decades. The science clearly suggests that predicting the impacts of habitat restoration, fisheries, changes in environmental drivers (e.g., climate, changes in nutrient loading, invasive species) on the ecological carrying capacity and productivity of the Delta, as well as the bioaccumulation of contaminants on species or the ecosystem, requires an understanding of food web processes.

Exploring the Origins of Snow Drought in the Northern Sierra Nevada, California

American Meteorological Society (AMS) | February 22nd, 2018

The concept of snow drought is gaining widespread interest as the climate of snow-dominated mountain watersheds continues to change. Warm snow drought is defined

The concept of snow drought is gaining widespread interest as the climate of snow-dominated mountain watersheds continues to change. Warm snow drought is defined as above- or near-average accumulated pre- cipitation coinciding with below-average snow water equivalent at a point in time. Dry snow drought is defined as below-average accumulated precipitation and snow water equivalent at a point in time. This study contends that such point-in-time definitions might miss important components of how snow droughts originate, persist, and terminate. Using these simple definitions and a variety of observations at monthly, daily, and hourly time scales, the authors explore the hydrometeorological origins of potential snow droughts in the northern Sierra Nevada from water years 1951 to 2017. This study finds that snow droughts can result from extreme early season precipitation, frequent rain- on-snow events, and low precipitation years. Late-season snow droughts can follow persistent warm and dry periods with effects that depend upon elevation. Many snow droughts were characterized by lower snow fractions and midwinter peak runoff events. These findings can guide improved evaluations of historical and potential future snow droughts, particularly with regards to how impacts on water resources and mountain ecosystems may vary depending on how snow droughts originate and evolve in time.

Exploring the Potential for Water-Limited Agriculture in the San Joaquin Valley

Public Policy Institute of California (PPIC) | July 21st, 2022

The rollout of California’s Sustainable Groundwater Management Act (SGMA) is altering the state’s agricultural landscape. As groundwater sustainability measures are

The rollout of California’s Sustainable Groundwater Management Act (SGMA) is altering the state’s agricultural landscape. As groundwater sustainability measures are implemented and water scarcity increases, at least half a million acres are projected to come out of irrigated production in the San Joaquin Valley, the state’s agricultural heartland. Rather than widespread land idling—which comes with unintended consequences such as dust, weeds, pests, and soil degradation — a switch from summer irrigated crops to winter crops produced with limited water (including winter cereals and forage crops, among others) might keep some of this land in production. Although water-limited agriculture faces large hurdles, some promising aspects warrant further exploration.