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190 records · Page 11Linked to original sources
USGS2017

Water-quality trends in the nation’s rivers and streams, 1972–2012—Data preparation, statistical methods, and trend results

Since passage of the Clean Water Act in 1972, Federal, State, and local governments have invested billions of dollars to reduce pollution entering rivers and streams. To understand the return on these investments and to effectively manage and protect the Nation’s water resources in the future, we need to know how and why water quality has been changing over time. As part of the National Water-Quality Assessment Project, of the U.S. Geological Survey’s National Water-Quality Program, data from the U.S. Geological Survey, along with multiple other Federal, State, Tribal, regional, and local agencies, have been used to support the most comprehensive assessment conducted to date of surface-water-quality trends in the United States. This report documents the methods used to determine trends in water quality and ecology because these methods are vital to ensuring the quality of the results. Specific objectives are to document (1) the data compilation and processing steps used to identify river and stream sites throughout the Nation suitable for water-quality, pesticide, and ecology trend analysis, (2) the statistical methods used to determine trends in target parameters, (3) considerations for water-quality, pesticide, and ecology data and streamflow data when modeling trends, (4) sensitivity analyses for selecting data and interpreting trend results with the Weighted Regressions on Time, Discharge, and Season method, and (5) the final trend results at each site. The scope of this study includes trends in water-quality concentrations and loads (nutrient, sediment, major ion, salinity, and carbon), pesticide concentrations and loads, and metrics for aquatic ecology (fish, invertebrates, and algae) for four time periods: (1) 1972–2012, (2) 1982–2012, (3) 1992–2012, and (4) 2002–12. In total, nearly 12,000 trends in concentration, load, and ecology metrics were evaluated in this study; there were 11,893 combinations of sites, parameters, and trend periods. The final trend results are presented with examples of how to interpret the results from each trend model. Interpretation of the trend results, such as causal analysis, is not included.

Scientific Investigations Report↗
USGS2022

To catch a (marsh) predator: Modified trapping methods for breeding and wintering Northern Harriers (Circus hudsonius)

Although there are a variety of methods available for trapping raptors, some species, such as Northern Harriers ( Circus hudsonius ), are not easily captured with standard methods. We tested several existing trapping methods and modified two of them based on Northern Harrier ecology and behavior across seasons in a study population in California. No previously successful methods described in the literature were effective for our study population. Two modified methods were most effective for trapping Northern Harriers: (1) placing two dho-gazas around the nest in a V-shape and flushing the adult female into the nets during the breeding season, and (2) using remote-triggered bow nets baited with waterbird carcasses in winter. Dho-gazas at the nest worked well during the early nestling-rearing stage, when nestlings were younger than 2 wk old and adult females were most attentive. This method was not suitable during the incubation stage because Northern Harriers are prone to nest abandonment. In the winter, Northern Harriers are known to scavenge, yet this aspect of their behavioral ecology has previously been rarely exploited for trapping purposes. These two methods allow for selective Northern Harrier trapping across seasons and provide modified options for research on this understudied and declining species in North America.

California↗
USGS2025

Landsat surface product validation instrumentation: The BigMAC exercise

Users of Earth remotely sensed optical imagery are increasingly demanding a surface reflectance or surface temperature product instead of the top-of-atmosphere products that have been produced historically. Validating the accuracy of surface products remains a difficult task since it involves assessment across a range of atmospheric profiles, as well as many different land surface types. Thus, standard approaches from the satellite calibration community do not apply and new technologies need to be developed. The Big Multi-Agency Campaign (BigMAC) was developed to assess current technologies that might be used for validation of surface products derived from satellite imagery, with emphasis on Landsat. Conducted in August, 2021, in Brookings, SD, USA, a variety of measurement technologies were fielded and assessed for accuracy, precision, and deployability. Each technology exhibited its strengths and weaknesses. Handheld spectroradiometers are capable of surface reflectance measurements with accuracies in the 0.01 - 0.02 absolute reflectance units, but are expensive to deploy. Unmanned Aircraft System (UAS)-based radiometers have the potential of making measurements with similar accuracy, but are also difficult to deploy. Mirror-based empirical line methods showed improving accuracy potential, but deployment also remains an issue. However, there are inexpensive radiometers designed for long-term autonomous use that exhibited good accuracy and precision, as well as being easy to deploy. Thermal measurement technologies showed accuracy potential in the 1 - 2K range, and some easily deployable instruments are available. Results from BigMAC indicate there are technologies available today to begin making operational surface reflectance/temperature measurements and strong potential for improvements in the future.

Sensors↗
USGS1986

Domingo's story

Explore the source record for details and available documents.

North American Falconers Association Journal↗
USGS1985

PRELIMINARY EVALUATION OF LANDSAT-4 THEMATIC MAPPER DATA FOR THEIR GEOMETRIC AND RADIOMETRIC ACCURACIES.

This report describes results of some preliminary analyses of Landsat-4 Thematic Mapper data for the NASA Landsat Image Quality Analysis program. The work is being done under interagency agreement S-12407-C between the U. S. Geological Survey and NASA-Goddard Space Flight Center. Landsat-4 TM scenes for Washington, D. C. Macon, Georgia (40050-15333, September 4, 1982) and Cape Canaveral, Florida have been examined to determine their geometric and radiometric accuracy. In addition, parts of these scenes are also being analyzed to determine the ability to identify specific rock types with the added near-infrared TM bands.

Conference Paper↗
USGS2011

The population crash of the white-rumped vulture, and its struggle to recover

The white-rumped vulture Gyps bengalensis was once the most abundant bird of prey on the Indian sub-continent. This species easily adapted to life in urban settings; thriving as a keystone species that maintained an ecological balance between the living and the dead. Dead livestock comprised the bulk of the white-rumped vulture diet and was ultimately responsible for its catastrophic population crash. Within ten years of the first documented population declines more than 99% of the white-rumped vultures were lost. The white-rumped vulture was listed as critically endangered in 2000 and has since remained at high risk for extinction.

The Falconer↗
USGS2018

Ground-nesting great horned owl in Suisun Marsh, California

Great horned owls (Bubo virginianus) are widespread throughout North, Central, and parts of South America (Artuso et al. 2013). Across this range, great horned owls are generalists, occupying a diverse range of habitats including deciduous and coniferous forests, wetlands, and agricultural landscapes. Within these habitats, great horned owls are generally found near upland or short-vegetation habitat suitable for locating prey (Artuso et al. 2013). In Suisun Marsh, California, great horned owls primarily occupy stands of non-native eucalyptus (Eucalyptus spp.), as well as man-made structures like waterfowl-nesting platforms (Figure 1) and on dock pilings over water (Figure 2), and they forage in nearby upland fields and seasonally flooded, diked wetlands managed primarily for waterfowl (USGS unpublished data).

California↗