USGS Publications Warehouse

3D Elevation Program—Conterminous United States

Jonesi, Alexander; Thatcher, Cindy; Stoker, Jason — Thu, 2 Jul 2026 14:22:46

Using 3D Elevation Program data, a modern illustration of the conterminous United States’ landscape showcases its elevation differences in vivid detail. This map has been consistently adjusted and colorized according to the highest and lowest elevations, accentuating differences across the conterminous United States. To further emphasize landforms, shaded relief has been added on top of the elevation colors.

Determination of baseline water-quality conditions using continuous specific conductance and discrete measurements of total dissolved solids and selected major ions, Arkansas River Basin, Colorado

Miller, Lisa; Eng, Lauren; Sharp, Jackson B. — Thu, 2 Jul 2026 13:53:16

From 2022 through 2024, the U.S. Geological Survey (USGS) in cooperation with the Regional Resources Planning Group (Southeastern Colorado Water Conservancy District, Colorado Springs Utilities, Pueblo Water, Lower Arkansas Valley Water Conservancy District, Aurora Water, and Upper Arkansas Water Conservancy District) established a basinwide water-quality monitoring network in the Arkansas River Basin in Colorado. The study leveraged ongoing continuous measurements of streamflow and specific conductance (SC) at 13 sites along the main stem Arkansas River and Fountain Creek from the USGS 07108600 Arkansas River at Granite, Colo., (Ark Granite) site to the USGS 07137500 Arkansas River near Coolidge, Kansas, (Ark Coolidge) site. Baseline water-quality conditions were established using data from October 1989 through September 2022 to help identify changes in water quality that could result from changes in land and water use.

Total dissolved solids (TDS) concentration was the main indicator of general water quality in this study because it can be accurately estimated from SC and is sensitive to changes in streamflow, water operations, and source contributions. Median TDS concentrations in Arkansas River samples (October 1989 through December 2023) ranged from 75 milligrams per liter (mg/L) at Ark Granite near the headwaters to 3,660 mg/L at Ark Coolidge near the Colorado–Kansas State line. Distinct seasonal differences in median streamflow and TDS were apparent during the winter and summer months.

Seasonal Kendall tests showed no significant trends in monthly mean streamflow (October 1995 through September 2022) at Arkansas River sites upstream from Pueblo Reservoir. Upward trends in TDS concentrations and loads occurred only at Ark Granite. Downward trends in streamflow, TDS concentrations, and TDS loads occurred at Arkansas River sites from USGS 07109500 Arkansas River near Avondale, Colo., to Ark Coolidge. Downward trends in streamflow and SC (surrogate for TDS) were more prevalent during winter base flow months and may indicate changes in groundwater quantity, and possibly groundwater quality, potentially affecting the river water-quality condition.

Mars as one system: Insights from the 8th international conference on Mars polar science and exploration

Tue, 5 May 2026 15:59:07

The 8th International Conference on Mars Polar Science and Exploration (ICMPSE) provided new insights into the complex interplay between Martian ice, climate, and atmospheric dynamics. The conference emphasized a holistic view of Mars as a system, where surface processes, subsurface ice, atmospheric dynamics, and historical climate shifts are interconnected. Research updates spanned cutting-edge remote sensing techniques and observations, terrestrial analog studies, and theoretical modeling, providing a multidimensional view of Mars' dynamic history and present-day activity. Numerous presentations highlighted the importance of understanding Mars as an integrated and dynamic system where surface and atmospheric processes interact over various timescales. This paper synthesizes unresolved questions and the major themes discussed, including mid-latitude glaciation, the evolution of the polar layered deposits (PLDs), terrestrial analog studies, climate modeling, and future mission planning. The findings contributed to refining models of Martian climate history, assessing the potential for extant life, and planning future human exploration. We also discuss the historical perspective of Mars Polar Science and new findings since the 7th conference in this series and anticipate the next four to 20 years of science on Mars related to ice, climate, and the atmosphere.

A simplified two-station approach for modeling metabolism in dam tailwaters subject to diel flow variation

Wed, 1 Jul 2026 15:11:21

Tailwaters are ubiquitous and highly managed ecosystems whose food webs often rely disproportionately on autochthonous energy. In situ continuous dissolved oxygen data are increasingly being used to estimate gross primary productivity and ecosystem respiration in rivers, but this approach is complicated in tailwaters, where upriver discontinuities (i.e., dams) violate commonly employed one-station approaches. In such cases, two-station metabolism models can be applied, although substantial diel variation in flow (a common outcome of hydropower production) requires more complex treatment of water parcel travel times. Here, we present a new two-station metabolism model that allows estimation of reach-scale gross primary productivity and ecosystem respiration in streams and rivers that experience within-day variation in flow. Our approach simplifies two-station variable flow model implementation compared to previous efforts. We apply our model to a 6-yr dissolved oxygen time series and use Bayesian inference to estimate daily gross primary productivity, ecosystem respiration, and gas exchange velocity (k₆₀₀) for a ~12-km reach of the Colorado River downriver of Glen Canyon Dam. We compare our model's performance to a more mechanistically detailed and computationally intensive Eulerian dynamic flow model and also to a widely-used one-station model that uses assumptions of reach uniformity that are often strongly violated in tailwaters. These comparisons show that our metabolism estimates conform with output from the more detailed dynamic flow model and that the one-station approach deviates substantially from both two-station approaches. Our new stream metabolism model can help resolve a fundamental analytical impediment in tailwater ecology.

Mercury biomagnification across food webs with varying non-native fish presence: Implications for native fish conservation in the upper Colorado River Basin

Wed, 1 Jul 2026 14:53:39

Environmental contaminants and non-native species introductions negatively affect aquatic ecosystem conservation. Mercury (Hg) accumulates within food webs where it can biomagnify to toxic concentrations, which can be affected by altered trophic relationships from non-native species. This study examined Hg concentrations (n samples = 655) and stable carbon and nitrogen isotope (n = 746) compositions in native (n = 313) and non-native (n = 342) species among four river subbasins (Gunnison, Lower Green, Colorado-Dolores, and White-Yampa), in the Upper Colorado River Basin (UCRB) during 2016 and 2017 to inform the potential combined effects of Hg exposure and non-native species interactions on native fishes of conservation concern. We assessed Hg biomagnification at the fish assemblage level, compared concentrations to risk thresholds for fish and human health, and evaluated niche overlap among trophic levels across subbasins. The generalist-invertivores feeding guild had the lowest Hg concentrations (0.001–0.191 μg g⁻¹ wet weight), and no individuals exceeded the U.S. Environmental Protection Agency aquatic life criterion (0.225 μg g⁻¹). Piscivores had the highest concentrations (0.008–1.840 μg g⁻¹), and 74% of individuals exceeded the criterion. Biomagnification across trophic levels was observed throughout the UCRB, yet varied by subbasin, with higher magnification factors in the Lower Green and White-Yampa subbasins which also had the highest proportion of non-native species. Stable isotope compositions revealed niche overlap among native and non-native species. Additionally, trophic position varied within species among the subbasins. The proliferation of non-native species has likely reshaped food webs and may have intensified the potential threat Hg poses to native fish recovery and conservation. This study documented increased Hg concentrations relative to past assessments, suggesting that continued monitoring could assist in evaluating trends in Hg accumulation. Particularly studies that focus on sources entering the food web, vectors for accumulation, and competitive interactions among native and non-native species.

Flood-frequency estimates for Kentucky streamgages based on data through water year 2021 and results of updating the fundamental layers in Kentucky StreamStats

VonIns, Branden; Webber, J.; Follette, Danielle; Jeffords, Thomas — Wed, 1 Jul 2026 17:15:34

The U.S. Geological Survey, in cooperation with the Kentucky Transportation Cabinet, analyzed flood-frequency statistics for streamgages in Kentucky. Using annual peak-flow data through water year 2021, flood-frequency estimates were computed for 261 streamgages, including unregulated and regulated sites as well as sites with mixed regulation records. Methods followed those outlined in “Guidelines for Determining Flood Flow Frequency—Bulletin 17C” (U.S. Geological Survey Techniques and Methods 4–B5). These estimates included flows corresponding to annual exceedance probabilities of 50, 20, 10, 4, 2, 1, and 0.2 percent. Temporal trend analyses using the Mann-Kendall test indicated that 18 percent of unregulated streamgages with (1) at least 30 years of peak-flow record and (2) peak-flow record at least as recent as water year 2000 showed statistically significant trends, most of which were weak to moderate increases in peak flows. Concurrently, the fundamental geospatial datasets that support the Kentucky StreamStats application were updated by using high-resolution digital elevation models and hydrography datasets to derive flow direction, flow accumulation, and stream definition rasters. Comparisons of regression-based flood-frequency models using the old and new layers demonstrated consistent results, with a statewide root-mean-square error of 0.019, in the base-10 logarithm of cubic feet per second. Furthermore, to assess model performance, flood-frequency estimates made by using the updated layers and previously published regression-based models were compared to flood-frequency estimates newly computed by following Bulletin 17C. This analysis showed the models performed adequately for most Kentucky stream locations. The updated statistics and geospatial layers provide stakeholders with more accurate, current data for flood-risk assessment, infrastructure design, and water-resource management.

Improved estimates of relative occurrence and abundance using opportunistic surveys and presence-only observations: A zero-inflated integrated species distribution model

Mon, 29 Jun 2026 16:01:32

Modeling tools for estimating and forecasting shifts in species distributions are becoming increasingly valuable for conservation planning and response. This is especially true for wild bird populations, which have been declining across habitats and regions. Species distribution models (SDM) represent a diverse set of tools with options for addressing various sources of bias. Complex spatial processes associated with rare or clustered species can be accounted for using zero-inflated SDMs, whereas biased survey data can be integrated with additional data sources to improve estimates. Each option addresses an important and common source of bias, but the two SDM frameworks have not been implemented together previously. We present a novel zero-inflated extension of an integrated SDM framework for a Poisson regression (ZI-iSDM), allowing for the estimation of independent occurrence and abundance processes by integrating opportunistic survey and presence-only data. We validated performance of this ZI-iSDM using simulated datasets under different degrees of species rarity and density on the landscape as well as sampling bias in opportunistic datasets. We additionally applied this model to real survey data for multiple wild bird species using publicly available observation data combined with open-access environmental information to describe habitat associations. We found that integrating presence-only data, such as banding or harvest events, can compensate for potential deficiencies in opportunistic surveys by expanding sampling to be more representative of available and used habitat. Additionally, models that first differentiated occurrence and abundance using a ZI term were better suited for approximating distributions of spatially clustered species.

Geochemistry of the 2022 Mauna Loa eruption: A comparison with earlier historical summit reservoir eruptions, with implications for magma supply and recharge

Rhodes, J.; Trusdell, Frank A.; Lynn, Kendra; Downs, Drew; Vollinger, Michael — Mon, 29 Jun 2026 14:32:36

On November 28th, 2022, following a record historical repose period of 38 years, Mauna Loa erupted about 145 × 10⁶ m³ of lava and tephra over a 15-day period. The eruption was confined to the summit caldera region and the upper Northeast Rift Zone and is remarkably homogeneous in composition in both time and space. In these respects, it is typical of prior shallow summit reservoir magma bodies, recently estimated to be at a depth of around 1–2 km beneath the caldera. In contrast with these earlier magma bodies, which typically contain 6.7–7.1% MgO and are perched at the low-MgO end of olivine-control trends, the 2022 lava and tephra are more evolved with 6.24 + / − 0.03% MgO. This implies a temperature difference of around 11 °C with the prior 1984 magma. The simplest explanation is that over 38 years, cooling and crystallization of the remaining 1984 magma body has significantly exceeded magma recharge, giving rise to the evolved 2022 magma. The problem with this model is that we know from a variety of geophysical observations that in those 38 years, Mauna Loa has been erratically inflating, with heightened periods since around 2000 attributed to magma recharge. To reconcile these differences, we suggest instead that the 1984 magma cooled and crystallized much more extensively, from 1166 °C to around 1106 °C, co-crystallizing plagioclase, clinopyroxene, pigeonite and subsequently enstatite instead of pigeonite. At this point, the residual 1984 magma would have an MgO content around 4.2% and been about 50% solidified. Subsequent recharge and mixing by dominantly reservoir magmas, derived from a deeper 3–4-km intermediate magma reservoir, eventually produced the 2022 magma.

Assessment of undiscovered conventional oil and gas resources in the Buda Limestone of Texas, 2025

Wed, 1 Jul 2026 17:12:12

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 12 million barrels of oil and 184 billion cubic feet of gas in the Buda Limestone of Texas.

Mid-Cretaceous porphyritic magmatism in the Beartooth Mountains of the northern Laramide foreland and its connection to Frontier Formation sediment dispersal in Bighorn basin, Montana-Wyoming (USA), and Cordilleran tectonism

Tue, 30 Jun 2026 14:50:54

Porphyritic intrusions in the southeast Beartooth Mountains and porphyritic cobbles from the Torchlight conglomerate of the Cenomanian Frontier Formation in Bighorn basin (Montana-Wyoming, USA) bear striking resemblance. We utilize geologic mapping, petrography, geochemistry, and geochronology to characterize rocks from both locations and test whether the Beartooth Mountains area was the provenance for Bighorn basin cobbles. Mapping on Line Creek Plateau in the Beartooth Mountains shows three units with porphyritic phenocrysts consisting dominantly of plagioclase, plagioclase + potassium feldspar, and plagioclase + quartz. Petrography shows embayed quartz, opacitic rims, and zoned plagioclase. Geochemistry characterizes the intrusions as trachydacite to trachyte and trace elements exhibit enrichment in light rare earth elements and slight depletion in heavy rare earth elements relative to primitive mantle. Zircon U-Pb dating shows substantial Archean inheritance and ca. 104−92 Ma dates; some samples display multiple mid-Cretaceous date populations. Bighorn basin porphyritic cobbles exhibit similar modal mineralogy, near-identical geochemistry, and Archean inheritance and mid-Cretaceous geochronology. We suggest the porphyritic cobbles were sourced from basement-hosted porphyritic intrusions now exposed in the Beartooth Mountains, given that geochemistry does not agree with coeval volcanic sources along the Frontier Formation depositional fairway (Idaho batholith) or sedimentary-hosted Beartooth Mountains porphyritic sills intruded into Cambrian shale. Stratigraphic evidence does not support kilometer-scale mid-Cretaceous Beartooth Mountains exhumation to expose basement-hosted porphyritic intrusions, and we therefore present a volcanic hypothesis to bring rocks to the surface. This mid-Cretaceous multimillion-year magmatism is unexplained by tectonic models for the north-central Laramide foreland, and thus we further explore the emplacement processes, spatiotemporal significance, and tectonic implications of these rocks.

Thermal infrared and ultraviolet remote sensing of sulfur dioxide gas emitted during the 2018 lower East Rift Zone eruption of Kilauea, Hawaiʻi

Mon, 29 Jun 2026 16:10:12

Ultraviolet (UV) remote sensing is widely used to detect volcanic sulfur dioxide (SO₂) due to its high sensitivity and favorable spatial and temporal resolution. However, significant discrepancies have been reported between ground-based and satellite-based UV observations of dense volcanic plumes. A notable example is the 2018 lower East Rift Zone eruption of Kīlauea, where SO₂ emission rates derived from ground-based Differential Optical Absorption Spectroscopy (DOAS) measurements differed substantially from those obtained by the spaceborne Tropospheric Monitoring Instrument (TROPOMI). In this study, we investigate these differences by applying thermal infrared (TIR) satellite retrievals using a modified version of the SO₂-ALTA algorithm to Moderate Resolution Imaging Spectroradiometer (MODIS) observations. The resulting TIR-derived SO₂ fluxes are compared with ground-based DOAS data, satellite UV observations, and petrological estimates of gas emissions. Our results show strong agreement between TIR-derived fluxes, ground-based DOAS measurements, and petrological estimates, particularly during the peak and plateau phases of the eruption. In contrast, satellite UV-derived SO₂ emissions are systematically lower. We find that TIR observations are more effective in quantifying high-concentration SO₂ plumes in the near-vent region, while UV measurements are more sensitive under lower-concentration conditions but more affected by scattering in optically dense plumes. These findings highlight the complementary strengths of UV and TIR remote sensing techniques and emphasize the importance of accounting for plume density and observation geometry when interpreting satellite SO₂ retrievals.

Colored shaded-relief bathymetric and acoustic-backscatter maps of Jenkinson Lake with orthomosaic of the Sly Park Creek and Hazel Creek area, California

Wed, 24 Jun 2026 14:17:19

The Caldor Fire was ignited on August 14, 2021, and burned almost 222,000 acres (898 square kilometers) in forested terrain of the central and western Sierra Nevada, California. During the subsequent two months, the fire burned nearly all of Sly Park Creek watershed in El Dorado County. The El Dorado Irrigation District manages the water supply for the area using storage in Jenkinson Lake, a 1.6-kilometer- (1.0-mile-) wide and 3.6-kilometer- (2.2-mile-) long reservoir, located south of the town of Pollock Pines. Several weeks after the fire, the U.S. Geological Survey began investigations into post-fire landscape responses, including sediment yield, by measuring new sediment deposition in Jenkinson Lake. This study focused on the collection and processing of bathymetric and acoustic-backscatter data, as well as onshore aerial imagery in and around Jenkinson Lake, to support wildfire science after the Caldor Fire. A colored shaded-relief bathymetric map (sheet 1) and an acoustic backscatter map (sheet 2) show the lake floor morphology and backscatter intensities.

Flood-inundation maps of the Blue River and major tributaries in and near Kansas City, Missouri, 2023–25

Wed, 1 Jul 2026 17:10:31

Digital flood-inundation maps for 35.5 miles of the Blue River, in and near Kansas City, Missouri, were created by the U.S. Geological Survey (USGS) in cooperation with the City of Kansas City. Maps were also developed for a combined 7.3 miles of Brush Creek (4.4 miles) and Indian Creek (2.9 miles), two primary tributaries to the Blue River in the study reach. The flood-inundation maps, available through the USGS Flood Inundation Mapping Program website at https://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding, depth of water above first-floor elevations in selected buildings, water velocity, water-surface elevations, and time of travel corresponding to selected water levels or gage heights (hereafter referred to as “stages”) at nine reference USGS streamgages—five on the Blue River (USGS station numbers 06893590, 06893578, 06893500, 06893150, and 06893100), two on Brush Creek (USGS station numbers 06893562 and 06893557), one on Indian Creek (USGS station number 06893390), and one on the Missouri River (USGS station number 06893000). Near-real-time stages at these streamgages may be obtained from USGS Water Data for the Nation at https://doi.org/10.5066/F7P55KJN or the National Weather Service National Water Prediction Service at http://water.noaa.gov/, which also forecasts flood hydrographs at seven of these sites (USGS station numbers 06893000, 06893590, 06893578, 06893500, 06893150, 06893557, and 06893390).

Flood profiles were computed for eight map reaches by means of two-dimensional hydraulic models. The models were calibrated using the USGS-developed stage–streamflow relations at each reference streamgage. Two map reaches on the lower Blue River also include the effects of backwater from the Missouri River on flood inundation extent and hydraulic characteristics.

The hydraulic models were used to compute water-surface profiles for flood stages at 1-foot intervals referenced to the streamgage datums. The profile stages ranged from the National Weather Service “Action Stage” or near bankfull to a stage exceeding the highest recorded water level at each streamgage. The simulated water-surface profiles were then combined with a digital elevation model (derived from light detection and ranging data having a nonvegetated vertical accuracy of a maximum 10-centimeter root-mean-square error) to delineate the area flooded at each water level and the associated hydraulic characteristics.

The availability of these maps, along with information regarding current stage from the USGS streamgage and forecasted high-flow stages from the National Weather Service, will provide emergency management personnel, resource managers, and residents with information that could be critical for flood-response activities such as evacuations and road closures, as well as for postflood recovery efforts.

Perceptions of parcel-level wildfire risk differ between homeowners and trained assessors in wildland-urban interface communities across the western United States

Wed, 24 Jun 2026 16:03:55

Wildfire risk mitigation on private property is central to reducing community wildfire vulnerability. Homeowners have control over many of the key factors that contribute to wildfire risk on their parcels, yet vulnerable conditions persist. One potential explanation is a misalignment between homeowners' and trained assessors' perceptions of parcel-level wildfire risk. Prior research has documented a “risk gap” in a single community wherein owners often underestimate their parcel-level wildfire risk; however, it is unclear whether such misalignments are widespread. This study replicates and expands previous research by examining the parcel-level wildfire risk gap in 38 wildland–urban interface (WUI) communities across the Western United States using paired data from household surveys and parcel-level wildfire risk assessments by trained assessors. We find that homeowners and assessors often perceive parcel characteristics differently. Homeowners may systematically mis-weight their importance, tending to underweight key controllable factors such as building materials and defensible space, leading to meaningful divergence from trained assessor ratings. Accordingly, we also find that homeowners generally underestimate overall parcel wildfire risk compared to trained assessors. These results suggest that even when homeowners recognize attributes on their parcels that contribute to wildfire risk, they may not fully grasp how much the attributes contribute to overall parcel risk, potentially failing to recognize the need to undertake meaningful mitigation actions. The findings from this study contribute to the broader natural hazards literature on expert-layperson risk perception gaps and offer insights for improving wildfire communication, education, and mitigation strategies in WUI communities.

The path to FAIR research models: Lessons learned

Kettner, Albert; Hsu, Leslie; Serna, Brandon — Wed, 24 Jun 2026 15:42:13

Numerical modeling of Earth surface processes emerged as an important scientific tool in the late 1960s to mid-1970s, driven by the development of finite element methods in computer science. These advancements, initially applied in civil engineering, enabled scientists to simulate complex geological phenomena. At that time, models were often only described in publications, access was limited to researchers with direct connections to the developers, and the code was rarely documented for reuse, limiting their application beyond the original research context. The FAIR principles (Findability, Accessibility, Interoperability, and Reusability) as applied to data began to take shape in the 21st century with the rise of open science, digital repositories, and standardized data sharing frameworks. In the late 2010s, grassroots movements began to apply some of the FAIRness goals to numerical models. Subsequently, more formalized FAIR model principles were developed that addressed the specific needs of the scientific modeling community, resulting in the formulation of the FAIR principles for research software (FAIR4RS).

In this study, we examine the development and implementation of strategies by two geoscience research infrastructures – the CSDMS (Community Surface Dynamics Modeling System) Model Repository and the U.S. Geological Survey Model Catalog – to enhance the FAIRness of models guided by FAIR4RS. Some of the development and implementation efforts described predate the formalization of FAIR and FAIR4RS principles, making this an ongoing and adaptive process. We evaluate the temporal progression towards increased FAIR4RS alignment across three phases of research infrastructure development: prototype, refinement, and growth and iteration. Although certain principles were more straightforward to implement early in prototypes of the catalog infrastructures, others required broader community collaboration during refinement, and some continue to pose practical challenges in the growth and iteration phase. By tracing these dynamics, our aim is to provide insights that can guide other modeling initiatives in effectively adopting FAIR4RS principles within their communities.

A ground-motion model derived using a generalized mean rupture distance for large slab interface earthquakes

Murray, Jessica; Parker, Grace — Tue, 30 Jun 2026 15:29:39

Source–station distance is a central input to ground‐motion models (GMMs) for predicting seismic shaking. GMM development uses distance metrics including the Joyner–Boore distance, which is the shortest distance from an observation point to the surface projection of the earthquake rupture, and R_rup the shortest distance to the rupture in three dimensions. Thompson and Baltay (2018) proposed the generalized mean rupture distance R_p to address observed near‐fault ground‐motion saturation. R_p accounts for the contribution to the shaking of all parts of the rupture and provides a simple method for incorporating spatially variable slip. They used R_p to develop a GMM for shallow crustal earthquakes, assuming uniform slip. Here, we investigate the improvement offered by an R_p‐based GMM for large subduction interface earthquakes by recalibrating the path term for a published GMM (Parker et al., 2022) using R_p derived from distributed slip models (DSMs). Inspection of within‐event and total residuals indicates that the recalibrated model fits the data at least as well as an alternative in which the path term was recalibrated using R_rup and the same dataset. Incorporating slip information in its entirety or trimming the DSM geometry is preferable to assuming uniform moment release on a prescribed model fault that extends beyond the actual ruptured area. R_p tuned to minimize model uncertainty is closer to the maximum distance to rupture for peak ground velocity (PGV) than acceleration, possibly reflecting the contribution to high‐frequency shaking of slip on local asperities. However, when the moment is concentrated far from stations, PGV is fit adequately with R_p closer to R_rup⁠. Our results suggest incorporating slip‐derived moment release through R_p could improve GMMs for slab interface events, especially if the implementation of R_p‐based models is refined using a larger dataset of earthquakes with greater geographic diversity to account for regional ground‐motion variations.

The US XPD-24–200—An isokinetic suspended-sediment and water-quality collapsible-bag sampler with point- or depth-integrating sampling capabilities

Mon, 22 Jun 2026 21:29:05

Accurate collection of fluvial suspended‑sediment and water‑quality samples is essential for understanding transport processes, evaluating river health, quantifying loads, and supporting regulatory and management decisions. Since 1939, the Federal Interagency Sedimentation Project (FISP) has led the development and standardization of sediment‑sampling equipment and methods across Federal agencies. Although substantial advancements have been made, the most recent point‑integrating sampler developed in 2006 has notable limitations, including insufficient sample volume for low‑concentration analyses and a mechanically complex pressure‑equalization system required for a rigid-bottle sample container. To address these limitations, FISP collaborated with Carnet Technology to design, fabricate, and test a new collapsible‑bag sampler capable of collecting larger sample volumes and operating as either a point‑integrating or depth‑integrating sampler. The resulting sampler, the US XPD‑24‑200, was evaluated through controlled tow‑tank tests and field testing in a lake environment.

Results indicate that the US XPD‑24‑200 can collect a 5.5-fold increase in maximum sample volume than a pre-existing point sampler developed in 2006. The US XPD‑24‑200 performs isokinetically within the expected intake efficiency (IE) range under most conditions. Approximately 73 percent of IEs fell within the target range of 0.9–1.1. A mild bias was observed with IE values outside this range that were predominantly lower than 0.9 and occurred most frequently at the lower test velocities, whereas only 2 percent of IEs exceeded 1.1, primarily at the highest velocities tested. Tow‑tank tests produced tightly clustered IE values with low variability, demonstrating stable performance under controlled conditions. Lake towing tests exhibited more variability, reflecting natural environmental influences such as turbulence, temperature gradients, and unsteady inflow. Collectively, the results demonstrate that the US XPD‑24‑200 provides reliable IEs comparable to existing samplers while offering increased sample volume, reduced mechanical complexity, and enhanced operational flexibility.

Abundance, trends, and challenges facing mountain goats throughout their North American distribution

Tue, 30 Jun 2026 15:27:45

Recent declines among some mountain goat (Oreamnos americanus) populations have heightened concern about their current status and ability to cope with future challenges. We conducted a range-wide assessment of the status of mountain goats across their distribution to understand the extent and patterns of change in recent years. We queried states, provinces, National Parks, and Indigenous governments with territories and reserves containing local wild populations, requesting updates on estimated mountain goat abundance and trends over time, as well as qualitative assessments of conservation challenges. We supplemented the questionnaires with existing literature (both published and available from agency websites). We subjected a subset of mountain goat population time−series to exploratory meta-analyses, examining covariates associated with rates of change. Respondents identified 203 units within which estimates were documented, a majority of which were raw counts from aircraft; fewer jurisdictions used site-specific sightability models, mark-recapture statistics, or other approaches to account for imperfect detection. Jurisdictions updated unit-specific estimates on average every 4.0 years (SD = 2.9, Min–Max = 1–24 years). Among 152 qualitative estimates of trends of native populations, 3% were reported as having increased substantially, 10% as having increased slightly, 24% as having declined slightly, and 14% as having declined substantially (49% reported either no detectable trend or insufficient data to identify a trend). Among 133 estimates of trends of introduced or pioneering populations, 5% increased substantially, 24% increased slightly, 20% declined slightly, and 11% declined substantially (40% reported no detectable trend). Jurisdiction-wide abundance estimates were lower than those previously published in all jurisdictions except Colorado and Oregon, and in Alaska, where trends were unclear. Intrinsic rates of increase (r) were positively associated with the population being introduced or pioneering, negatively associated with heavy snow and, to a lesser extent, with drought, but were not associated with abundance or presence of hunter harvest. Existing evidence suggested that many local populations, especially native populations, have declined, but understanding of specific causes has been constrained by limited monitoring capacity. Greater spatiotemporal monitoring effort and detailed studies would inform appropriate strategies to address threats and future challenges to mountain goats.

Evaluating groundwater quality influences from oil field operations and other anthropogenic activities in an urban setting, Santa Fe Springs, California

Thu, 25 Jun 2026 14:16:43

Groundwater quality is often affected by anthropogenic activities in urban settings. This study examines groundwater quality in and around the Santa Fe Springs Oil Field in Los Angeles County, California, where oil and gas production commonly intersects with high density industrial, commercial and residential land uses. Utilizing a combination of new and historical data, we evaluated potential pathways that would allow for oil field formation fluids to migrate into groundwater and whether mixing may have occurred based on the distribution of groundwater and oil field formation fluid tracers in samples. Samples were analyzed for a wide array of constituents including volatile organic compounds, light hydrocarbons, major ions, and various isotopic compositions. Despite evidence of oil field infrastructure providing potential pathways of migration via uncemented annular spaces, casing breaches and historical disposal of oil field formation water in surface ponds, the distribution and occurrence of stable isotopes of water, chloride, boron, and total dissolved solids do not indicate mixing of oil field formation water and groundwater. However, methane isotopic signatures and the presence of heavier alkanes suggest gas from oil-bearing formations have migrated from depth via oil field well infrastructure. Volatile organic compound detections were mainly from manufactured compounds unrelated to oil and gas production, with a relatively limited number of petroleum hydrocarbons also detected. Volatile organic compounds were generally found in wells tapping shallow, modern aged groundwater, indicating anthropogenic activities occurring at or near land surface as the source. Study results suggest that while oil field infrastructure provides migration pathways for oil field formation fluids to be introduced into groundwater, urban land uses not related to oil and gas production are the primary drivers of groundwater quality degradation.

Landscape change and age ratios for mule deer (Odocoileus hemionus) herd units in Wyoming,1980-2019

Tue, 30 Jun 2026 13:44:12

No abstract available.

Evidence for a biological origin of uranium-rich carbon masses within the Ediacaran Salt Range Formation of Pakistan

Tue, 23 Jun 2026 17:52:09

Thucholites are unique organic structures found in igneous and sedimentary rocks composed of a U-C-rich interior enclosed by an organic outer shell. Their formation and occurrence have perplexed scientists for over 100 years. Typically, thucholites are sparse in sedimentary rocks but where found in abundance, they may be the result of rapid paleoecological disruptions, e.g., volcanic ashfall. Here, we evaluated thucholites from the Ediacaran Salt Range Formation of the Indus Basin in Pakistan using field emission scanning electron microscopy (FESEM) and nanoscale secondary ion mass spectroscopy (NanoSIMS) to propose a two-stage mechanism for thucholite development. NanoSIMS results suggest organic matter in thucholite cores formed by biological fractionation (represented by the presence of lighter ¹³C/¹²C and ³⁴S/³²S) while the outer organic mantle formed via radiolysis-induced polymerization. FESEM elemental analysis confirms compositional differences between the two thucholite components (core and mantle), further implying their contrasting origins. Dimensional comparison of thucholite cores and their U-bearing mineral morphologies to ancient and modern U-biomineralized microbes suggests that the thucholite cores formed from metal-biological interactions. The presence of volcanogenic biotite, alkali feldspar, and clay spherules (interpreted as devitrified volcanic glass) with thucholite suggests that the thucholite cores in the Salt Range Formation are biological responses to rapid paleoenvironmental change from volcanic eruption which preserved the fossilized morphologies of Proterozoic microorganisms.

Incorporating location uncertainty improves inference with stop-level North American Breeding Bird Survey data

Burner, Ryan; Hostetler, J.; Kirschbaum, Alan — Tue, 23 Jun 2026 17:24:19

Ecological models should account for uncertainty to be most effective and useful. Yet, uncertainty from model covariates—unlike that from other sources, such as sampling error or process variability—is seldom explicitly incorporated. This can cause underestimates of uncertainty to cascade through model parameter estimates, predictions, and downstream uses. Burner et al. proposed a method for quantifying uncertainty in covariates and incorporating it into models using informative Bayesian priors. This method was applied to stop-level Breeding Bird Survey (BBS) analyses, where land cover uncertainty at each stop arises from substantial stop location uncertainty. A limited validation of model-estimated land cover, using stops with known locations, indicated the method’s potential effectiveness, but it was not rigorously evaluated. We conduct a robust simulation-based test, generating stop locations, extracting land cover, and simulating bird communities across 210 BBS routes in the upper Midwest. We compare 3 models: a “known” model with true land cover, a “naive” model assuming consistent 800-m stop spacing, and a “full” model using informative priors to estimate land cover. Species parameter estimates and predicted prevalence patterns across gradients in land cover from the full model approached those of the known model and were substantially closer to the true values used in simulations relative to those from the naive model. Naive model parameters were more biased relative to the other models, and credible intervals of predicted species prevalence rarely included the true simulated values. The full model also produced land cover covariate estimates closer to true simulation values relative to the mean informative priors. Our results show that, for the BBS, informative priors enable more accurate stop-level analyses despite location uncertainty. In contrast, naive models that ignore this uncertainty yield poor inferences. More broadly, we demonstrate empirically the utility of informative priors to account for covariate uncertainty in ecological models.

Osmium isotope constraints on Mauna Loa–Kilauea magmatic connectivity, Island of Hawai‘i

Tue, 23 Jun 2026 13:27:36

The Hawaiian volcanic chain exhibits a long-recognized double track of volcanism defined by the Loa and Kea trends, which erupt chemically and isotopically distinct lavas. Mauna Loa and Kīlauea, the two most frequently active volcanoes of the Loa and Kea trends, produce distinct endmember compositions. However, historical periods of compositional convergence have prompted debate regarding a potential magmatic connection between the two adjacent volcanoes. Proposed links include a shallow edifice-level plumbing system, a common magma source at ∼40 km depth, or a deeper asthenospheric source. In the latter scenario, based on correlated Sr–Nd–Pb isotopes and trace-element systematics, a “shared” mantle source supplies melt alternately to both volcanoes on multi-decadal timescales. Here, we use Os isotopes to evaluate the proposed connections. We measured Os isotopes in eight historical Mauna Loa tholeiites along with three Kīlauea tholeiites (1832 summit eruption; Uēkahuna Bluff; 2000 Pu‘u‘ō‘ō eruption) previously identified as isotopically intermediate between Mauna Loa and Kīlauea endmembers. We found that the acidic bromide leachates of all samples yield more radiogenic ¹⁸⁷Os/¹⁸⁸Os than corresponding bulk residues, with the labile Os-bearing phase comprising ∼0.4–27% of bulk Os. Mauna Loa tholeiites display nearly constant ¹⁸⁷Os/¹⁸⁸Os over the past ∼200 years (0.134–0.136; mean = 0.1357 ± 0.0013, n = 8, 2SD), despite large variations in total [Os] ranging from ∼30 pg/g (2022 tholeiite) to ∼966 pg/g (1868 picrite). The Kīlauea 1832 sample has ¹⁸⁷Os/¹⁸⁸Os = 0.1302 ± 0.0008, slightly higher than the Kīlauea endmember (0.1285 ± 0.0008), whereas the Uēkahuna Bluff and Pu‘u‘ō‘ō samples exhibit more elevated ratios (0.1314 ± 0.0008 and 0.1327 ± 0.0008, respectively). We conclude that the “shared” mantle source exerts negligible control on Mauna Loa Os isotope systematics. In contrast, the Kīlauea mantle source is more heterogeneous, with contributions from small-scale recycled domains with variable time-integrated Re/Os ratios.

Development of a two-dimensional hydraulic model for the Kalamazoo River between the Trowbridge and Allegan City Dams, Michigan

Roland, Collin; Vaughan, Angus; Fitzpatrick, Faith; Broerman, Heidi M.; Lund, J. — Wed, 24 Jun 2026 13:58:05

The U.S. Geological Survey developed a two-dimensional hydraulic model for a 9.2-mile reach of the Kalamazoo River between the Trowbridge and Allegan City Dams. The model simulates streamflow conditions with spatial coverage and resolution that would be difficult or dangerous to document with field measurements, enabling assessments of habitat connectivity and substrate stability to support dam removal and restoration planning. The model was calibrated with surveyed water surface elevation (WSE) profiles, streamgage WSE time series, and measured depth-average velocities. Modeled WSE profiles had root mean square error (RMSE) values of 0.20 and 0.32 foot. Cross-sectional average velocities were slightly underpredicted, with RMSE of 0.28 and 0.30 foot per second (ft/s). Channel roughness varied with stage, and the high-flow model reproduced streamgage WSE time series with an RMSE of 0.04 foot. Quasi-steady simulations at 4,000 cubic feet per second (ft³/s), about the 50-percent annual exceedance probability streamflow, indicated that cross-sectional average velocities within 3.4 miles downstream from Trowbridge Dam were commonly between 3 and 4 ft/s, occasionally exceeding 4 ft/s. Farther downstream, velocities seldom exceeded 3 ft/s. Simulated shear stresses were used to estimate substrate stability in the reach. At 4,000 ft³/s, the minimum stable grain size along most of the main channel was predicted to be in the pebble range (4–64 millimeters), and sands and silts were predicted to be stable in the floodplain and backwaters.

Preliminary geology of the North Meadow Creek Area, Tobacco Root Mountains, southwest Montana: The North Meadow Creek Fault

Fuis, Gary; LeClair, Parker; Ruleman, Chester — Mon, 22 Jun 2026 21:04:05

This report documents a previously unmapped fault, informally referred to herein as the North Meadow Creek fault, on the east flank of the Tobacco Mountains of southwestern Montana. This fault has an apparently long and complex history, including Quaternary offset of an older alluvial terrace, offset of a debris flow of presumed Pleistocene age, offset of rhyolite lava flows of presumed Tertiary age from their presumed source several kilometers east, on the opposite side of the fault, and offset and possible rotation of blocks of Archean gneiss on northeast side of the fault. The western part of the fault is covered by glacial moraines of two apparent ages, both Pleistocene.

Long-term intermittent connection between the western Snake River Plain and Columbia basin: A two-phased incision history of Hells Canyon

Wed, 1 Jul 2026 11:16:07

For more than a century, researchers have debated the route of the Snake River across the northern Cordillera and U.S. Pacific Northwest, including the associated incision history of Hells Canyon. Here, we use detrital zircon U-Pb provenance analysis of Miocene strata upstream and downstream of Hells Canyon to constrain the evolution in fluvial pathways over time. Downstream of Hells Canyon, we show that the ca. 10−6 Ma Clarkston Heights gravel was dominantly sourced from the nearby Salmon and Clearwater rivers but also with substantial input from drainages that now flow into the western Snake River Plain. These same western Snake River Plain drainages were contributing to time-equivalent Lake Idaho strata, upstream of Hells Canyon, indicating a Hells Canyon fluvial connection between the western Snake River Plain and Columbia basin before 6 Ma. Results from Lake Idaho strata suggest a two-phased lacustrine history in the western Snake River Plain: Before ca. 6.0 Ma, lake strata were derived from local tributaries, suggesting that the western Snake River Plain was isolated from the modern upper Snake River system. Between ca. 4.3 Ma and 2.2 Ma, the source area expanded to include eastern tributaries in conjunction with migration of high-standing topography of the Yellowstone hotspot. Our results challenge the long-held hypothesis of “capture” of the Snake River through Hells Canyon. Instead, we infer that Hells Canyon was a long-established route for outflow of lakes occupying the western Snake River Plain, possibly intermittently, during a ca. 10−2 Ma phase of slow regional incision, followed by rapid incision in Hells Canyon starting ca. 2 Ma in conjunction with erosion of the topographic barrier impounding Lake Idaho.

Glacier fed deltas and new age constraints for glacial Lake Grand Gorge in the northern Catskill Mountains of New York State, USA

Thu, 18 Jun 2026 14:09:27

Ice-dammed lakes were common along the southern margin of the Laurentide Ice Sheet during deglaciation. In the Schoharie Valley of the northern Catskill Mountains, New York, a 171 km² lake known as glacial Lake Grand Gorge formed in an interlobate area. Previous researchers suggested that deltas developed into this glacial lake from meltwater supplied by the adjacent Hudson Lobe during deglaciation. This study investigates stratigraphy and sedimentology of Pleistocene deltas and lake deposits to determine the source of meltwater and sediment. Detailed examination of stratigraphy from quarries, stream exposures, and new exploration borings was combined with radiocarbon and OSL geochronology to establish event stratigraphy. Sedimentologic and geomorphic data from deltas in the Manor Kill and Platter Kill Valleys demonstrates that braided outwash was supplied directly from the Westerlo Sublobe that crossed the northeastern escarpment of the Catskill Mountains. New geochronologic data indicates that the lake was established by 28 ka and likely persisted to at least 22 ka. Insects and twigs recovered from lake sediments complement the OSL data and indicate: (1) that the lake was present significantly earlier than previous deglacial models predict, and (2) that it existed in an ice-free area of the northern Catskill Mountains during the last glacial maximum of the MIS 2 glaciation.

The 3D Elevation Program—Supporting North Dakota's economy

Guidero, Elaine — Mon, 22 Jun 2026 17:08:36

Introduction

As the northernmost Great Plains State encompassing two geomorphological areas divided by the Missouri River, North Dakota has varied needs for high-resolution elevation data. The top industry in North Dakota is agriculture and related products, and the fastest growing sector is natural resources led by oil and gas extraction and mining, all of which contribute to the State’s economy (U.S. Department of Agriculture, National Agricultural Statistics Service, 2024b). Critical applications that meet the State’s management needs depend on light detection and ranging (lidar) data that provide a highly detailed three-dimensional (3D) model of the Earth’s surface and aboveground features.

The 3D Elevation Program (3DEP; refer to sidebar) is managed by the U.S. Geological Survey (USGS) in partnership with Federal, State, Tribal, U.S. territorial, and local agencies to acquire consistent lidar coverage at quality level 2 or better (table 1) to meet the many needs of the Nation and North Dakota. The status of available and in-progress 3DEP baseline lidar data in North Dakota is shown in figure 1. 3DEP baseline lidar data include quality level 2 or better, 1-meter or better digital elevation models, and lidar point clouds, and must meet the Lidar Base Specification 2025 Rev. A (https://www.usgs.gov/3dep/lidarspec) or newer requirements. The National Enhanced Elevation Assessment (Dewberry, 2012) identified user requirements and conservatively estimated that availability of lidar data would result in at least $12.39 million in new benefits annually to the State. The top nine North Dakota business uses for 3D elevation data, which are based on the estimated annual conservative benefits of 3DEP, are shown in table 2.

Petrography and mineralogy of selected pre-Middle Jurassic basement rocks beneath the Atlantic and Gulf Coastal Plains in Florida

Deasy, Ryan; Lupo, Mary; McAleer, Ryan; Horton,, J. Wright — Tue, 30 Jun 2026 17:01:48

Florida is covered by flat-lying sedimentary strata of the Atlantic and Gulf Coastal Plains. These strata have accumulated since Middle Jurassic time. The pre-Middle Jurassic, or basement, rocks that underlie the Coastal Plain in Florida are known only from drill cores and cuttings recovered from a relatively small number of boreholes. This data report presents petrographic observations and the results of X-ray diffraction analyses of basement rocks from 18 boreholes across Florida in support of the identification, discrimination, and correlation of units for a subcrop geologic map of pre-Middle Jurassic rocks composing Florida’s sub-Coastal Plain geology.

Geologic map of pre-Middle Jurassic basement rocks beneath the Atlantic and Gulf Coastal Plains in Florida

Thu, 18 Jun 2026 13:37:12

Much of the southeastern United States, including all of Florida, is covered by flat-lying sedimentary strata of the Atlantic and Gulf Coastal Plains which have accumulated since Middle Jurassic time. The pre-Middle Jurassic rocks that underlie these coastal plains in Florida, here collectively referred to as “basement,” are known only from a relatively small number of boreholes. This scientific investigations map presents an interpretation of the basement geology in a 1:1,000,000-scale subsurface geologic map with supporting text, data, and figures. The subsurface mapping methodology integrates petrographic, geochronological, thermochronological, geochemical, and mineralogical analyses of drill cores and cuttings in the context of regional geophysical data.

The pre-Middle Jurassic rocks of Florida consist of the Gondwanan (West African) Suwannee terrane which was accreted to Laurentia during the Alleghanian orogeny and subsequently intruded by Permian granites, superposed by early Mesozoic rift basins, and partially overlain by bimodal Jurassic volcanic rocks. The younger basement components, specifically the Southwest Florida volcanic province, North Florida tholeiites, early Mesozoic rift basins, and Alleghanian granitoids, have correlative and contemporaneous units throughout the Appalachian orogen. In contrast, Florida’s older basement rocks, including Paleozoic siliciclastic strata of the Suwannee basin, North Florida volcanic series, Osceola and Gaskin intrusive complexes, and the St. Lucie Metamorphic Complex, have neither surface exposures nor unequivocal correlates. Major structures include early Mesozoic normal faults and northwest-striking transfer zones such as the Jay fault. Many of these faults define the boundaries of subbasins within the South Georgia rift system. Top-of-basement structure contours show gentle arches and embayments that are also recognized in overlying coastal plain strata.

Quantifying Landsat’s contributions to U.S. agricultural and forestry applications

Tue, 23 Jun 2026 17:31:20

The Landsat program has provided over 54 years of multispectral imagery, contributing vital information for agricultural and forestry scientific research and operational activities. Freely available Landsat data have enabled scientists to analyze land use patterns, assess ecological impacts, and develop strategies for sustainable management. We explored Landsat’s pivotal role through the lens of the United States Group on Earth Observations 2023 Earth Observation Assessment (EOA). The EOA included comprehensive surveys of more than 2000 federally supported Earth observation data products. We subsequently analyzed how Landsat satellite data and derived products support agricultural and forestry-related priorities compared to other Earth observation inputs. We evaluated both direct and indirect applications of the data, identifying key users across federal agencies and assessing how Landsat data contribute to critical products, services, and objectives. The results indicate that Landsat provides key information to support diverse activities across agriculture and forestry sectors, such as enhancing food supply, improving resilience to disaster and disturbance events, maximizing ecosystem productivity and conservation, and supporting regulatory requirements and decision-making. The Landsat OLI and TIRS sensors ranked 4th and 10th, respectively, out of 1171 Earth observation inputs identified in the study, underscoring their value to agriculture and forestry.

Assessing the state of hydrologic science in the Upper Klamath Basin—A comprehensive review of data, tools, and models

Stonewall, Adam; Harden, Tessa M.; Reale, Justin; Cameron, Cortney — Wed, 24 Jun 2026 01:49:41

Water demand in the Upper Klamath Basin (UKB) from various stakeholders and ecological needs often outstrips available supply, leading to persistent management challenges. This study reviews the state of hydrologic science within the UKB as of 2025—specifically, the tools, data, and models available for assessing five key components of the water system: (1) surface water; (2) precipitation; (3) evapotranspiration; (4) groundwater; and (5) water use. The UKB water supply is critical for Native American communities, regional agriculture, and federally listed fishes and faces challenges from competing needs, climate variability, and operational/regulatory requirements. We assess existing datasets, regional and national models, and historical studies to understand the available resources and identify gaps that may hinder integrated water assessments and management. Our findings indicate areas where improvements in data collection and model precision could improve the accuracy of water-availability forecasts and support water-management practices. This review can inform near-term forecasting, assist in optimizing water-resource data collection and management strategies, and support regional water-availability assessments of the basin.

Continental-scale prediction of hydrologic signatures and processes

Wed, 17 Jun 2026 14:40:48

Understanding how dominant hydrologic processes and their drivers vary across diverse continental-scale landscapes is critical for hydrologic modeling and water management applications. Our research addresses this question by synthesizing large-sample watershed datasets, Caravan and GAGES-II, and developing random forest models to identify patterns in hydrologic function. We assessed dominant processes by examining hydrologic signatures – summary indicators of watershed function derived from hydroclimatic time series and random forest models across 14 146 gauged United States watersheds. The results reveal clear continental-scale gradients in hydrologic processes, including baseflow, overland flow, storage, and water balance losses. Our map of dominant processes highlights, for example, the transition from baseflow to fast responses and back to baseflow along the elevation gradient from the Appalachian spine, through the Piedmont, to the Eastern Coastal Plain; a distinct outer ring around the Great Lakes region; and sharp contrasts between coastal and inland processes in the West. Variable importance analysis from random forest models show that processes in the western U.S. are primarily controlled by climate, whereas in the eastern U.S., soil, geology, and topography play larger roles, with distinct human influences apparent in urban areas. Our approach of estimating dominant processes and their drivers facilitates extending process knowledge from research watersheds to the continental scale, assessing current hydrological understanding, and evaluating hydrological model structures.

Field methods, quality-assurance, and data management plan for water-quality activities and water-level measurements, Idaho National Laboratory, Idaho

Treinen, Kerri; Trcka, Allison; Zingre, Jeffrey; Wehnke, Amy — Wed, 24 Jun 2026 01:42:53

Introduction

Water-quality activities and water-level measurements conducted by the U.S. Geological Survey (USGS) Idaho National Laboratory (INL) Project Office coincide with the USGS mission of evaluating the quantity and quality of the Nation’s water resources. The activities are conducted in cooperation with the U.S. Department of Energy’s (DOE) Idaho Operations Office. Results of water-quality and hydraulic head research efforts are presented in various USGS and scientific journal publications (refer to Fisher, 2022). These data are stored internally in the Aquarius Time Series and Aquarius Samples databases and are publicly accessible through National Water Quality Monitoring Council (2025) and U.S. Geological Survey (2025). Data collected from our studies are used by researchers, Federal and State agencies, water management and regulatory organizations, as well as the public.

This quality assurance plan (QAP) describes the methods and processes for field methods, data collection, data management, data auditing, and equipment management for both the water-quality and water-level programs at the USGS INL Project Office (hereto referred to as INL Project Office). A comprehensive quality assurance (QA) plan ensures that the processes defined in this document will guide the program staff to collect and publish reliable, useful, and defensible data products for stakeholders. This QAP supersedes previous versions of this document and is intended to complement the Quality Assurance and Data Management (QADM) Plan for the Idaho Water Science Center (IDWSC; Christopher Mebane and Lauren Zinsser, written commun., 2024).

Ecosystem metabolism as an early warning indicator of lake algal blooms

Tassone, Spencer; Foster, Brendan; Maas, Carly; Jastram, John — Wed, 24 Jun 2026 14:30:12

Algal blooms represent ecosystem state shifts that degrade drinking water, restrict recreation, threaten public health, and lower property values. Detecting blooms in advance on management relevant timescales of days to weeks can support proactive intervention. Early warning statistics derived from indicator time series offer a framework for detecting state shifts, but the use of lake metabolic estimates (gross primary production, ecosystem respiration, and net ecosystem production) in this context has been limited. Here, we modeled lake metabolism using water-quality monitoring data from eight U.S. lakes spanning a trophic gradient to test the hypothesis that metabolic estimates serve as effective early warning indicators of algal blooms. Time series of early warning statistics were analyzed using the conventional Kendall’s tau approach and a complementary threshold-based approach. The threshold-based approach yielded higher bloom detection rates, longer early warning lead times, and fewer false alarms than the Kendall’s tau approach. Across lakes, metabolic metrics detected 86% of blooms, with the strongest early warning signals in oligotrophic, eutrophic, and hypereutrophic systems. However, directly measured water-quality parameters, particularly water temperature and chlorophyll concentration, were the primary early warning indicators of blooms. Overall, these results demonstrate that metabolic estimates can provide early warning signals of bloom development but are secondary to directly measured water-quality parameters, indicating a complementary rather than primary role in early bloom detection.

Bright spot in eDNA monitoring: Early detection of invasive New Zealand mudsnails (Potamopyrgus antipodarum) prompted effective rapid response for fish hatchery

Slobodian, Devin; Hutchins, Patrick; Graves, Jennifer; Sepulveda, Adam — Thu, 18 Jun 2026 13:59:07

The New Zealand mudsnail (NZMS; Potamopyrgus antipodarum) is a widespread aquatic invasive species that is parthenogenic, requiring only a single individual to initiate an infestation. Fish hatcheries–which are critical infrastructure that raise fish to support conservation, recreation, and subsistence fisheries–frequently use local water sources to provide cool water and are especially vulnerable to NZMS invasion from the contamination of water supplies. If an invasion proceeds undetected, hatcheries pose a risk for compounding the spread of NZMS because their operations transfer live organisms and associated water between hatchery facilities and, when stocking, to rivers and lakes. The U.S. Fish and Wildlife Service's Alchesay National Fish Hatchery, located on the Fort Apache Indian Reservation in Whiteriver, Arizona, produces trout to stock in Tribal reservoirs, lakes, and rivers across the southwestern U.S. New Zealand mudsnails were first documented in Arizona in 1995, are now widespread in this region, and occur at the confluence of the hatchery's outflow with the North Fork White River. Contamination of water supplies is the principal pathway for NZMS invasion into the hatchery. Here, we describe early detection environmental DNA (eDNA) surveillance efforts for NZMS at Alchesay National Fish Hatchery. Positive eDNA detections initiated a chain of events that ultimately led to four NZMS individuals being discovered and a rapid response eradication effort. Follow-up eDNA sampling and visual observation efforts after the eradication effort have yielded no detections of NZMS eDNA. We credit the success of this case with four key elements: rapid turnaround times, a robust quality assurance scheme, a proactive eDNA sampling design, and established partnerships. To our knowledge, this is the first published case of eDNA monitoring being used for early detection and successful rapid response for complete removal of an invasive species in a fish hatchery.

Benchmark dataset of historical annual peak floods classified by causal mechanisms for select US river basins

Mon, 22 Jun 2026 14:33:26

Considering the causal mechanisms of floods can improve estimates of flood recurrence intervals given that certain flood types can be associated with higher magnitude and more damaging floods. However, few verified datasets of flood types are available to validate the semiautomated and automated classification algorithms needed to apply flood-typing across large hydrologically diverse regions. To address this gap, a benchmark dataset of manually classified flood types was compiled for 1,763 annual maximum flood peaks from 18 stream gauges in six different river basins across the conterminous United States from 1851 to 2022. Within each basin, three representative stream gauges were selected for manual flood typing. A flexible classification framework is introduced that facilitates flood typing across hydrologically diverse regions and accommodates unique combinations of weather and antecedent watershed conditions specific to each region. Floods were manually typed by domain experts using multiple lines of evidence to identify a primary surface water input of each flood (rainfall, snowmelt, or both) and, if relevant, associated storm type and secondary causal mechanisms characterizing antecedent watershed conditions. Across all the study basins, 49% of historical annual maximum flood peaks were attributable to rainfall, 28% to snowmelt, 22% to mixed precipitation, and 1% could not be assigned to a mechanism due to missing or incomplete data. The proposed flood-typing schema supports varying levels of flood typing specificity required for mixed population flood-frequency analysis, flood-type-specific design hydrographs, water quality response studies, and additional applications. This detailed, manually determined benchmark dataset serves as a resource that can be used developing and validating automated or machine learning-based algorithms capable of operationalizing expanded flood peak information.

Potential flood events in the lower Missouri River basin over multiple centuries identified using tree-ring based multi-model streamflow reconstructions

Tue, 16 Jun 2026 14:05:43

The Missouri River basin (MRB), the largest river basin in the United States, presents major water management challenges due to its complex topology and extensive infrastructure designed to manage high annual flows. Severe hydroclimatic events, particularly floods in 1993, 2011, and 2019, have highlighted vulnerabilities, leading the U.S. Army Corps of Engineers to enhance flood risk assessments in 2023. This study focuses on the full MRB, using tree-ring based streamflow reconstructions to extend the Basin's historic streamflow perspective. We developed annual streamflow reconstructions for the Hermann, Missouri streamgage from water years 1360–1900 using K-nearest neighbor and principal component regression methods. These reconstructions incorporate 183 tree-ring chronologies (1360–2020) and modeled natural streamflow (1901–‍2020). Reconstructions were evaluated for consistency using statistical measures and wavelet analysis. Both methods produced similar results, confirming their reliability in reconstructing multi-century streamflows. This novel methodology, guided by wavelet analysis, was developed to identify potential flood events in the lower Missouri River basin (LMRB), resulting in the identification of 172 potential flood events from water years 1360–2020, with 126 events common to the two versions of the MRB reconstructions. The reconstructed streamflow records showed an increase in the number of events until the late-18th- or mid-19th-century. These findings provide insights into evolving flood characteristics in the LMRB. The novel methodology developed in this study can be used to identify potential flood events from tree-ring based annual streamflow reconstructions and generally be applicable to other river basins.

Production of mineral commodities and geospatial map of the mineral industries and related infrastructure of China

Chung, Jaewon; Neustaedter, Elizabeth; Moon, Ji Won; Xun, Sean; Textoris, Steven — Wed, 24 Jun 2026 01:33:49

As part of the U.S. Geological Survey’s (USGS) mission to distribute global mineral information and analyze supply chains, this study provides a comprehensive review of the global significance of China’s mineral production and capacity in 2023. Of 77 mineral commodities in the USGS dataset, China produced 74 and was the world’s first-ranked producer for 39 of the 74. Compared to the high share of global mineral production, including up to 98 percent of global gallium production, the country’s share of global mineral reserves was relatively small, ranging from 20 percent (zinc ore) to 52 percent (tungsten ore). China’s imports of metal ores, slag, and ash accounted for 64 percent of global imports of such commodities by value. The country’s exports of base metals and articles of base metal accounted for 17 percent of the global exports. To help nongeographic information system users assess the spatial distribution of mineral mines, processing facilities, and ports for trades in China, this study created a geospatial (also called “georeferenced”) portable document format (GeoPDF) map. In addition, the GeoPDF contains mineral resource tracts (such as antimony, copper, potash, coal, and oil and gas), exploration sites, and energy infrastructure based on the preexisting USGS data.

Tephra from Kīlauea’s 2008–2018 lava lake eruption—Proximal deposits and dispersal characteristics

Swanson, Don; Orr, Tim R.; Patrick, Matthew; Houghton, Bruce — Mon, 22 Jun 2026 17:15:53

A network of ten buckets was established early in the 2008–2018 summit eruption at Kīlauea to collect proximal tephra ejected from the new, informally named the “Overlook crater”; the buckets were emptied on most days of the eruption thereafter. This report summarizes the results of more than 2,400 different sampling intervals (most 1–3 days long) during the eruption, focusing on the physical and dispersal characteristics of the tephra deposits. The network was within about 300 meters south of the vent to capture tephra dispersed by the dominant northeast trade wind. The juvenile tephra mainly reflected spattering at the southeast (SE) sink, a downwelling area in the southeastern part of the lava lake in the Overlook crater that remained in the same area throughout the eruption, with admixtures of solid rock and secondary minerals derived from the wall of the crater. The proportion of juvenile material to lithic material ranged widely early in the eruption but was generally greater than 90 percent for the last 6 years of the eruption as lake level rose and the crater walls decreased in height and became more stable. The accumulation rate of tephra at each bucket was strongly dependent on the location of the bucket and reflects the interplay between lava lake level and wind direction and speed. The mass per unit area (m/a) of collected tephra was a maximum of about 97 kilograms per square meter for the entire eruption, equivalent to a thickness of about 75 millimeters. Thirty-two explosive events with a volcanic explosivity index of −2 to −4 deposited much of the tephra in the network. Fifteen of these rock-fall-induced events occurred within 6 days of one another. Pele’s hair, a volcanic glass predominantly associated with quieter activity at the vent in the final half of the eruption, was dispersed more than 60 kilometers downwind from the lava lake and formed a nearly continuous deposit near the Overlook crater. This eruption was probably the most frequently sampled long-lasting eruption in history, but most of the deposits are ephemeral. The collected samples, although generally of small mass, are retained by the Hawaiian Volcano Observatory and are available for detailed study.

A genomic tool to tackle cryptic diversity demonstrates the potential for off-target use of GT-seq panels

Tue, 16 Jun 2026 13:38:33

A comprehensive understanding of life history is vital to successful species conservation and management. When different life history stages are accompanied by considerable morphological or cryptic variation, such as the egg and larval phases exhibited by most fishes, genomic tools are essential for identifying species so that early-life ecology questions can be studied. Genotyping-in-thousands by sequencing (GT-seq) has recently emerged as a targeted and efficient approach for species identification. We leveraged existing genomic and transcriptomic data to develop a GT-seq panel capable of differentiating the members of the Coregonus artedi complex, a radiation of salmonids in the Laurentian Great Lakes whose members are indistinguishable with mitochondrial DNA barcoding loci and are the focus of bi-national conservation initiatives. Our panel of 494 loci was able to assign fishes in the C. artedi complex to species and lake. We examined cross-amplification in other coregonines with overlapping distributions and found that congeneric Lake Whitefish (C. clupeaformis) cross-amplified at 94% of loci and confamilial Round and Pygmy Whitefish (Prosopium spp.) cross-amplified at 42% and 38% of loci, respectively. We adapted bioinformatic probes to account for Prosopium-specific variants including 22 new SNPs and developed a whitelist of 428 SNPs capable of distinguishing these whitefishes. Finally, we demonstrated performance by identifying 3,066 coregonine larvae and juveniles collected in spring 2019-2021 from Lake Superior. These results hold promise for future insights into the species-specific ecology of early life coregonines and demonstrate the flexibility of GT-seq panels, which may cross-amplify hundreds of informative genome-wide loci in related taxa.

Availability of dark daytime refuge may limit mysid abundance in the Laurentian Great Lakes

Mon, 15 Jun 2026 15:18:28

The zooplankton Mysis diluviana is a major component of the Laurentian Great Lakes food web and has recently declined in abundance in both lakes Michigan and Huron. Drivers of these declines are not well understood. Here, we explore the hypothesis that recent increases in water clarity have contributed to the decline of M. diluviana (mysids) by limiting the availability of daytime dark refuge from visual predators. Using Secchi depth data from 1996 to 2021, we estimate that dark refuge has decreased substantially in lakes Michigan and Huron where mysids have declined, but dark refuge has remained more stable in lakes Ontario and Superior where mysid populations did not decline. Results from a 2021 uncrewed surface vessel hydroacoustic survey and lake-wide, net-based sampling in lakes Michigan and Huron revealed significantly more mysids in areas with dark refuge, such as Lake Michigan’s northern basin. Conversely, Lake Huron contains sparse dark refuge consistent with low mysid densities in that lake. Higher water clarity leading to increased predation may be a primary driver of mysid declines in the Great Lakes.

Estimation, distribution, and development of a surrogate model for Escherichia coli in the New River, New River Gorge National Park and Preserve, West Virginia, 2021–23

Kearns, Matthew; Chambers, Douglas — Mon, 22 Jun 2026 17:14:14

The New River Gorge National Park and Preserve in West Virginia receives more than 1 million visitors each year, many of whom come to enjoy the New River, which is known for its whitewater recreation. However, most of the tributaries within the New River Gorge are impaired by fecal-coliform bacteria, which are at concentrations that may exceed recreational-contact standards, posing a potential health risk to the public and, therefore, creating a need to better understand the spatial and temporal distribution of fecal-coliform bacteria and to communicate this information to park visitors.

Concentrations of Escherichia coli, a species of fecal-coliform bacteria, were monitored in the New River and selected tributaries from October 2021 through September 2023, with emphasis placed on the primary recreational-contact season from May through October. Composite and cross-sectional water samples were taken from three U.S. Geological Survey (USGS) monitoring locations: the New River at Highway 41 at Prince, West Virginia (USGS 03184905), New River at Thurmond, West Virginia (USGS 03185400; hereafter, Thurmond), and New River at Fayette, West Virginia (USGS 03186000). Periodic longitudinal transects included water samples collected below seven major tributaries of the New River within the gorge. Water-quality parameters, including water temperature, pH, specific conductance, dissolved oxygen, and turbidity, were recorded with each E. coli water sample.

During the 2 years of sampling, E. coli concentrations in samples collected from the New River ranged from less than 1 to 1,100 most probable number (MPN) per 100 milliliters (MPN/100 mL). The recreational-contact standard, which is based on the U.S. Environmental Protection Agency 90th-percentile statistical threshold value for E. coli concentrations (320 MPN/100 mL), was exceeded in 11 of the 110 samples collected from the New River during this study. Water-quality parameter measurements and E. coli concentrations in collected samples were generally consistent among USGS monitoring locations throughout the New River Gorge; however, storm events created notable exceptions because they increased tributary streamflow and E. coli concentrations in samples, particularly at the New River below Piney Creek at McCreery, West Virginia (USGS 03185208), and New River Below Arbuckle Creek at Thurmond, West Virginia (USGS 03185440), monitoring locations. Escherichia coli concentrations of cross-sectional samples tended to be consistent across the New River, except for a few nearshore samples.

Sample E. coli concentrations and corresponding measurements of continuous water-quality parameters, streamflow, and precipitation data from Thurmond and the Piney Creek at Raleigh, West Virginia (USGS 03185000; tributary to the New River) monitoring locations were evaluated for use in a near-real-time E. coli surrogate model. The antecedent mean 24-hour turbidity at Thurmond was selected as the best variable for a simple linear regression surrogate model for the log₁₀ E. coli concentration in the New River and had an adjusted coefficient of determination of 0.556 and a p-value of less than 0.001. The regression equation surrogate model suggests that the recreational-contact standard is exceeded when the antecedent mean 24-hour turbidity at Thurmond is 23.6 formazin nephelometric units or higher (with a 95-percent confidence interval of 19.4–30.7 formazin nephelometric units). Evaluated against a turbidity duration curve, this standard is exceeded 7.5 percent of the time at Thurmond. This surrogate model could help New River Gorge National Park and Preserve staff provide near-real-time information about E. coli concentrations and related recreational-contact risks to the public.

Controls on natural hydrogen generation during serpentinization of mantle rocks

Mon, 15 Jun 2026 15:03:29

Mantle rocks undergoing serpentinization can generate significant amounts of natural hydrogen, yet the rates and controlling processes remain poorly understood. Here, we constrain the possible hydrogen generation rates in two distinct mantle rock types, the fertile lherzolites of the Western Pyrenees and the depleted harzburgites of Northern California, to relatively low rates of ~0.1 to ~0.5 tonnes H₂ yr⁻¹ km⁻³ of reactive rock. When integrated over the full reactive volumes, this corresponds to total production rates of ~300 to ~600 tonnes H₂ yr⁻¹. By combining three-dimensional geophysical inversion with numerical modelling of fluid-rock processes, we show that hydrogen generation rates are mainly limited by H₂ saturation in the fluid and reaction kinetics. Under these constraints, hydrogen generation in mantle-derived serpentinization systems proceeds slowly, making rapid large-scale replenishment unlikely and suggesting that large, economically relevant accumulations, would require timescales of thousands to tens of thousands of years to develop.

Development of projected depth-duration-frequency curves for precipitation in Florida, 2020–59 and 2050–89

Irizarry-Ortiz, Michelle — Mon, 22 Jun 2026 17:17:13

The planning, permitting, and design of stormwater-management projects require estimates of the depths of extreme precipitation for current and future events with specified durations and return periods. In this project, precipitation data from six downscaled climate datasets were used to determine changes in precipitation depth-duration-frequency curves from the period 1966–2005 to the periods 2020–59 and 2050–89. The downscaled climate datasets are from the Coupled Model Intercomparison Project Phases 5 and 6 and include (1) Coordinated Regional Downscaling Experiment (CORDEX), (2) Localized Constructed Analogs (LOCA), (3) Multivariate Adaptive Constructed Analogs (MACA), (4) Jupiter Intelligence Weather Research and Forecasting model (JupiterWRF), (5) LOCA version 2 (LOCA2), and (6) National Aeronautics and Space Administration Earth Exchange Global Daily Downscaled Projections (NEX-GDDP). Change factors—multiplicative changes in expected extreme precipitation magnitude from a historical to future period—were computed for grid cells containing National Oceanic and Atmospheric Administration Atlas 14 stations in Florida. Change factors for specific durations and return periods were developed to scale the National Oceanic and Atmospheric Administration Atlas 14 historical depth-duration-frequency values to the periods 2020–59 and 2050–89 on the basis of changes in extreme precipitation derived from six downscaled climate datasets.

Overall, a large variation in change factors across downscaled climate datasets was found, with change factors generally being greater than 1 and increasing with return period. In general, median change factors were found to range within 1.01–1.58 for 2020–59 and 1.01–1.63 for 2050–89, depending on the downscaled climate dataset, region, duration, and return period, indicating a projected overall increase in future extreme-precipitation events. When data from all datasets are considered together, median change factors range within 1.04–1.18 for the period 2020–59 and within 1.04–1.23 for the period 2050–89, depending on the region, duration, and return period. Spatial patterns in median change factors were found to vary by dataset.

On the importance of ichthyoplankton monitoring for invasive grass carp control in the Laurentian Great Lakes

Mon, 15 Jun 2026 14:49:01

Grass carp (Ctenopharyngodon idella) is an invasive herbivore observed in small numbers in the Laurentian Great Lakes since the 1980 s with records from all lakes except Lake Superior. Identification of diploid, age-1 + grass carp from the Sandusky River, a Lake Erie tributary, in 2012, prompted targeted efforts to evaluate the status of grass carp reproduction in the Lake Erie Basin. In 2014, researchers from the U.S. Geological Survey and University of Toledo began surveys to assess grass carp spawning in the Great Lakes, with the first fertilized eggs discovered in 2015 in the Sandusky River. Eight Great Lakes tributaries in the United States have been surveyed for evidence of grass carp spawning, identifying three confirmed spawning tributaries (Sandusky, Maumee, and Huron Rivers in Ohio). Initial work identified specific flow and temperature conditions that likely stimulate spawning. Egg and larval drift modeling estimated spawning locations based on egg development and flow characteristics, which helped removal crews locate and target spawning fish in the Sandusky River and later, the Maumee River. The research synthesized herein demonstrates the value of ichthyoplankton research to inform control of emerging invasive species and could inform management of other invasive carps with similar reproductive life histories, should they enter the Great Lakes.

Comparing in vivo methylmercury detoxification in hunted duck: Implications for wildlife and human health

Thu, 25 Jun 2026 14:30:57

Great Salt Lake (GSL) waterfowl have elevated mercury (Hg) concentrations, and in vivo detoxification of neurotoxic and bioaccumulative methylmercury (MeHg) can occur through Hg-selenium (Se) complexation, influencing the suitability of Hg consumption advisories. Here, we present Hg chemical speciation and Hg stable isotope measurements of brain, breast muscle, liver, and kidney samples from two GSL duck species─northern shoveler (Spatula clypeata) and cinnamon teal (Spatula cyanoptera). Chemical and stable isotope measurements, along with high energy resolution fluorescence detected X-ray absorption near-edge structure (HERFD-XANES) spectroscopy, indicate the occurrence of in vivo MeHg demethylation in both bird species. The percentage of total Hg (THg) as MeHg (% MeHg) varied with tissue type (brain > breast muscle > kidney > liver), and differences between δ²⁰² THg and δ²⁰² MeHg were linearly correlated with % MeHg. Demethylated inorganic Hg was a mixture of Hg-dithiolate (Hg(SR)₂) and Hg-tetraselenolate (Hg(Sec)₄) in both bird species. Notably, liver THg concentrations were elevated in northern shoveler liver tissues relative to those of cinnamon teal (7.54 ± 4.69 mg/kg versus 2.19 ± 1.27 mg/kg, dry weight, respectively) and % MeHg liver values were significantly lower (40% ± 19% versus 68% ± 14%), indicating taxonomic differences in Hg detoxification and depuration. THg concentrations in waterfowl species from this study were comparable to previously reported levels, indicating that elevated Hg concentrations in northern shoveler and cinnamon teal at GSL have persisted over the past two decades. Due to in vivo demethylation, we show that THg is not an effective proxy for MeHg within duck species, carrying implications for current GSL waterfowl consumption advisories and assessments exposure risk. This study highlights important differences in MeHg detoxification between waterbird taxa and provides further insights into Hg toxicity risk to GSL waterbirds.

Network-wide assessment of soil water content calibration and sensitivity to biomass proxies using cosmic-ray neutron sensing in the Roaring Fork Basin, Colorado

Mon, 15 Jun 2026 14:07:26

Soil water content (SWC) is a key state variable of the climate system but is often uncertain in water balance monitoring, especially in alpine environments. SWC measurements can be challenging in alpine environments due to the topography and rocky soils. In 2022, the US Geological Survey's Next Generation Water Observing System Program began research to evaluate water balance monitoring technologies, including cosmic-ray neutron sensors (CRNS). This work evaluated the uncertainty resulting from network-wide calibration of CRNS for SWC monitoring in an alpine watershed and investigated the stability of the calibration parameters across space and time, focusing on potential influence of biomass dynamics. Fifteen stations with moderated and unmoderated (bare) CRNS were deployed and made operational within the Roaring Fork Basin in west-central Colorado. The root mean squared error of the network-wide calibration using the moderated CRNS was 0.042 or 0.047 cm³ cm⁻³, depending on the calibration equation used. Relative SWC dynamics from CRNS were correlated with the in situ probes with a correlation coefficient of 0.91 or 0.87 (depending on calibration equation). We did not find significant relationships between the calibration parameters and stationary site-specific variables. However, the calibration parameters derived from in situ probe SWC dynamics varied over time and were correlated with biomass proxies of cumulative growing degree-day, cumulative growing season index, and bare neutron counts. Future use of the CRNS network can leverage the reliable relative SWC data from network-wide calibration for watershed modeling and continue to research sensitivity of bare neutron measurements to biomass dynamics.

Assessment of undiscovered continuous oil and gas resources in the Amu Darya Basin Province of Turkmenistan, Uzbekistan, and Afghanistan, 2026

Wed, 10 Jun 2026 19:18:27

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean continuous resources of 519 million barrels of oil and 82.9 trillion cubic feet of gas in the Amu Darya Basin Province of Turkmenistan, Uzbekistan, and Afghanistan.

Evaluation of a eutrophication Beneficial Use Impairment in the Grand Calumet River Area of Concern in northwest Indiana, 2021–22

Wed, 10 Jun 2026 17:44:10

Eutrophication has been regularly documented in the Grand Calumet River and Indiana Harbor Canal in northwest Indiana. The area has undergone various remediation efforts since the development of a Remedial Action Plan for the area in response to a 1987 amendment to the Great Lakes Water Quality Agreement of 1978 between the United States and Canada and the designation of the Grand Calumet River Area of Concern by the U.S. Environmental Protection Agency. To address concerns of eutrophication and its effects, the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency and the Indiana Department of Environmental Management, collected data from the Grand Calumet River and Indiana Harbor Canal in 2021 and 2022 to document the effects of remediation and combined sewer overflow releases on water quality.

This study used continuous monitors to collect real time data for dissolved oxygen, water temperature, chlorophyll fluorescence, specific conductance, and pH. Discrete sample analysis included biological oxygen demand, chemical oxygen demand, nutrients, nitrogen and oxygen isotopes in nitrate, nitrogen isotopes in ammonia, hydrogen and oxygen isotopes in water, and identification of algal communities (cyanobacteria and eukaryotic algae) by metabarcoding.

Eutrophic conditions were found throughout the area. Isotopic results indicated the source of nitrate in samples was either from soil organic nitrogen or combined sewer overflows. Combined sewer overflows were shown to have considerable effects on the sites, and remediation status did not have a great effect. Algal community results identified several taxa capable of becoming nuisance species, including Microcystaceae (cyanobacteria) and Chrysophyceae, Cryptophyceae, and Bacillariophyceae (all eukaryotic algae). When sites with irregular flow patterns were excluded from datasets, minimum dissolved oxygen concentrations were often higher downstream from remediated sites than from unremediated sites. This study shows the potential for further and more targeted exploration into the unusual conditions found throughout the Grand Calumet River and Indiana Harbor Canal area.

Bathymetric maps, surface areas, and storage capacities of Council Grove Lake and Marion Reservoir, Kansas, and Pine Creek Lake, Oklahoma, 2024

Smith, Kevin; Pierson, Nicholas; Trevisan, Adam R. — Wed, 24 Jun 2026 01:22:17

The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, completed high-resolution multibeam bathymetric surveys to compute new elevation-area-capacity tables for Council Grove Lake and Marion Reservoir, Kansas, and Pine Creek Lake, Oklahoma. Elevation-area-capacity tables identify the relation between the water-surface elevation, surface area, and storage capacity of the lake. The surface areas and storage capacities of each lake were computed from bathymetric surfaces combining multibeam echo sounder data collected in 2024 and light detection and ranging point-cloud data collected in 2016 and 2018.

Characterizing the annual cycle of steroid hormones in males from an invasive vertebrate (Python bivittatus) of management concern

Tue, 30 Jun 2026 14:25:49

South Florida's subtropical climate has facilitated the establishment of numerous invasive species, including the Burmese python (Python bivittatus). Despite decades of efforts to manage the invasive python population across South Florida, we lack a comprehensive understanding of their reproductive physiology, limiting the development of targeted control strategies. Here, we characterized seasonal patterns of testosterone (T) and corticosterone (CORT) in free-ranging adult male pythons and evaluated environmental correlates of hormone variation. Results indicate that T peaks before the onset of the breeding season and declines through the season to baseline levels in the non-breeding season. CORT did not show a clear seasonal trend but showed greater variability during the breeding season. These findings reveal that photoperiod and ambient temperature are key environmental correlates of male hormone cycles, contributing to our understanding of the endocrine phenology of a tropical ectotherm in a novel environment.

Facilitating water resilience in wildfire affected communities: Lessons learned from rapid response research

Fri, 12 Jun 2026 15:05:18

Wildland–urban interface fires (WUI fires) can pose a significant threat to water resources, including drinking water supplies, water treatment infrastructure, ecosystem function, and agricultural irrigation. Wildfires, especially WUI fires, are expected to increase in frequency and severity. Despite the need for effective mitigation and response strategies for wildfires, rapid research co-production to support decision-making for water incident response and water management is generally limited. This manuscript draws on five U.S. wildfire case studies to highlight how research co-production between scientists, water agencies, and managers supports more effective decision-making for water resilience and recovery. The case studies demonstrate the importance of rapid response activities, coordinating collaborative response, pre-wildfire preparation, and knowledge co-production among agencies, researchers, and managers in addressing the impacts of wildfires on water supply and quality. The lessons learned emphasize opportunities to pivot wildfire-water research and operations from reactive to proactive, focusing on mutually beneficial activities such as understanding watershed health, fostering collaboration, embracing new discoveries and tools, and enabling pre-wildfire research through table-top activities, workshops, pre-fire data collection and analysis, and appointing a central water response lead. These outcomes inform the development of a research-to-operations and operations-to-research (R2O2R) co-production framework and future opportunities to guide proactive response and management efforts before, during, and after wildfire.

Southwest Climate Adaptation Science Center general information handout

Brown, Sierra — Thu, 18 Jun 2026 15:09:52

No abstract available.

Distribution, abundance, and breeding activities of Southwestern Willow Flycatchers (Empidonax traillii extimus) on the San Dieguito River and upper San Luis Rey River, San Diego County, California—2025 data summary

Howell, Scarlett; Kus, Barbara E. — Wed, 10 Jun 2026 15:00:12

Executive Summary

We surveyed for Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) at the San Dieguito River and the upper San Luis Rey River in 2025. Surveys were completed at five locations: one along the San Dieguito River (San Dieguito [SD]), which was last surveyed in 2016, and four along the upper San Luis Rey River, including three downstream from Lake Henshaw that have been surveyed annually since 2015 (Rey River Ranch [RRR], Cleveland National Forest [CNF], Vista Irrigation District [VID]), and one upstream at VID Lake Henshaw (VLH) that has been surveyed annually since 2018. There was a minimum of 57 territorial flycatchers (22 male, 35 female) and 3 transient flycatchers of unknown subspecies detected at 1 location (VLH). In total, 37 territories were established, containing 35 pairs (20 males and 35 females) and 2 male flycatchers of undetermined breeding status. Of the 35 pairs, 12 were monogamous pairings, and 23 were polygynous pairings consisting of 3 males each pairing with 2 different females [6 pairs], 3 males each pairing with 3 different females [9 pairs], and 2 males each pairing with 4 different females [8 pairs]).

No territorial flycatchers were detected downstream from Lake Henshaw or along the San Dieguito River. Brown-headed Cowbirds (Molothrus ater; cowbird) were detected at all five survey locations. No banded flycatchers were detected during surveys.

Flycatchers used only one habitat type at VLH, mixed willow riparian. All flycatcher locations were in habitat characterized as mixed willow riparian dominated by Goodding’s black willow (Salix gooddingii), and 93 percent were in habitat with greater than 95-percent native plant cover.

We monitored flycatcher nests at VLH to collect baseline data on nest success, productivity, and cowbird parasitism rate. There were 33 completed nests monitored in 26 territories; 10 were successful (30 percent). Of the 23 failed nests, 14 were depredated, 5 failed for unknown reasons, and 4 failed because of cowbird parasitism. There were 33 fledglings confirmed in monitored territories, yielding a seasonal productivity of 1.3 young/pair (33 young/26 monitored pairs). One additional fledgling was confirmed in an unmonitored territory during surveys at VLH. Based on 31 nests in which the contents were observed during the egg stage, 23 percent of nests in 2025 were parasitized. In two additional territories where nests were not located, adult flycatchers were observed feeding a cowbird fledgling.

Evaluation of nutrient, alkalinity, and acid-neutralizing capacity stabilities in water samples analyzed by the U.S. Geological Survey National Water Quality Laboratory, 2023–24

Struzeski, Tedmund M.; Wetherbee, Gregory A.; Morrison, Jonathan — Mon, 8 Jun 2026 18:27:12

The U.S. Geological Survey evaluated the stability of water-sample chemical analysis of nutrient, alkalinity, and acid-neutralizing capacity constituents with respect to the duration between sample collection and laboratory analysis, also known as the sample holding time. A study began in the spring of 2023 to evaluate the sample stability, between 2 and 180 days after sample collection, of the chemical properties and chemical constituents of alkalinity as calcium carbonate, filtered; acid-neutralizing capacity as calcium carbonate, unfiltered; total ammonia as nitrogen, filtered; total ammonia plus organic nitrogen as nitrogen, filtered and unfiltered; nitrite as nitrogen, filtered; nitrate plus nitrite as nitrogen, filtered; total nitrogen, filtered and unfiltered; orthophosphate as phosphorous, filtered; and total phosphorus as phosphorus (filtered and unfiltered) in water. Both surface water and groundwater matrices were represented.

Sample instability varied by observed property and matrix; therefore, providing general guidance for sample holding time is not possible based on matrices alone. No correlations between field measurements of sample characteristics and sample instability were observed. Although observations for some properties indicate sample stability that exceeds the recognized U.S. Geological Survey National Water Quality Laboratory method holding times, this is not necessarily the case for matrices and seasonal characteristics that were not investigated.

Based on the limited number of six sample sources used in this study, some patterns emerge for the 12 observed properties studied. Five observed properties generally indicate stability for as many as 180 days after sampling (total nitrogen as nitrogen, both filtered and unfiltered; orthophosphate as phosphorus, filtered; and phosphorus as phosphorus, both filtered and unfiltered). Other observed properties indicate stability for as many as 180 days for some matrices, but not for others. Finally, some observed properties indicate instability well before 180 days.

Spatial and temporal trends of mercury in fish from Duck Valley Reservation Reservoirs, southwestern Idaho and northern Nevada, 2007–24

Murray, Erin — Mon, 8 Jun 2026 16:38:33

The Shoshone-Paiute (Sho-Pai) Tribes of the Duck Valley Reservation, Nevada, manage reservoirs that support commercial and recreational activities, including robust Oncorhynchus mykiss (rainbow trout) fisheries that attract anglers year-round. Reservoirs are common environments for methylation and bioaccumulation of mercury, which is a potent neurotoxin when elevated levels are consumed. The U.S. Geological Survey (USGS), in cooperation with the Sho-Pai Tribes, measured total mercury concentrations in the muscle tissue of rainbow trout from three Reservation reservoirs in Idaho and Nevada in 2007, 2009, 2013, and 2024. This report highlights spatial and temporal trends of mercury concentrations in rainbow trout in the Duck Valley Reservation reservoirs from 2007 through 2024, and presents limited data on other commonly consumed species, specifically Perca flavescens (yellow perch), Micropterus dolomieu (smallmouth bass), and Micropterus salmoides (largemouth bass). Mercury data are also presented for nearby sites and lower trophic level species. In 2024, two fish sampling methods were used and compared: biopsy muscle plugs and muscle fillets. Results show good agreement between mercury concentrations of biopsy and fillet muscle samples taken from the same fish, with most sample pairs differing by less than 20 percent, though biopsied fish had an unexpectedly high mortality rate. Mercury concentrations increased in Sheep Creek Reservoir during the study period, but no significant trend was observed in Mountain View Reservoir or Lake Billy Shaw. Only 1 rainbow trout out of 160 sampled in the Reservation reservoirs during the study period exceeded the U.S. Environmental Protection Agency’s recommended methylmercury criterion of 0.3 milligram per kilogram of wet weight (mg/kg ww). Largemouth bass, smallmouth bass, and yellow perch had higher mercury concentrations than rainbow trout and may pose a greater risk to consumers. Mercury concentrations in largemouth bass exceeded 0.3 mg/kg ww, although only two fish were sampled, both from Sheep Creek Reservoir. Fish consumption advisories on Tribal lands are determined by the Tribes, and these results may help Sho-Pai managers determine the mercury exposure risk to Tribal members and visiting anglers.

Magnitude and frequency of peak and low flows in the Elkhorn River Basin, Nebraska, 1881–2022

Strauch, Kellan R.; Dietsch, Benjamin — Mon, 8 Jun 2026 17:31:38

Flood-frequency analysis is based on records of annual maximum instantaneous flows observed at long-term streamgages with 10 years or more of operation. Since the last flood-frequency analysis in Nebraska, an additional 30 years of annual peak-flow data have become available, and new flood-frequency analysis techniques have been developed. Moreover, the Elkhorn River Basin in north-central and eastern Nebraska has experienced two of the three highest magnitude floods on record in 2010 and 2019. The U.S. Geological Survey, in cooperation with the Nebraska Department of Transportation, analyzed flow frequency at streamgages in the Elkhorn River Basin in Nebraska.

Flow data from the U.S. Geological Survey and the Nebraska Department of Water, Energy, and Environment annual hydrographic reports were utilized to analyze peak flows. The Peak flow FreQuency (PeakFQ) software was used to perform a flood-frequency and nonstationarity analysis on the selected streamgages in the Elkhorn River Basin in Nebraska. Results of the peak-flow nonstationarity analysis indicate that, of the 23 streamgages analyzed for peak-flow frequency, 4 showed trends that were likely increasing for annual peak flows, whereas 3 indicated trends that were somewhat likely to be increasing. For 11 streamgages, the trend was categorized as about as likely as not, meaning there is less than a 70-percent chance of the trend being either upward or downward. Additionally, 2 streamgages exhibited trends that were somewhat likely to be decreasing, and 3 streamgages showed trends that were likely decreasing.

Low-flow streamflows and nonstationarity in the Elkhorn River Basin were analyzed for low flow periods representing the 1-day, 7-day, and 30-day flows at 21 streamgages using the Hydrologic Toolbox software. Spatially, the nonstationarity analysis results indicated likely increasing or somewhat increasing trend likelihoods for the 1-day, 7-day, and 30-day low flows for many of the Elkhorn streamgages downstream from the Elkhorn River at Ewing, Nebr., streamgage (U.S. Geological Survey station 06797500) and on eastern tributaries during the period of record.

Open water control of invasive mussels using benthic mats—Part 1, short-term infusion of carbon dioxide under a mat

Mon, 8 Jun 2026 16:46:20

This study compared the efficacy of a benthic mat alone with carbon dioxide infusion under a mat for killing Dreissena polymorpha (Pallas, 1771) (zebra mussel). Three sites were selected in Loon Lake, Sleeping Bear Dunes National Lakeshore, Benzie County, Michigan, for replication of reference, benthic mat, and carbon dioxide mat treatments. Within a site, three 4-meter (m) x 4-m plots were delineated for each treatment and a reference. Pretreatment samples were collected to estimate zebra mussel density and macroinvertebrate community composition in reference plots. Zebra mussels (about 360) from outside of the treatment plots were caged and placed in the plots before treatment. Benthic mats (4.25 m x 4.25 m; polyethylene with a vinyl coating) were anchored on the lake bottom with sandbags and weights. Carbon dioxide was infused under a mat of the same material to a maximum of 200 milligrams per liter (mg/L; pH=6.13) every 2–4 hours, for about 12 hours. Benthic and carbon dioxide mats were deployed for 5 days. One day after mat removal, we assessed mortality of resident and sentinel caged zebra mussels and macroinvertebrate community abundance and diversity in each plot. Average pH (as a proxy for carbon dioxide) under the carbon dioxide mats was between 6.38 and 6.80, equivalent to 170.5 and 103.0 mg/L carbon dioxide, respectively. In the posttreatment survey, few zebra mussels were observed in the benthic mat and carbon dioxide treatment plots compared to the reference plots; survival was lowest in the carbon dioxide plots. Mortality of sentinel caged mussels was greater than 80 percent in carbon dioxide treatments compared to mean mortalities of 20.6 percent and 12.7 percent in the benthic mat and reference plots, respectively. Macroinvertebrate community total abundance was lower in both mat treatments compared to reference plots, but diversity was comparable among all treatments. Our study demonstrated that carbon dioxide treatment near 200 mg/L could produce greater than 80-percent mortality of zebra mussels within 5 days. Refinement of the carbon dioxide mat and delivery system could increase spatial coverage of the treatment and broaden its use to other habitats.

Remotely sensed surface water storage shows distinct patterns from SWAT-simulated data

Tue, 9 Jun 2026 16:29:25

Quantifying and projecting the downstream benefits of water stored in lakes and wetlands (SW_storage) requires watershed hydrologic models, which often parameterize surface water storage in topographic depressions using static digital elevation model (DEM) data. Calibration and validation of modeled SW_storage dynamics using external data sets is uncommon, particularly across major river basins, with model calibration typically focused on observed discharge. Here, we develop and assess a novel remote sensing-based (RS) SW_storage data set (Sentinel-1 and Sentinel-2) for verifying simulated SW_storage estimates from a Soil and Water Assessment Tool (SWAT) model of the Upper Mississippi River Basin (UMRB; ∼440,000 km²). Our results suggest that static DEM-based parameterization as well as model calibration based solely on discharge do not adequately capture spatial and temporal SW_storage dynamics in the UMRB. Mean SW_storage as estimated by SWAT was 74% ± 122% (mean ± standard deviation) higher than RS SW_storage, where SW_storage in SWAT was underestimated in wetland-rich subbasins and overestimated in agricultural, tile-drained subbasins. Time series of SWAT SW_storage and RS SW_storage were positively correlated in only 38.8% of subbasins. As RS SW_storage is also vulnerable to error, storage estimates were compared to bathymetric data in select small wetlands. While uncertainty remains in the conversion from extent to storage for RS SW_storage, the method and data set presented here are a promising option for improved parameterization and calibration of SW_storage processes in SWAT and other process-based hydrologic models. Further consideration of these storage processes can potentially improve the accuracy of simulated streamflow in wetland-rich model domains.

Scenarios to assess the future water availability in the Mississippi River Valley Alluvial Aquifer for the Cache River and Grand Prairie Regions of Arkansas

Tue, 16 Jun 2026 13:41:01

The U.S. Geological Survey, as part of the Arkansas Groundwater Initiative, developed forecast scenarios using previously calibrated MODFLOW 6 groundwater models that focused on the Cache and Grand Prairie Critical Groundwater Areas to assess the impact of future climate and water management strategies on the Mississippi River Valley alluvial aquifer. A Soil Water Balance model was used to forecast recharge and irrigation water use. The forecast scenario period was from January 1, 2019, through December 31, 2055, with monthly stress periods. Twenty scenarios were simulated and included seven alternate climate forecasts, five 13 general groundwater pumping reduction scenarios (round 1), and groundwater pumping reduction scenarios by crop type and for the Bayou Meto Water Management Project and Grand Prairie Area Demonstration Project (round 2). Declines in saturated thickness within the Cache Critical Groundwater Area were larger for 18 of the 20 scenarios as compared to outside of the Critical Groundwater Area. The largest average increase in saturated thickness inside the Critical Groundwater Area was 6.4 m which occurred for the round 1, 50 percent reduction scenario. Automatic reductions in groundwater pumping by MODFLOW 6 in the Cache simulation ranged from 0.02 to 13.1 percent of total groundwater pumping. For the Grand Prairie model domain, the average change in saturated thickness of the Mississippi River Valley alluvial aquifer inside the Critical Groundwater Area for the forecast period ranged between -6.6 to 1.7 m. The average saturated thickness of the Mississippi River Valley alluvial aquifer inside the Grand Prairie Critical Groundwater Area declined for 16 of the 20 scenarios. The average reduction in requested groundwater pumping for all scenarios inside the Grand Prairie Critical Groundwater Area was 25.1 percent, and the largest reduction was 46.5 percent.

PFAS remediation in a bioelectrochemical system inoculated with the west branch consortium (WBC-2)

Yang, Haoran; Lorah, Michelle; Bender, Kelly; Xia, Chunjie; Sun, Jiasi; Liu, Jia — Tue, 9 Jun 2026 15:12:13

Groundwater contamination by per- and polyfluoroalkyl substances (PFAS) poses a persistent environmental and public health concern. This study evaluates a two-chambered bioelectrochemical system (BES) inoculated with the West Branch Consortium (WBC-2) for PFAS remediation. Under an applied cathodic potential of −450 mV (versus Ag/AgCl), the BES with active WBC-2 achieved >99.0% perfluorooctanesulfonic acid (PFOS) removal within 21 days in deionized water with culture medium and > 98.9% removal of PFOS, perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxA), and perfluorohexanesulfonic acid (PFHxS) in contaminated groundwater after 102 days. Intermediate formation (e.g., PFOA, 6:2 fluorotelomer sulfonate (6:2 FTS), perfluoropropionic acid (PFPrA), perfluorobutanoic acid (PFBA)) and background-corrected fluoride release were consistent with PFOS transformation under anaerobic reducing conditions potentially involving defluorination. Following repeated PFOS spikes (100 μg/L on Days 0, 50, and 399), PFOA, PFPrA, and PFBA accumulated over 664 days. Despite being the dominant accumulated compound, PFOA accounted for <1.8% of the total spiked PFOS mass. Minimal PFOS transformation occurred in controls without active WBC-2, highlighting the importance of microbial metabolism. Biofilm analysis revealed dense colonization of rod-shaped bacteria on carbon fiber brushes. Enrichment of Bacillus, Agrobacterium, and other low-abundance taxa suggests selective adaptation to BES and PFAS conditions. These findings highlight BES driven by electrochemically stimulated microbial activity as a promising strategy for PFAS remediation.

Widespread reproductive deficits in Chesapeake Bay ospreys

Thu, 11 Jun 2026 14:25:15

Introduction:

Ospreys (Pandion haliaetus) are well-known sentinels of aquatic ecosystem health and are indicators of both environmental contaminants and fish stocks. The Chesapeake Bay supports one of the largest osprey breeding populations in the world, but recent studies have documented declining reproductive performance and increasing food stress in some portions of the estuary.

Methods:

We monitored osprey nests (N = 571) throughout the Chesapeake Bay during the 2024 breeding season and compared breeding metrics between high-salinity (>10 parts per thousand [ppt]) and low-salinity (<5 ppt) study areas. We also compared contemporary breeding performance within four high-salinity sites to historical data collected during the 1980s.

Results:

Salinity was strongly associated with breeding performance and the likelihood that pairs achieved productivity levels required for population maintenance. All high-salinity study areas functioned as demographic sinks, whereas low-salinity areas functioned as demographic sources. Breeding metrics including the proportion of pairs breeding, clutch size, nesting failure, brood reduction, and nestling loss all suggested greater food stress within high-salinity areas. Temporal comparisons documented substantial declines in reproductive performance between the 1980s and 2024 within high-salinity study sites. High-salinity sites during the 1980s exhibited breeding performance comparable to low-salinity sites in 2024.

Discussion:

Although several factors may influence osprey productivity within the Chesapeake Bay, we suggest that reduced availability of Atlantic menhaden (Brevoortia tyrannus) is a primary driver of poor reproductive performance within high-salinity waters.

High-resolution magnetic survey using an unoccupied aerial vehicle to constrain buried lava flow geometry, volume, and eruptive history of Little Cones, Crater Flat, Nevada

Wed, 17 Jun 2026 00:41:00

Magnetic surveys are an important tool used to augment geologic mapping in distributed volcanic fields. Using magnetic anomalies, it is possible to model the geometry of shallowly buried volcanic features, such as conduits, sills, and lava flows. This subsurface mapping is important for understanding eruption dynamics and emplacement of lava flows, and it sometimes reveals buried volcanoes no longer visible at the surface. These data are critical to better interpret the numbers, styles, and magnitudes of eruptions in distributed volcanic fields and their associated volcanic hazards. New advances in unoccupied aerial vehicles (UAVs) offer an attractive middle range of resolution and aerial coverage between ground-based magnetic surveys and aeromagnetic surveys.

Here, we present the results of a UAV fluxgate magnetic survey of the Little Cones, Nevada, scoria cones, which have been the target of previous ground and aeromagnetic surveys. The magnetic anomalies at Little Cones are of interest because the surrounding alluvium conceals lava flows that erupted from Little Cones, making it very difficult to understand the volume and morphology of lava flows from geologic mapping alone. Nonlinear inversion of UAV-collected magnetic data were used to model the thickness and morphology of buried Little Cones’ lava flows with higher precision than achieved previously. The sequence of events and calculated flow characteristics are then interpreted. The total volume of Little Cones, including concealed lava flows, is approximately 0.016 cubic kilometer, and the initial sheet flow erupted in less than 24 hours. The findings presented herein demonstrate that UAV-based magnetic surveys are a reliable method of data collection and an efficient alternative to other survey methods, facilitating development of a three-dimensional perspective of distributed volcanic fields.

Fluvial sediment data for Iowa—Suspended-sediment concentrations, loads and sizes; bed-material sizes; and reservoir siltation

Schuetz, Joel; Matthes, Wilbur — Mon, 8 Jun 2026 18:12:28

This report is a compilation of the fluvial sediment data collected and published by the U.S. Geological Survey and other Federal agencies for the State of Iowa. The compilation includes daily extremes, monthly summaries, particle-size analyses of suspended-sediment, particle-size analyses of bed materials at some daily suspended-sediment stations, suspended-sediment concentrations and loads for samples collected at periodic and miscellaneous sites, and reservoir sedimentation studies on streams.