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At least 1,333 records · Page 74Linked to original sources
USGS2016

Application of a Weighted Regression Model for Reporting Nutrient and Sediment Concentrations, Fluxes, and Trends in Concentration and Flux for the Chesapeake Bay Nontidal Water-Quality Monitoring Network, Results Through Water Year 2012

In the Chesapeake Bay watershed, estimated fluxes of nutrients and sediment from the bay’s nontidal tributaries into the estuary are the foundation of decision making to meet reductions prescribed by the Chesapeake Bay Total Maximum Daily Load (TMDL) and are often the basis for refining scientific understanding of the watershed-scale processes that influence the delivery of these constituents to the bay. Two regression-based flux and trend estimation models, ESTIMATOR and Weighted Regressions on Time, Discharge, and Season (WRTDS), were compared using data from 80 watersheds in the Chesapeake Bay Nontidal Water-Quality Monitoring Network (CBNTN). The watersheds range in size from 62 to 70,189 square kilometers and record lengths range from 6 to 28 years. ESTIMATOR is a constant-parameter model that estimates trends only in concentration; WRTDS uses variable parameters estimated with weighted regression, and estimates trends in both concentration and flux. WRTDS had greater explanatory power than ESTIMATOR, with the greatest degree of improvement evident for records longer than 25 years (30 stations; improvement in median model R 2 = 0.06 for total nitrogen, 0.08 for total phosphorus, and 0.05 for sediment) and the least degree of improvement for records of less than 10 years, for which the two models performed nearly equally. Flux bias statistics were comparable or lower (more favorable) for WRTDS for any record length; for 30 stations with records longer than 25 years, the greatest degree of improvement was evident for sediment (decrease of 0.17 in median statistic) and total phosphorus (decrease of 0.05). The overall between-station pattern in concentration trend direction and magnitude for all constituents was roughly similar for both models. A detailed case study revealed that trends in concentration estimated by WRTDS can operationally be viewed as a less-constrained equivalent to trends in concentration estimated by ESTIMATOR. Estimates of annual mean flow-adjusted (ESTIMATOR) and flow-normalized (WRTDS) concentration for years initially constituting the end of a water-quality record showed a similar degree of variability as data for additional years were incrementally added and the initial estimates “aged.” On the basis of the results of this broad comparison of the two models, the U.S. Geological Survey is adopting WRTDS as the primary model for estimating constituent fluxes and trends throughout the CBNTN. Nutrient and sediment flux and trend estimates, based on WRTDS, are summarized narratively and tabulated in appendixes for all stations for which fluxes or trends were reported through water year 2012. WRTDS also was used to explore the sensitivity of flux and trend estimates to three data-quality issues common in many large-scale monitoring networks and evident in some of the CBNTN records. The potential effects of inconsistency in annual sampling effort and inconsistency in storm sampling effort were explored by way of a subsampling experiment using eight of the most densely sampled long-term (1985–2012) stations in the CBNTN as baseline datasets. From each dataset, a set of 10 “design guideline” subsamples was selected, consisting of 12 monthly samples and 8 targeted storm samples per year. The selection was conducted in a manner that preserved the overall intensity of storm sampling in the baseline data. These 10 subsamples were further manipulated to create “heterogeneous” subsamples by removing storm samples prior to 2003. The maximum relative difference between flow-normalized flux estimated in a single year from any of the 10 design guideline subsamples and values estimated in the corresponding year from baseline data was smallest for dissolved inorganic nitrogen (median of 8 stations = 6 percent of baseline estimate), but more appreciable for total phosphorus and sediment (medians of 22 and 32 percent, respectively). The maximum relative difference between flow-normalized flux estimated from from the 10 heterogeneous subsamples and values estimated in the corresponding year from baseline data was more pronounced, with medians for 8 stations of 15, 30, and 53 percent of the corresponding baseline estimates for dissolved inorganic nitrogen, total phosphorus, and sediment, respectively. The worst-case maximum relative differences between flow-normalize flux estimated in a single year from the 10 heterogeneous subsamples and values estimated in the corresponding year from baseline data were 25 percent for dissolved inorganic nitrogen, 37 percent for total phosphorus, and 250 percent for sediment. The results for the heterogeneous subsamples indicate that changes in storm sampling frequency can result in appreciable distortion of estimated trends in flow-normalized flux, especially for total phosphorus and sediment. Trend lines estimated from heterogeneous subsamples tended to converge with the trend lines estimated from baseline data after 2003. In contrast, 2003–12 trends based on subsamples truncated by discarding all data prior to the induced heterogeneity in 2003 showed appreciable biases and differences in slope, relative to the corresponding 2003–12 segment of the trend computed from the design guideline subsamples. Overall, the results indicate that for particulate constituents, load and trend estimates computed using long-term records recently converted to CBNTN design guideline sampling protocols will be most reliable if the trend is computed using the entire record, but reported only for the period that design guideline sampling protocols were followed. Inconsistencies related to changing laboratory methods were also examined via two manipulative experiments. In the first experiment, increasing and decreasing “stair-step” patterns of changes in censoring level, overall representing a factor-of-five change in the laboratory reporting limit, were artificially imposed on a 27-year record with no censoring and a period-of-record concentration trend of –68.4 percent. Trends estimated on the basis of the manipulated records were broadly similar to the original trend (–63.6 percent for decreasing censoring levels and –70.3 percent for increasing censoring levels), lending a degree of confidence that the survival regression routines upon which WRTDS is based are generally robust to data censoring. The second experiment considered an abrupt disappearance of low-concentration observations of total phosphorus, associated with a laboratory method change and not reflected through censoring, near the middle of a 28-year record. By process of elimination, an upward shift in the estimated flow-normalize concentration trend line around the same time was identified as a likely artifact resulting from the laboratory method change, although a contemporaneous change in watershed processes cannot be ruled out. Decisions as to how to treat records with potential sampling protocol or laboratory methods-related artifacts should be made on a case-by-case basis, and trend results should be appropriately qualified.

Maryland, New York, Pennsylvania, Virginia↗
USGS2019

Field trip guide to Mount St. Helens, Washington—Recent and ancient volcaniclastic processes and deposits

This field guide explores volcanic effusions, sediments, and landforms at Mount St. Helens in Washington. A detailed synopsis outlines the eruptive history of Mount St. Helens from about 300,000 years ago through 1980 and beyond. The five days in the field include about 28 stops and 12 potential stops. Exposures in valleys surrounding Mount St. Helens reveal records of diverse Pleistocene and Holocene processes including debris avalanche, lahar, huge water wave on a nearby lake, pyroclastic density currents (surge and flow), tephra fall, lava flow, the growth of domes, and Pleistocene glaciation. Many of the stops explore effects of the several catastrophes that constituted the 18 May 1980 eruption and made Mount St. Helens famous.

Washington↗
USGS2022

Potential effects of energy development on environmental resources of the Williston Basin in Montana, North Dakota, and South Dakota—Executive summary

Executive Summary The Williston Basin, which includes parts of Montana, North Dakota, and South Dakota in the United States and parts of Manitoba and Saskatchewan in Canada, has been explored as a potential source of energy resources since the early 20th century; however, commercially viable petroleum drilling and recovery began in earnest in the 1950s. When oil prices rose in the mid-1980s, the number of wells also increased and then subsequently declined. Interest in the Williston Basin increased again in the mid-2000s with the application of new drilling technology. Since then, development has increased rather quickly. Most of this new development has been facilitated by advances in horizontal drilling and hydraulic fracturing technologies. The North Dakota Department of Mineral Resources reported an increase of more than 10,000 producing wells between 2000 and the spring of 2016. In total, 84 percent of those 10,000 wells target the Bakken Formation, which is now home to one of the Nation’s largest energy booms. Current estimates suggest that exploration and drilling activities are expected to continue for the next 20 to 50 years; however, future activity will likely ebb and flow in response to energy prices. Although most energy has been developed on non-Federal property, more than 2,000 wells were started on federally managed lands in the three States that contain the Williston Basin between 2004 and 2015, though these numbers do not reflect whether or not these wells targeted the Bakken Formation. Executive Order no. 13604 (March 22, 2012) directs Federal agencies to improve the timeliness of the permitting process for extracting publically owned minerals, while minimizing negative environmental effects. This means that Federal agencies need information about how energy development may affect other resources they are tasked with managing. One example of where information about potential effects of development may be useful is the Bureau of Land Management’s permitting process. Permits may include stipulations or special conditions that limit unforeseen negative consequences or ameliorate potential conflicts of future development. Federal agencies also need to coordinate permitting actions to ensure that development complies with existing regulations (for example, the Endangered Species Act [16 U.S.C. § 1531 et seq.] or the National Environmental Protection Act [42 U.S.C. § 4321 et seq.]) without unnecessarily restricting or delaying development. Part of this coordination entails agreeing on the information that will be used to assess the potential effects of energy development, which should also improve efficiency of the permitting process. Within the Williston Basin, a group of Federal agencies called the Bakken Federal Executive Group is developing coordination strategies for numerous energy-related issues on Federal lands. This report was developed in cooperation with the Bureau of Land Management to provide them with the best available scientific information to support documentation of potential effects on resources that Federal agencies manage. This report summarizes information about the effects of energy development on air, water, and biological resources within the U.S. part of the Williston Basin. The topics discussed in the report were based on a prioritized list of information needs elicited from the Bakken Federal Executive Group. The list was developed using a process known as structured decision making or decision analysis. This process began with an initial scoping workshop to determine the range of decisions made by those involved directly in managing energy development and resources on public land. U.S. Geological Survey staff then developed a simple quantitative ranking tool to assess which information needs were of greatest importance to those decisions.

Montana, North Dakota, South Dakota↗
USGS2018

Bend-scale geomorphic classification and assessment of the Lower Missouri River from Sioux City, Iowa, to the Mississippi River for application to pallid sturgeon management

Management actions intended to increase growth and survival of pallid sturgeon ( Scaphirhynchus albus ) age-0 larvae on the Lower Missouri River require a comprehensive understanding of the geomorphic habitat template of the river. The study described here had two objectives relating to where channel-reconfiguration projects should be located to optimize effectiveness. The first objective was to develop a bend-scale (that is, at the scale of individual bends, defined as “cross-over to cross-over”) geomorphic classification of the Lower Missouri River to help in the design of monitoring and evaluation of such projects. The second objective was to explore whether geomorphic variables could provide insight into varying capacities of bends to intercept drifting larvae. The bend-scale classification was based on geomorphic and engineering variables for 257 bends from Sioux City, Iowa, to the confluence with the Mississippi River near St. Louis, Missouri. We used k-means clustering to identify groupings of bends that shared the same characteristics. Separate 3-, 4-, and 6-cluster classifications were developed and mapped. The three classifications are nested in a hierarchical structure. We also explored capacities of bends to intercept larvae through evaluation of linear models that predicted persistent sand area or catch per unit effort (CPUE) of age-0 sturgeon as a function of the same geomorphic variables used in the classification. All highly ranked models that predict persistent sand area contained mean channel width and standard deviation of channel width as significant variables. Some top-ranked models also included contributions of channel sinuosity and density of navigation structures. The sand-area prediction models have r-squared values of 0.648–0.674. In contrast, the highest-ranking CPUE models have r-squared values of 0.011–0.170, indicating much more uncertainty for the biological response variable. Whereas the persistent sand model documents that physical processes of transport and accumulation are systematic and predictable, the poor performance of the CPUE models indicate that additional processes will need to be considered to predict biological transport and accumulation.

Iowa, Missouri↗
USGS2019

Assessing water quality from highway runoff at selected sites in North Carolina with the Stochastic Empirical Loading and Dilution Model (SELDM)

In 2015, the U.S. Geological Survey (USGS) entered into a cooperative agreement with the North Carolina Department of Transportation (NCDOT) to develop a North Carolina-enhanced variation of the national Stochastic Empirical Loading and Dilution Model (SELDM) with available North Carolina-specific streamflow and water-quality data and to demonstrate use of the model by documenting selected simulation scenarios. The USGS developed the national SELDM in cooperation with the Federal Highway Administration (FHWA) to provide the tools and techniques necessary for performing stormwater-quality simulations. SELDM uses a stochastic mass-balance approach to estimate combinations of flows, concentrations, and loads of stormwater constituents from the site of interest (often a highway catchment; nonhighway areas, such as a large impervious area at a shopping center complex, also can be used) and the basin upstream from the stormwater outfall to assess the risk for adverse effects of runoff. SELDM also can be used to simulate the effectiveness of volume reduction, hydrograph extension, and water-quality concentration reductions by stormwater best management practices (BMPs), which are designed to help mitigate the effects of runoff on receiving water bodies. Some of the statistical inputs needed for the North Carolina-enhanced SELDM were either calculated or augmented using local or regional data from North Carolina. Streamflow statistics used by SELDM were determined for 266 streamgages across North Carolina on the basis of data available through the 2015 water year. Recession ratio statistics used for triangular hydrographs were also developed for 30 streamgages across the State. The NCDOT identified previous research reports on highway-runoff and BMP studies in North Carolina for review of potential data addition to the national FHWA Highway-Runoff Database (HRDB). Following USGS review of these data, a total of 25,087 event mean concentration values and 1,140 storm events for 39 highway-runoff sites and 195 analytes were uploaded to the national HRDB from six North Carolina highway-runoff research reports and a recent USGS bridge deck runoff study. Using data for 27 streamgages in North Carolina, a total of 57 water-quality transport curves were developed for seven constituents for use in simulating water-quality conditions in the upstream basin. Performance data for three BMPs (bioretention, grass strip or swale, and wetland channel) from NCDOT research data were incorporated into the North Carolina-enhanced SELDM for volume-reduction statistics, including the effectiveness of treating four water-quality constituents (total suspended solids, total nitrogen, total phosphorus, nitrate plus nitrite) and turbidity. Simulations using the North Carolina-enhanced SELDM are presented for two hypothetical upstream basins in the Piedmont ecoregion and one hypothetical highway site to demonstrate how simulations can be used to provide risk-based information about potential effects of stormwater runoff on downstream water quality and the potential for mitigating those risks by using BMPs. The first group of simulations explores the stochastic variability in dilution factors (the ratio of the highway runoff to the total downstream stormflow) for a hypothetical Piedmont rural creek having drainage areas ranging from 1 to 100 square miles. The second group of simulations examines dilution factors based on variations in precipitation, streamflow, and recession ratios for two hypothetical Piedmont upstream basins (rural and urban) where the drainage area was held constant at 25 square miles. These simulations indicate the sensitivity of results to variations in each of the three variables. The third group of simulations examines the effects of varied concentrations in the upstream basin on water-quality conditions downstream from the highway crossing. Variations in upstream water-quality conditions for three constituents (suspended sediment concentration, total nitrogen, and total phosphorus) are based on water-quality transport curves selected from among the 57 curves developed as part of this study to represent low-, medium-, and high-concentration statistics. Simulations completed for this third group also examine the potential effects of grass swale and bioretention BMP treatment on total nitrogen and total phosphorus concentrations in highway runoff. The BMP performance data from the NCDOT research reports were applied in this group of simulations. The stochastic mass-balance approach used in SELDM analyses and simulations provides a strong tool for engineers and water-resource managers to use in exploring a wide range of possible hydrologic and water-quality inputs and their effects on downstream water quality. The results of this study can not only aid engineers and managers in planning for potential adverse effects of runoff at site-specific locations, they can also help the USGS and other Federal and State agencies with oversight responsibilities in stormwater-quality issues to continue gathering data on potential water-quality effects in receiving streams.

North Carolina↗
USGS2019

Trends in streamflow and concentrations and flux of nutrients and total suspended solids in the Upper White River at Muncie, near Nora, and near Centerton, Indiana

The U.S. Geological Survey (USGS), in cooperation with The Nature Conservancy, completed a study to estimate and assess trends in streamflow and annual mean concentrations and flux of nutrients (nitrate plus nitrite, total Kjeldahl nitrogen, and total phosphorus) and total suspended solids at three USGS streamgages (hereafter referred to as “study gages”) on the Upper White River at Muncie (USGS station 03347000), near Nora (USGS station 03351000), and near Centerton (USGS station 03354000), Indiana. Water-quality data used in the analyses were collected by several agencies between calendar years 1991 and 2017, and streamflow (discharge) data were collected by the USGS. For most of the water-quality constituents, there were suitable data to facilitate an analysis of the 26-year period extending from calendar years 1991 to 2017 (water years 1992 to 2017); however, shorter analytical periods were necessary for total Kjeldahl nitrogen for the study gages at Muncie and near Centerton and for total suspended solids for the study gage near Centerton. Temporal trends in streamflows at the study gages for the period extending from water years 1978 to 2017 were assessed using Exploration and Graphics for RivEr Trends (EGRET) and Mann-Kendall and Pettitt tests. With just one exception, the annual maximum and mean daily streamflows and the annual minimum 7-day mean streamflows at the study gages demonstrated upward trends (increasing streamflows) in the EGRET analyses. The exception was the annual 7-day minimum streamflow at the study gage near Nora, which indicated no trend. Mann-Kendall tests also indicated that the average trend for the annual maximum daily, annual mean daily, and annual 7-day minimum streamflow statistics between water years 1978 and 2017 was upward at each of the study gages; however, only the trends in the annual mean daily streamflows at the study gage at Muncie and the annual maximum daily streamflows at the study gages near Nora and near Centerton were statistically significant at a 0.05 probability level. The Pettitt tests indicated that a statistically significant step trend (abrupt change) in annual mean daily streamflows occurred at each of the study gages around water year 2001. The seasonal distributions of total suspended solids, total phosphorus, nitrate plus nitrite, and total Kjeldahl nitrogen concentrations at the study gages were evaluated to identify patterns and other distinguishing characteristics by examining boxplots of concentrations as a function of month of the year. Seasonal distributions of nitrate plus nitrite concentrations and total suspended solids concentrations differed from each other but were generally similar among the three study gages for a given constituent. Median concentrations of nitrate plus nitrite were highest during the January–June months, whereas median concentrations of total suspended solids were highest during June and July. Seasonal distributions of total phosphorus concentrations were similar at the study gages near Nora and near Centerton, but the seasonal distribution was noticeably different at the study gage at Muncie, which had monthly median concentrations that were substantially lower than at the two downstream study gages (near Nora and near Centerton). The seasonal distribution of total Kjeldahl nitrogen concentrations differed in pattern among the three study gages; however, in general, some of the higher monthly median total Kjeldahl nitrogen concentrations at each study gage were associated with the late spring and summer periods. The Weighted Regressions on Time, Discharge, and Season (WRTDS) method implemented in EGRET was used to estimate water-year annual mean daily concentrations and flux of nutrients and total suspended solids, as well as estimates of concentrations and flux that were “normalized” to remove the effect of year-to-year variation in streamflow. The approximate coefficients of determination for the WRTDS regression models ranged from a high of 0.82 for total phosphorus for the study gage near Centerton to a low of 0.19 for nitrate plus nitrite for the study gage near Nora. Loads and yields of total suspended solids, total phosphorus, nitrate plus nitrite, and total Kjeldahl nitrogen were estimated for analytical periods consisting of the longest periods of concurrent record at the three study gages. Loads of each of the constituents increased sequentially from the most upstream study gage to the most downstream study gage; however, the same was not true for yields. The highest yields of total suspended solids, total phosphorus, and total Kjeldahl nitrogen occurred at the most upstream study gage (at Muncie); however, the highest yield of nitrate plus nitrite occurred at the most downstream study gage (near Centerton). WRTDS bootstrap tests were used to assess the magnitude, direction, and likelihood of changes in annual flow-normalized mean daily concentrations and flux of total suspended solids, total phosphorus, nitrate plus nitrite, and total Kjeldahl nitrogen at the study gages between water years 1997 and 2017. Changes in flow-normalized concentrations and flux of the constituents between water years 1997 and 2017 were mostly downward (decreasing). The exceptions were likely to highly likely upward (increasing) changes in (1) flow-normalized annual mean daily concentration and annual flux for total suspended solids and total phosphorus at the study gage at Muncie, (2) flow-normalized annual mean daily total phosphorus concentration at the study gage near Centerton, (3) flow-normalized annual flux of total phosphorus at the study gage near Centerton, and (4) flow-normalized annual mean daily nitrate plus nitrite concentration at the study gage near Centerton. Although an upward change in flow-normalized nitrate plus nitrite concentrations was likely at the study gage near Centerton, flow-normalized annual flux of nitrate plus nitrite at that study gage was determined to have a highly likely downward change. EGRET and Exploration and Graphics for RivEr Trends Confidence Intervals (EGRETci) analyses can be used to improve our understanding of how concentrations and flux change as functions of time and streamflow, as well as provide information on how the relations between streamflow and constituent concentrations have changed within the calendar year between any 2 years included in the analyses. Examples of those uses, illustrating changes between calendar years 1992 and 2017, were given for total suspended solids concentrations at the study gage near Nora and for nitrate plus nitrite concentrations at the study gage near Centerton.

Indiana↗
USGS2020

Grade and tonnage model for tungsten skarn deposits—2020 update

This report presents an updated grade and tonnage model for tungsten skarn deposits. As a critical component of the U.S. Geological Survey’s three-part form of quantitative mineral resource assessment, robust grade and tonnage models are essential to transforming mineral resource assessments into effective tools for decision makers. Using the best data available at the time of publication, this represents the first attempt in nearly 30 years to capture current mineral inventory and cumulative production data for worldwide tungsten skarn deposits. The accuracy of modern assessments of undiscovered tungsten skarn resources is highly influenced by the use of current data on the distribution of the grades and tonnages of well-explored tungsten skarn deposits. Primary factors affecting the changes to these distributions in the model presented here compared with those of previous models are the inclusion of important deposits, especially those in China that had been omitted in previous models; expanded mineral inventories resulting from increased exploration; and changes to international reporting standards. These factors have resulted in dramatic increases in average ore tonnage and slight decreases in the average grade of tungsten skarn deposits compared with previous models. Large increases in contained metal are observed among many of the individual deposits incorporated within this model that were also included in previous tungsten skarn grade and tonnage models. This report also provides recommendations for input parameters related to grade and tonnage models to use with software tools designed to facilitate the three-part form of quantitative mineral resource assessments.

Scientific Investigations Report↗
USGS2023

Groundwater residence times in glacial aquifers—A new general simulation-model approach compared to conventional inset models

Groundwater is important as a drinking-water source and for maintaining base flow in rivers, streams, and lakes. Groundwater quality can be predicted, in part, by its residence time in the subsurface, but the residence-time distribution cannot be measured directly and must be inferred from models. This report compares residence-time distributions from four areas where groundwater flow and travel time were simulated with conventional simulation-inset models (IMs) and with a new automated model-construction method called general simulation models (GSMs). The comparison provides an opportunity to explore controls on travel time and improve the methods used in the creation of GSMs. These models can be useful for three main-use cases: (1) rapid testing of relationships that govern groundwater flow and age, (2) generation of consistent examples for training a machine-learning metamodel, and (3) serving as a starting point for more detailed models. Comparison of the GSMs to IMs indicated a qualified pattern of agreement for residence-time distributions as indicated by the Nash-Sutcliffe efficiency and Spearman’s correlation coefficient. The agreement was best for the median values of the simulated residence times in young fractions of groundwater (defined as the fractions of groundwater in samples less than 65 years old) at the scale of the eight-digit hydrologic-unit code. Generally, the median values of the young fractions in the IMs were correlated with the median values from the GSMs. The relative trends across the four areas also were similar for the other residence-time metrics. The medians of residence-time metrics at finer scales show a fair degree of scatter. The GSM results compared most poorly for median travel times in the older fraction of groundwater (older than 65 years). The GSM approach is intended as a flexible framework for developing models that can be useful individually as screening tools or collectively to support projects in statistical learning. Although one set of GSM algorithms was presented here, the approach can accommodate many types of data and also different categories of prior information. Comparison of GSMs and IMs suggests ways in which the GSMs, while remaining easy to construct and calibrate, can be improved for estimating groundwater travel times. IMs do not yield exact travel times, and matching GSMs to IMs does not guarantee an improvement; however, IMs provide a convenient benchmark against which to explore relations between physical characteristics of watersheds and the distribution of travel times within them. This effort was undertaken as part of the National Water Quality Program of the U.S. Geological Survey to assist in determining the susceptibility of groundwater in glacial aquifers to a variety of natural and anthropogenic contaminants.

Illinois, Indiana, Michigan, Wisconsin↗
USGS2023

The Science Application for Risk Reduction (SAFRR) Scenario Retrospective 2006–21

The U.S. Geological Survey Science Application for Risk Reduction (SAFRR) Project has created four major hazard scenarios—ShakeOut, ARkStorm, Tsunami Scenario, and HayWired—with multidisciplinary teams of scientists, academics, and practitioners. By presenting a clear and highly detailed narrative of potential damage from earthquakes, tsunamis, and winter storms, the scenarios are intended to foster science-based preparedness strategies and disaster risk reduction innovations. This evaluation explores the presence of these scenarios in cultures of preparedness and their role in disaster risk reduction, and reports barriers and enablers to creating and using these scenarios. To do this, the evaluation team developed a mixed-methods study that includes background research for each scenario, qualitative interviews, data collection of media and academic engagement, and examples of SAFRR scenario use in hazard planning. The data collection led to the development of a hazard scenario evaluation tool that combines theories from multiple disciplines to create a best practice set of categories that aid in scenario use and efficacy. The evaluation tool categories—actionable, longitudinal, educational, relevant, and thorough—are organized as a series of checklists that are used to determine how the scenario planners prioritized different aspects of the scenarios to achieve their goals. The tool could also be used to aid scenario planning for other regional disaster risk reduction scenarios of a similar scope. Findings from this evaluation include detailed narratives of scenario use over time, demonstrating that the scenarios have continued to be useful in hazard planning and preparedness across the globe. Examples of use include using the scenarios to advocate for resilient building and development policy, to promote hazard response exercises, and as source data for the development of new hazard models and science. The scenarios themselves are innovative, both in the hazard science created for scenario development and in their branding and public engagement as U.S. Geological Survey products. This SAFFR retrospective is a descriptive evaluation and does not formally address the effects of the scenarios. Nevertheless, this report does include evidence of scenario affects as discovered through qualitative interviews and research, which is presented to explore how the SAFRR scenarios have been received by cultures of preparedness.

Scientific Investigations Report↗
USGS2024

Water-quality trends in the Kansas River, Kansas, since enactment of the Clean Water Act, 1972–2020

The Clean Water Act was passed by Congress in 1972 to regulate pollution within the waters of the United States. The U.S. Geological Survey (USGS), in cooperation with the Kansas Department of Health and Environment (KDHE), the Kansas Water Office, the Nature Conservancy, the City of Lawrence, the City of Manhattan, the City of Olathe, the City of Topeka, WaterOne, and Evergy, compiled and analyzed historical streamflow and water-quality data collected by USGS and KDHE to characterize trends in water-quality constituents of interest because of their relation to water supply, drinking-water treatment, and sediment and nutrient transport, among others (total dissolved solids, chloride, ammonia, dissolved inorganic nitrogen [ammonia and nitrate plus nitrite], total nitrogen, orthophosphate, total phosphorus, total suspended solids, and fecal coliform bacteria) during mean- and low-flow conditions in the Kansas River since the passage of the Clean Water Act in 1972 through 2020. Trends in water-quality concentrations, or densities, and loads were analyzed using the Exploration and Graphics for RivER Trends R package and Weighted Regressions on Time, Discharge, and Season (WRTDS) model at upstream (Kansas River at Wamego, Kansas; USGS station 06887500) and downstream (Kansas River at De Soto, Kansas; USGS station 06892350) locations along the Kansas River using streamflow and water-quality data collected by the USGS and KDHE during 1972 through 2020. The Exploration and Graphics for RivER Trends Confidence Intervals R package and WRTDS bootstrap test estimated direction, uncertainty, and likelihood of trends in concentration and loads for each water-quality constituent of interest. Downward trends in concentration and load were observed for 5 of the 9 water-quality constituents at both sites during mean-flow conditions during the study period. During low-flow conditions, 7 of the 9 constituents exhibited downward trends, possibly reflecting reductions in point-source contributions to the Kansas River. Downward trends in ammonia, dissolved inorganic nitrogen, and total nitrogen during mean- and low-flow conditions were observed at both Kansas River sites, which were similar to patterns observed nationally. Upward trends were generally observed for orthophosphate and total phosphorus, which were similar to patterns observed at sites in the Mississippi River Basin. Downward trends, or no trend, were observed for chloride. Upward and downward trends were observed for total dissolved solids. Downward trends in total suspended solids and fecal coliform bacteria were observed at both sites, which were also similar to patterns observed nationally. The long-term trend analyses in this report are an essential step to understanding how water-quality conditions have changed in the Kansas River since the passage of the Clean Water Act.

Kansas↗
USGS2025

Tracking status and trends in seven key indicators of river and stream condition in the Chesapeake Bay watershed

Freshwater streams and rivers are recognized as vital habitats within the Chesapeake Bay watershed, which has been undergoing extensive restoration efforts for more than 30 years. Resource managers need to understand stream and river condition and how these conditions are changing over time to determine whether regional long-term restoration and conservation goals are being met. The objective of this report was to document the spatial and temporal variability of conditions for seven indicators of river and stream health across the nontidal Chesapeake Bay watershed. The framework for the U.S. Geological Survey’s Nontidal Network (NTN), a network of more than 100 nutrient and suspended sediment monitoring locations, was extended to assess conditions for six additional indicators of stream health: temperature, salinity, toxic contaminants, streamflow, hydromorphology, and biological aquatic communities. For each indicator, the latest available data from multiple sources were compiled and harmonized, and key metrics were identified to describe indicator conditions across space and time. A status condition was defined for each indicator to describe overall spatial variability in recent condition, and trend analyses were used to describe changes in each indicator metric over time. The analysis revealed clear differences in spatial and temporal data coverage across the seven indicators, so individual indicator trend analyses were not constrained to a common time interval. However, a status snapshot was conducted across all indicators for the 2015–17 period to simultaneously explore spatial variability across all indicators. The status snapshot highlighted general degraded conditions across multiple indicators in large metropolitan regions, such as the Baltimore–Washington, D.C., metropolitan area. Regression analysis between indicator status metrics and major land cover for the sites suggest urbanization as a potential driver of degraded conditions for many of the indicator metrics, including total phosphorus, salinity, temperature, high-flow frequency, and metrics of habitat and biological assemblage quality. A final analysis exploring the spatial representation of each indicator network showed that some indicator monitoring networks did not cover certain settings, such as small watersheds. These results provided an initial assessment of stream health status and trends and will continue to be leveraged to describe conditions across the Chesapeake Bay watershed to help inform local and regional management decisions. These results also highlighted the need for improved coordination among monitoring organizations to support long-term multi-indicator monitoring and assessment.

Chesapeake Bay watershed↗
USGS1950

Carnotite resources in the Charles T. area and vicinity, San Miguel County, Colorado

Between November 1947 and September 1949, the United States Geological Survey, at the request of the Atomic Energy Commission, conducted an exploratory drilling program in the Charles T. area and vicinity. The purpose of the exploration was to discover new carnotite deposits to support milling operations on the Colorado Plateau, and to appraise the uranium and vanadium resources of the area explored.

Colorado↗
USGS1952

Pegmatites of the Crystal Mountain district, Larimer County, Colorado

The Front Range of Colorado is composed chiefly of schists of the pre-Cambrian Idaho Springs formation which have been intruded by a variety of granitic batholiths. In the Crystal Mountain district the Mount Olympus granite, a satellite of the Longs Peak batholith, forms sills and essentially concordant multiple intrusions in quartz-mica schist that dips southward at moderate to steep angles. A great number of pegmatites accompanied and followed the intrusion of the sills, and formed concordant and discordant bodies in schist and granite. Over 1,300 pegmatites in the Hyatt area north of the Big Thompson River are mapped and individually described. There are 27 pegmatites in the area that are made up of a wall zone and a core, and one, the pegmatite at the Hyatt mine, is composed of five zones. The largest pegmatites in the area are discordant in schist and occupy zones that are interpreted to be tear faults and tension fractures produced by the successive intrusions of granite that formed multiple sills. The majority of pegmatites in the large multiple sills were emplaced along the foliation and fractures. The composition of 96 percent of the pegmatites is granitic, 3.5 percent are quartz-rich pegmatites, and a few are tourmaline-rich. The pegmatites were intruded over a period of time and probably were derived from a granitic magma at different stages during differentiation. Solutions escaping from many of the pegmatites tournalinized and silicified the wall rocks for a few inches to two feet, but chemical and spectrographic analyses fail to show the transport of any other constituents. Perthite, plagioclase, and quartz are the essential minerals of the pegmatites, and muscovite is a minor but widespread constituent. Tourmaline, garnet, beryl, and apatite are common accessory minerals, and lithiophillitite-triphylite, bismuthinite, uraninite, columbite-tantalite, and chrysoberyl are rare constituents. Beryl is found in 250 or 27 percent of the pegmatites and makes up 0.01 percent or more of 77 bodies. The beryl-bearing pegmatites are richest in two of the three large granite masses, and are somewhat less rich at a distance of more than a thousand feet from the margins of the intrusives, but contain the least beryl in the thousand-foot belt immediately surrounding the intrusives. The Hyatt pegmatite is by far the richest deposit of beryl in the area mapped. Most of the pegmatites mapped are "unzoned" or homogeneous pegmatites. All gradations are visible between bodies consisting of uniform texture and mineral distribution to zoned pegmatites. The interpretation is made that, for most pegmatites, the initial composition determines whether or not zones will form. Pegmatites containing many zones can form from a magma composed of the elements in perthite, plagioclase, quartz, and muscovite, depending on the proportions of the components crystallizing at any given time. The complexly zoned deposits depend for their formation on the presence of a number of the rarer elements, principally lithium. Replacement textures in zones result from the interaction of the rest-liquid with the earlier-formed solid crystals. No mappable pegmatite in the Crystal Mountain district formed from the replacement of pre-existing pegmatite by solutions escaping from the rest-liquid, or by solutions originating outside the pegmatite. Three beryl-bearing zoned pegmatites, the Hyatt, Big Boulder, and Buckhorn Mica deposits, were explored by core drilling. Each deposit is mapped and described in detail, and the mineral reserves evaluated. The exploration indicates a total of 2,000 tons of beryl, of which 480 tons is estimated to be recoverable by hand sorting. The mapping of the 3 3/4-square mile Hyatt area indicates beryl in sufficient abundance to infer beryl resources of an additional 1,150 tons. Small tonnages of scrap mica and perthite may be obtained from the Hyatt and Big Boulder prospects, and columbite-tantalite may occur in sufficient amounts at the Buckhorn Mica mine and Tantalum claim to produce several hundred pounds as a byproduct of beryl mining. Dumps at the various deposits contain 25 to 50 tons of beryl.

Colorado↗
USGS1951

Carnotite resources of the upper group area, San Miguel County, Colorado

The Upper group area, which consists of 10 Government claims and adjoining public land, is 2 miles southeast of Slick Rock, San Miguel County, Colo., in unsurveyed secs. 5 and 6, T. 43 N., R. 18 W., New Mexico principal meridian. The area is equidistant from mills at Monticello, Utah, and Naturita, Colo. Both mills are reached by about 45 miles of all-weather roads. About 2,700 tons of carnotite ore was produced from the area between 1921 and 1943 (tons used in this report are short tons). This ore had an estimated average grade of 0.25 percent U30g and 1.7 percent V205. The ore deposits are in the top sandstone stratum of the Salt Wash sandstone member of the Tipper Jurassic Morrison formation. The principal ore-bearing minerals, which mainly impregnate the sandstone, consist of uranium-bearing carnotite and a micaceous vanadium-bearing mineral called “roscoelite." The deposits are mostly in small podlike masses called "rolls." The size of the rolls ranges from less than 50 to more than 1,500 tons each. The long axes of the rolls have a dominant northeasterly to easterly trend. Exploration by the Geological Survey was done on behalf of the Atomic Energy Commission to test unexplored ground for new deposits of carnotite ore and to gain a better appraisal of the reserves in the area. From 1948 to 1950, 186 diamond-drill holes were completed for a total of 14,577 feet. The areas of favorable sandstone were found and defined by holes drilled 300 to 500 feet apart. Altered mudstone, carbonaceous material in the sandstone, and color of the sandstone were used to determine the favorability of the sandstone. Within areas containing favorable sandstone holes were drilled on 100- to 150-foot centers to find deposits. Where deposits were found more than 20 feet below the surface, they were roughly outlined by holes drilled on 50- to 75- foot centers. Deposits discovered within 20 feet of the surface were not outlined. Reserves in deposits found by the drilling are classed as indicated and inferred, whereas those reserves that are predicted solely on geologic evidence are classed as potential. Indicated reserves computed at the highest thickness and grade cut-offs (1 foot or more thick and 0.10 percent U3O8 or .10 percent V205) total 5,000 tons, averaging 0.19 percent U308 and 1.6 percent V205. Inferred reserves computed at the same cut-offs total 3,500 tons, averaging .22 percent U308 and 1.7 percent V205. Both the indicated and inferred reserves, as well as the pounds of contained U3O8and V205, are summarized in table 1. Potential reserves are predicted to total about 1,500 tons, averaging about 0.20 percent U3O8 and 1.6 percent V205. Most of the potential reserves are expected to be in small scattered deposits within 20 feet of the surface. No additional diamond drilling by the Geological Survey is planned in the Upper group area. Several specific localities, principally in the central part of the area, are recommended for further exploration by jackhammer and wagon drilling by lessees and operators.

Colorado↗
USGS1952

Carnotite resources of Club Mesa, Montrose County, Colorado

Club Mesa is 1 mile west of Uravan, Montrose County, Colo. About 200,000 short tons of carnotite ore containing an estimated 0.45 percent U 3 O 8 and 2.1 percent V 2 O 5 has been mined from the mesa. This production represents about one-fifth of the carnotite ore mined from the Colorado Plateau. All the principal deposits on the mesa are in the main ore-bearing sandstone which is in the top part of the Salt Wash sandstone member of the Jurassic Morrison formation. The deposits are in tabular masses of uneven thickness lying more or less parallel to the enclosing strata. The ore consists mainly of sandstone impregnated with carnotite and vanadiferous clay minerals. The sandstone near the deposits is generally over 30 feet in thickness, contains noticeable quantities of carbon, and vivid patches of limonite (?) stain. Also near ore deposits, the mudstone in contact with the sandstone is altered from red to gray or green through a thickness of 3 or 4 feet. Certain linear features of the ore bodies and of favorable parts of the main ore-bearing sandstone offer clues by their orientation to extensions of known ore bodies and of favorable ground. These features on Club Mesa trend mostly east to northeast. Between March 6, 1948, and January 22, 1952, the U.S. Geological Survey drilled 651 holes for a total of 167,495 feet. As a result of this drilling, 18 deposits were discovered and partly outlined. These range in size from 200 to 55,000 short tons of indicated ore reserves and are in layers 1 foot or more thick containing 0.10 percent or more U 3 O 8 or 1.0 percent or more V 2 O 5 . About 85 percent of this ore is in public land; the remainder is in claims owned by the United States Vanadium Co. Reserves in deposits known from drill holes or exposures are classed as indicated or inferred, and those in deposits that are predicted solely on geologic evidence are classed as potential. The tons of indicated and inferred reserves and the pounds of contained U 3 O 8 and V 2 O 5 are summarized in table 1. These reserves are subdivided also by thickness and grade cutoffs. At the higher grade cutoff, reserve figures express approximately the tonnage and grade of material that might actually be mined from these deposits under 1951 conditions. Indicated and inferred reserves of this type total 198,000 short tons, averaging 0.35 percent U 3 O 8 and 1.8 percent V 2 O 5, and contain 1,1,372,000 pounds of U 3 O 8 and 7,260,000 pounds of V 2 O 5. These reserves are based on Geological Survey drilling. Potential reserves are predicted to total about 40,000 short tons, averaging about 0.35 percent U 3 O 8 and 1.9 percent V 2 O 5 . No additional exploration on Club Mesa is planned by the Geological Survey, but exploration by private companies is recommended.

Colorado↗
USGS1952

Carnotite resources of Outlaw Mesa, Mesa County, Colorado

The U.S. Geological Survey explored Outlaw Mesa for carnotite deposits from 1949 through 1951 with 1,302 diamond-drill holes that totaled 222,150 feet. Total production from Outlaw Mesa from 1914 through 1951 was about 30,000 short tons of carnotite ore, having an estimated grade of about 0.40 percent U3O8 and 1.7 percent V205. The known carnotite deposits are in a number of sandstone lenses in the upper part of the Salt Wash sandstone member of the Jurassic Morrison formation. The deposits are mainly impregnations of sandstone by carnotite and vanadium-bearing clay minerals. Commonly, the deposits are irregular tabular layers or pod-like or crescentic masses ("rolls") connected by thin layers of mineralized rock. The deposits and rolls have a dominant northeasterly trend. Useful criteria for recognizing-sandstone that might contain mineralized rock are: (1) thick, light-brown sandstone, (2) gray mudstone at the base of and in this sandstone, and (3) abundant carbonaceous material. The indicated and inferred reserves of carnotite-bearing material, and the pounds of contained U308 and V205 are summarized in table 1. Potential reserves, whose existence is based on geologic evidence alone, are estimated to total about 80,000 short tones, averaging about 0.35 percent U308 and 1.5percent V205. No further exploration by the Geological Survey is planned; however, additional drilling by private operators is recommended, particularly in ground underlain by mineralized rock.

Colorado↗
USGS1953

Thorium investigations, 1950-52, Wet Mountains, Colorado

The Wet Mountain thorium district was discovered in 1950 by members of the U.S. Geological Survey during reconnaissance investigations for uranium made on the behalf of the Atomic Energy Commission The size of this new district is incompletely known, but the deposits found to date are in an area 20 miles long and about 10 miles wide, the southwest boundary of which extends northwest from Querida and Rosita Custer County, into Fremont County. Most of the deposits, however, are in the southeastern half of this area The thorium minerals occur in barite-sulfide veins along northwest-trending shear zones that cut a pre-Cambrian complex or amphibolite, biotite-granite gneiss, metagabbro, migmatite, microcline granites, pegmatite and white granite, and syenite (?) o Along the shear zones are premineralization basic (lamprophyre (?)) dikes. Thorite has been tentatively identified as the principal radio- active mineral It is associated with barite: quartz, galena, fluorite, limonite, and pyrite Some of the shear zones perhaps can be traced for as much as 2 miles, but the largest known thorium-bearing ore body is as much as 300 feet long, 26 feet wide, and 400 feet deep. Samples from the veins contain as much as 1.6 percent equivalent Th0 2 Eleven diamond drill holes, totaling 3,292.4 feet have explored five shear zones on the Haputa Ranch. Three ore bodies of possible economic interest are indicated in two interconnecting shear zones. No other deposits in the wet Mountains have been explored, or even sampled adequately to hazard an estimate as to grade and tonnage of reserves.

Colorado↗
USGS1954

Monazite in Atlantic shore-line features

This report is a survey of present and potential production of monazite from part of the Maryland-Florida section of the Atlantic Coastal Plain. The part of the Coastal Plain covered here is the outer (shore-ward) half. In this area, all the large heavy-mineral placers so far discovered occur in sand bodies that, by their shape, size, orientation, and lithology, appear to be ancient beaches, spits, bars, or dunes. Smaller placers have produced from recent shore-line features. The inner part of the Coastal Plain, to be treated in another report, is underlain generally by older rocks, ranging in age from Cretaceous to older Pleistocene. Only two large heavy-mineral placers are now in production at Trail Ridge, and near Jacksonville, both in Florida. Production is planned for the near future near Yulee, Fla.: in Folkston, Ga.: and at one or two localities in eastern North Carolina. Each of these three will produce monazite as a byproduct; the total new reserve for the three placers is about 33,000 tons of monazite. In large heavy-mineral placers of this type, monazite has not been found to run more than about 1 percent of total heavy minerals. In some large placers, notably Trail Ridge, it is almost or completely lacking. No reason for its sporadic occurrence has been found in this investigation. Two placers of potential economic value have been found by this project in Virginia, one west and one east of Chesapeake Bay. Neither is of promise for monazite production, but if they serve to open up exploration or production in the area, there is a chance for monazite as a byproduct from other placers. A discovery of considerable scientific interest has to do with the occurrence of two different suites of heavy minerals in the Coastal Plain, at least south of Virginia. One, an “older” suite, lacks epidote, hornblende, and garnet; this suite occurs in all older formations and in Pleistocene deposits lying above about 50 or 60 feet above sea level. The other, “younger” suite contains these three minerals: it is restricted to recent beaches and streams, and to Pleistocene deposits at low altitudes. Monazite may occur with either of these suites. The percentage of titania (TiO 2 ) in illmenite is of both scientific and economic interest. Illmenite is by far the most sought-for mineral in present exploration, and whether it contains the “normal” 53 percent of titania or, as it commonly does in Florida, 60 percent, is often of decisive importance in its exploitation. The nature, time, and place of this “enrichment” in titania has not been worked out. The heavy-mineral industry of the area seems to give promise of considerable expansion in the near future, and a greater monazite production seems assured.

Florida;Maryl;North Carolina;South Carolina;Virgin↗