Undelivered Water: Fulfilling the CVPIA promise to Central Valley refuges

U.S. Bureau of Reclamation (USBR) | November 3rd, 2009

The 1992 Central Valley Project Improvement Act transformed California’s federal water management system by providing fish and wildlife a co-equal priority with other u

The 1992 Central Valley Project Improvement Act transformed California’s federal water management system by providing fish and wildlife a co-equal priority with other uses. In so doing, the Act mandated that the federal government establish a program, now known as the Refuge Water Supply Program (RWSP), to manage, secure, and deliver a reliable, clean water supply to serve the wetland habitat needs of nineteen federal, state, and private wildlife refuges in California’s Central Valley. The refuges protect a significant portion of the last remaining 5 percent of the historic Central Valley wetlands and provide birds of the Pacific Flyway habitat during critical periods when no other wetlands habitat may be available. In response to a request from OMB, the Bureau of Reclamation and the Fish and Wildlife Service established an Independent Panel to evaluate the performance of the RWSP component of the Central Valley Project Improvement Act.

Underestimating the Challenges of Avoiding a Ghastly Future

Frontiers in Conservation Science (Frontiers) | January 13th, 2021

We report three major and confronting environmental issues that have received little attention and require urgent action. First, we review the evidence that future enviro

We report three major and confronting environmental issues that have received little attention and require urgent action. First, we review the evidence that future environmental conditions will be far more dangerous than currently believed. The scale of the threats to the biosphere and all its lifeforms—including humanity—is in fact so great that it is difficult to grasp for even well-informed experts. Second, we ask what political or economic system, or leadership, is prepared to handle the predicted disasters, or even capable of such action. Third, this dire situation places an extraordinary responsibility on scientists to speak out candidly and accurately when engaging with government, business, and the public. We especially draw attention to the lack of appreciation of the enormous challenges to creating a sustainable future. The added stresses to human health, wealth, and well-being will perversely diminish our political capacity to mitigate the erosion of ecosystem services on which society depends. The science underlying these issues is strong, but awareness is weak. Without fully appreciating and broadcasting the scale of the problems and the enormity of the solutions required, society will fail to achieve even modest sustainability goals.

Understanding End-of-Century Snowpack Changes Over California’s Sierra Nevada

American Geophysical Union (AGU) | January 29th, 2019

Understanding Microplastic Levels, Pathways, and Transport in the San Francisco Bay Region

San Francisco Estuary Institute (SFEI) | October 2nd, 2019

Microplastics (particles less than 5 mm) are ubiquitous and persistent pollutants in the ocean and a pervasive and preventable threat to the health of marine ec

Microplastics (particles less than 5 mm) are ubiquitous and persistent pollutants in the ocean and a pervasive and preventable threat to the health of marine ecosystems. Microplastics come in a wide variety of shapes, sizes, and plastic types, each with unique physical and chemical properties and toxicological impacts. Understanding the magnitude of the microplastics problem and determining the highest priorities for mitigation require accurate measures of microplastic occurrence in the environment and identification of likely sources. To develop critical baseline data and inform solutions, the San Francisco Estuary Institute and the 5 Gyres Institute have completed the first comprehensive regional study of microplastic pollution in a major estuary.

Understanding the Contributions of Paleo-Informed Natural Variability and Climate Changes to Hydroclimate Extremes in the San Joaquin Valley of California

American Geophysical Union (AGU) | November 13th, 2023

Understanding the Cost of Basic Drinking Water Services in the United States: A National Assessment

American Water Works Association (AWWA) | January 23rd, 2025

The cost of basic drinking water services has implications for affordability, investment capacity, and public health. The fragmentation of drinking water services in the

The cost of basic drinking water services has implications for affordability, investment capacity, and public health. The fragmentation of drinking water services in the United States makes it difficult to reliably track and compare what customers pay for basic drinking water services. This paper uses a new, national dataset to examine the social, political, environmental, and institutional drivers of the cost of basic drinking water services, measured as the cost to households of 6000 gal of water per month. We find basic drinking water service costs vary widely across the United States. Costs are generally higher in smaller and more liberal cities and lower in places that rely on groundwater sources. Our findings provide a unique national perspective on variation in, and drivers of, the cost of basic water services and can inform efforts to improve the affordability, accessibility, and quality of drinking water services in the United States.

Understanding the recent increase in multiyear La Niñas

Nature Portfolio (Springer Nature) | September 18th, 2023

Understanding Uncertainties in Future Colorado River Streamflow

American Meteorological Society (AMS) | January 1st, 2014

The Colorado River is the primary water source for more than 30 million people in the United States and Mexico. Recent studies that project streamf low changes in the Col

The Colorado River is the primary water source for more than 30 million people in the United States and Mexico. Recent studies that project streamf low changes in the Colorado River all project annual declines, but the magnitude of the projected decreases range from less than 10% to 45% by the mid-twenty-first century. To understand these differences, we address the questions the management community has raised: Why is there such a wide range of projections of impacts of future climate change on Colorado River streamflow, and how should this uncertainty be interpreted? We identify four major sources of disparities among studies that arise from both methodological and model differences. In order of importance, these are differences in 1) the global climate models (GCMs) and emission scenarios used; 2) the ability of land surface and atmospheric models to simulate properly the high-elevation runoff source areas; 3) the sensitivities of land surface hydrology models to precipitation and temperature changes; and 4) the methods used to statistically downscale GCM scenarios. In accounting for these differences, there is substantial evidence across studies that future Colorado River streamflow will be reduced under the current trajectories of anthropogenic greenhouse gas emissions because of a combination of strong temperature-induced runoff curtailment and reduced annual precipitation. Reconstructions of preinstrumental streamflows provide additional insights; the greatest risk to Colorado River streamf lows is a multidecadal drought, like that observed in paleoreconstructions, exacerbated by a steady reduction in flows due to climate change. This could result in decades of sustained streamflows much lower than have been observed in the ~100 years of instrumental record.

Underwater Videographic Observations of Domesticated Delta Smelt in Field Enclosures

U.S. Geological Survey (USGS) | May 24th, 2022

The delta smelt (Hypomesus transpacificus) is a small, euryhaline fish species endemic to the Sacramento–San Joaquin Delta; it is protected under the U.S. and Californi

The delta smelt (Hypomesus transpacificus) is a small, euryhaline fish species endemic to the Sacramento–San Joaquin Delta; it is protected under the U.S. and California Endangered Species Acts, and because of declines in population abundance, the delta smelt may be vulnerable to extinction. The California Department of Water Resources (DWR) is conducting studies to test the viability of using domesticated fish to supplement the wild population of delta smelt. These studies have focused on examining the health and survival of domesticated delta smelt placed inside enclosures (circular cages that are approximately 1.5 meters tall by 1 meter in diameter) into the wild. We completed two parts within this study using underwater cameras inside the enclosures to observe fish behavior and their responses to certain stimuli. In both parts of the study, delta smelt behaviors were broadly categorized into two basic categories: (1) normal and (2) alarm. Normal behavior was characterized as calm, non-polarized, and docile swimming behavior. Alarm behavior was characterized by sudden and rapid darting, polarized frantic swimming activity, and tighter schooling polarization of individuals. The first part of the study took place in a semi-controlled agricultural pond on the campus of the University of California, Davis. At this agricultural pond, we developed methods of observation and documented how fish behaved in response to enclosure disturbances associated with routine cleaning and service that is required during extended field deployments of the enclosures. We observed that delta smelt behavior changed from normal to alarm at the onset of an enclosure service and from alarm to normal within about 2 minutes after the service ended. The second part of the study was completed in cooperation with the DWR. In October 2019, DWR deployed three enclosures in the Sacramento River near Rio Vista, California. To monitor survival rate of delta smelt, DWR permitted us to deploy cameras in one enclosure to document the frequency and duration of alarm behaviors exhibited by delta smelt and the frequency, duration, and intensity of three types of disturbances: (1) noise generated from passing boats, (2) noise generated from the enclosure moving in response to wave energy, and (3) vertical movements of the enclosure generated from wave energy. Alarm behaviors averaged about 2 minutes in duration and occurred most frequently during the evening compared to midday or morning. Each disturbance variable exhibited substantial variability in duration and intensity and occurred least frequently during the morning and evening compared to midday. Alarm behaviors appeared to be most associated with high intensity enclosure noises and vertical movements; however, limited replicate samples prohibited developing a statistical relation. Alarm behaviors did not directly contribute to injury or mortality of individual delta smelt; however, indirect or sublethal effects of alarm behaviors were not examined.

Unintended consequences of using maps to communicate sea-level rise

Nature Portfolio (Springer Nature) | June 26th, 2024