Empirical Return Periods of the Most Intense Vapor Transports during Historical Atmospheric River Landfalls on the U.S. West Coast

American Meteorological Society (AMS) | August 21st, 2018

Atmospheric rivers (ARs) come in all intensities, and clear communication of risks posed by individual storms in observations and forecasts can be a challenge. Modest AR

Atmospheric rivers (ARs) come in all intensities, and clear communication of risks posed by individual storms in observations and forecasts can be a challenge. Modest ARs can be characterized by the percentile rank of their integrated water vapor transport (IVT) rates compared to past ARs. Stronger ARs can be categorized more clearly in terms of return periods or, equivalently, historical probabilities that at least one AR will exceed a given IVT threshold in any given year. Based on a 1980–2016 chronology ofAR landfalls on the U.S. West Coast from NASA’s Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), datasets, the largest instantaneous IVTs—greater than 1700 kgm21 s21—have occurred in ARs making landfall between 418 and 468Nwith return periods longer than 20 years. IVT values with similar return periods are smaller to the north and, especially, to the south (declining to ;750 kgm21 s21). The largest storm-sequence IVT totals have been centered near 42.58N, with scatter among the top few events, and these large storm-sequence totals depend more on sequence duration than on the instantaneous IVT that went into them. Maximum instantaneous IVTs are largest in the Pacific Northwest in autumn, with largest IVT values arriving farther south as winter and spring unfold, until maximum IVTs reach Northern California in spring.

Endangered and Threatened Fishes in the Klamath River Basin: Causes of Decline and Strategies for Recovery (2003)

National Academy of Sciences (NAS) | January 1st, 2004

Instead of focusing primarily on how water levels and flows affect endangered and threatened fish in Oregon's Upper Klamath Lake and the Klamath River -- which run fr

Instead of focusing primarily on how water levels and flows affect endangered and threatened fish in Oregon's Upper Klamath Lake and the Klamath River -- which run from the lake in Oregon through northern California before emptying into the Pacific -- the federal agencies charged with protecting the fish should focus on other kinds of initiatives, such as removal of migration obstacles, prevention of entrainment by water management structures, improvement and creation of habitat, and reduction of summer water temperatures in tributaries. Key Messages The committee found some proposed actions as given in the 2001 biological opinions to lack substantial scientific support. In their biological opinions of 2002, the listing agencies appear to have resolved this issue either by obtaining concessions from USBR through mechanisms that are generally consistent with USBR?s goal of delivering irrigation water. Adaptive management is accepted in principle by the listing agencies but has not been implemented in the Klamath basin for the benefit of the listed species, except as part of the Trinity River Restoration Project. Although suckers of all age classes are present in Upper Klamath Lake, population densities of suckers are low, and there are no signs that the populations are returning to their previously high abundance. An alternate hypothesis is that an unusual combination of temperature, flow, and migration conditions occurred in 2002, possibly in association with weather that prevented the river from showing nocturnal cooling to an extent that would usually be expected. Barriers to passage caused by dams and diversion structures are important to coho salmon. The main-stem dams on the Klamath River block spawning movements, as do Dwinnell Dam on the upper Shasta River and the Trinity River Diversion project on the Trinity River. Dams also have contributed to habitat degradation. CDFG has proposed that the shape of the channel in the lowermost reaches of the Klamath main stem changed in 1997?1998 under the influence of high flows, which caused fish entering the river to be unable to proceed upstream under low-flow conditions. Causes of extreme temperatures include diversion of cold flows for use in agriculture, flow depletion that leads to warming of cool water, and destruction of riparian vegetation that leads to loss of shading. Coho habitat has been seriously degraded in the tributaries. Lack of cover and impairment of substrate through deposition of sediments are common. Woody debris, which is critical as cover for young fish, has largely been lost as a result of human activity. Excessive depletion of flow may separate fish from adequate habitat in the last half of summer. Coho salmon, unlike Chinook salmon, remain in freshwater for an entire year, during which they mainly occupy tributaries, where summer water temperatures can be dangerously high. Decrease in main-stem temperatures by augmentation of main-stem flows is problematic because augmentation water must be derived from the surface layer of Iron Gate Reservoir, which is very warm in summer. During the second half of September 2002, numerous fish died in the lowermost 40 mi of the Klamath River main stem, 150 mi below Iron Gate Dam. Most of the dead fish were adult Chinook salmon that had just entered the lower Klamath River. If a lasting change in channel configuration was responsible, recurrence of the episode can be expected with similar low flows in the future. If other factors were responsible, recurrence may be much less likely. It is unclear what the effect of specific amounts of additional flow drawn from controllable upstream sources (waters from reservoirs on the Trinity River or Iron Gate Reservoir) would have been. Information collected through monitoring and research has been valuable, but the absence of an integrated, evolving management plan connected to monitoring, research, review, and periodic readjustment of management actions will hamper progress in the future. Mass mortality of large fish in Upper Klamath Lake has occurred for many decades, but anthropogenic factors, especially those leading to strong dominance of Aphanizomenon, probably have increased its severity and frequency. Poor water quality may also challenge the sucker populations in other ways. High pH, for example, could be harmful to young fish even if they are not subject to the mass mortality of larger fish. No obvious explanation of the fish kill based on unique flow or temperature conditions is possible. Nonnative fishes, which are diverse and abundant in Upper Klamath Lake, may be suppressing the populations of endangered suckers there, but no practical mechanisms for reducing their abundance are known. Reservoirs of the main stem Klamath have created new habitat capable of holding endangered suckers, but recruitment of young fish has not been observed. Reservoirs have low potential to support self-sustaining populations. The fish kill, although important for Chinook salmon, did not involve many coho salmon (about 1% of the total dead fish) because coho enter the river later than Chinook, and thus were mostly absent when conditions leading to mass mortality occurred. The immediate cause of death was massive infection by two types of pathogens that are widely distributed and generally become harmful to fish under stress, particularly if crowding occurs. The most important cause of impairment of coho salmon probably is excessively high summer temperatures in tributary waters. There is no evidence of a causal connection between water level and water quality or fish mortality over the broad operating range in the 1990s, the period for which the most complete data are available for Upper Klamath Lake. Neither mass mortality of fish nor extremes of poor water quality shows any detectable relationship to water level.

Endangered and Threatened Species: Status for the San Francisco Bay-Delta Distinct Population Segment of the Longfin Smelt

U.S. Fish and Wildlife Service (FWS) | February 27th, 2023

Endangered and Threatened Wildlife and Plants; Endangered Species Act Compensatory Mitigation Policy

Federal Register | December 27th, 2016

SUMMARY: We, the U.S. Fish and Wildlife Service (Service or USFWS), announce the final Endangered Species Act (ESA) Compensatory Mitigation Policy. The new policy steps d

SUMMARY: We, the U.S. Fish and Wildlife Service (Service or USFWS), announce the final Endangered Species Act (ESA) Compensatory Mitigation Policy. The new policy steps down and implements recent Executive Office, Department of the Interior, and Service mitigation policies that reflect a shift from project-by-project to landscape-scale approaches to planning and implementing compensatory mitigation. The new policy is established to improve consistency and effectiveness in the use of compensatory mitigation as recommended or required under the ESA. The ESA Compensatory Mitigation Policy covers permittee-responsible mitigation, conservation banking, in-lieu fee programs, and other third-party mitigation mechanisms, and stresses the need to hold all compensatory mitigation mechanisms to equivalent and effective standards. DATES: This policy is effective on December 27, 2016.

Endangered Species Act (ESA): The Exemption Process

Congressional Research Service (CRS) | January 27th, 2017

The Endangered Species Act (ESA) is designed to protect species from extinction, but it includes an exemption process for those unusual cases where the public benefit fro

The Endangered Species Act (ESA) is designed to protect species from extinction, but it includes an exemption process for those unusual cases where the public benefit from an action is determined to outweigh the harm to the species. This process was created by a 1978 amendment to the ESA, but it is rarely used. This report will discuss the exemption process for an agency action, with examples from past controversies, and its potential for application to actions that may affect current controversies, such as water supply. The ESA mandates listing and protecting species that are endangered or threatened with extinction. Listing a species limits activities that could affect that species and provides penalties for taking individuals of that species. The ESA also requires federal agencies to consult with the Fish and Wildlife Service or the National Marine Fisheries Service (together, the Services) to determine whether a federal action may jeopardize the continued existence of a species or harm its critical habitat. The consultation process may lead to an opinion by one of the Services that the action will jeopardize listed species or harm their critical habitats unless certain reasonable and prudent alternatives are included in the action. Rarely, the federal action agency may hold that those alternatives are inconsistent with the agency action. In other extremely rare cases, the Services may find that no alternatives are available that would allow the project to proceed and still prevent jeopardy. In either case, the following are the categories of potential applicants that can apply for an exemption for a federal action despite its effects on listed species or their critical habitat: the federal action agency interested in proceeding with the action, an applicant for a federal license or permit whose application was denied primarily because of the prohibitions of ESA requiring that federal agency actions avoid jeopardy to threatened or endangered species or harm to their critical habitats, or the governor of the state where the action was to have occurred. An exemption application is considered by a specially convened committee which may exempt the federal agency’s action from the prohibitions of the ESA. The exemption process allows major economic factors to be judged to outweigh the ESA’s mandate to recover a species when the federal action is found to be in the public interest and is nationally or regionally significant. The exemption process has been invoked with a dam on the Tellico River (TN), a water project in the Platt River (WY and NE), and timber sales (OR). In three other instances, the process was begun but was aborted before a decision was reached. In addition, there has been interest over the years in invoking the process in light of controversies over management of federal and state water resource projects in California, although no application has ever been filed. When a project achieves such levels of controversy, Congress is sometimes asked to intervene in the outcome, as it did in the case of the Tellico Dam and an endangered fish in the late 1970s.

Endangered Species Status for the San Francisco Bay-Delta Distinct Population Segment of the Longfin Smelt

U.S. Fish and Wildlife Service (FWS) | July 30th, 2024

We, the U.S. Fish and Wildlife Service (Service), determine endangered species status under the Endangered Species Act of 1973, as amended (Act), for the San Francisco Ba

We, the U.S. Fish and Wildlife Service (Service), determine endangered species status under the Endangered Species Act of 1973, as amended (Act), for the San Francisco Bay-Delta distinct population segment (DPS) of longfin smelt (Spirinchus thaleichthys), a fish species of the Pacific Coast. This rule extends the protections of the Act to this DPS and adds it to the List of Endangered and Threatened Wildlife.... This final rule is available on the internet at https://www.regulations.gov. Comments and materials we received on the proposed rule are available for public inspection at https://www.regulations.gov at Docket No. FWS-R8-ES-2022-0082. Availability of supporting materials: Supporting materials we used in preparing this rule, such as the species status assessment report, are available at https://www.regulations.gov at Docket No. FWS-R8-ES-2022-0082.

Ending groundwater overdraft without affecting food security

Nature Portfolio (Springer Nature) | June 14th, 2024

Enduring Solutions on the Colorado River

Arizona State University (ASU) | August 16th, 2024

As we work to reduce water use on the post-2026 Colorado River, two paths lie open before us. One is to incentivize conservation by giving water users the chance to bank

As we work to reduce water use on the post-2026 Colorado River, two paths lie open before us. One is to incentivize conservation by giving water users the chance to bank saved water for later use. Known most commonly as Intentionally Created Surplus (ICS), and more broadly in a series of increasingly creative implementations as “Assigned Water,” this creates short term savings. But in the long run, the approach entitles the users to take the water back out of thE bank. The other involves permanent reductions – “System Water.” Water use is reduced for the benefit of the Colorado River as a whole. Investment in Assigned Water, attractive to water managers because of the allure that they can get their water back, has crowded out investment in the more durable System Water reductions that will be needed to bring the Colorado River into balance. As we develop new operating rules for the river, we need to be mindful of the differences involved. Accounting for water as Assigned Water is a means to reduce total water use in the short-term but the basin requires a means to reduce total water use over the long-term. Enduring solutions on the river can only be found by addressing overallocation, which at its most basic means that there needs to be more unassigned water in Lake Mead. Click here for Part II

Enduring Solutions on the Colorado River Part II Floating Pools and Grand Bargains

Arizona State University (ASU) | April 18th, 2025

Conserving water now in reservoir savings banks, as a hedge against future risks associated with drought and declining flows, has emerged as one of the central tools for

Conserving water now in reservoir savings banks, as a hedge against future risks associated with drought and declining flows, has emerged as one of the central tools for managing the Colorado River. The Lower Basin "Intentionally Created Surplus" program, created in the 2007 Interim Guidelines, has shown the idea's promise and given the basin nearly two decades to learn the strengths and weaknesses of the approach. With tweaks to allow similar efforts in the Upper Basin and other modifications based on what we have learned about the current ICS approach, such "Floating Pools" are one of the key tools being considered as negotiators try to thread the needle of a seven-state agreement for post-2026 Colorado River management.mDone properly, they have the potential to finesse the states' disagreement over the terms of the 1922 Colorado River Compact in a way that could avoid potentially disruptive litigation. But getting the details right will be crucial to the development of an enduring bargain that can help the basin avoid the risk of interstate litigation. Click here for Part 1

Energizing Water Efficiency: California Energy Sector Experiences Can Advance State’s Water Conservation and Efficiency

Pacific Institute | December 29th, 2013

As a dry December accentuates the stress on California’s limited water supplies, the success of the state’s energy sector in implementing efficiency programs offers v

As a dry December accentuates the stress on California’s limited water supplies, the success of the state’s energy sector in implementing efficiency programs offers valuable lessons to the water sector. A new report from the Pacific Institute examines the rules, regulations, and policies that promote energy efficiency and finds models for water management in drivers like the energy sector’s appliance standards, building codes, pricing policies, and utility-sponsored efficiency programs. California has made remarkable improvements in energy efficiency over the last several decades and is recognized as a national leader. The state’s per capita electricity and natural gas consumption is about 45% and 30% less, respectively, than other Americans. Indeed, California’s per capita electricity consumption has remained largely unchanged since the mid-1970s – while increasing by more than 50% across the U.S.  Efficiency policies, including incentive and education programs, have been a major factor in reducing per capita energy use in California. In water conservation and efficiency, California has also made major advances. Many urban areas across the state, including Los Angeles and San Francisco, are serving a larger population with the same or even less water than 20 years ago. But with increasing pressure on water supply from population and economic growth, the need to restore freshwater ecosystems, and climate change, greater water conservation and efficiency are essential. “Reductions in per-capita water demand have been driven first by a shift to a less water-intensive service-oriented economy, and second by federal, state, and local policies as well as utility programs facilitating water-efficiency improvements,” said Heather Cooley, co-director of the Pacific Institute Water Program. “We must examine new approaches for achieving even greater savings to address the water challenges we now face.” The Pacific Institute report identifies programs that have worked for the energy sector and offers recommendations for how they could be adapted to the water sector. First among them are to continuously update standards and codes for fixtures and buildings to capture new technologies and practices.