Climate change risk index and municipal bond disclosures of United States drinking water utilities

Nature Portfolio (Springer Nature) | January 26th, 2026

Climate change increases risks to the operations and financial reliability of drinking water utilities across the United States (US). Here we develop a comparative climat

Climate change increases risks to the operations and financial reliability of drinking water utilities across the United States (US). Here we develop a comparative climate risk index that includes hazard, vulnerability, and exposure components for 1455 medium and large municipal US drinking water utilities. We find that 67 million customers are serviced by utilities with higher climate risk. Drinking water utilities in the Western US have higher risk due to expected large changes in climate hazards, while utilities in the Northeast and Midwest have higher risk due to existing vulnerabilities and exposure. We use this climate risk index, along with an analysis of municipal bond official statements, to identify utilities in need of climate adaptation and resilience planning. Of the analyzed bonds, 36% were issued by high risk utilities and didn’t mention climate change. This work offers recommendations for multiple decision-makers, including utility customers, bond purchasers, and government agencies.

Best Management Practices of the Sustainable Management of Groundwater Land Subsidence

California Department of Water Resources (DWR) | January 21st, 2026

The Subsidence Best Management Practices document (Subsidence BMP) provides a guide on the fundamentals of land surface subsidence (also called “land subsidence” or �

The Subsidence Best Management Practices document (Subsidence BMP) provides a guide on the fundamentals of land surface subsidence (also called “land subsidence” or “subsidence”), technical assistance related to subsidence, and best practices for managing subsidence. The Subsidence BMP also provides specific information about subsidence in California and how it must be considered within the structure of the Sustainable Groundwater Management Act (SGMA). Subsidence is one of the six sustainability indicators required to be managed under SGMA. The Subsidence BMP does not supersede or replace any existing local, state, or federal regulations. Rather, it is meant to help groundwater managers, especially Groundwater Sustainability Agencies and the public, better understand land subsidence and how it can be managed.

Evaluation of water quality in the Langford Valley–Irwin Groundwater Subbasin, Fort Irwin National Training Center, California, 1993–2019

U.S. Geological Survey (USGS) | January 9th, 2026

The U.S. Army Fort Irwin National Training Center (NTC), 120 miles northeast of Los Angeles in the Mojave Desert of California, obtains its potable water supply from the

The U.S. Army Fort Irwin National Training Center (NTC), 120 miles northeast of Los Angeles in the Mojave Desert of California, obtains its potable water supply from the Bicycle Valley and Langford Valley groundwater basins; Langford Valley groundwater basin is further subdivided into the Langford Well Lake and Irwin groundwater subbasins. The Irwin groundwater subbasin contains younger, unconsolidated deposits that have a saturated thickness of as much as 200 feet (ft) and a lower aquifer within older unconsolidated deposits as thick as 650 ft. Groundwater recharge under predevelopment conditions (before 1941) occurred primarily from infiltration of intermittent streamflow in small washes that cross the Irwin groundwater subbasin. Since that time, groundwater recharge has increased because of growth of the NTC in recent years and as a result of other processes, including (1) infiltration of treated wastewater into the aquifer through ponds near the NTC wastewater treatment facility (WWTF) and (2) infiltration of imported water and treated wastewater used for landscape irrigation at base housing and athletic fields. Water samples were collected from 17 wells and analyzed for field parameters, chemical constituents, and isotope composition in the Irwin groundwater subbasin between 2014 and 2019. These data were supplemented with water- chemistry data collected during 1993–95 and at other times if available. Between 1993–95 and 2015–19, median dissolved solids and nitrate concentrations in water from wells in the Irwin groundwater subbasin increased from 620 to 1,030 milligrams per liter (mg/L) and from 2.8 to 4.5 mg/L as nitrogen, respectively. After 2014, dissolved solids and nitrate concentrations in water from wells near the NTC WWTF decreased as a result of changes in source water quality attributable to reverse osmosis of treated drinking water delivered within the Irwin groundwater subbasin and to increased levels of treatment at the NTC WWTF. Based on delta oxygen- 18 and delta deuterium isotope data, increases in dissolved solids concentrations in water from most wells were consistent with evaporation prior to recharge and mobilization of soluble salts from the unsaturated zone. Arsenic and fluoride concentrations in water from wells decreased between 1993–95 and 2015–19 as the basin filled with treated wastewater, but 2015–19 concentrations generally exceeded the California State Water Resources Control Board maximum contaminant levels of 10 micrograms per liter for arsenic and 2 mg/L for fluoride. Most groundwater in the Irwin groundwater subbasin has unadjusted carbon- 14 ages ranging from 18,400 to 12,350 years before present. However, water from well 10E3, located along the wash near the subbasin outflow in the southeastern part of the Irwin groundwater subbasin, contained measurable tritium, which is consistent with infiltration of intermittent streamflow and groundwater recharge from the wash after 1952. Chemical and isotopic data indicate that treated wastewater is present in water from most wells in the upper aquifer that underlies the Irwin groundwater subbasin. Wells were not sampled to adequately determine the extent of treated wastewater and changes in water quality within the lower aquifer that underlies the Irwin groundwater subbasin.

National assessment of river protection in the United States

Nature Portfolio (Springer Nature) | January 9th, 2026

To address the enduring and deepening crisis facing fresh waters, many nations have recently set bold targets for freshwater protection. However, the lack of comprehensiv

To address the enduring and deepening crisis facing fresh waters, many nations have recently set bold targets for freshwater protection. However, the lack of comprehensive databases and integrative frameworks hampers a robust evaluation of current freshwater protections and prioritization of future opportunities to meet these goals. This study provides a comprehensive assessment of river protection for the USA by reconciling the disparate array of major federal, state, tribal and private protection mechanisms into a single, multifaceted index. We report that just over one tenth of the river length of the contiguous USA and less than one fifth of rivers nationwide are currently protected at a level deemed viable. Lowland headwater streams and intermittent watercourses are consistently underprotected. Protection is also often spatially misaligned with other conservation objectives, where only a small fraction of watersheds with high biodiversity, habitat intactness and importance to drinking water supply are adequately (30% of river length) protected. Our assessment of river protection highlights the urgency to increase new and fortify existing protections for rivers in the years to come if we are to meet ambitious conservation targets, reverse the curve of biodiversity loss and ensure that healthy rivers benefit everyone.

Human contributions to evapotranspiration mitigate swings in dry-to-wet year transitions

Nature Portfolio (Springer Nature) | January 9th, 2026

California’s food and economic security depends on water availability, particularly under increasingly extreme climate scenarios. A key component of the water balance i

California’s food and economic security depends on water availability, particularly under increasingly extreme climate scenarios. A key component of the water balance is evapotranspiration, the combination of soil and surface evaporation and plant transpiration. Evapotranspiration is influenced by natural drivers (e.g., climate, vegetation cover) and human intervention (e.g., irrigation, land management). Here, we analyze the transition between one of California’s driest years (2022) to an exceptionally wet year (2023) to assess evapotranspiration responses to climate extremes. Despite increased precipitation, total statewide evapotranspiration changed less than 10%. In 2022, human contributions accounted for 30% of statewide evapotranspiration and 80% in managed lands. In 2023, natural evapotranspiration increased, and human contributions fell by 30%, yet still comprised nearly 50% of evapotranspiration in managed areas. Our findings underscore the enduring role of human activity on California’s hydrology, even during wet years, and demonstrate a framework to separate natural and anthropogenic controls on evapotranspiration.

Assessing future hydrologic extremes using an integrated hydrology and river operations model in the Russian River watershed

Elsevier | January 6th, 2026

This paper introduces an integrated hydrology and river operations model for the Russian River watershed. This model is distinct from models in previous studies because i

This paper introduces an integrated hydrology and river operations model for the Russian River watershed. This model is distinct from models in previous studies because it represents surface-groundwater interactions and uses climate forcings to estimate dynamic water use demands that are superimposed onto both reservoir operations and water supply constraints. The model was used to examine three historical (1990–2015) and eight future (2016–2099) water use and climate change scenarios.

Quantifying the impacts of rainfall and evaporation on Lake Bonneville

American Association for the Advancement of Science (AAAS) | January 1st, 2026

Improved understanding of hydroclimatic drivers in water-stressed regions enables more accurate forecasting of future climate change impacts. Lake Bonneville was the larg

Improved understanding of hydroclimatic drivers in water-stressed regions enables more accurate forecasting of future climate change impacts. Lake Bonneville was the largest Pleistocene lake in western North America, with a maximum surface area of ~52,000 km2, before shrinking markedly to become the modern Great Salt Lake. After more than a century of study, the balance between enhanced precipitation and reduced evaporation as drivers of lake growth continues to be debated. Multiple studies identify precipitation as the main factor associated with the highest lake levels, but most proxies provide an estimate of net evaporation and cannot independently resolve precipitation from evaporation. Therefore, factors associated with lake size, growth, and retreat remain uncertain. This study uses the thermodynamically based carbonate clumped isotope geothermometer to estimate temperature, evaporation, and precipitation at Lake Bonneville from 23 to 16 thousand years ago (ka). Clumped isotope derived constraints on hydroclimate are also applied to assess the accuracy of regional climate model outputs. During transgressive and open phases of the lake, we find that regional and large-scale precipitation delivery were the driving factors of lake expansion. In contrast, at its maximum extent (~17.5 ka), Lake Bonneville was maintained via suppressed evaporation rates at 50% relative to modern while precipitation rates were similar to modern levels.

Effect of passive integrated transponder tag size on survival, tag loss, and growth of Santa Ana Sucker

American Fisheries Society (AFS) | December 30th, 2025

The Santa Ana Sucker Pantosteus santaanae is endemic to southern California and is listed as threatened under the U.S. Endangered Species Act. Seasonal limitations on con

The Santa Ana Sucker Pantosteus santaanae is endemic to southern California and is listed as threatened under the U.S. Endangered Species Act. Seasonal limitations on conventional sampling and inconsistencies in survey methodologies have led to an incomplete understanding of population dynamics. Alternative sampling methods have the potential to fill important knowledge gaps in biology and life history. One option is to use passive integrated transponder (PIT) tags to identify individuals and track their movements. The objective of this study was to test the effect of PIT tag size on survival, tag loss, and growth of Santa Ana Suckers.

Status of Clear Lake Hitch in Lower Blue Lake, Lake County, California, 2024

California Fish and Wildlife Scientific Journal | December 29th, 2025

Clear Lake Hitch (Lavinia exilicauda chi) is a native minnow found primarily in Clear Lake, Lake County, California that is listed as threatened under the California Enda

Clear Lake Hitch (Lavinia exilicauda chi) is a native minnow found primarily in Clear Lake, Lake County, California that is listed as threatened under the California Endangered Species Act and has been petitioned for listing under the United States Endangered Species Act. Management interest in Clear Lake Hitch originates, in part, from historical accounts which indicate it was formerly highly abundant and an important resource for Native American Tribes (Moyle 2002; CDFW 2014). A variety of factors are thought to have contributed to a substantial decline in Clear Lake Hitch abundance. These factors include the loss and degradation of stream habitat used for spawning and rearing caused by changes in land and water use in the watershed, and the loss and degradation of lacustrine habitat caused by shoreline development, reclamation of wetlands, and broad-scale changes to biological and physio-chemical components of Clear Lake (Moyle 2002; CDFW 2014).

Assessing Environmental Drivers and Protist Community Dynamics that Shaped the Historic August 2022 Heterosigma akashiwo Bloom in San Francisco Bay, California

Springer Nature | December 22nd, 2025