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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 973 records · Page 54Linked to original sources
USGS2013

Analytical properties of some commercially available nitrate reductase enzymes evaluated as replacements for cadmium in automated, semiautomated, and manual colorimetric methods for determination of nitrate plus nitrite in water

A multiyear research effort at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) evaluated several commercially available nitrate reductase (NaR) enzymes as replacements for toxic cadmium in longstanding automated colorimetric air-segmented continuous-flow analyzer (CFA) methods for determining nitrate plus nitrite (NO x ) in water. This research culminated in USGS approved standard- and low-level enzymatic reduction, colorimetric automated discrete analyzer NO x methods that have been in routine operation at the NWQL since October 2011. The enzyme used in these methods (AtNaR2) is a product of recombinant expression of NaR from Arabidopsis thaliana (L.) Heynh. (mouseear cress) in the yeast Pichia pastoris. Because the scope of the validation report for these new automated discrete analyzer methods, published as U.S. Geological Survey Techniques and Methods 5–B8, was limited to performance benchmarks and operational details, extensive foundational research with different enzymes—primarily YNaR1, a product of recombinant expression of NaR from Pichia angusta in the yeast Pichia pastoris—remained unpublished until now. This report documents research and development at the NWQL that was foundational to development and validation of the discrete analyzer methods. It includes: (1) details of instrumentation used to acquire kinetics data for several NaR enzymes in the presence and absence of known or suspected inhibitors in relation to reaction temperature and reaction pH; and (2) validation results—method detection limits, precision and bias estimates, spike recoveries, and interference studies—for standard- and low-level automated colorimetric CFA-YNaR1 reduction NO x methods in relation to corresponding USGS approved CFA cadmium-reduction (CdR) NO x methods. The cornerstone of this validation is paired sample statistical and graphical analysis of NOx concentrations from more than 3,800 geographically and seasonally diverse surface-water and groundwater samples that were analyzed in parallel by CFA-CdR and CFA enzyme-reduction methods. Finally, (3) demonstration of a semiautomated batch procedure in which 2-milliliter analyzer cups or disposable spectrophotometer cuvettes serve as reaction vessels for enzymatic reduction of nitrate to nitrite prior to analytical determinations. After the reduction step, analyzer cups are loaded onto CFA, flow injection, or discrete analyzers for simple, rapid, automatic nitrite determinations. In the case of manual determinations, analysts dispense colorimetric reagents into cuvettes containing post-reduction samples, allow time for color to develop, insert cuvettes individually into a spectrophotometer, and record percent transmittance or absorbance in relation to a reagent blank. Data presented here demonstrate equivalent analytical performance of enzymatic reduction NO x methods in these various formats to that of benchmark CFA-CdR NO x methods.

Scientific Investigations Report↗
USGS2026

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

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.

Hawaii↗
USGS2014

Modeling marbled murrelet (Brachyramphus marmoratus) habitat using LiDAR-derived canopy data

LiDAR (Light Detection And Ranging) is an emerging remote-sensing tool that can provide fine-scale data describing vertical complexity of vegetation relevant to species that are responsive to forest structure. We used LiDAR data to estimate occupancy probability for the federally threatened marbled murrelet ( Brachyramphus marmoratus ) in the Oregon Coast Range of the United States. Our goal was to address the need identified in the Recovery Plan for a more accurate estimate of the availability of nesting habitat by developing occupancy maps based on refined measures of nest-strand structure. We used murrelet occupancy data collected by the Bureau of Land Management Coos Bay District, and canopy metrics calculated from discrete return airborne LiDAR data, to fit a logistic regression model predicting the probability of occupancy. Our final model for stand-level occupancy included distance to coast, and 5 LiDAR-derived variables describing canopy structure. With an area under the curve value (AUC) of 0.74, this model had acceptable discrimination and fair agreement (Cohen's κ = 0.24), especially considering that all sites in our sample were regarded by managers as potential habitat. The LiDAR model provided better discrimination between occupied and unoccupied sites than did a model using variables derived from Gradient Nearest Neighbor maps that were previously reported as important predictors of murrelet occupancy (AUC = 0.64, κ = 0.12). We also evaluated LiDAR metrics at 11 known murrelet nest sites. Two LiDAR-derived variables accurately discriminated nest sites from random sites (average AUC = 0.91). LiDAR provided a means of quantifying 3-dimensional canopy structure with variables that are ecologically relevant to murrelet nesting habitat, and have not been as accurately quantified by other mensuration methods.

Oregon↗
USGS2010

The age of the Keystone thrust: Laser-fusion 40Ar/39Ar dating of foreland basin deposits, southern Spring Mountains, Nevada

Nonmarine sedimentary and volcaniclastic foreland-basin deposits in the Spring Mountains of southern Nevada are cut by the Contact and Keystone thrusts. These synorogenic deposits, informally designated the Lavinia Wash sequence by Carr (1980), previously were assigned a Late Jurassic to Early Cretaceous(?) age. New 40 Ar/ 39 Ar laserfusion and incremental-heating studies of a tuff bed in the Lavinia Wash sequence support a best estimate age of 99.0±0.4 Ma, indicating that the Lavinia Wash sequence is actually late Early Cretaceous in age and establishing a maximum age for final emplacement of the Contact and Keystone thrust plates consistent with the remainder of the Mesozoic foreland thrust belt. The reinterpretation of the age of the Lavinia Wash sequence and the consequent limit on the age of foreland thrust faults in the southern Spring Mountains strengthen widely accepted correlations of the Contact-Red Springs and Keystone thrusts with the Cretaceous Summit-Willow Tank and Muddy Mountain-Glendale thrusts in the Muddy Mountains. These correlations were partly in conflict with previously reported ages and geologic interpretations of structures in the Spring Mountains.

Nevada↗
USGS2008

Comparisons of Simulated Hydrodynamics and Water Quality for Projected Demands in 2046, Pueblo Reservoir, Southeastern Colorado

Pueblo Reservoir is one of southeastern Colorado's most valuable water resources. The reservoir provides irrigation, municipal, and industrial water to various entities throughout the region. The reservoir also provides flood control, recreational activities, sport fishing, and wildlife enhancement to the region. The Bureau of Reclamation is working to meet its goal to issue a Final Environmental Impact Statement (EIS) on the Southern Delivery System project (SDS). SDS is a regional water-delivery project that has been proposed to provide a safe, reliable, and sustainable water supply through the foreseeable future (2046) for Colorado Springs, Fountain, Security, and Pueblo West. Discussions with the Bureau of Reclamation and the U.S. Geological Survey led to a cooperative agreement to simulate the hydrodynamics and water quality of Pueblo Reservoir. This work has been completed and described in a previously published report, U.S. Geological Survey Scientific Investigations Report 2008-5056. Additionally, there was a need to make comparisons of simulated hydrodynamics and water quality for projected demands associated with the various EIS alternatives and plans by Pueblo West to discharge treated water into the reservoir. Plans by Pueblo West are fully independent of the SDS project. This report compares simulated hydrodynamics and water quality for projected demands in Pueblo Reservoir resulting from changes in inflow and water quality entering the reservoir, and from changes to withdrawals from the reservoir as projected for the year 2046. Four of the seven EIS alternatives were selected for scenario simulations. The four U.S. Geological Survey simulation scenarios were the No Action scenario (EIS Alternative 1), the Downstream Diversion scenario (EIS Alternative 2), the Upstream Return-Flow scenario (EIS Alternative 4), and the Upstream Diversion scenario (EIS Alternative 7). Additionally, the results of an Existing Conditions scenario (water years 2000 through 2002) were compared to the No Action scenario (projected demands in 2046) to assess changes in water quality over time. All scenario modeling used an external nutrient-decay model to simulate degradation and assimilation of nutrients along the riverine reach upstream from Pueblo Reservoir. Reservoir modeling was conducted using the U.S. Army Corps of Engineers CE-QUAL-W2 two-dimensional water-quality model. Lake hydrodynamics, water temperature, dissolved oxygen, dissolved solids, dissolved ammonia, dissolved nitrate, total phosphorus, algal biomass, and total iron were simulated. Two reservoir site locations were selected for comparison. Results of simulations at site 3B were characteristic of a riverine environment in the reservoir while results at site 7B (near the dam) were characteristic of the main body of the reservoir. Simulation results for the epilimnion and hypolimnion at these two sites also were evaluated and compared. The simulation results in the hypolimnion at site 7B were indicative of the water quality leaving the reservoir. Comparisons of the different scenario results were conducted to assess if substantial differences were observed between selected scenarios. Each of the scenarios was simulated for three contiguous years representing a wet, average, and dry annual hydrologic cycle (water years 2000 through 2002). Additionally, each selected simulation scenario was evaluated for differences in direct- and cumulative-effects on a particular scenario. Direct effects are intended to isolate the future effects of the scenarios. Cumulative effects are intended to evaluate the effects of the scenarios in conjunction with all reasonably foreseeable future activities in the study area. Comparisons between the direct- and cumulative-effects analyses indicated that there were not large differences in the results between most of the simulation scenarios and, as such, the focus of this report was on results for the direct-effects analysis. Addi

Scientific Investigations Report↗
USGS1983

Middle and Late Ordovician solitary rugose corals of the Cincinnati Arch region

Middle Ordovician (Kirkfieldian) solitary rugose corals have been reported from the Tyrone Limestone of the High Bridge Group and the Curdsville Limestone Member of the Lexington Limestone in central Kentucky. Lambeophyllum? spp. A and B are recognized in the Tyrone Limestone. Grewingkia canadensis (Billings, 1862) and Streptelasma divaricans (Nicholson, 1875b) are the only solitary Rugosa known from the Upper Ordovician in the Cincinnati Arch region of Kentucky-Indiana-Ohio. Their earliest occurrence suggests introduction during an early Richmondian transgression. The two species have similar distributions; they favored normal marine waters of intermediate depth where calcium carbonate sediments accumulated and brachiopods and bryozoans thrived. G. canadensis probably lived in stable, low-energy environments, but the corals were transported during higher energy conditions before final deposition and rapid burial. S. divaricans was epifaunal on stabilized carbonate substrates during periods of nondeposition. Energy conditions remained low, and subsequent, usually argillaceous sediments often buried these corals in growth position. G. canadensis and S. divaricans attained their greatest diameter and length, respectively, on the southwestern side of the Cincinnati Arch region. The average number of septa in G. canadensis generally increased during Richmondian time, and simpler axial regions became more predominant in both species. These trends may be related to decreasing water depth. G. canadensis and S. divaricans are confined to the Richmond Solitary Coral Province, which formed a narrow belt extending from the Nashville Dome, along the Cincinnati Arch region to northern Michigan, and through southern Ontario and Quebec. The Red River-Stony Mountain Solitary Coral Province occupied the remainder of North America during the Richmondian. Because the taxa in these provinces are different, solitary corals cannot now be used to correlate strata outside the geographically restricted Richmond Province with the North American Upper Ordovician type sections in the Cincinnati Arch region. G. canadensis and S. divaricans became extinct during regression of the epicontinental sea at the end of Richmondian time.

Professional Paper↗
USGS2021

Perspectives from natural resource professionals: Attitudes on lead ammunition risks and use of nonlead ammunition

Hunting is a popular activity but continued use of lead ammunition poses risks to wildlife and human health. To inform adoption of the voluntary use of nonlead ammunition, natural resource professionals were surveyed to understand their attitudes about threats to bald eagles, lead poisoning in bald eagles, human health risks from lead bullet fragments in venison, use of nonlead hunting ammunition, and socio-economic nonlead ammunition factors. Differences were examined by hunter status, ammunition type used, and intentions to use nonlead ammunition. Of participants surveyed, 61.0% were hunters and 39.0% nonhunters, with 59.5% of hunters using lead ammunition and 40.5% using nonlead. Concurrently, 68.5% of hunters reported likely intentions to continue using nonlead or convert to nonlead in the future, while 31.5% reported nonlead use was unlikely. Also, some hunters currently using nonlead ammunition indicated they would unlikely continue using nonlead (17.8%). Nonhunters agreed more strongly than hunters regarding general mortality threats to bald eagles. Additionally, nonhunters, hunters using nonlead, and likely nonlead users more strongly agreed about threats of lead exposure to eagles than their counterparts. Nonhunters and likely nonlead users also more strongly agreed than hunters and unlikely nonlead users about the human health risks of lead ammunition and about shooting characteristics of nonlead. Finally, nonhunters and nonlead users agreed more strongly than their counterparts about the socio-economic factors of using nonlead ammunition. Understanding natural resource professional hunters’ attitudes may help with audience segmentation when designing future nonlead outreach messages.

Journal of Outdoor Recreation and Tourism↗
USGS2018

Structural evolution of a gold-bearing transtensional zone within the Archean Porcupine-Destor deformation zone, southern Abitibi greenstone belt, eastern Ontario, Canada

The Garrison camp comprises four structurally distinct orogenic gold deposits that formed in different host lithologies during progressive deformation. Detailed field mapping, drill core logging, and geochronological constraints suggest that the 2678 ± 2 Ma Garrison granitic stock played a fundamental rheological role in the location of the four deposits. Initial local shear movement occurred along the southwestern margin of the stock leading to the development of the NW-trending sinistral NE-side-up Buffonta shear zone, which hosts the Buffonta deposit. Subsequently, a transtensional zone formed between the NE-trending sinistral Porcupine-Destor and Munro deformation zones, which host the 903 and Jonpol deposits, respectively. Finally, a local change in shortening orientation from NE to NNW caused westerly directed extension resulting in the formation of the younger gold-bearing veins composing the Garrcon deposit. In situ U-Pb laser ablation-inductively coupled plasma-mass spectrometry performed on monazite grains formed within the shear fabric of the Munro deformation zone indicates that transtension occurred at 2657 ± 15 Ma. Therefore, at least three of the four deposits formed subsequent to crystallization of the Garrison granitic stock. The reported U-Pb dates represent the first direct age constraints on the movement along a gold-bearing deformation zone in the southern Abitibi greenstone belt.

Ontario↗
USGS2013

An alternative to soil taxonomy for describing key soil characteristics

We are pleased to see the letter by Schimel and Chadwick (Front Ecol Environ 2013; 11[8]: 405–06), highlighting the importance of soil characterization in ecological and biogeochemical research and explaining the value of soil taxonomy, and we agree with the authors that reporting soil taxonomic classification would greatly increase the interpretive value of many studies. However, in our extensive work with land managers and scientists, we have found that taxonomic classifications are not particularly useful because they are poorly understood. For those unfamiliar with soil taxonomy, deconstructing the meaning of a classification is not a simple task. Furthermore, because the US system of soil taxonomy is not applied universally, its utility as a means for effectively describing soil characteristics to readers in other countries is limited. Finally, and most importantly, even at the finest level of soil classification there are often large within-taxa variations in critical properties that can determine ecosystem responses to drivers such as climate and land-use change.

Frontiers in Ecology and the Environment↗
USGS1947

Instructions for flood frequency compilations

These instructions are designed to facilitate work in this field, but are not to be considered as final and complete. They will be revised as needed to incorporate new ideas and experience gained in this field. For that reason, if use is planned any great period after the date shown on the cover, write the Chief Hydraulic Engineer for advice as to changes. Comments are always welcome.

Report↗
USGS1980

Quaternary stratigraphic sections with radiocarbon dates, Chandler Lake Quadrangle, Alaska

Twenty-eight organic samples from 17 localities in the Anaktuvuk, Tulunga, and Itkillik Valleys and at Shainin Lake range in age from more than 40,000 to about 1000 14C yr B.P. These dates, combined with fossil identifications and measured stratigraphic sections, provide significant insights into the history of glaciation, climatic change, and related events of late Quaternary time in the north-central Brooks Range. Two dates from Tulunga Valley show that peat-forming intervals during the middle Wisconsin and during an earlier period were terminated by episodes of loess accretion that probably correspond to glaciations in the Brooks Range. The Anayaknaurak Bluff exposure in Anaktuvuk Valley contains a weathered till of the Banded Mountain (Itkillik I) glaciation overlain by unweathered outwash gravel of Antler Valley (Itkillik II) age. Radiocarbon dates from finer alluvium above the outwash indicate that a subsequent glacial readvance north of the range front occurred shortly after 13,000 yr B.P. This event was synchronous with a major glacial readvance that culminated between about 12,900 and 12,700 yr B.P. farther east in the Atigun and Sagavanirktok Valleys. Additional dates from Anaktuvuk Valley show that glacier ice had retreated from the Antler Valley end-moraine complex by 10,600 yr B.P. The elongate basin that formed behind the moraine dam was being filled by alluvium at this time, and filling continued as late as 6200 yr B.P. near the range front. A possible climatic reversal during this interval is suggested by dates from Anaktuvuk Valley and from Toolik Valley farther east, which show peat formation between about 9500 and 8200 yr B.P. followed by solifluction and fan-building. Soil test pits and other excavations near Anaktuvuk Pass show that the pass was deglaciated some time prior to 7250 yr B.P., and was suitable for human habitation by at least 6500 yr B.P. Dated buried peat suggests a change to more severe frost climate sometime after about 4750 yr B.P. Other dates from the Chandler Lake quadrangle bear mainly on formation of low (generally 2.5 to 6 m) river terraces during intervals of renewed glaciation at valley heads during the late Holocene. Neoglaciation in the north-central Brooks Range evidently began about 3500 yr B.P., or at least was perceptible by this time as increased loess influx to sites north of the range front. Stream alluviation was in progress 2800-2700 yr B.P. at sites near Anaktuvuk Pass, and continued until sometime after 2000 yr B.P. Final phases of alluviation began about 1200 and 450 yr B.P. Independent dating of cirque-glacier advances by lichenometry supports the alluvial chronology and suggests that alluviation was controlled largely by increased sediment yield to streams during times of cirque-glacier expansion and increased rock-glacier activity.

Alaska↗
USGS2019

Intermountain west drought social science synthesis working group: Report to the National Climate Adaptation Science Center

Throughout the Intermountain West, there has been significant investment in understanding how social factors influence manager and citizen experiences of drought in particular locations. Yet there is still a gap in knowledge of how human dimensions of drought impacts, planning, and resilience are similar and different across cases and regions. Building on the natural science understanding developed by the USGS’ various ecological drought projects as well as a range of other place-based social science case studies of drought and its impacts, this project explored human dimensions of ecological drought across the intermountain west from a comparative, regional perspective. The Working Group brought together agency and university experts in the field of drought social science, including researchers affiliated with the North Central and South Central Climate Adaptation Science Centers (USGS), Western Water Assessment (a NOAA RISA program), the Northern Plains Climate Hub (USDA), and the USGS-supported SNAPP Ecological Drought Working Group. The group held three virtual meeting during Spring 2018 in preparation for an extended in-person workshop in June 2018 in Fort Collins, CO, followed by monthly calls to finalize products. The group’s objectives were to (1) integrate insights from existing social science studies of drought to identify commonalities and trends that generalize across cases while simultaneously accounting for the complexity experienced in particular places by individual decision makers, (2) develop a common lexicon and analytic framework for understanding drought across the Intermountain West from a social-ecological systems perspective, (3) identify emergent research themes, questions, and needs, (4) consider strategies for social scientists to contribute to drought management, (5) facilitate coordination among federal and university researchers for future collaborative activities, and (6) develop a typology of drought decision making that captured group insights. Project outputs included two conference sessions, a typology manuscript to be submitted by the end of FY19, and the conceptual framing of a rapid assessment methodology that was subsequently developed into a standalone project.

Cooperator Report↗
USGS2020

Kelp forest monitoring at Naval Base Ventura County, San Nicolas Island, California: Fall 2017 and Spring 2018, Fourth Annual Report

To assess and track changes to the rocky subtidal communities surrounding San Nicolas Island, the U.S. Navy entered into an agreement with the U.S. Geological Survey (USGS) in 2014 to conduct an ecological monitoring program at several sites around the island. Four permanent sites—Nav Fac 100, West End, Dutch Harbor, and Daytona 100—were established. The sites were based on ones that had been monitored since 1980 by USGS and were combined or expanded for better comparability with monitoring programs conducted at the other California Channel Islands. At the sites, scientists from USGS and our cooperator, the University of California, Santa Cruz, measured bottom cover of algae and sessile invertebrate species in quadrats, counted and sized fish on swimming transects, and counted a suite of kelps and invertebrates on benthic band transects. Holdfast diameter and number of stipes of giant kelp ( Macrocystis pyrifera ) were recorded on these transects, and size data were collected for urchins, sea stars, and shelled mollusks. Bottom temperatures were recorded at hourly intervals by archival data loggers that were deployed at the sites. This report focuses primarily on data collected in fall 2017 and spring 2018 and makes comparisons with data collected in previous years, beginning in fall 2014. Nav Fac 100 is a site with a relatively low benthic profile, situated on the north side of San Nicolas Island. It was previously urchin dominated but underwent a dramatic decline in purple sea urchins in 2015 and 2016. Since then, macroalgae has become more prevalent as both annual brown algae, such as Dictyota, and perennials (for example, Cystoseira ) have become established. The invasive brown alga Sargassum horneri has also become established. West End, on the southwest side of the island, also lacks much bottom relief but has more crevice habitat associated with boulders. It remains dominated by kelps and red algae, but red algae have decreased recently. Dutch Harbor, on the south side, has many high relief rocky reefs and had the greatest fish and non-motile invertebrate densities. It remains the most stable of the sites. Daytona 100, on the southeast side, has moderate relief and has remained a patchwork of kelp and urchin dominated areas with moderate fish density. The main change at the sites during the last 4 years was the decline in urchin numbers at Nav Fac 100. There was storm-related mortality and subsequent recruitment in the M. pyrifera population at several of the sites in both 2016 and 2017. The winter of 2018, however, was relatively mild, with less destructive storm-related disturbance. The invasive brown alga S. horneri , first seen at San Nicolas Island at Nav Fac 100 in fall 2015, has become firmly established there during the last 2 sampling years. Finally, moderate increases were observed in purple urchin densities at all sites this spring. Long-term data are presented to illustrate trends and changes over the past three decades. Results indicate continued monitoring to evaluate ecosystem effects from perturbations owing to natural processes and anthropomorphic factors, including recovery of the sea otter population, changes in fisheries, invasive species and changing environmental conditions, could be valuable to inform managers’ decision-making.

California↗
USGS2022

Assessment of significant sand resources in Federal and California State Waters of the San Francisco, Oceanside, and Silver Strand littoral cell study areas along the continental shelf of California

Executive Summary The Sand Resources Project was established through collaborative agreements between the U.S. Geological Survey (USGS), the Bureau of Ocean Energy Management (BOEM), and the California Ocean Protection Council (OPC) with the purpose of evaluating sand and gravel resources in Federal and California State Waters for potential use in future beach-nourishment projects. Project partners worked in collaboration with California Coastal Sediment Management Workgroup (CSMW) members to define priority study areas for this work based on the potential for finding sand within the broader region and the needs for this sand as shown by beach erosion areas of concern in the adjacent littoral cells. The final study areas were defined to be (1) the San Francisco Littoral Cell, (2) the Oceanside Littoral Cell, and (3) the Silver Strand Littoral Cell. A two-stage approach was used to assess the study areas. The initial stage was a synthesis of the existing geophysical and sediment-sampling data in each area. This allowed for evaluations of the data availability, data gaps, and general patterns of sediment thickness and grain size. This synthesis was published in a separate USGS open-file report (Warrick and others, 2022). The findings from this assessment were used to refine study area boundaries and develop sampling plans for stage two of the project. Stage two of the project is the collection, processing, and synthesis of new data, including high-resolution geophysical surveys and sediment cores—this report addresses the second stage. The work focuses on two of the study areas—the San Francisco and the Oceanside Littoral Cells, where several research cruises have been conducted. A more limited, exploratory approach was used for the Silver Strand Littoral Cell, owing to the lack of existing high-resolution bathymetric data for this study area. The data collected provide new information about the three study areas, including sediment thickness, grain-size distributions, and total organic carbon. Sediment in all three study areas of the Sand Resources Study was suitable for beach nourishment, as reflected by their grain-size distributions and sediment thicknesses. For example, sandy sediment in the San Francisco Littoral Cell study area was on and immediately outside of the ebb-tidal bar of the San Francisco Bay, a landform that has a strong influence on grain-size patterns of the region. The presence of thick sediment deposits in this area was interpreted to be a function of tectonics, which has caused physical features that include a graben north of the Golden Gate whose deposits were thicker and siltier than the remaining area. Sandy sediment on the inner and outer parts of the continental shelf in the Oceanside Littoral Cell may be useful for nourishment, whereas the midshelf between these areas was dominated by silty sediment. Sediment in the Silver Strand Littoral Cell, which was only sampled selectively, had the greatest potential for beach nourishment because of the greater prevalence of beach-comparable grain sizes, especially in the more distal and deeper areas where medium sands were found. The Sand Resources Project did identify several sandy regions of the continental shelf that are deeper than dredging technologies currently (2022) available in the United States, which are generally limited to 30 meters (m) water depth or less. Although sandy sediment exists in all three study areas at water depths of 30 m or less, additional sediment supplies—most of which are in Federal Waters—are present in deeper settings, especially for the Oceanside and Silver Strand Littoral Cell study areas. Although the Silver Strand Littoral Cell study area was found to be considerably replete in sand resources, these conclusions are based on a limited sampling exercise across that study area. Thus, it may be beneficial to complete a more thorough characterization of the sediment resources in the Silver Strand Littoral Cell study area if it is determined that a need for sandy coastal sediment exists in this region. As a result of the Sand Resources Project, several areas of sand resources in Federal and California State Waters were found where they were previously unknown. As such, this project may provide important data for future coastal-management decisions in California, and it should provide a model for future investigations of sediment resources in other regions of the State.

California↗
USGS2010

U.S. Geological Survey Streamgage Operation and Maintenance Cost Evaluation...from the National Streamflow Information Program

To help meet the goal of providing earth-science information to the Nation, the U.S. Geological Survey (USGS) operates and maintains the largest streamgage network in the world, with over 7,600 active streamgages in 2010. This network is operated in cooperation with over 850 Federal, tribal, State, and local funding partners. The streamflow information provided by the USGS is used for the protection of life and property; for the assessment, allocation, and management of water resources; for the design of roads, bridges, dams, and water works; for the delineation of flood plains; for the assessment and evaluation of habitat; for understanding the effects of land-use, water-use, and climate changes; for evaluation of water quality; and for recreational safety and enjoyment. USGS streamgages are managed and operated to rigorous national standards, allowing analyses of data from streamgages in different areas and spanning long time periods, some with more than 100 years of data. About 90 percent of USGS streamgages provide streamflow information real-time on the web. Physical measurements of streamflow are made at streamgages multiple times a year, depending on flow conditions, to ensure the highest level of accuracy possible. In addition, multiple reviews and quality assurance checks are performed before the data is finalized. In 2006, the USGS reviewed all activities, operations, equipment, support, and costs associated with operating and maintaining a streamgage program (Norris and others, 2008). A summary of the percentages of costs associated with activities required to operate a streamgage on an annual basis are presented in figure 1. This information represents what it costs to fund a 'typical' USGS streamgage and how those funds are utilized. It should be noted that some USGS streamgages have higher percentages for some categories than do others depending on location and conditions. Forty-one percent of the funding for the typical USGS streamgage is for labor costs of the USGS staff responsible for the measurement of the streamflow in the field and the time in the office to quality assure and finalize the data. It is reasonable that funding for the entire national streamgage network would closely follow the percentages shown in figure 1 as to how the funds are invested in the network. However, actual costs are specific to a particular streamgage and can vary substantially depending on location and operational issues.

Fact Sheet↗
USGS2009

Summary of Migration and Survival Data from Radio-Tagged Juvenile Coho Salmon in the Trinity River, Northern California, 2008

The survival of hatchery-origin juvenile coho salmon from the Trinity River Hatchery was estimated as they migrated seaward through the Trinity and Klamath Rivers. The purpose of the study was to collect data for comparison to a similar study in the Klamath River and provide data to the Trinity River Restoration Program. A total of 200 fish fitted with radio transmitters were released into the Trinity River near the hatchery (river kilometer 252 from the mouth of the Klamath River) biweekly from March 19 to May 28, 2008. Fish from the earliest release groups took longer to pass the first detection site 10 kilometers downstream of the hatchery than fish from the later release groups, but travel times between subsequent sites were often similar among the release groups. The travel times of individuals through the 239 kilometer study area ranged from 15.5 to 84.6 days with a median of 43.3 days. The data and models did not support differences in survival among release groups, but did support differences among river reaches. The probability of survival in the first 53 kilometers was lower than in the reaches farther downstream, which is similar to trends in juvenile coho salmon in the Klamath River. The lowest estimated survival in this study was in the first 10 kilometers from release in the Trinity River (0.676 SE 0.036) and the highest estimated survival was in the final 20 kilometer reach in the Klamath River (0.987 SE 0.013). Estimated survivals of radio-tagged juvenile coho salmon from release to Klamath River kilometer 33 were 0.639 per 100 kilometers for Trinity River fish and 0.721 per 100 kilometers for Klamath River fish.

Open-File Report↗
USGS2012

Use of real-time monitoring to predict concentrations of select constituents in the Menomonee River drainage basin, Southeast Wisconsin, 2008-9

The Menomonee River drainage basin in southeast Wisconsin is undergoing changes that may affect water quality. Several rehabilitation and flood-management projects are underway, including removal of concrete channels and the construction of floodwater retention basins. The city of Waukesha may begin discharging treated wastewater into Underwood Creek, thus approximately doubling the current base-flow discharge. In addition, the headwater basins, historically dominated by agriculture and natural areas, are becoming increasingly urbanized. In an effort to monitor these and future changes to the basin, the U.S. Geological Survey and the Milwaukee Metropolitan Sewerage District initiated a study in 2008 to develop regression models to estimate real-time concentrations and loads of selected water-quality constituents. Water-quality sensors and automated samplers were installed at five sites in the Menomonee River drainage basin. The sensors continuously measured four explanatory variables: water temperature, specific conductance, dissolved oxygen, and turbidity. Discrete water-quality samples were collected and analyzed for five response variables: chloride, total suspended solids, total phosphorus, Escherichia coli bacteria, and fecal coliform bacteria. Regression models were developed to continuously estimate the response variables on the basis of the explanatory variables. The models to estimate chloride concentrations all used specific conductance as the explanatory variable, except for the model for the Little Menomonee River near Freistadt, which used both specific conductance and turbidity as explanatory variables. Adjusted R 2 values for the chloride models ranged from 0.74 to 0.97. Models to estimate total suspended solids and total phosphorus used turbidity as the only explanatory variable. Adjusted R 2 values ranged from 0.77 to 0.94 for the total suspended solids models and from 0.55 to 0.75 for the total phosphorus models. Models to estimate indicator bacteria used water temperature and turbidity as the explanatory variables, with adjusted R 2 values from 0.54 to 0.69 for Escherichia coli bacteria models and from 0.54 to 0.74 for fecal coliform bacteria models. Dissolved oxygen was not used in any of the final models. These models may help managers measure the effects of land-use changes and improvement projects, establish total maximum daily loads, estimate important water-quality indicators such as bacteria concentrations, and enable informed decision making in the future.

Wisconsin↗
USGS2015

Efforts to eradicate yellow crazy ants on Johnston Atoll: Results from Crazy Ant Strike Team IX, December 2014-June 2015

The ecologically destructive yellow crazy ant (YCA; Anoplolepis gracilipes ) was first detected on Johnston Atoll in January 2010. Within eight months, the U.S. Fish and Wildlife Service had mobilized its first crazy ant strike team (CAST), a group of biologists dedicated to testing and identifying insecticidal baits to be used to eradicate the ant on the atoll. During December 2014‒May 2015 CAST IX focused on testing hydrogel crystals saturated with sucrose solution (25%) carrying the insecticides thiamethoxam and dinotefuran against YCA. A series of experiments, including artificial nest box trials, and field-based palatability trials and eradication tests on small (500 m2 or 0.05 ha) and large plots (2500 m2 or 0.25 ha), were conducted to test concentrations of thiamethoxam ranging from 0.0005% to 0.01%, and dinotefuran at 0.05%. Additionally, the cat food-based matrix containing dinotefuran (0.05%), the standard bait used to suppress YCA on Johnston since 2011, and textured vegetable protein (TVP) carrying dinotefuran at 0.1% and 0.05% were included in large plot tests. Nest box trials were inconclusive due to a consistent loss of queen and worker ants in control boxes, so they were discontinued. Palatability trials suggested higher dosages of thiamethoxam (0.005 and 0.01%) were less attractive than lower dosages (0.0005 and 0.001%) and controls (sucrose only), but small and large plot experiments failed to identify a thiamethoxam concentration that was consistently effective at killing YCA. In contrast, hydrogel containing dinotefuran was consistently effective, killing >95% of YCA on small and large plots. As expected, the cat food bait effectively reduced YCA abundances, but was slightly less effective than hydrogel containing dinotefuran over time. Three successive, approximately weekly treatments of large plots with hydrogel bait, or other baits followed by hydrogel bait, suggest an increasing overall effectiveness, with no aversion of YCA to the bait. This finding is important in that it indicates that hydrogel bait can be applied at short time intervals, potentially resulting in relatively constant exposure of YCA to highly attractive, yet toxic, sucrose-based bait. TVP performed similar to hydrogel, reducing YCA abundance >92% at both concentrations tested. Finally, dosages of hydrogel containing dinotefuran at 6, 12 and 24 l/0.25 ha were all effective at reducing YCA on large plots. Overall, results from these experiments suggest that hydrogel containing dinotefuran (0.05%) is a promising tool for eradicating YCA on Johnston Atoll.

Hawaii↗