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At least 1,135 records · Page 63Linked to original sources

USGS2002

Comparison of two probability distributions used to model sizes of undiscovered oil and gas accumulations: Does the tail wag the assessment?

Undiscovered oil and gas assessments are commonly reported as aggregate estimates of hydrocarbon volumes. Potential commercial value and discovery costs are, however, determined by accumulation size, so engineers, economists, decision makers, and sometimes policy analysts are most interested in projected discovery sizes. The lognormal and Pareto distributions have been used to model exploration target sizes. This note contrasts the outcomes of applying these alternative distributions to the play level assessments of the U.S. Geological Survey's 1995 National Oil and Gas Assessment. Using the same numbers of undiscovered accumulations and the same minimum, medium, and maximum size estimates, substitution of the shifted truncated lognormal distribution for the shifted truncated Pareto distribution reduced assessed undiscovered oil by 16% and gas by 15%. Nearly all of the volume differences resulted because the lognormal had fewer larger fields relative to the Pareto. The lognormal also resulted in a smaller number of small fields relative to the Pareto. For the Permian Basin case study presented here, reserve addition costs were 20% higher with the lognormal size assumption. ?? 2002 International Association for Mathematical Geology.

Mathematical Geology↗

USGS2002

USGS Coal Desorption Equipment and a Spreadsheet for Analysis of Lost and Total Gas from Canister Desorption Measurements

We have updated a simple polyvinyl chloride plastic canister design by adding internal headspace temperature measurement, and redesigned it so it is made with mostly off-the-shelf components for ease of construction. Using self-closing quick connects, this basic canister is mated to a zero-head manometer to make a simple coalbed methane desorption system that is easily transported in small aircraft to remote localities. This equipment is used to gather timed measurements of pressure, volume and temperature data that are corrected to standard pressure and temperature (STP) and graphically analyzed using an Excel(tm)-based spreadsheet. Used together these elements form an effective, practical canister desorption method.

Open-File Report↗

USGS2005

Acoustic Flow Monitor System - User Manual

INTRODUCTION The Acoustic Flow Monitor (AFM) is a portable system that was designed by the U.S. Geological Survey Cascades Volcano Observatory to detect and monitor debris flows associated with volcanoes. It has been successfully used internationally as part of real-time warning systems in valleys threatened by such flows (Brantley, 1990; Marcial and others, 1996; Lavigne and others, 2000). The AFM system has also been proven to be an effective tool for monitoring some non-volcanic debris flows. This manual is intended to serve as a basic guide for the installation, testing, and maintenance of AFM systems. An overview of how the system works, as well as instructions for installation and guidelines for testing, is included. Interpretation of data is not covered in this manual; rather, the user should refer to the references provided for published examples of AFM data.

Open-File Report↗

USGS2024

Target and suspect per- and polyfluoroalkyl substances in fish from an AFFF-impacted waterway

A major source of toxic per - and polyfluoroalkyl substances (PFAS) is aqueous film-forming foams (AFFF) used in firefighting and training at airports and military installations, however, PFAS have many additional sources in consumer products and industrial processes. A field study was conducted on fish tissues from three reaches of the Columbia Slough, located near Portland International Airport, OR, that are affected by AFFF and other PFAS sources. Fishes including largescale sucker ( Catostomus macrocheilus ), goldfish ( Carassius auratus ), and largemouth bass ( Micropterus salmoides ) were collected in 2019 and 2020. Fish blood, liver, and fillet (muscle) were analyzed for target and suspect PFAS by liquid chromatography high resolution mass spectrometry (LC-HRMS). Data were analyzed for patterns by fish species, tissue type, and river reach. Thirty-three out of 50 target PFAS and additional suspect compounds were detected at least once during the study, at concentrations up to 856 ng/g. Seven carboxylic acids (PFOA, PFNA, PFDA, PFUdA, PFDoA, PFTrDA, PFTeDA), three sulfonates (PFHxS, PFOS, PFDS), three electrofluorination-based compounds (FBSA, FHxSA, FOSA), and two fluorotelomer-based compounds (8:2 FTS, 10:2 FTS) were the most frequently detected compounds in all tissue types. The C6 (PFHxS) to C10 (PFDS) homologs were detected with PFOS and FHxSA at concentrations 1–3 orders of magnitude greater than the other PFAS detected. This is the first report of Cl-PFOS, FPeSA, and FHpSA detected in fish tissue. In all fish samples, fillet concentrations of PFAS were the lowest, followed by liver, and blood concentrations of PFAS were the highest. Differences in PFAS concentrations were driven primarily by tissue types and to a lesser extent fish species, but weakly by river reach. The Oregon Health Authority modified an existing fish consumption advisory on the Columbia Slough to recommend no whole-body consumption of most fish to avoid elevated levels of PFOS in fish liver. Measured PFAS concentrations in fish tissues indicate the potential for adverse ecological effects.

Oregon↗

USGS2015

Validation of mercury tip-switch and accelerometer activity sensors for identifying resting and active behavior in bears

Activity sensors are often included in wildlife transmitters and can provide information on the behavior and activity patterns of animals remotely. However, interpreting activity-sensor data relative to animal behavior can be difficult if animals cannot be continuously observed. In this study, we examined the performance of a mercury tip-switch and a tri-axial accelerometer housed in collars to determine whether sensor data can be accurately classified as resting and active behaviors and whether data are comparable for the 2 sensor types. Five captive bears (3 polar [ Ursus maritimus ] and 2 brown [ U. arctos horribilis ]) were fitted with a collar specially designed to internally house the sensors. The bears’ behaviors were recorded, classified, and then compared with sensor readings. A separate tri-axial accelerometer that sampled continuously at a higher frequency and provided raw acceleration values from 3 axes was also mounted on the collar to compare with the lower resolution sensors. Both accelerometers more accurately identified resting and active behaviors at time intervals ranging from 1 minute to 1 hour (≥91.1% accuracy) compared with the mercury tip-switch (range = 75.5–86.3%). However, mercury tip-switch accuracy improved when sampled at longer intervals (e.g., 30–60 min). Data from the lower resolution accelerometer, but not the mercury tip-switch, accurately predicted the percentage of time spent resting during an hour. Although the number of bears available for this study was small, our results suggest that these activity sensors can remotely identify resting versus active behaviors across most time intervals. We recommend that investigators consider both study objectives and the variation in accuracy of classifying resting and active behaviors reported here when determining sampling interval.

Ursus↗

USGS2019

Columbia Environmental Research Center

The U.S. Geological Survey Columbia Environmental Research Center performs research to solve challenging environmental problems related to contaminants and habitat alterations in aquatic and terrestrial ecosystems. The research is interdisciplinary and pursued through partnerships within the U.S. Geological Survey and with national, international, state, and local agencies; nongovernmental organizations; and universities. Research is prioritized to provide science to the U.S. Department of the Interior and other natural resource management agencies to inform rehabilitation of degraded habitats and imperiled fish and wildlife populations. The Columbia Environmental Research Center was established in 1966 in Columbia, Missouri, as the U.S. Fish and Wildlife Service’s Fish Pesticide Research Laboratory; the Columbia Environmental Research Center was incorporated into the U.S. Geological Survey in 1996. The U.S. Geological Survey’s staff of 130 includes 90 scientists of which one-half have advanced degrees in ecology, toxicology, biology, biochemistry, chemistry, hydrology, geology, and information technology.

Missouri↗

USGS1993

Hydrology and water quality of Wind Lake in southeastern Wisconsin

The hydrology and water quality of Wind Lake-a recreational lake in a densely populated area of southeastern Wisconsin was studied from October 1, 1987 through September 30,1989. A drought in 1988 affected the hydrologic budget of Wind Lake in water years 1988-89. Precipitation was 5.9 inches less than normal in water year 1988 but was 2.3 inches greater than normal in water year 1989. Streamflows were near normal in water year 1988 and 25 percent less than normal in water year 1989 as indicated by data from a nearby streamflow-gaging station. Surface runoff was the dominant source of water to the lake in water year 1988 and 75 percent of the inflow was from Big Muskego Lake. The water level in Big Muskego Lake was 1.1 feet below the dam crest at the start of the 1989 water year because of the 1988 drought. About 2,510 acre-feet of water had to fill Big Muskego Lake before water could discharge to Wind Lake. In water year 1989, surface runoff was still the dominant source of water to the lake, but Big Muskego Lake only contributed 52 percent of the water inflow. Streamflow dominated the outflow budget for both years. In water year 1988, 88 percent of the outflow budget left by way of Wind Lake outlet and 12 percent evaporated from the lake surface. In water year 1989, 81 percent of the outflow budget left by way of Wind Lake outlet and 19 percent evaporated from the lake surface. On the basis of outflow from Wind Lake for water year 1988, the hydraulic residence time was 0.46 year; in water year 1989 it was 1.05 years. The total phosphorus input to Wind Lake from external sources was the same for both years, 3,160 pounds. The largest percentage of the phosphorus load came from Big Muskego Lake-- 70 percent in water year 1988 and 65 percent in water year 1989. Analysis of data by use of Vollenweider's model indicates that the phosphorus loadings for each year would cause eutrophic conditions. Data from a nearby gaging station indicate that phosphorus loading to Wind Lake was less than normal. Phosphorus retention in the lake is small and averages 14 percent of the incoming load for both years. Oxygen depletion occurs in the bottom waters during winter and summer months. A maximum anoxic zone was reached on July 18, 1988, when depths greater than 15 feet (about 21 percent of the lake bottom area) were anoxic. Total phosphorus concentrations at the lake surface for both years ranged from 11 to 78 micrograms per liter. Mean total phosphorus concentrations in June, July, and August that had averaged 49 micrograms per liter in 1985 through 1987 declined to 20 micrograms per liter in water year 1988 and 22 micrograms per liter in water year 1989. This reduction was related to the drought and reduced phosphorus loadings. Phosphorus concentrations 1.5 feet above the lake bottom increase during summer anoxic periods. The phosphorus concentration increased at a rate of 5.2 and 4.8 micrograms per liter per day for total and dissolved orthophosphate phosphorus. A maximum concentration of 760 micrograms per liter of total phosphorus and 650 micrograms per liter of dissolved orthophosphate phosphorus occurred on September 21, 1988, just before autumn turnover. Internal loading of phosphorus for the period October 15, 1987 through October 14, 1988, was estimated to be 2,890 pounds. This represents 48 percent of the combined internal and external total-phosphorus input of 5,960 pounds. Algal populations in water year 1988 ranged from 28,200 to 1,610,000 cells per milliliter. A total of 143 species were identified. Blue-green algae dominated the algal population and ranged from 56 percent (February 16, 1988) to 99 percent (five other sampling dates). Aphanocapsa delicatissima caused the largest algal bloom, which reached a maximum concentration of 934,000 cells per milliliter (September 7, 1988). Zooplankton populations in water year 1988 ranged from 52.5 to 686 organisms per liter. Eighteen species were identified. The cladoceran, Daphnia, dominated 12 of the 18 samples.

Wisconsin↗

USGS2006

The National Assessment of Shoreline Change: A GIS compilation of vector shorelines and associated shoreline change data for the sandy shorelines of the California coast

Introduction The Coastal and Marine Geology Program of the U.S. Geological Survey has generated a comprehensive data clearinghouse of digital vector shorelines and shoreline change rates for the sandy shoreline along the California open coast. These data, which are presented herein, were compiled as part of the U.S. Geological Survey's National Assessment of Shoreline Change Project. Beach erosion is a chronic problem along many open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information including rates and trends of shoreline migration. There is also a critical need for shoreline change data that is consistent from one coastal region to another. One purpose of this work is to develop standard, repeatable methods for mapping and analyzing shoreline movement so that periodic, systematic, and internally consistent updates of shorelines and shoreline change rates can be made at a National Scale. This data compilation for open-ocean, sandy shorelines of the California coast is one in a series that already includes the Gulf of Mexico and the Southeast Atlantic Coast (Morton et al., 2004; Morton et al., 2005) and will eventually cover Washington, Oregon, and parts of Hawaii and Alaska. Short- and long-term shoreline change evaluations are determined by comparing the positions of three historical shorelines digitized from maps, with a modern shoreline derived from LIDAR (light detection and ranging) topographic surveys. Historical shorelines generally represent the following time-periods: 1850s-1880s, 1920s-1930s, and late 1940s-1970s. The most recent shoreline is from data collected between 1997 and 2002. Long-term rates of change are calculated by linear regression using all four shorelines. Short-term rates of change are end-point rate calculations using the two most recent shorelines. Please refer to our full report on shoreline change of the California coastline at http://pubs.usgs.gov/of/2006/1219/ for additional information regarding methods and results (Hapke et al., 2006). Data in this report are organized into downloadable layers by region (Northern, Central and Southern California) and are provided as vector datasets with metadata. Vector shorelines may represent a compilation of data from one or more sources and these sources are included in the dataset metadata. This project employs the Environmental Systems Research Institute's (ESRI) ArcGIS as it's GIS mapping tool and contains several data layers (shapefiles) that are used to create a geographic view of the California Coast. These vector data form a basemap comprised of polygon and line themes that include a U.S. coastline (1:80,000), U.S. cities, and state boundaries.

California↗

USGS1992

Pre-Elsonian mafic magmatism in the Nain Igneous Complex, Labrador: The bridges layered intrusion

Decades of work on the pristine, unmetamorphosed, and well exposed anorthositic, mafic and granitic rocks of the Nain igneous complex, Labrador, have led to the conclusion that all plutonic rocks in that area were emplaced in a short time intercal at about 1300 ± 10 Ma). We report here new isotopic data for mafic intrusive rocks that appear to have crystallized several hundred Ma earlier than the bulk of the plutonic activity in the Nain complex. The Bridges layered intrusion (BLI) is a small (15–20 km 2 ) lens of layered mafic rocks about 1.5 km thick, surrounded and intruded by anorthositic, leuconoritic and leucotroctolitic plutons in the middle of the coastal section of the Nain igneous complex. BLI shows very well developed magmatic structures, including channel scours, slump structures, and ubiquitous modally graded layering. Most rocks, however, show granular textures indicative of recrystallization, presumably caused by emplacement of younger anorthositic rocks. BLI contains cumulate rocks with slightly more primitive mineral compositions (An 60–83 , Fo 66–71 ) than those of other mafic intrusions in the Nain igneous complex, including Kiglapait. Sm-Nd isotopic data for 7 BLI whole-rocks ranging in composition between olivine melagabbro and olivine leucogabbro yield an age of 1667 ± 75 Ma, which we interpret as the time of primary crystallization. The internal isotopic systematics of the BLI have been reset, probably by intrusion of adjacent anorthositic plutons. A SmNd mineral isochron (plag, whole-rock, mafics) for a BLI olivine melagabbro gives an age of 1283 ± 22 Ma, equivalent within error of a mineral array (plag, whole-rock, opx, cpx) for an adjacent, igneous-textured, leuconorite vein (1266 ± 152 Ma). The initial Nd ratio for BLI corresponds to ϵ Nd = −3.18 ± 0.44. Other whole-rock samples, however, some with vein-like alteration (Chlorite, serpentine, amphiboles), show ϵ Nd values as low as −9.1, suggesting variable contamination by direct assimilation of early Archean crustal rocks and/or by fluids that have interacted with such crust. Adjacent anorthositic rocks also show variable ϵ Nd some as low as −14.7, implying larger degrees if crustal assimilation, perhaps by parental magmas during lower crustal ponding prior to emplacement. These contamination effects preclude straightforward determination of the isotopic character of mantle sources for both BLI and the anorthositic rocks.

Labrador↗

USGS2009

Determination of diffusion coefficients of hydrogen in fused silica between 296 and 523 K by Raman spectroscopy and application of fused silica capillaries in studying redox reactions

Diffusion coefficients ( D ) of hydrogen in fused silica capillaries (FSC) were determined between 296 and 523 K by Raman spectroscopy using CO 2 as an internal standard. FSC capsules (3.25 × 10 −4 m OD, 9.9 × 10 −5 m ID, and ∼0.01 m long) containing CO 2 and H 2 were prepared and the initial relative concentrations of hydrogen in these capsules were derived from the Raman peak-height ratios between H 2 (near 587 cm −1 ) and CO 2 (near 1387 cm −1 ). The sample capsules were then heated at a fixed temperature ( T ) at one atmosphere to let H 2 diffuse out of the capsule, and the changes of hydrogen concentration were monitored by Raman spectroscopy after quench. This process was repeated using different heating durations at 296 (room T ), 323, 375, 430, 473, and 523 K; the same sample capsule was used repeatedly at each temperature. The values of D (in m 2 s −1 ) in FSC were obtained by fitting the observed changes of hydrogen concentration in the FSC capsule to an equation based on Fick’s law. Our D values are in good agreement with the more recent of the two previously reported experimental data sets, and both can be represented by: ln D = - ( 16.471 ± 0.035 ) - 44589 ± 139 RT ( R 2 = 0.99991 ) "> lnD=-(16.471±0.035)-44589±139RT(R2=0.99991) where R is the gas constant (8.3145 J/mol K), T in Kelvin, and errors at 1 σ level. The slope corresponds to an activation energy of 44.59 ± 0.14 kJ/mol. The D in FSC determined at 296 K is about an order of magnitude higher than that in platinum at 723 K, indicating that FSC is a suitable membrane for hydrogen at temperature between 673 K and room temperature, and has a great potential for studying redox reactions at these temperatures, especially for systems containing organic material and/or sulphur.

Geochimica et Cosmochimica Acta↗

USGS2026

Surface-wave relocation and characterization of the 2024–2025 dyking episode along the Fentale–Dofen segment of the Ethiopian rift

From late-December 2024 to mid-March 2025, a 50-km-long dyke intrusion triggered over 300 earthquakes (magnitude 4 to 5.9) between Fentale and Dofen volcanoes along the Northern Main Ethiopian Rift. Dyke intrusions periodically occur along the Fentale–Dofen magmatic segment and are an expression of ongoing rift extension. Preliminary analyses using interferometric synthetic aperture radar revealed extensive ground deformation (up to 60 cm), which closely matched the temporal and spatial evolution of surface manifestations and earthquake locations from global catalogues. While global catalogues are critical for real-time monitoring, the precision of locations in remote and or sparsely instrumented regions can be low. In this investigation, we present surface-wave relocation results of the dyking episode that began near Fentale volcano in December 2024. We estimate relative locations using differential traveltimes measured from regional-to-teleseismic distance surface-wave observations of earthquakes reported by the U.S. Geological Survey. Relative relocations reduce the initial region of diffuse seismicity to a 50-km-long narrow band bounding the strike of surface manifestations and the zone of maximum surface deformation. We demonstrate the precision of surface-wave relocations over incremental time periods, capturing the progression of dyking from seismic onset through seismic migration and caldera subsidence. Results showcase the utility of surface-wave relocations in the characterization of dyking episodes and provide complementary insights into the current understanding of the Fentale–Dofen volcanic plumbing system.

Geophysical Journal International↗

USGS2026

Fossil footprints and Ice Age ecosystems of White Sands National Park

Introduction In September 2021, National Park Service staff, U.S. Geological Survey scientists, and an international team of researchers revealed evidence in the form of human footprints at White Sands National Park, New Mexico, that showed people were present in North America between 23,000 and 21,000 years ago. This time was during the Last Glacial Maximum, when large ice sheets covered much of the continent. The results stunned the scientific community and sparked a global debate. The story of how the discoveries were made, how they upended traditional thought, and how they “rewrote the book” on the earliest phases of North American prehistory is a classic example of the process of science.

New Mexico↗

USGS2019

From Manitoba to Texas: A study of the population genetic structure of bur oak (Quercus macrocarpa)

In the taxonomic world, the oaks are known as a rambunctious group, notorious for hybridizing. In this report, we present preliminary information to address the question of how much hybridization is occurring between bur oak and white oaks with which it is sympatric, through rangewide sampling of bur oak and five co-occurring species: white oak ( Q. alba L. ), swamp white oak ( Q. bicolor Willd. ), post oak ( Q. stellata Wangenh. ), chinkapin oak ( Q. muehlenbergii Engelm. ), and overcup oak ( Q. lyrata Walter ). Bur oak is known to hybridize with all of these species (Hardin 1975). Using our multilocus dataset, we find that despite apparent introgression, these oak species are genetically cohesive.

International Oaks↗

USGS2010

Gas, oil, and water production from Jonah, Pinedale, Greater Wamsutter, and Stagecoach Draw fields in the Greater Green River Basin, Wyoming

Gas, oil, and water production data were compiled from selected wells in four gas fields in rocks of Late Cretaceous age in southwestern Wyoming. This study is one of a series of reports examining fluid production from tight-gas reservoirs, which are characterized by low permeability, low porosity, and the presence of clay minerals in pore space. Production from each well is represented by two samples spaced five years apart, the first sample typically taken two years after commencement of production. For each producing interval, summary diagrams of oil versus gas and water versus gas production show fluid production rates, the change in rates during five years, the water-gas and oil-gas ratios, and the fluid type. These diagrams permit well-to-well and field-to-field comparisons. Fields producing water at low rates (water dissolved in gas in the reservoir) can be distinguished from fields producing water at moderate or high rates, and the water-gas ratios are quantified. The ranges of first-sample gas rates in Pinedale field and Jonah field are quite similar, and the average gas production rate for the second sample, taken five years later, is about one-half that of the first sample for both fields. Water rates are generally substantially higher in Pinedale than in Jonah, and water-gas ratios in Pinedale are roughly a factor of ten greater in Pinedale than in Jonah. Gas and water production rates from each field are fairly well grouped, indicating that Pinedale and Jonah fields are fairly cohesive gas-water systems. Pinedale field appears to be remarkably uniform in its flow behavior with time. Jonah field, which is internally faulted, exhibits a small spread in first-sample production rates. In the Greater Wamsutter field, gas production from the upper part of the Almond Formation is greater than from the main part of the Almond. Some wells in the main and the combined (upper and main parts) Almond show increases in water production with time, whereas increases in water production are rare in the upper part of the Almond, and a higher percentage of wells in the upper part of the Almond show water decreasing at the same rate as gas than in the main or combined parts of the Almond. In Stagecoach Draw field, the gas production rate after five years is about one-fourth that of the first sample, whereas in Pinedale, Jonah, and Greater Wamsutter fields, the production rate after five years is about one-half that of the first sample. The more rapid gas decline rate seems to be the outstanding feature distinguishing Stagecoach Draw field, which is characterized as a conventional field, from Pinedale, Jonah, and Greater Wamsutter fields, which are generally characterized as tight-gas accumulations. Oil-gas ratios are fairly consistent within Jonah, Pinedale, and Stagecoach Draw fields, suggesting similar chemical composition and pressure-temperature conditions within each field, and are less than the 20 bbl/mmcf upper limit for wet gas. However, oil-gas ratios vary considerably from one area to another in the Greater Wamsutter field, demonstrating a lack of commonality in either chemistry or pressure-temperature conditions among the six areas. In all wells in all four fields examined here, water production commences with gas production—there are no examples of wells with water-free production and no examples where water production commences after first-sample gas production. The fraction of records with water production higher in the second sample than in the first sample varies from field to field, with Pinedale field showing the lowest percentage of such cases and Jonah field showing the most. Most wells have water-gas ratios exceeding the amount that could exist dissolved in gas at reservoir pressure and temperature.

Wyoming↗

USGS2010

Dinosaur tracks from the Cedar Mountain Formation (Lower Cretaceous), Arches National Park, Utah

The seventh and largest known dinosaur tracksite from the Cedar Mountain Formation is reported from two important stratigraphic levels in the Ruby Ranch Member within the boundaries of Arches National Park. Previous reports of sites with a few isolated tracks are of limited utility in indicating the fauna represented by track makers. The Arches site reveals evidence of several theropod morphotypes, including a possible match for the coelurosaur Nedcolbertia and an apparently didactyl Utahraptor -like dromeosaurid. Sauropod tracks indicate a wide-gauge morphotype (cf. Brontopodus ). Ornithischian tracks suggest the presence of an iguandontid-like ornithopod and a large ankylosaur. Dinosaur track diversity is high in comparison with other early Cretaceous vertebrate ichnofaunas, and it correlates well with faunal lists derived from skeletal remains, thus providing a convincing census of the known fauna.

Utah↗

USGS2013

The Borderlands - A region of physical and cultural diversity: Chapter 2 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

The area surrounding the United States–Mexican border is very physically and culturally diverse and cannot be generalized by any single description. To assist in an accurate appraisal and understanding of this remarkable region, the Borderlands team has divided it into eight subareas based on the watershed subareas of the U.S. Geological Survey Border Environmental Health Initiative (http://borderhealth.cr.usgs.gov) (fig. 2–1), the boundaries of which are defined primarily by surface-water drainage basins. The drainage basins directly adjacent to or crossing the international boundary were automatically included in the defined border region, as were those basins that contain unconsolidated aquifers that extend to or cross the international boundary. Also, “protected areas” adjacent to included basins were selectively added to the defined border region. Though some geographic features are entirely within the Borderlands, many features—deserts, mountain ranges, rivers, etc.— extend beyond the region boundaries but are still influential to Borderlands environments (fig. 2–2). In some cases, the authors of the following chapters have made fine adjustments to the Borderlands boundaries, and they have described those alterations where necessary. By describing and studying these subareas individually and comparing them to one another, we can emphasize the physical and cultural diversity that makes the Borderlands such an important geographic area.

United States-Mexico Borderlands↗

USGS2011

Evaluation of the genetic distinctiveness of Greater Sage-grouse in the Bi-State Planning Area

The purpose of this study was to further characterize a distinct population of Greater Sage-grouse: the population located along the border between Nevada and California (Bi-State Planning Area) and centered around the Mono Basin. This population was previously determined to be genetically distinct from other Greater Sage-grouse populations across their range. Previous genetic work focused on characterizing genetic variation across the species' range and thereby used a coarse sampling approach for species characterization. The goal of this study was to investigate this population further by obtaining samples from breeding locations within the population and analyzing those samples with the same mitochondrial and microsatellite loci used in previous studies. Blood samples were collected in six locations within the Bi-State Planning Area. Genetic data from subpopulations were then compared with each other and also with two populations outside of the Bi-State Planning Area. Particular attention was paid to subpopulation boundaries and internal dynamics by drawing comparisons among particular regions within the Bi-State Planning Area and regions proximal to it. All newly sampled subpopulations contained mitochondrial haplotypes and allele frequencies that were consistent with the genetically unique Bi-State (Mono Basin) Greater Sage-grouse described previously. This reinforces the fact that this group of Greater Sage-grouse is genetically unique and warrants special attention. Maintaining the genetic integrity of this population could protect the evolutionary potential of this population of Greater Sage-grouse. Additionally, the White Mountains subpopulation was found to be significantly distinct from all other Bi-State subpopulations.

Open-File Report↗

USGS2018

Geospatial data for developing nutrient SPARROW models for the Midcontinental region of Canada and the United States

Through the International Watersheds Initiative of the International Joint Commission (IJC), the SpatiallyReferenced Regressions on Watershed attributes (SPARROW) model developed by the U.S. Geological Survey (USGS) is being applied to the Great Lakes, Rainy River – Lake of the Woods and Red-Assiniboine basins. The objective of this binational application of the SPARROW model is to better understand and quantify the sources of phosphorus (P) and nitrogen (N) that contribute to regional water-quality issues like algal blooms and eutrophication in Lake Erie and other parts of the Great Lakes, as well as Lake of the Woods. Led by the IJC, a team of researchers from the National Research Council of Canada – Ocean, Coastal and River Engineering Research Centre, USGS, and IJC are extending the SPARROW modelling work previously completed for the Red-Assiniboine basin and the U.S. portions of the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy river basins to cover all of the Great Lakes, Rainy River – Lake of the Woods and RedAssiniboine basins. The current effort is termed the Midcontinent SPARROW modelling study. This report describes the data used to develop the Midcontinent SPARROW models, specifically the sources of original data, assembling the data, and the processing and harmonization required between the U.S. and Canada data needed to produce these models. Details provided include the: development of a digital stream network and related catchments – most significantly in the Canadian regions of the Great Lakes and Rainy River – Lake of the Woods basins where these data were not available to create a seamless binational network across the model domain; calculation of variables to aid in the determination of in-stream and in-reservoir decay of P and N; quantification of Canadian diversions within the Midcontinental region (i.e., Lake St. Joseph, Long Lake and the Ogoki Reservoir); development of binational input nutrient sources considered for model development (i.e., land cover, inorganic farm fertilizer, manure, atmospheric deposition, point-source pollution from wastewatertreatment plants and contribution from non-modelled watersheds); and development of delivery variables considered to be most predominant (i.e., temperature, precipitation and ensuing runoff, soil permeability and clay content, slope of the catchments, and tile drainage). The majority of the geospatial data collection and processing was required for Canadian datasets because many of the U.S. datasets were already assembled for previous SPARROW model applications in the U.S. The task of harmonizing data between the U.S. and Canada was important to ensure consistency of the datasets used in the models. The harmonized digital stream network, delineated catchments and input data for each catchment (i.e., source and delivery variables), created for the Midcontinent SPARROW models, are available for download at url: https://doi.org/10.4224/300.0001.

Technical Report↗