Inyo County: Monitoring Groundwater Dependent Vegetation to Inform Groundwater Management

Nature Conservancy | August 1st, 1989

Inyo County and the City of Los Angeles have shown innovative and progressive leadership in the protection of groundwater dependent ecosystems in Owens Valley,

Inyo County and the City of Los Angeles have shown innovative and progressive leadership in the protection of groundwater dependent ecosystems in Owens Valley, and thanks to a landmark agreement between Inyo County and the Los Angeles Department of Water and Power (LADWP), the outlook for groundwater dependent ecosystems (GDEs) in this area is promising. In 1991, the Inyo/Los Angeles Long-Term Water Agreement (Agreement) established an elaborate system to manage groundwater pumping by LADWP to avoid substantial declines in groundwater dependent vegetation in the Owens Valley. Implemented to settle the County’s 1971 CEQA challenge of LADWP’s proposed method to fill its second aqueduct, the Agreement resolved years of litigation between the County and LADWP.

Irrigation in the Earth system

Nature Portfolio (Springer Nature) | June 20th, 2023

Is there an urban pesticide signature? Urban streams in five U.S. regions share common dissolved-phase pesticides but differ in predicted aquatic toxicity

Science of the Total Environment (Elsevier) | June 15th, 2021

Pesticides occur in urban streams globally, but the relation of occurrence to urbanization can be obscured by regional differences. In studies of five regions of the Unit

Pesticides occur in urban streams globally, but the relation of occurrence to urbanization can be obscured by regional differences. In studies of five regions of the United States, we investigated the effect of region and urbanization on the occurrence and potential toxicity of dissolved pesticide mixtures. We analyzed 225 pesticide compounds in weekly discrete water samples collected during 6–12 weeks from 271 wadable streams; development in these basins ranged from undeveloped to highly urbanized. Sixteen pesticides were consistently detected in 16 urban centers across the five regions—we propose that these pesticides comprise a suite of urban signature pesticides (USP) that are all common in small U.S. urban streams. These USPs accounted for the majority of summed maximum pesticide concentrations at urban sites within each urban center. USP concentrations, mixture complexity, and potential toxicity increased with the degree of urbanization in the basin. Basin urbanization explained the most variability in multivariate distance-based models of pesticide profiles, with region always secondary in importance. The USPs accounted for 83% of pesticides in the 20 most frequently occurring 2-compound unique mixtures at urban sites, with carbendazim+prometon the most common. Although USPs were consistently detected in all regions, detection frequencies and concentrations varied by region, conferring differences in potential aquatic toxicity. Potential toxicity was highest for invertebrates (benchmarks exceeded in 51% of urban streams), due most often to the neonicotinoid insecticideimidacloprid and secondarily to organophosphate insecticides and fipronil. Benchmarks were rarely exceeded in urban streams for plants (at 3% of sites) or fish (<1%). We propose that the USPs identified here would make logical core (nonexclusive) constituents for monitoring dissolved pesticides in U.S. urban streams, and that unique mixtures containing imidacloprid, fipronil, and carbendazim are priority candidates for mixtures toxicity testing.

Issue Paper for the San Joaquin River spring-run Chinook experimental population – Delta impacts

National Marine Fisheries Service (NMFS) | July 23rd, 2013

Joshua Tree National Park: A History of Preserving the Desert

National Park Service (NPS) | March 16th, 2015

Juvenile Production Estimate (JPE) Calculation and Use/Application of Survival Data from Acoustically-tagged Chinook Salmon Releases Report

Delta Stewardship Council (Delta Council) | February 21st, 2014

Each year, NOAA’s National Marine Fisheries Service (NMFS) estimates the number of juvenile winter-run Chinook salmon expected to enter the Delta. NMFS’ June 4, 2009

Each year, NOAA’s National Marine Fisheries Service (NMFS) estimates the number of juvenile winter-run Chinook salmon expected to enter the Delta. NMFS’ June 4, 2009, biological and conference opinion on the long-term operation of the Central Valley Project and State Water Project provides an incidental take limit on natural juvenile winter-run based on the juvenile production estimate.

Juvenile salmonids traverse coastal meta-nurseries that connect rivers via the sea

Ecological Society of America (ESA) | April 30th, 2025

Conventionally, juvenile salmonids are thought to migrate unidirectionally from freshwater systems to marine systems and therefore only inhabit natal drainages. Although

Conventionally, juvenile salmonids are thought to migrate unidirectionally from freshwater systems to marine systems and therefore only inhabit natal drainages. Although scattered evidence suggests juveniles can move bidirectionally between freshwater rivers and the ocean, including into non-natal drainages, such movements have never been documented with high replication. Here, we detected hundreds of movements of juvenile salmonids between drainages that involved 0–22% of cohort emigrants in Washington State and California. Individuals moved up to nine times and between drainages up to 70 km apart. These findings reveal a life-history type of salmonids whose remarkably complex migrations have gone unnoticed. Implicitly, juveniles may use any coastal freshwater habitat accessible from the sea and may not descend from spawning populations of drainages they inhabit. Consequently, typical conservation focused on natal drainages may overlook freshwater habitat elsewhere. A concept of coastal areas as meta-nurseries formed by multiple watersheds connected by the sea may accurately describe anadromous species’ habitat options and better inform management.

Keeping up with the status of freshwater fishes: A California (USA) perspective

Conservation Science and Practice (Wiley) | May 29th, 2021

Klamath River Basin Issues: An Overview of Water Use Conflicts

Congressional Research Service (CRS) | June 13th, 2002

Severe drought in 2001 affected the Klamath River Basin, an area on the California-Oregon border, exacerbating competition for scarce water resources and generating confl

Severe drought in 2001 affected the Klamath River Basin, an area on the California-Oregon border, exacerbating competition for scarce water resources and generating conflict among several interests – farmers, municipal and industrial users, commercial and sport fishermen, other recreationists, federal wildlife refuges, environmental groups, and Indian Tribes. The conflicts over water distribution and allocation are physically and legally complex, reflecting the varied and sometimes competing uses of limited water supplies in the Upper Basin. On April 6, 2001, the Bureau of Reclamation (Bureau), which has supplied water to farms in the Upper Basin for nearly 100 years, announced that “no water [would] be available” for farms normally receiving water from the Upper Klamath Lake, so that scarce water could be used to protect species listed as endangered or threatened under the Endangered Species Act (ESA). Water was available to some farmers from other sources (e.g., wells and other Bureau sources); however, many farmers were not able to plant or harvest crops due to severe cutbacks in water supplies. Emotions ran high on all sides of the issues, and the water control gates were unlawfully opened by protesters. Although the Basin has received significantly more precipitation in 2002, many issues remain in dispute. In addition, several judicial decisions have affected the issues with respect to the listed species as well as tribal rights. On May 31, 2002, the U.S. Fish and Wildlife Service and the National Marine Fisheries Service both issued Final Biological Opinions on the Bureau’s 10-year Operation Plan for the Klamath Project. The agencies found that the Bureau’s proposed action is likely to jeopardize the continued existence of the two listed suckers and coho salmon, as well as result in the adverse modification of proposed critical habitat; however, both Opinions also included “reasonable and prudent alternatives” for operating the Project that would remove the jeopardizing effects of the proposed action. However, on June 3, 2002, the Bureau formally rejected both Final Biological Opinions, but opted instead to operate under a one-year plan that it asserts complies with the Opinions. Independently, in March 2002, the President appointed a high-level working group to develop solutions. Congress has responded to the controversy in a number of ways, including holding several oversight hearings and appropriating funds for water conservation activities in the area. This report provides background on the geographic, historic, and legal underpinnings of the current conflicts. Because the report focuses on the current conflicts, it deals primarily with Klamath Project operations in the Upper Klamath Basin and effects associated with water releases from Upper Klamath Lake.

Land Reclamation Impacts on Tidal Landscape Evolution

American Geophysical Union (AGU) | August 21st, 2025

Fertile and low-lying coastal landscapes are often densely populated due to food supply (agriculture, aquaculture, and fisheries) and easy navigability (shipping lanes).

Fertile and low-lying coastal landscapes are often densely populated due to food supply (agriculture, aquaculture, and fisheries) and easy navigability (shipping lanes). Much of the low-lying land that is regularly inundated by the sea has been converted to agricultural land or urban environments to meet the need for land. This reclamation of land influences the tidal dynamics of the coastal environment, which in turn modifies its morphology. Through various complex tide-topography interactions identified in this paper, we explore how the location and extent of land reclamation influences tides and bed levels in various tidal environments. We especially point to the key role of sediments herein, introducing feedback mechanisms that lead to large impacts on tidal landscapes, but also long adaptation times. This is especially the case for estuaries due to their confinement and the typically large availability of sediments.