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At least 73 records · Page 4Linked to original sources
USGS1989

Summary of water-resources activities of the U.S. Geological Survey in Colorado– Fiscal year 1989

The biennial summary of water resources activities in Colorado is presented for fiscal year 1989. The report includes an introduction of these activities and names of the management personnel to whom information requests may be addressed, a summary of the U.S. Geological Survey mission and of the Water Resources Division mission, and a discussion of the water resources in Colorado in fiscal year 1989, including data collection on surface water and groundwater. All current Colorado hydrologic investigations are listed--their problems, objectives, approaches, progress, and plans for fiscal year 1989. A list of current cooperators, for fiscal year 1989 and a list of reports published or released during fiscal years 1987, 1988, and 1989 also are given. (USGS)

Colorado↗
USGS2021

Mass eruption rate, column height, and duration dataset for volcanic eruptions

This report describes a dataset assembled and curated as part of a project funded by the Earthquake Commission Biennial Grant 20781, Towards real-time probabilistic ash deposition forecasting for Aotearoa New Zealand. This dataset compiles measured, estimated, and calculated values for volcanic eruption mass eruption rates, column heights, and durations. Data comes from 213 eruptions, with about a third from New Zealand volcanoes. 65% of eruptions have a value for all three parameters. Eruptions are further classified according to magma and eruption type to prepare for further analysis. This dataset will be used to develop prior probability density functions (PDFs) for mass eruption rate (MER), column height, and duration to quantify uncertainty in volcanological inputs with the aim of production of real-time probabilistic ashfall forecasts.

GNS Science Report↗
USGS2025

Interspecific interactions moderate direct effects of vegetation change resulting from prescribed fires

Savannas depend on frequent, low-intensity fires that shape animal and plant communities. These fires alter animal populations, movement, and habitat use. Here, we report on how fires in a longleaf pine (Pinus palustris) savanna affected small mammal microhabitat use via changes in competition and predation. We monitored small mammal populations and vegetation subjected to biennial prescribed fires and compared microhabitat use of three small mammal populations [hispid cotton rats (Sigmodon hispidus), cotton mice (Peromyscus gossypinus) and oldfield mice (Peromyscus polionotus)] in the presence and absence of mesocarnivores while accounting for changes in density and movement of each small mammal species. Densities of cotton rats varied greatly across years but were similar between predator exclosures and controls. However, frequency of use was greater in exclosures than in controls irrespective of vegetation characteristics, suggesting predation risk altered cotton rat microhabitat use. Conversely, higher relative abundance of cotton rats was associated with lower cotton mouse and oldfield mouse use, suggesting spatial separation in niche and indicating that cotton mice expand their realized niche following predation-induced declines of cotton rats associated with prescribed burn events. Our results contribute to a better understanding of pyrodiversity and how interspecific interactions can moderate effects of vegetation changes following prescribed fires.

Georgia↗
USGS2022

Black Abalone surveys at Naval Base Ventura County, San Nicolas Island, California—2021, annual report

The U.S. Geological Survey monitors a suite of intertidal black abalone sites at San Nicolas Island, California, in cooperation with the U.S. Navy, which owns the island. The nine rocky intertidal sites were established in 1980 to study the potential effect of translocated sea otters on the intertidal black abalone population at the island. The sites were monitored from 1981 to 1997, usually annually or biennially. Monitoring resumed in 2001 and has been completed annually since then. Since 2018, the work has been carried out by the U.S. Geological Survey Western Ecological Research Center. The study sites became particularly important, from a management perspective, after a virulent disease decimated black abalone populations throughout southern California beginning in the mid-1980s. The disease, withering syndrome, was first observed on San Nicolas Island in 1992 and during the next few years, it reduced the population there by more than 99 percent. The species was subsequently listed as endangered under the Endangered Species Act in 2009. The subject of this report is the 2021 survey of the sites and how the measured population status compares to the long-term data (collected over several decades) at San Nicolas Island. During the last two decades, the total monitored black abalone population at the island has grown approximately ten-fold after the disease related decline, from about 200 to more than 2,000 abalone. Since it was first consistently measured in 2005, the mean distance between adjacent black abalone has decreased substantially from approximately 50 centimeters to less than 15 centimeters, indicating that abalone are close enough together at several of the sites to reproduce successfully. The 2021 counts were the first since 2016 to indicate a possible decline in the monitored population at San Nicolas Island. Although still more than ten times the population counted in 2001, counts on the transects dropped by 13.6 percent from the survey count in 2020. The most significant decline was the loss of 341 abalone, from the previous count of 547, on a transect that since 2002 had the highest count of all 44 transects. Between 2020 and 2021, there were increases and decreases at the sites and the transects at each site. Although the 2021 count was lower than the 2020 count, it was the second highest since 1997. Based on the number of small abalone counted, recruitment rates were similar to most years since 2008 and higher than the rates observed before the population declines resulting from withering syndrome.

California↗
USGS2026

Black abalone surveys at Naval Base Ventura County, San Nicolas Island, California—2023 annual report

The U.S. Geological Survey monitors a suite of intertidal black abalone ( Haliotis cracherodii ) sites at San Nicolas Island, California, in cooperation with the U.S. Navy, which owns the island. The nine rocky intertidal sites were established in 1980 to study the potential effect of translocated sea otters on the intertidal black abalone population at the island. The sites were monitored from 1981 to 1997, typically annually or biennially. Monitoring resumed in 2001 and has been completed annually thereafter. Since 2018, the work has been carried out by the U.S. Geological Survey Western Ecological Research Center. The study sites became particularly important, from a management perspective, after a virulent disease decimated black abalone populations throughout southern California beginning in the mid-1980s. The disease, withering syndrome ( Candidatus Xenohaliotis californiensis ), was first observed on San Nicolas Island in 1992 and over the next few years, withering syndrome reduced the black abalone population on San Nicolas Island by more than 99 percent. In 2009, the black abalone subsequently was listed as endangered under the Endangered Species Act. The subject of this report is the 2023 survey of the sites and the status of the measured population in comparison to long-term patterns (based on data collected since 1981) at San Nicolas Island. Between the years 2000 and 2023, the total monitored black abalone population at the island has grown from roughly 200 to more than 2,500 abalone following disease-related decline. Since it was first consistently measured in 2005, the average distance between adjacent black abalone has decreased substantially from approximately 50 centimeters to less than 15 centimeters, indicating that abalone are sufficiently close together at several of the sites to reproduce successfully. The total abalone count in 2023 was 2,570, which was 19.2 percent higher than in 2022 and the highest count since 1993. All nine sites had higher counts in 2023 than in the previous year. Over 25 percent of the black abalone counted in 2023 were classified as recruits, defined as having a shell length of 3 centimeters or less.

California↗
USGS2025

Black abalone surveys at Naval Base Ventura County, San Nicolas Island, California—2022 annual report

The U.S. Geological Survey monitors a suite of intertidal black abalone ( Haliotis cracherodii ) sites at San Nicolas Island, California, in cooperation with the U.S. Navy, which owns the island. The nine rocky intertidal sites were established in 1980 to study the potential effect of translocated southern sea otters ( Enhydra lutris nereis ) on the intertidal black abalone population at San Nicolas Island. The sites were monitored, typically annually or biennially, from 1981 to 1997. Monitoring resumed in 2001 and has been completed annually thereafter. Since 2018, the monitoring has been carried out by the U.S. Geological Survey Western Ecological Research Center. The study sites became particularly important from a management perspective after a virulent disease decimated black abalone populations throughout southern California beginning in the mid-1980s. The disease, withering syndrome, was first observed on San Nicolas Island in 1992, and during the next few years, withering syndrome reduced the black abalone population on San Nicolas Island by more than 99 percent. The black abalone was subsequently listed as endangered under the Endangered Species Act in 2009. The subject of this report is the 2022 survey of the sites and the status of the measured population of black abalone in comparison to long-term patterns (based on data collected since 1981) at San Nicolas Island. Between the years 2000 and 2022, the total monitored black abalone population on the island has grown from roughly 200 to more than 2,000, approximately a ten-fold increase following the disease-related decline. Since it was first consistently measured in 2005, the distance between adjacent black abalone has decreased substantially from approximately 50 centimeters to less than 15 centimeters, indicating that black abalone are sufficiently close together at several of the sites to reproduce successfully. The total black abalone count in 2022 was 2,156, which was 7.9 percent lower than the total count in 2020 but 6.6 percent higher than in 2021. There were increases and decreases among the sites and transects within each site in 2022, but six of the nine sites had higher counts than in the previous year. The 2022 count is one of the highest since 1993, second only to the 2020 count. In 2022, the annual recruitment rate, defined as the percentage of measured black abalone with a shell length of 3 centimeters or less, was the second highest recorded, only slightly less than in 2017.

California↗
USGS1994

Idaho's surface-water-quality monitoring program: results from five sites sampled during water years 1990-93

In 1990, the U.S. Geological Survey (USGS), in cooperation with the Idaho Department of Health and Welfare, Division of Environmental Quality, implemented a statewide water-quality monitoring program in response to Idaho's antidegradation policy as required by the Clean Water Act. The program objective is to provide water-quality managers with a coordinated statewide network to detect trends in surface-water quality. The monitoring program includes the collection and analysis of samples from 56 sites on the Bear, Clearwater, Kootenai, Pend Oreille, Salmon, Snake, and Spokane Rivers and their tributaries (fig. 1). Samples are collected every year at 5 sites (annual sites) in drainage basins where long-term water-quality management is practiced, every other year at 19 sites (biennial sites) in basins where land and water uses change slowly, and every third year at 32 sites (triennial sites) where future development may affect water quality. Each year, 25 of the 56 sites are sampled. This report discusses results of sampling at five annual sites. During water years 1990-93 (October 1, 1989, through September 30, 1993), samples were collected six times per year at the five annual sites (fig. 1). Onsite analyses were made for discharge, specific conductance, pH, temperature, dissolved oxygen, bacteria (fecal coliform and fecal streptococci), and alkalinity. Laboratory analyses were made for major ions, nutrients, trace elements, and suspended sediment. Suspended sediment, nitrate, fecal coliform, trace elements, and specific conductance were used to characterize surface-water quality. Because concentrations of all trace elements except zinc were near detection limits, only zinc is discussed.

Idaho↗
USGS2015

Air- and stream-water-temperature trends in the Chesapeake Bay region, 1960-2014

Water temperature is a basic, but important, measure of the condition of all aquatic environments, including the flowing waters in the streams that drain our landscape and the receiving waters of those streams. Climatic conditions have a strong influence on water temperature, which is therefore naturally variable both in time and across the landscape. Changes to natural water-temperature regimes, however, can result in a myriad of effects on aquatic organisms, water quality, circulation patterns, recreation, industry, and utility operations. For example, most species of fish, insects, and other organisms, as well as aquatic vegetation, are highly dependent on water temperature. Warming waters can result in shifts in floral and faunal species distributions, including invasive species and pathogens previously unable to inhabit the once cooler streams. Many chemical processes are temperature dependent, with reactions occurring faster in warmer conditions, leading to degraded water quality as contaminants are released into waterways at greater rates. Circulation patterns in receiving waters, such as bays and estuaries, can change as a result of warmer inflows from streams, thereby affecting organisms in those receiving waters. Changes in abundance of some aquatic species and (or) degradation of water quality can reduce the recreational value of water bodies as waters are perceived as less desirable for water-related activities or as sportfish become less available for anglers. Finally, increasing water temperatures can affect industry and utilities as the thermal capacity is reduced, making the water less effective for cooling purposes. Chesapeake Bay is the largest estuary in the United States. Eutrophication, the enrichment of a water body with excess nutrients, has plagued the bay for decades and has led to extensive restoration efforts throughout the bay watershed. The warming of stream water can exacerbate eutrophication through increased release of nutrients from in-stream sediments, so understanding changes in stream-water temperature throughout the bay watershed is critical to resource managers seeking to restore the bay ecosystem. The U.S. Environmental Protection Agency (EPA) uses indicators that “represent the state or trend of certain environmental or societal conditions … to track and better understand the effects of changes in the Earth’s climate” (U.S. Environmental Protection Agency, 2014). Updates to these indicators are published biennially by the EPA. The U.S. Geological Survey (USGS), in cooperation with the EPA, has completed analyses of air- and stream-water-temperature trends in the Chesapeake Bay region to be included as an indicator in a future release of the EPA report.

Delaware, Maryland, New York, Pennsylvania, Virgin↗
USGS1995

Proceedings of the second biennial conference on research in Colorado Plateau National Parks

On 25-28 October 1993 in Flagstaff, Arizona, the National Biological Service Colorado Plateau Research Station (formerly National Park Service Cooperative Park Studies Unit) and Northern Arizona University hosted the Second Biennial Conference of Research on the Colorado Plateau. The conference theme focused on research, inventory, and monitoring on the federal, state, and private lands in the Colorado Plateau biogeographic province.

Utah;Colorado;Arizona;New Mexico↗
USGS2009

Atomic weights of the elements 1999

The biennial review of atomic-weight, Ar(E), determinations and other cognate data have resulted in changes for the standard atomic weights of the following elements: Presented are updated tables of the standard atomic weights and their uncertainties estimated by combining experimental uncertainties and terrestrial variabilities. In addition, this report again contains an updated table of relative atomic-mass values and half-lives of selected radioisotopes. Changes in the evaluated isotopic abundance values from those published in 1997 are so minor that an updated list will not be published for the year 1999. Many elements have a different isotopic composition in some nonterrestrial materials. Some recent data on parent nuclides that might affect isotopic abundances or atomic-weight values are included in this report for the information of the interested scientific community.

Pure and Applied Chemistry↗
USGS2011

Assessment of groundwater/surface-water interaction and simulation of potential streamflow depletion induced by groundwater withdrawal, Uinta River near Roosevelt, Utah

Roosevelt City, Utah, asserts a need for an additional supply of water to meet municipal demands and has identified a potential location for additional groundwater development at the Sprouse well field near the West Channel of the Uinta River. Groundwater is commonly hydraulically linked to surface water and, under some conditions, the pumpage of groundwater can deplete water in streams and other water bodies. In 2008, the U.S. Geological Survey, in cooperation with Roosevelt City, the Utah Department of Natural Resources, and the Ute Indian Tribe, began a study to improve understanding of the local interconnection between groundwater and surface water and to assess the potential for streamflow depletion from future groundwater withdrawals at a potential Roosevelt City development location—the Sprouse well field near the West Channel of the Uinta River. In the study, streamflow gains and losses at the river/aquifer boundary near the well field and changes in those conditions over time were assessed through (1) synoptic measurement of discharge in the stream at multiple sites using tracer-dilution methods, (2) periodic measurement of the vertical hydraulic gradient across the streambed, and (3) continuous measurement of stream and streambed water temperature using heat as a tracer of flow across the streambed. Although some contradictions among the results of the three assessment methods were observed, results of the approaches generally indicated (1) losing streamflow conditions on the West Channel of the Uinta River north of and upstream from the Sprouse well field within the study area, (2) gaining streamflow conditions south of and downstream from the well field, and (3) some seasonal changes in those conditions that correspond with seasonal changes in stream stage and local water-table altitudes. A numerical groundwater flow model was developed on the basis of previously reported observations and observations made during this study, and was used to estimate potential streamflow depletion that might result from future groundwater withdrawals at the Sprouse well field. The model incorporates concepts of transient groundwater flow conditions including fluctuations in groundwater levels and storage, and the distribution of and temporal variations in gains to and losses from streamflow in the West Channel of the Uinta River near the Sprouse well field. Two predictive model simulations incorporated additional future discharge from the Sprouse well field totaling 325 acre-feet annually and biennially during summer months. Results of the predictive model simulations indicate that the water withdrawn by the additional pumping was derived initially from aquifer storage and then, with time, predominantly from streamflow depletion. By the 10th year of the predictive simulation incorporating annual summer pumping from an additional public-supply well in the Sprouse well field, the simulation results indicate that 89 percent of a future annual 325 acre-feet of discharge is derived from depletion of streamflow in the West Channel of the Uinta River. A similar result was observed in a predictive model simulating the same discharge rate but with the new well being pumped every other year.

Utah↗
USGS2012

Methods for evaluating temporal groundwater quality data and results of decadal-scale changes in chloride, dissolved solids, and nitrate concentrations in groundwater in the United States, 1988-2010

Decadal-scale changes in groundwater quality were evaluated by the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. Samples of groundwater collected from wells during 1988-2000 - a first sampling event representing the decade ending the 20th century - were compared on a pair-wise basis to samples from the same wells collected during 2001-2010 - a second sampling event representing the decade beginning the 21st century. The data set consists of samples from 1,236 wells in 56 well networks, representing major aquifers and urban and agricultural land-use areas, with analytical results for chloride, dissolved solids, and nitrate. Statistical analysis was done on a network basis rather than by individual wells. Although spanning slightly more or less than a 10-year period, the two-sample comparison between the first and second sampling events is referred to as an analysis of decadal-scale change based on a step-trend analysis. The 22 principal aquifers represented by these 56 networks account for nearly 80 percent of the estimated withdrawals of groundwater used for drinking-water supply in the Nation. Well networks where decadal-scale changes in concentrations were statistically significant were identified using the Wilcoxon-Pratt signed-rank test. For the statistical analysis of chloride, dissolved solids, and nitrate concentrations at the network level, more than half revealed no statistically significant change over the decadal period. However, for networks that had statistically significant changes, increased concentrations outnumbered decreased concentrations by a large margin. Statistically significant increases of chloride concentrations were identified for 43 percent of 56 networks. Dissolved solids concentrations increased significantly in 41 percent of the 54 networks with dissolved solids data, and nitrate concentrations increased significantly in 23 percent of 56 networks. At least one of the three - chloride, dissolved solids, or nitrate - had a statistically significant increase in concentration in 66 percent of the networks. Statistically significant decreases in concentrations were identified in 4 percent of the networks for chloride, 2 percent of the networks for dissolved solids, and 9 percent of the networks for nitrate. A larger percentage of urban land-use networks had statistically significant increases in chloride, dissolved solids, and nitrate concentrations than agricultural land-use networks. In order to assess the magnitude of statistically significant changes, the median of the differences between constituent concentrations from the first full-network sampling event and those from the second full-network sampling event was calculated using the Turnbull method. The largest median decadal increases in chloride concentrations were in networks in the Upper Illinois River Basin (67 mg/L) and in the New England Coastal Basins (34 mg/L), whereas the largest median decadal decrease in chloride concentrations was in the Upper Snake River Basin (1 mg/L). The largest median decadal increases in dissolved solids concentrations were in networks in the Rio Grande Valley (260 mg/L) and the Upper Illinois River Basin (160 mg/L). The largest median decadal decrease in dissolved solids concentrations was in the Apalachicola-Chattahoochee-Flint River Basin (6.0 mg/L). The largest median decadal increases in nitrate as nitrogen (N) concentrations were in networks in the South Platte River Basin (2.0 mg/L as N) and the San Joaquin-Tulare Basins (1.0 mg/L as N). The largest median decadal decrease in nitrate concentrations was in the Santee River Basin and Coastal Drainages (0.63 mg/L). The magnitude of change in networks with statistically significant increases typically was much larger than the magnitude of change in networks with statistically significant decreases. The magnitude of change was greatest for chloride in the urban land-use networks and greatest for dissolved solids and nitrate in the agricultural land-use networks. Analysis of data from all networks combined indicated statistically significant increases for chloride, dissolved solids, and nitrate. Although chloride, dissolved solids, and nitrate concentrations were typically less than the drinking-water standards and guidelines, a statistical test was used to determine whether or not the proportion of samples exceeding the drinking-water standard or guideline changed significantly between the first and second full-network sampling events. The proportion of samples exceeding the U.S. Environmental Protection Agency (USEPA) Secondary Maximum Contaminant Level for dissolved solids (500 milligrams per liter) increased significantly between the first and second full-network sampling events when evaluating all networks combined at the national level. Also, for all networks combined, the proportion of samples exceeding the USEPA Maximum Contaminant Level (MCL) of 10 mg/L as N for nitrate increased significantly. One network in the Delmarva Peninsula had a significant increase in the proportion of samples exceeding the MCL for nitrate. A subset of 261 wells was sampled every other year (biennially) to evaluate decadal-scale changes using a time-series analysis. The analysis of the biennial data set showed that changes were generally similar to the findings from the analysis of decadal-scale change that was based on a step-trend analysis. Because of the small number of wells in a network with biennial data (typically 4-5 wells), the time-series analysis is more useful for understanding water-quality responses to changes in site-specific conditions rather than as an indicator of the change for the entire network.

Scientific Investigations Report↗
USGS1998

Changes to Idaho's statewide surface-water quality monitoring program since 1995

In 1990, the U.S. Geological Survey (USGS), in cooperation with the Idaho Division of Environmental Quality (formerly Idaho Department of Health and Welfare, Division of Environmental Quality), implemented a statewide water- quality monitoring program in response to Idaho’s antidegradation policy as required by the Clean Water Act (CWA). The objective was to provide water-quality managers with a coordinated state- wide program to detect trends in surface-water quality. The program design included chemical analyses of water samples collected at 56 sites on the Bear, Clearwater, Kootenai, Pend Oreille, Salmon, Snake, and Spokane Rivers and their tributaries (fig. 1). Samples were collected every year (1990 through 1995) at 5 sites (annual sites), every other year at 19 sites (biennial sites), and every third year at 32 sites (triennial sites). Each year, 25 of the 56 sites were sampled. During water years 1990–95 (October 1, 1989, to September 30, 1995), samples were collected bimonthly. Onsite analyses consisted of discharge, specific conductance, pH, temperature, dissolved oxygen, bacteria (fecal coliform and fecal streptococci), and alkalinity. Laboratory analyses consisted of major ions, nutrients, trace elements, turbidity, and suspended sediment. Analytical results from the five annual sites sampled during water years 1990–93 are presented in a report by O’Dell and Berenbrock (1994).

Idaho↗
USGS2001

Atomic weights of the elements 1999

The biennial review of atomic-weight, Ar(E), determinations and other cognate data have resulted in changes for the standard atomic weights of the following elements: from to nitrogen 14.006 74??0.000 07 14.0067??0.0002 sulfur 32.066??0.006 32.065??0.005 chlorine 35.4527??0.0009 35.453??0.002 germanium 72.61??0.02 72.64??0.01 xenon 131.29??0.02 131.293??0.006 erbium 167.26??0.03 167.259??0.003 uranium 238.0289??0.0001 238.028 91??0.000 03 Presented are updated tables of the standard atomic weights and their uncertainties estimated by combining experimental uncertainties and terrestrial variabilities. In addition, this report again contains an updated table of relative atomic mass values and half-lives of selected radioisotopes. Changes in the evaluated isotopic abundance values from those published in 1997 are so minor that an updated list will not be published for the year 1999. Many elements have a different isotopic composition in some nonterrestrial materials. Some recent data on parent nuclides that might affect isotopic abundances or atomic-weight values are included in this report for the information of the interested scientific community. ?? 2001 American Institute of Physics.

Journal of Physical and Chemical Reference Data↗
USGS1993

Proceedings of the first biennial conference of research in Colorado Plateau National Parks

The 19 papers in this volume were selected from the 46 presentations given at the First Biennial Conference on Research in Colorado Plateau National Parks. The overall theme for this meeting was research, inventory, and monitoring in National Park Service units on the Colorado Plateau. The conference, held in Flagstaff Arizona, on 22-25 July 1991, was sponsored by the National Park Service Cooperative Park Studies Unit, Northern Arizona University, and the Petrified Forest, Zion, and Grand Canyon natural history associations.

Utah;Colorado;Arizona;New Mexico↗
USGS2001

Clutch sizes and nests of tailed frogs from the Olympic Peninsula, Washington

In the summers 1995-1998, we sampled 168 streams (1,714 in of randomly selected 1-m bands) to determine distribution and abundance of stream amphibians in Olympic National Park, Washington. We found six nests (two in one stream) of the tailed frog, compared to only two nests with clutch sizes reported earlier for coastal regions. This represents only one nest per 286 in searched and one nest per 34 streams sampled. Tailed frogs occurred only in 94 (60%) of the streams and, for these waters, we found one nest per 171 in searched or one nest per 20 streams sampled. The numbers of eggs for four masses ((x) over bar = 48.3, range 40-55) were low but one single strand in a fifth nest had 96 eggs. One nest with 185 eggs likely represented communal egg deposition. Current evidence indicates a geographic trend with yearly clutches of relatively few eggs in coastal tailed frogs compared to biennial nesting with larger clutches for inland populations in the Rocky Mountains.

Northwest Science↗