USGS Science⌕ Search

SEARCH · USGS Science

Results for “Scientific Reports”

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

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,009 records · Page 56Linked to original sources
USGS2008

Distribution of Igneous Rocks in Medina and Uvalde Counties, Texas, as Inferred from Aeromagnetic Data

A high-resolution aeromagnetic survey was flown in 2001 over Medina and Uvalde Counties, Texas, as part of a multi-disciplinary investigation of the geohydrologic framework of the Edwards aquifer in south-central Texas. The objective of the survey was to assist in mapping structural features that influence aquifer recharge and ground-water flow. The survey revealed hundreds of magnetic anomalies associated with igneous rocks that had previously been unmapped. This report presents an interpretation of the outcrops and subcrops of igneous rocks, based upon procedures of matched-filtering and potential field modeling.

Scientific Investigations Report↗
USGS2009

Method for Estimating Water Withdrawals for Livestock in the United States, 2005

Livestock water use includes ground water and surface water associated with livestock watering, feedlots, dairy operations, and other on-farm needs. The water may be used for drinking, cooling, sanitation, waste disposal, and other needs related to the animals. Estimates of water withdrawals for livestock are needed for water planning and management. This report documents a method used to estimate withdrawals of fresh ground water and surface water for livestock in 2005 for each county and county equivalent in the United States, Puerto Rico, and the U.S. Virgin Islands. Categories of livestock included dairy cattle, beef and other cattle, hogs and pigs, laying hens, broilers and other chickens, turkeys, sheep and lambs, all goats, and horses (including ponies, mules, burros, and donkeys). Use of the method described in this report could result in more consistent water-withdrawal estimates for livestock that can be used by water managers and planners to determine water needs and trends across the United States. Water withdrawals for livestock in 2005 were estimated by using water-use coefficients, in gallons per head per day for each animal type, and livestock-population data. Coefficients for various livestock for most States were obtained from U.S. Geological Survey water-use program personnel or U.S. Geological Survey water-use publications. When no coefficient was available for an animal type in a State, the median value of reported coefficients for that animal was used. Livestock-population data were provided by the National Agricultural Statistics Service. County estimates were further divided into ground-water and surface-water withdrawals for each county and county equivalent. County totals from 2005 were compared to county totals from 1995 and 2000. Large deviations from 1995 or 2000 livestock withdrawal estimates were investigated and generally were due to comparison with reported withdrawals, differences in estimation techniques, differences in livestock coefficients, or use of livestock-population data from different sources. The results of this study were distributed to U.S. Geological Survey water-use program personnel in each State during 2007. Water-use program personnel are required to submit estimated withdrawals for all categories of use in their States to the National Water-Use Information Program for inclusion in a national report describing water use in the United States during 2005. Water-use program personnel had the option of submitting these estimates, a modified version of these estimates, or their own set of estimates or reported data. Estimated withdrawals resulting from the method described in this report are not presented herein to avoid potential inconsistencies with estimated withdrawals for livestock that will be presented in the national report, as different methods used by water-use personnel may result in different withdrawal estimates. Estimated withdrawals also are not presented to avoid potential disclosure of data for individual livestock operations.

Scientific Investigations Report↗
USGS2011

Mass of chlorinated volatile organic compounds removed by Pump-and-Treat, Naval Air Warfare Center, West Trenton, New Jersey, 1996-2010

Pump and Treat (P&T) remediation is the primary technique used to contain and remove trichloroethylene (TCE) and its degradation products cis 1-2,dichloroethylene (cDCE) and vinyl chloride (VC) from groundwater at the Naval Air Warfare Center (NAWC), West Trenton, NJ. Three methods were used to determine the masses of TCE, cDCE, and VC removed from groundwater by the P&T system since it became fully operational in 1996. Method 1, is based on the flow volume and concentrations of TCE, cDCE, and VC in groundwater that entered the P&T building as influent. Method 2 is based on withdrawal volume from each active recovery well and the concentrations of TCE, cDCE, and VC in the water samples from each well. Method 3 compares the maximum monthly amount of TCE, cDCE, and VC from Method 1 and Method 2. The greater of the two values is selected to represent the masses of TCE, cDCE and VC removed from groundwater each month. Previously published P&T monthly reports used Method 1 to determine the mass of TCE, cDCE, and VC removed. The reports state that 8,666 pounds (lbs) of TCE, 13,689 lbs of cDCE, and 2,455 lbs of VC were removed by the P&T system during 1996-2010. By using Method 2, the mass removed was determined to be 8,985 lbs of TCE, 17,801 lbs of cDCE, and 3,056 lbs of VC removed, and Method 3, resulted in 10,602 lbs of TCE, 21,029 lbs of cDCE, and 3,496 lbs of VC removed. To determine the mass of original TCE removed from groundwater, the individual masses of TCE, cDCE, and VC (determined using Methods 1, 2, and 3) were converted to numbers of moles, summed, and converted to pounds of original TCE. By using the molar conversion the mass of original TCE removed from groundwater by Methods 1, 2, and 3 was 32,381 lbs, 39,535 lbs, and 46,452 lbs, respectively, during 1996-2010. P&T monthly reports state that 24,805 lbs of summed TCE, cDCE, and VC were removed from groundwater. The simple summing method underestimates the mass of original TCE removed by the P&T system.

New Jersey↗
USGS2018

Data analysis considerations for pesticides determined by National Water Quality Laboratory schedule 2437

In 2013, the U.S. Geological Survey National Water Quality Laboratory (NWQL) made a new method available for the analysis of pesticides in filtered water samples: laboratory schedule 2437. Schedule 2437 is an improvement on previous analytical methods because it determines the concentrations of 225 fungicides, herbicides, insecticides, and associated degradates in one method at similar or lower concentrations than previously available methods. Additionally, the pesticides included in schedule 2437 were strategically identified in a prioritization analysis that assessed likelihood of occurrence, prevalence of use, and potential toxicity. When the NWQL reports pesticide concentrations for analytes in schedule 2437, the laboratory also provides supplemental information useful to data users for assessing method performance and understanding data quality. That supplemental information is discussed in this report, along with an initial analysis of analytical recovery of pesticides in water-quality samples analyzed by schedule 2437 during 2013–2015. A total of 523 field matrix spike samples and their paired environmental samples and 277 laboratory reagent spike samples were analyzed for this report (1,323 samples total). These samples were collected in the field as part of the U.S. Geological Survey National Water-Quality Assessment groundwater and surface-water studies and as part of the NWQL quality-control program. This report reviews how pesticide samples are processed by the NWQL, addresses how to obtain all the data necessary to interpret pesticide concentrations, explains the circumstances that result in a reporting level change or the occurrence of a raised reporting level, and describes the calculation and assessment of recovery. This report also discusses reasons why a data user might choose to exclude data in an interpretive analysis and outlines the approach used to identify the potential for decreased data quality in the assessment of method recovery. The information provided in this report is essential to understanding pesticide data determined by schedule 2437 and should be reviewed before interpretation of these data.

Scientific Investigations Report↗
USGS2018

Methods for peak-flow frequency analysis and reporting for streamgages in or near Montana based on data through water year 2015

This report documents the methods for peak-flow frequency (hereinafter “frequency”) analysis and reporting for streamgages in and near Montana following implementation of the Bulletin 17C guidelines. The methods are used to provide estimates of peak-flow quantiles for 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities for selected streamgages operated by the U.S. Geological Survey Wyoming-Montana Water Science Center (WY–MT WSC). These annual exceedance probabilities correspond to 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively. Standard procedures specific to the WY–MT WSC for implementing the Bulletin 17C guidelines include (1) the use of the Expected Moments Algorithm analysis for fitting the log-Pearson Type III distribution, incorporating historical information where applicable; (2) the use of weighted skew coefficients (based on weighting at-site station skew coefficients with generalized skew coefficients from the Bulletin 17B national skew map); and (3) the use of the Multiple Grubbs-Beck Test for identifying potentially influential low flows. For some streamgages, the peak-flow records are not well represented by the standard procedures and require user-specified adjustments informed by hydrologic judgement. The specific characteristics of peak-flow records addressed by the informed-user adjustments include (1) regulated peak-flow records, (2) atypical upper-tail peak-flow records, and (3) atypical lower-tail peak-flow records. In all cases, the informed-user adjustments use the Expected Moments Algorithm fit of the log-Pearson Type III distribution using the at-site station skew coefficient, a manual potentially influential low flow threshold, or both. Appropriate methods can be applied to at-site frequency estimates to provide improved representation of long-term hydroclimatic conditions. The methods for improving at-site frequency estimates by weighting with regional regression equations and by Maintenance of Variance Extension Type III record extension are described. Frequency analyses were conducted for 99 example streamgages to indicate various aspects of the frequency- analysis methods described in this report. The frequency analyses and results for the example streamgages are presented in a separate data release associated with this report consisting of tables and graphical plots that are structured to include information concerning the interpretive decisions involved in the frequency analyses. Further, the separate data release includes the input files to the PeakFQ program, version 7.1, including the peak-flow data file and the analysis specification file that were used in the peak-flow frequency analyses. Peak-flow frequencies are also reported in separate data releases for selected streamgages in the Beaverhead River and Clark Fork Basins and also for selected streamgages in the Ruby, Jefferson, and Madison River Basins.

Montana↗
USGS2020

An enhanced hydrologic stream network based on the NHDPlus medium resolution dataset

The National Hydrography Dataset Plus, Version 2.1 (NHDPlusV2.1) is an attribute-rich digital stream network for the conterminous United States, serving as a foundational infrastructure for reporting hydrologic information at both regional and national scales. SPAtially Referenced Regressions On Watershed attributes (SPARROW) is a process-based statistical model that relies on a digital hydrologic network like NHDPlusV2.1 to establish spatial relations between quantities of monitored contaminant loads and contaminant sources, accounting for the physical characteristics along flow paths affecting contaminant transport. The U.S. Geological Survey National Water Quality Assessment project adopted and modified the medium-resolution NHDPlusV2.1 network for use as the primary framework supporting SPARROW modeling. This report describes the enhancements made to improve the routing capabilities and the value-added attributes of NHDPlusV2.1 to support modeling and other hydrologic analyses. These enhancements include corrections to inconsistencies in network/routing information, filling in missing attribute values of associated characteristics, accounting of water use affecting flow, new variables useful for interpreting network data, revised flowline attributes such as slope and flow, and incorporation of ancillary spatial data into the network. The resulting dataset containing the enhancements to the network is named E2NHDPlusV2_US. Although the enhancements described in the report were developed for use in SPARROW modeling, the enhancements are expected to be useful for a wide variety of hydrologic studies within the United States.

Conterminous United States↗
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↗
USGS2026

Monitoring recreation on federally managed lands and waters—Aspects of visitor use

Federally managed public lands and waters receive around 1 billion recreational visits each year. Data on these visitors can aid in guiding policy decisions, managing resources effectively, and communicating the economic contributions of lands and waters. This report explores the methods used by agencies to collect data on aspects of recreational visitor use to Federal lands and waters (apart from visitation numbers, which are the focus of a companion publication). Aspects of recreational visitor use include visitor demographics, recreational activity participation, visitor satisfaction, visitor attitudes and experiences, trip characteristics, and economic contributions. We review practices used to understand aspects of visitor use across seven Federal agencies, revealing similarities such as the use of visitor intercept surveys and coverage of similar topic areas, and differences in how survey programs are operationalized and how specific questions on visitor surveys are worded. We also evaluate emerging technologies, such as geolocated social media and mobile device location data, for their potential to aid in understanding aspects of visitor use. This report concludes with potential opportunities to enhance data collection and coordination, ensuring cost-effective data collection and informed decision making.

Scientific Investigations Report↗
USGS2006

Water resources of Monroe County, New York, water years 2000-02: Atmospheric deposition, ground water, streamflow, trends in water quality, and chemical loads in streams

This report, the fifth in a series that presents analyses of the hydrologic data collected in Monroe County since 1984, interprets data from four surface-water-monitoring sites in the Irondequoit Creek basin (Irondequoit Creek at Railroad Mills, East Branch Allen Creek at Pittsford, Allen Creek near Rochester, and Irondequoit Creek above Blossom Road); and from three sites on tributaries to the Genesee River (Oatka Creek at Garbutt, Honeoye Creek at Honeoye Falls, and Black Creek at Churchville) and from the Genesee River at Charlotte Docks. It also interprets data from a site on Northrup Creek, which provides information on nutrient loads delivered to Long Pond, a small eutrophic embayment of Lake Ontario. The report also includes water-level and water-quality data from nine observation wells in Ellison Park, and atmospheric-deposition data from a collection site at Mendon Ponds. Atmospheric Deposition : Average annual precipitation for 2000–02 was 33.11 in., 0.94 in. below normal. Average annual loads of some chemical constituents in atmospheric deposition for 2000–02 differed considerably from those for the previous period of record. Loads of all nutrients except ammonia decreased by amounts ranging from 28 percent (ammonia + organic nitrogen and phosphorus) to 2 percent (nitrite + nitrate), whereas ammonia loads an increased by 8 percent. Loads of dissolved sodium and total zinc in atmospheric deposition increased by 56 percent, and 54, percent respectively, over the previous period of record. Average annual loads of other constituents showed decreases ranging from 41 percent (dissolved magnesium) to 17 percent (dissolved chloride). Loads of all nutrients deposited in the Irondequoit Creek basin from atmospheric sources during 2000–02 greatly exceeded those transported by Irondequoit Creek. The ammonia load deposited in the basin was 165 times the load transported at Blossom Road (the most downstream site); the ammonia + organic nitrogen load was 2.8 times greater, orthophosphate 9.7 times greater, total phosphorus 1.2 times greater, and the nitrite + nitrate load was 1.6 times greater. Average yields of dissolved chloride and dissolved sulfate from atmosphoric sources were much less than those transported by streamflow at Blossom Road—chloride was about 1.5 percent and sulfate about 9.1 percent of the amount transported by Irondequoit Creek. Ground water : Ground-water-levels and water quality data were collected from 9 observation wells in Ellison Park in Monroe County. All wells except Mo 2 and Mo 659 are in the flood plain of Irondequoit Creek. Water levels indicate frequent reversals in direction of lateral flow toward or away from Irondequoit Creek, and all wells except Mo2 and Mo 659 respond to water level fluctuations in the Creek. Trend tests on water levels for the period of record indicate a slight upward trend in water levels at all nine wells, two of which (Mo 3 and Mo 667) were statistically significant. Concentrations of ammonia and ammonia + organic nitrogen showed a general decrease for the current period of record. Total phosphorus concentrations showed an increase at four wells and a decrease at four wells. Water quality data showed that the highest median concentrations of nutrients continues to occur in Mo 667 and the highest median concentrations of common ions was at Mo 664. Streamflow : Statistical analysis of long-term (greater than 15 years) streamflow records for unregulated streams in Monroe County indicated that annual mean flows for water years (A water year is the 12-month period from October 1 through September 30 of the following year.) 2000–02 generally were in the normal range (75th to 25th percentile), although Allen Creek continued to show a significant downward trend in mean monthly streamflow during the 1984–2002 water years. Chemical Concentration in Streams : Concentrations of several constituents in streams of the Irondequoit Creek basin showed statistically significant (α = 0.05) trends from the beginning of their period of record through 2002. Three of the four Irondequoit Creek sites (Allen Creek, Blossom Road, and Railroad Mills) showed downward trends in ammonia (4.6 to 12.0 percent per year) and ammonia + organic nitrogen (2.8 to 5.3 percent per year). Allen Creek showed downward trends in nitrite + nitrate and total phosphorus (both 1.2 percent per year), and Irondequoit Creek above Blossom Road showed an upward trend in orthophosphate (1.8 percent per year). Three Irondequoit Creek sites showed upward trends in dissolved chloride: Railroad Mills (4.8 percent per year), Allen Creek, and Blossom Road (both 1.9 percent per year). Allen Creek showed a downward trend in sulfate of 0.98 percent per year, whereas Blossom Road showed a downward trend in suspended solids of 4.0 percent per year. Volatile suspended solids showed an upward trend of 3.2 percent per year at Allen Creek and a downward trend of 2.2 percent per year at Blossom Road. Northrup Creek in western Monroe County, showed significant downward trends in concentrations of volatile suspended solids (2.5 percent per year), total phosphorus (5.3 percent per year), and orthophosphate (9.9 percent per year). The Genesee River at Charlotte Docks showed downward trends in volatile suspended solids (2.1 percent per year) and ammonia + organic nitrogen (4.5 percent per year). Oatka Creek at Garbutt showed an upward trend of 21.4 percent per year in turbidity. Chemical Loads in Streams : Mean annual yields (pounds or tons per square mile) of many constituents at the Irondequoit Creek sites were lower than those in previous reporting periods. Suspended solids and nitrite + nitrate yields were lower at three of the sites, and yields of volatile suspended solids, ammonia, and total phosphorus were lower at two of the sites. East Branch Allen Creek showed lower yields for five of the nine constituents for 2000–02, than for previous reporting periods. The decreased yields at East Branch Allen Creek are likely due to the Jefferson Road stormflow-detention basin and the much lower than normal runoff for the 2000–02 period.

New York↗
USGS2009

Methods for Estimating Water Withdrawals for Aquaculture in the United States, 2005

Aquaculture water use is associated with raising organisms that live in water - such as finfish and shellfish - for food, restoration, conservation, or sport. Aquaculture production occurs under controlled feeding, sanitation, and harvesting procedures primarily in ponds, flow-through raceways, and, to a lesser extent, cages, net pens, and tanks. Aquaculture ponds, raceways, and tanks usually require the withdrawal or diversion of water from a ground or surface source. Most water withdrawn or diverted for aquaculture production is used to maintain pond levels and/or water quality. Water typically is added for maintenance of levels, oxygenation, temperature control, and flushing of wastes. This report documents methods used to estimate withdrawals of fresh ground water and surface water for aqua-culture in 2005 for each county and county-equivalent in the United States, Puerto Rico, and the U.S. Virgin Islands by using aquaculture statistics and estimated water-use coefficients and water-replacement rates. County-level data for commercial and noncommercial operations compiled for the 2005 Census of Aquaculture were obtained from the National Agricultural Statistics Service. Withdrawals of water used at commercial and noncommercial operations for aquaculture ponds, raceways, tanks, egg incubators, and pens and cages for alligators were estimated and totaled by ground-water or surface-water source for each county and county equivalent. Use of the methods described in this report, when measured or reported data are unavailable, could result in more consistent water-withdrawal estimates for aquaculture that can be used by water managers and planners to determine water needs and trends across the United States. The results of this study were distributed to U.S. Geological Survey water-use personnel in each State during 2007. Water-use personnel are required to submit estimated withdrawals for all categories of use in their State to the U.S. Geological Survey National Water-Use Information Program for inclusion in a national report describing water use in the United States during 2005. Water-use personnel had the option of submitting the estimates determined by using the methods described in this report, a modified version of these estimates, their own set of estimates, or reported data for the aquaculture category. Estimated withdrawals resulting from the method described in this report are not presented herein to avoid potential inconsistencies with estimated withdrawals for aquaculture that will be presented in the national report, as different methods used by water-use personnel may result in different withdrawal estimates. Estimated withdrawals also are not presented to avoid potential disclosure of confidential information for individual aquaculture operations.

Scientific Investigations Report↗
USGS2013

Prediction of suspended-sediment concentrations at selected sites in the Fountain Creek watershed, Colorado, 2008-09

In 2008, the U.S. Geological Survey (USGS), in cooperation with Pikes Peak Area Council of Governments, Colorado Water Conservation Board, Colorado Springs City Engineering, and the Lower Arkansas Valley Water Conservancy District, began a small-scale pilot study to evaluate the effectiveness of the use of a computational model of streamflow and suspended-sediment transport for predicting suspended-sediment concentrations and loads in the Fountain Creek watershed in Colorado. Increased erosion and sedimentation damage have been identified by the Fountain Creek Watershed Plan as key problems within the watershed. A recommendation in the Fountain Creek Watershed plan for management of the basin is to establish measurable criteria to determine if progress in reducing erosion and sedimentation damage is being made. The major objective of this study was to test a computational method to predict local suspended-sediment loads at two sites with different geomorphic characteristics in order to evaluate the feasibility of using such an approach to predict local suspended-sediment loads throughout the entire watershed. Detailed topographic surveys, particle-size data, and suspended-sediment samples were collected at two gaged sites: Monument Creek above Woodmen Road at Colorado Springs, Colorado (USGS gage 07103970), and Sand Creek above mouth at Colorado Springs, Colorado (USGS gage 07105600). These data were used to construct three-dimensional computational models of relatively short channel reaches at each site. The streamflow component of these models predicted a spatially distributed field of water-surface elevation, water velocity, and bed shear stress for a range of stream discharges. Using the model predictions, along with measured particle sizes, the sediment-transport component of the model predicted the suspended-sediment concentration throughout the reach of interest. These computed concentrations were used with predicted flow patterns and channel morphology to determine fluxes of suspended sediment for the median particle size and for the measured range of particle sizes in the channel. Three different techniques were investigated for making the suspended-sediment predictions; these techniques have varying degrees of reliance on measured data and also have greatly differing degrees of complexity. Based on these data, the calibrated Rouse method provided the best balance between accuracy and both computational and data collection costs; the presence of substantial washload was the primary factor in eliminating the simpler and the more complex techniques. Based on this work, using the selected technique at additional sites in the watershed to determine relative loads and source areas appears plausible. However, to ensure that the methodology presented in this report yields reasonable results at other selected sites in the basin, it is necessary to collect additional verification data sets at those locations.

Colorado↗
USGS2015

Satellite monitoring of dramatic changes at Hawai'i's only alpine lake: Lake Waiau on Mauna Kea volcano

Lake Waiau is a small, typically 100-meter-long lake, located near the summit of Mauna Kea volcano, on the Island of Hawaiʻi. It is Hawaiʻi’s only alpine lake and is considered sacred in Hawaiian cultural tradition. Over the past few years, the lake has diminished in size, and, by October 2013, surface water had almost completely disappeared from the lake. In this study, we use high-resolution satellite images and aerial photographs to document recent changes at the lake. Based on our reconstructions covering the past 200 years, the historical lake surface area has typically ranged from 5,000 to 7,000 square meters, but in 2010 a dramatic plunge in lake area ensued. The lake area rebounded significantly in early 2014, following heavy winter storms. This near disappearance of the lake, judging from analysis of visitor photographs and field reports, appears to be highly unusual, if not unprecedented, in the historical record. The unusually low water levels in the lake are consistent with a recent severe drought in Hawaiʻi.

Hawaii↗
USGS2018

Model methodology for estimating pesticide concentration extremes based on sparse monitoring data

This report describes a new methodology for using sparse (weekly or less frequent observations) and potentially highly censored pesticide monitoring data to simulate daily pesticide concentrations and associated quantities used for acute and chronic exposure assessments, such as the annual maximum daily concentration. The new methodology is based on a statistical model that expresses log-transformed daily pesticide concentration in terms of a seasonal wave, flow-related variability, long-term trend, and serially correlated errors. Methods are described for estimating the model parameters, generating conditional simulations of daily pesticide concentration given sparse (weekly or less frequent) and potentially highly censored observations, and estimating concentration extremes based on the conditional simulations. The model can be applied to datasets with as few as 3 years of record, as few as 30 total observations, and as few as 10 uncensored observations. The model was applied to atrazine, carbaryl, chlorpyrifos, and fipronil data for U.S. Geological Survey pesticide sampling sites with sufficient data for applying the model. A total of 112 sites were analyzed for atrazine, 38 for carbaryl, 34 for chlorpyrifos, and 33 for fipronil. The results are summarized in this report; and, R functions, described in this report and provided in an accompanying model archive, can be used to fit the model parameters and generate conditional simulations of daily concentrations for use in investigations involving pesticide exposure risk and uncertainty.

Scientific Investigations Report↗
USGS2018

Federal lands greenhouse emissions and sequestration in the United States—Estimates for 2005–14

In January 2016, the Secretary of the U.S. Department of the Interior tasked the U.S. Geological Survey (USGS) with producing a publicly available and annually updated database of estimated greenhouse gas emissions associated with the extraction and use (predominantly some form of combustion) of fossil fuels from Federal lands. In response, the USGS has produced estimates of the greenhouse gas emissions resulting from the extraction and end-use combustion of fossil fuels produced on Federal lands in the United States, as well as estimates of ecosystem carbon emissions and sequestration on those lands. American Indian and Tribal lands were not included in this analysis. The emissions estimates span a 10-year period (2005–14) and are reported for 28 States and two offshore areas. Nationwide emissions from fossil fuels produced on Federal lands in 2014 were 1,279.0 million metric tons of carbon dioxide equivalent (MMT CO 2 Eq.) for carbon dioxide (CO 2 ), 47.6 MMT CO 2 Eq. for methane (CH 4 ), and 5.5 MMT CO 2 Eq. for nitrous oxide (N 2 O). Compared to 2005, the 2014 totals represent decreases in emissions for all three greenhouse gases (decreases of 6.1 percent for CO 2 , 10.5 percent for CH 4 , and 20.3 percent for N 2 O). Emissions from fossil fuels produced on Federal lands represent, on average, 23.7 percent of national emissions for CO 2 , 7.3 percent for CH 4 , and 1.5 percent for N 2 O over the 10 years included in this estimate. In 2005, Federal lands of the conterminous United States stored 82,289 MMT CO 2 Eq. in terrestrial ecosystems. By 2014, carbon storage, or sequestration, was estimated at 83,600 MMT CO 2 Eq., representing an increase of 1.6 percent, or 1,311 MMT CO 2 Eq. Soils stored most of the ecosystem carbon (63 percent), followed by live vegetation (26 percent) and dead organic matter (11 percent). The rate of net carbon uptake in ecosystems ranged from a sink (sequestration) of 475 million metric tons of carbon dioxide per year (MMT CO 2 Eq./yr) to a source (emission) of 51 MMT CO 2 Eq./yr because of annual variability in climate and weather, rates of land-use and land-cover change, and wildfire frequency, among other factors. At the national level, the USGS estimates that terrestrial ecosystems (forests, grasslands, and shrublands) on Federal lands sequestered an average of 195 MMT CO 2 Eq./yr between 2005 and 2014, offsetting approximately 15 percent of the CO 2 emissions resulting from the extraction of fossil fuels on Federal lands and their end-use combustion. The USGS estimates presented in this report represent a first-of-its-kind accounting for the emissions resulting from fossil fuel extraction on Federal lands and the end-use combustion of those fuels, as well as for the sequestration of carbon in terrestrial ecosystems on Federal lands. The net CO 2 emissions estimate, which is the difference between the emitted and sequestered CO 2 , provides an informative combined result describing the emissions (fossil fuel extraction and end-use combustion) associated with a State’s Federal lands and sequestration on those same lands. The estimates included in this report can provide context for future energy decisions, as well as a basis to track change in the future.

Scientific Investigations Report↗
USGS2022

Treatment of the Chicot and Evangeline aquifers as a single hydrogeologic unit and use of geostatistical interpolation methods to develop gridded surfaces of water-level altitudes and water-level changes in the Chicot and Evangeline aquifers (undifferentiated) and Jasper aquifer, greater Houston area, Texas, 2021

The greater Houston area of Texas includes approximately 11,000 square miles and encompasses all or part of 11 counties (Harris, Galveston, Fort Bend, Montgomery, Brazoria, Chambers, Grimes, Liberty, San Jacinto, Walker, and Waller). From the early 1900s until the mid-1970s, groundwater withdrawn from the three primary aquifers that compose the Gulf Coast aquifer system—the Chicot, Evangeline, and Jasper aquifers—had been the primary source of water for the greater Houston area. The withdrawal of groundwater was unregulated prior to 1975, resulting in land-surface subsidence caused by large water-level declines in the greater Houston area. This report, prepared by the U.S. Geological Survey in cooperation with the Harris-Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, Lone Star Groundwater Conservation District, and Brazoria County Groundwater Conservation District, describes updates to the ways in which water-level altitudes and water-level changes in the greater Houston area are presented relative to previous U.S. Geological Survey reports. The first update involves presenting water-level altitudes and water-level changes as a combined (undifferentiated) representation of the Chicot and Evangeline aquifers. The second update concerns the methods used to depict water-level altitudes and water-level changes in the greater Houston area in interpretive reports, with geostatistical interpolation methods replacing manual contouring methods. The Chicot and Evangeline aquifers have historically been described as distinct hydrogeologic units for the purpose of water-level mapping. A confining unit does not separate these two aquifers in the study area, and water-level data from colocated wells screened in these aquifers indicate that there is likely a substantial degree of hydrogeologic connection. From a groundwater-flow perspective, these two aquifer units predominantly function as a single unit. Hence, the decision was made to combine the Chicot and Evangeline aquifers into a single, undifferentiated hydrogeologic unit for the purposes of assessing water-level altitudes and water-level changes over time. The 2020 water-level altitudes for the Chicot, Evangeline, and Jasper aquifers were re-created in this report from computer algorithms of the contoured datasets as gridded surfaces to demonstrate the similarity of results from geostatistical interpolation methods to those from manual contouring methods.

Texas↗
USGS2023

Occurrence of pharmaceutical compounds in the San Antonio segment of the Edwards (Balcones fault zone) aquifer, south-central Texas, June 2018–August 2020

The occurrence of pharmaceutical compounds (hereinafter referred to as “pharmaceuticals”) in surface water that recharges the San Antonio segment of the Edwards aquifer in south-central Texas is of concern with respect to potential effects on groundwater quality. This study, conducted during June 2018–August 2020 by the U.S. Geological Survey in cooperation with the San Antonio Water System, used a source-to-sink approach (that is, from aquifer recharge to aquifer discharge) to compare the occurrences and concentrations of pharmaceuticals in recharging (losing) streams to those in relatively shallow and relatively deep groundwater. Individual pharmaceutical concentrations in surface water were all less than 200 nanograms per liter, and most were less than 50 nanograms per liter. The two most common pharmaceuticals in surface water were metformin (50-percent detection frequency) and caffeine (25-percent detection frequency). In contrast to surface-water sites, few detections of pharmaceuticals above the detection limit were quantified at groundwater sites. On the basis of studied sample sites that are considered to be representative of the Edwards aquifer recharge zone, groundwater results collectively indicate that pharmaceuticals currently (2020) do not substantially impair water quality in the shallow unconfined part of the Edwards aquifer. Although groundwater pharmaceutical detections were not common, two detections of acetaminophen occurred in samples collected from a relatively deep confined part of the aquifer, indicating that this part of the aquifer is potentially vulnerable to pharmaceutical contamination. The near absence of wastewater treatment plant discharges and Texas Land Application Permit facilities within the drainage areas of streams in this study could explain reduced inputs of pharmaceuticals relative to pesticides on the Edwards aquifer recharge zone and their reduced occurrence in unconfined groundwater. In the western part of the study area, numerous pharmaceutical detections in the Frio River indicate that pharmaceutical sources in rural areas also exist with potential water-quality effects. Although reported pharmaceutical concentrations for the San Antonio segment of the Edwards aquifer are currently (2020) low, ongoing development in the region has the potential to increase contaminant loads, including for pharmaceuticals.

Texas↗
USGS2007

Variations in City Exposure and Sensitivity to Tsunami Hazards in Oregon

Evidence of past events and modeling of potential future events suggest that tsunamis are significant threats to Oregon coastal communities. Although a potential tsunami-inundation zone from a Cascadia Subduction Zone earthquake has been delineated, what is in this area and how communities have chosen to develop within it have not been documented. A vulnerability assessment using geographic-information-system tools was conducted to describe tsunami-prone landscapes on the Oregon coast and to document city variations in developed land, human populations, economic assets, and critical facilities relative to the tsunami-inundation zone. Results indicate that the Oregon tsunami-inundation zone contains approximately 22,201 residents (four percent of the total population in the seven coastal counties), 14,857 employees (six percent of the total labor force), and 53,714 day-use visitors on average every day to coastal Oregon State Parks within the tsunami-inundation zone. The tsunami-inundation zone also contains 1,829 businesses that generate approximately $1.9 billion in annual sales volume (seven and five percent of study-area totals, respectively) and tax parcels with a combined total value of $8.2 billion (12 percent of the study-area total). Although occupancy values are not known for each facility, the tsunami-inundation zone also contains numerous dependent-population facilities (for example, adult-residential-care facilities, child-day-care facilities, and schools), public venues (for example, religious organizations and libraries), and critical facilities (for example, police stations). Racial diversity of residents in the tsunami-inundation zone is low, with 96 percent identifying themselves as White, either alone or in combination with one or more race. Twenty-two percent of the residents in the tsunami-inundation zone are over 65 years in age, 36 percent of the residents live on unincorporated county lands, and 37 percent of the households are renter occupied. The employee population in the tsunami-inundation zone is largely in accommodation and food services, retail trade, manufacturing, and arts and entertainment sectors. Results indicate that vulnerability, described here by exposure (the amount of assets in tsunami-prone areas) and sensitivity (the relative percentage of assets in tsunami-prone areas) varies considerably among 26 incorporated cities in Oregon. City exposure and sensitivity to tsunami hazards is highest in the northern portion of the coast. The City of Seaside in Clatsop County has the highest exposure, the highest sensitivity, and the highest combined relative exposure and sensitivity to tsunamis. Results also indicate that the amount of city assets in tsunami-prone areas is weakly related to the amount of a community's land in this zone; the percentage of a city's assets, however, is strongly related to the percentage of its land that is in the tsunami-prone areas. This report will further the dialogue on societal risk to tsunami hazards in Oregon and help identify future preparedness, mitigation, response, and recovery planning needs within coastal cities and economic sectors of the state of Oregon.

Scientific Investigations Report↗