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At least 181 records · Page 10Linked to original sources
USGS1993

Historical saturated thickness of the Edwards-Trinity aquifer system and selected contiguous hydraulically connected units, west-central Texas

The Edwards-Trinity Regional Aquifer-System Analysis (RASA) is one of 25 completed or ongoing studies conducted by the U.S. Geological Survey on regional aquifer systems that individually provide essential quantities of ground water to large parts of the country. Underlying about 42,000 mi 2 of west-central Texas, the Edwards-Trinity aquifer system extends approximately from Atascosa County in the southeast to Culberson County in the northwest and from the Rio Grande in the southwest to the Colorado River in the northeast (sheet 2). The Edwards-Trinity aquifer system spans four geographic subareas: Trans-Pecos, Edwards Plateau, Hill Country, and Balcones fault zone (fig. 1). The names of all aquifers in the study area were adopted for RASA purposes directly from nomenclature mandated by the Texas Water Plan (Texas Water Development Board, 1990). The Cretaceous rocks that compose the Edwards-Trinity aquifer system are primarily limestone and dolomite rock, with lesser quantities of terrigenous sand. Although the lithology varies locally and the rocks are not everywhere permeable in all directions, they combine to form a single regional aquifer system. The aquifer system comprises three aquifers and two confining units (figs. 2 and 3). The water-yielding units are the Edwards aquifer of the Balcones fault zone, the Trinity aquifer of the Balcones fault zone and Hill Country, and the Edwards-Trinity aquifer of the Edwards Plateau and Trans-Pecos. The confining units are the Hammett confining unit, which confines basal parts of the Trinity aquifer in the Hill Country and the Edwards-Trinity aquifer in the eastern part of the Edwards Plateau, and the Navarro-Del Rio confining unit, which confines the Edwards and Trinity aquifers along the southeastern margin of the Balcones fault zone. Parts of the aquifer system not overlain by one of these confining units are unconfined, or nearly so. The purposes of this report are to illustrate the historical distribution of saturated thickness (hereafter referred to as the saturated thickness) in the Edwards-Trinity aquifer system, summarize the reasons for the variation in the saturated thickness, and relate the regional effects of this variation to the distribution of transmissivity. The saturated thickness map (sheet 2) was determined for most of the area by subtracting the altitude of the base of the aquifer system (Barker and Ardis, 1992) from the altitude of the historical potentiometric surface (Bush and others, 1993). Where the Edwards and Trinity aquifers are confined in the Balcones fault zone, the saturated thickness is defined by the thickness of the aquifer system, which was determined by subtracting the altitude of the base of the aquifer system from the altitude of the base of the Navarro-Del Rio confining unit (G.E. Groschen and W.G. Stein, U.S. Geological Survey, written commun, 1990).

Texas↗
USGS2016

Archive of bathymetry and backscatter data collected in 2014 nearshore Breton and Gosier Islands, Breton National Wildlife Refuge, Louisiana

As part of the Barrier Island Monitoring Project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted nearshore geophysical surveys off Breton and Gosier Islands, Louisiana, in July and August of 2014. To assist the United States Fish and Wildlife Service (USFWS) with restoration planning efforts, the USGS was tasked with answering fundamental questions about the physical environment of the southern Chandeleur Islands, including the geology, morphology, and oceanography. Baseline data needed to answer these questions were either insufficient or missing. The USGS conducted a comprehensive geologic investigation in the summer of 2014, collecting geophysical and sedimentological data. Breton Island, located at the southern end of the Chandeleur Island chain in southeastern Louisiana, was recognized as a natural, globally significant nesting sanctuary for several bird species and was established as the Breton National Wildlife Refuge (NWR) in 1904. The areal extent of Breton Island has diminished 90 percent since 1920. Land loss is attributed to ongoing relative sea-level rise, diminished sediment supply, and storm impacts. The bird population on Breton Island has also declined over the years, most notably after Hurricane George in 1998 and after Hurricane Katrina in 2015; the latter completely submerged the island. Despite decreasing habitable acreage, migratory seabirds continue to return and nest on Breton Island. To prevent the island from being submerged in the future, and to protect, stabilize, and provide more nesting and foraging areas for the bird population, the USFWS proposed a restoration effort to rebuild Breton Island to its pre-Katrina footprint. This data series serves as an archive of processed interferometric swath and single-beam bathymetry data, and side-scan sonar data, collected in the nearshore of Breton and Gosier Islands, NWR, Louisiana. The data were collected during two USGS cruises (USGS Field Activity Numbers 2014-314-FA and 2014-317-FA) in July and August 2014. Geographic information system data products include a 100-meter-cell-size interpolated bathymetry grid, trackline maps, and point data files. Additional files include error analysis maps, Field Activity Collection System logs, and formal Federal Geographic Data Committee metadata. NOTE: These data are scientific in nature and are not to be used for navigation. Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Louisiana↗
USGS2025

Science needs for determining the effects of climate change on harmful algal blooms in the southeastern United States

The Southeastern United States has many lakes, streams, and reservoirs that serve as important drinking water sources with recreational, agricultural, and ecological uses. However, harmful algal blooms (HABs) are becoming more common in these waters, causing health issues for humans and animals. HABs have been listed as a contaminant of emerging concern, and the magnitude, frequency, and duration of HABs appear to be increasing at the global scale. While it is well known that nutrients stimulate algae growth, it is not clear how climate change and other parameters stimulate the development of toxin production by HABs. The scientific literature describes parameters, such as storm occurrence, temperature, dissolved metals, erosion of soils, increasing length of growing season, discharge, and hydroperiod, that may affect algae growth and toxin production. Climate and hydrologic models address many of the physical and environmental parameters that influence HABs, but no climate models directly address HABs. This report compiles information from the existing literature pertaining to HABs and the modeling and forecasting of HABS. This compilation is done through the incorporation of climate change models. HAB research that involves climate change will require multiple disciplines that bring together ecologists, hydrologists, climatologists, engineers, economists, and new technology. Resource managers could use geographic data about the occurrence and distribution of HABs to develop models that identify waterbodies more vulnerable to HAB events. Development of such models will require teams capable of integrating biological, chemical, and physical factors. Model development will require additional research that can resolve anthropogenic and climate-related environmental factors to identify trends in freshwater HABs. The complexity and interconnectedness of the parameters that influence HAB occurrences will make model development challenging and require rigorous regional calibration.

Open-File Report↗
USGS2019

Gopherus agassizii (Cooper 1861) – Agassiz’s Desert Tortoise, Mojave Desert Tortoise

The Mojave Desert Tortoise, Gopherus agassizii (Family Testudinidae), is a large terrestrial species that can reach >370 mm in straight midline carapace length (CL) but most individuals are smaller. Both sexes reach adulthood at 12 to 21 years and ca. 180 mm CL. The species is sexually dimorphic, with males typically larger than females; sexual characteristics of males become more obvious with increasing size and age. Females lay from 1 to 10 eggs per clutch and from 0 to 3 clutches annually, with eggs hatching after 67 to 104 days. Populations of G. agassizii have declined rapidly over the last several decades. Habitat throughout the geographic range has experienced major losses, degradation, and fragmentation as a result of urban and agricultural development, livestock grazing, military activities, transportation and utility corridors, high levels of visitor use, vehicle-oriented recreation, and energy development. Disturbed habitats were vulnerable to invading non-native grasses and forbs, creating an unnatural and destructive grass-fire cycle. When consumed by tortoises as their only diet, non-native (and native) grasses are harmful because of limited nutrients. Additionally, subsidized predators (Common Ravens, Coyotes, and dogs), infectious diseases, drought, and vandalism, add to the catastrophic effects of habitat loss and degradation. Tortoise populations have declined rapidly in density, and most populations are below viability, with fewer than 3.9 adults/km2. These declines occurred despite protections afforded by federal and state laws and regulations, ca. 26,000 km2 of federally designated critical habitat units, two Recovery Plans, and efforts to reduce the negative impacts of human activities. As noted by Allison and McLuckie (2018), the negative population trends in most of the critical habitat units suggest that under current conditions G. agassizii is on the path to extinction. Distribution. – USA. Distributed in parts of the southern Great Basin, Mojave, and western Sonoran deserts in southeastern California, southern Nevada, northwestern Arizona, and southwestern Utah, north and west of the Grand Canyon/Colorado River complex, with the exception of a small population east of the Colorado River. Synonymy. – Xerobates agassizii Cooper 1861, Testudo agassizii, Gopherus agassizii, Gopherus polyphemus agassizii, Scaptochelys agassizii, Xerobates lepidocephalus Ottley and Velázques Solis 1989. Subspecies . – None currently recognized. Status. – IUCN 2019 Red List: Vulnerable (VU A1acde+2cde; assessed 1996) ; TFTSG Provisional Red List: Critically Endangered (CR; assessed 2011, 2018); CITES: Appendix II (Testudinidae spp.); US ESA: Threatened.

Arizona, California, Nevada, Utah↗
USGS2021

Predicted spatial distribution of the Eastern Spotted Skunk (Spilogale putorius) in Virginia using detection and non-detection records

The geographic distribution of a species is a fundamental component in understanding its ecology and is necessary for forming effective conservation plans. For rare and elusive species of conservation concern, accurate maps of predicted occurrence are particularly problematic and often highly subjective. Spilogale putorius (Eastern Spotted Skunk) populations have experienced large declines since the 1940s. Their elusive behavior and perceived rarity result in low detection probability when using conventional methods for sampling small mammals. Low detection probability often causes uncertainty as to where Eastern Spotted Skunks could be a management concern. We modeled the distribution of predicted occurrence of Eastern Spotted Skunks using verifiable occurrence and non-detection records obtained throughout Virginia from 2010 to 2020. Occurrence data consisted of trapping records reported to the Virginia Department of Wildlife Resources, incidental photo-verified reports of sightings and road-killed animals, and remote-camera detections. Non-detections were presumed at baited remote-camera locations following intense survey efforts. We fit predicted occurrence models using generalized linear modeling in an information-theoretic framework using the package ‘stats’ in Program R. Our results incidated a greater probability of presence from the Blue Ridge westward, increasing with slope steepness along northeastern- to southeastern-facing slopes and decreasing with slope steepness along southeastern- to southwestern-facing slopes. Emergent rock outcrops prominent along northeastern slopes offer ample protective rocky cover, whereas mixed Quercus spp. (oak), Kalmia latifolia (Mountain Laurel), and Rhododendron maximum (Rosebay Rhododendron) forest communities along southern-facing slopes provide suitable areas of cover, both of which are critical for spotted skunk survival and reproductive success. Our analysis provides insight into the relationships between landscape features and Eastern Spotted Skunk distributions across Virginia. Understanding these relationships is critical for the effective management and conservation of this vulnerable species.

Virginia↗
USGS2007

Deep-water chaunacid and lophiid anglerfishes (Pisces: Lophiiformes) off the Southeastern United States

Recent research cruises to deep (80–910 m) reef habitats off the south-eastern U.S. and in the northern Gulf of Mexico have provided new information on the diagnostic characteristics, behaviours, colour patterns in life, bottom associations, distributions and maximum sizes of species of the anglerfish genera Chaunax , Lophiodes and Sladenia . Chaunax stigmaeus occurred much further south than previously known (Blake Plateau off South Carolina), and all C. stigmaeus observed were found associated with dense beds of dead coral ( Lophelia pertusa ) rubble or on broken hard bottom. In contrast, Chaunax suttkusi was found on soft bottoms. Chaunax stigmaeus and C. suttkusi appear to be sympatric over a major portion of their ranges. Because knowledge of pigmentation in live or freshly caught Chaunax is critical to distinguish some members of the genus, changes in the colouration of C. suttkusi were noted and documented photographically immediately after death and after fixation. The yellow spots found on some, but not all specimens, temporarily disappeared completely after death, but they reappeared after fixation, slowly disappearing thereafter along with other carotenoid pigments. Lophiodes beroe and Lophiodes monodi were collected for the first time off the Atlantic coast of the U.S., being previously known only from the Gulf of Mexico, Caribbean Sea and the northern coast of South America. For both species ( L. beroe and L. monodi ), the collections included the two largest known representatives of the species (400 and 325 mm standard length, respectively). Lophiodes beroe commonly occurred on L. pertusa rubble, and seemed to prefer this habitat. Occupying such a habitat that is deep and difficult to sample probably explains how this common species escaped detection. Only a single L. monodi was collected or observed, so this species appears to be uncommon in this geographic area or at least so on coral rubble habitat. Detailed aspects of the colour patterns of both species were noted. In particular, L. beroe displayed a characteristic pattern of white patches in life that were not apparent after death. The first photographic documentation of the colour pattern in life and of the pharyngeal pigmentation of Lophiodes reticulatus is provided. The third known specimen of Sladenia shaefersi , and the first to be taken in U.S. waters was collected from coral rubble near the base of a steep 200 m scarp on the Blake Plateau.

Gulf of Mexico↗
USGS2017

Life history attributes of Arizona Grasshopper Sparrow (Ammodramus savannarum ammolegus) and comparisons with other North American subspecies

Ammodramus savannarum ammolegus —commonly referred to as the Arizona Grasshopper Sparrow—occurs in the desert and plains grasslands of southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. Although a subspecies of conservation concern, this is the first intensive study of its life history and breeding ecology, providing baseline data and facilitating comparisons with other North American Grasshopper Sparrow subspecies. Specifically, I found A. s. ammolegus males generally weighed less than other subspecies (16.0 ± 0.8 g) but with intermediate exposed culmen length (11.6 ± 0.5 mm) and wing chord length similar to the other two migratory subspecies (62.7 ± 1.5 mm). Territory size for A. s. ammolegus was 0.72 ± 0.37 ha, with some variation between sites and among years, possibly indicating variation in habitat quality across spatial and temporal scales. The return rate for A. s. ammolegus males was 39.2%. Nest initiation for A. s. ammolegus was early to mid-July after the monsoons had begun. Domed nests were constructed on the ground, primarily under native bunch grasses, and frequently with a tunnel extending beyond the nest rim, with nest openings oriented north. Clutch size was 3.97 ± 0.68, with no evidence of Brown-headed Cowbird ( Molothrus ater ) nest parasitism. Extreme climate factors in the arid Southwest may have affected the life history and morphology of A. s. ammolegus as compared to other subspecies, influencing body size and mass, culmen length, breeding phenology, and nest orientation. Other geographic variation occurred in return rates, clutch size, and nest parasitism rates. The baseline data for A. s. ammolegus obtained in this study will inform future taxonomic and ecological studies as well as conservation planning. Comparisons of A. s. ammolegus morphometrics with those of other subspecies will assist field biologists in distinguishing among subspecies where they overlap, especially on wintering grounds.

Arizona↗
USGS1983

Biostratigraphic correlation chart of some Upper Cretaceous rocks from the Lost Soldier area, Wyoming to west of Craig, Colorado

This chart depicts the time-stratigraphic relations of some Upper Cretaceous rocks along the eastern and southeastern margins of the Greater Green River Basin, south-central Wyoming and northwestern Colorado. The purpose of this report is to release a preferred set of correlations based upon marine mollusk biostratigraphy. The senior author, with the help of B. E. Law, has acquired, synthesized, compiled, and interpreted data from various sources. These include selected published documents (see "References Cited") and unpublished reports of fossil identifications by W. A. Cobban who examined collections made by the late J. R. Gill. Numerous measured sections of Gill's were also utilized. It must be emphasized that all interpretations on this chart are based on information obtained from these sources and the senior author has yet to substantiate these correlations in the field. Not all data from the area of this study is included herein because it is either repetitive in nature or its reliability is uncertain. This uncertainty is due to the ambiguity inherent in both fossil identification and stratigraphic interpretation. Questionable unpublished material has been omitted while published data which is inconsistent with the senior author's correlations may be found in the footnotes portion of this report. The rock units are assigned to a range of ammonites that have been related to an absolute time scale. The ammonite zonation and age boundaries are adapted from Obradovich and Cobban (1975). "D" numbers are provided for each geographic locality where fossils were collected and described by personnel of the U.S. Geological Survey. These fossils may be accessed at the offices of the Survey in Lakewood, Colorado.

Colorado, Wyoming↗
USGS1903

Drainage modifications in southeastern Ohio and adjacent parts of West Virginia and Kentucky

The field work upon which this paper is based was carried on intermittently for several years. During the season of 1899 the work in Washington County, Ohio, was conducted under the direction of the Ohio State Academy of Science, the expenses being covered by a grant from the Emerson McMillin special research fund. The field work of the season of 1900 was done under the direction of Dr. T. C. Chamberlin, chief of the Division of Pleistocene Geology of the United States Geological Survey, and to him the author is greatly indebted for many valuable suggestions in relation to the work, and for an extended correspondence concerning the interpretations, during the preparation of this report. The study of this particular region was the natural result of earlier studies of drainage modifications in Ohio, in the region more nearly adjacent to the glaciated area. Until a few years ago but very little systematic study of the drainage features of Ohio had been made. It is not intended at present to make a complete review of the early literature, but to refer only to such portions of it as bear directly on the problem in hand. On account of the lack of good maps of Ohio it has not been possible to make the maps which accompany this paper as accurate as might be desired. They have been constructed from various published maps and from personal observations in the field; and, while they are not strictly accurate, it is hoped that they will set forth the facts with reference to the drainage modifications with sufficient clearness to enable anyone to follow the features in the field, or to serve for purposes of correlation. The map of Flatwoods and Teays valleys has been constructed from four topographic sheets of the United States Geological Survey Ironton, Kenova, Huntington, and Charleston. The author is under obligations to Mr. H. M. Wilson, geographer of the Survey, for data furnished from the unpublished map of the Kenova quadrangle. The photographs illustrating the report were all taken by the author.

Kentucky, Ohio, West Virginia↗
USGS2008

Detecting changes in riparian habitat conditions based on patterns of greenness change: A case study from the Upper San Pedro River Basin, USA

Healthy riparian ecosystems in arid and semi-arid regions exhibit shifting patterns of vegetation in response to periodic flooding. Their conditions also depend upon the amount of grazing and other human uses. Taking advantage of these system properties, we developed and tested an approach that utilizes historical Landsat data to track changes in the patterns of greenness (Normalized Difference Vegetation Index) within riparian zones. We tested the approach in the Upper San Pedro River of southeastern Arizona of the US, an unimpounded river system that flows north into the US from northern Mexico. We evaluated changes in the pattern of greenness in the San Pedro River National Conservation Area (SPRNCA), an area protected from grazing and development since 1988, and in a relatively unprotected area north of the SPRNCA (NA). The SPRNCA exhibited greater positive changes in greenness than did the NA. The SPRNCA also exhibited larger, more continuous patches of positive change than did the NA. These pattern differences may reflect greater pressures from grazing and urban sprawl in the NA than in the SPRNCA, as well as differences in floodplain width, depth to ground water, and base geology. The SPRNCA has greater amounts of ground and surface water available to support a riparian gallery forest than does the NA, and this may have influenced changes during the study period. Estimates of the direction of greenness change (positive or negative) from satellite imagery were similar to estimates derived from aerial photography , except in areas where changes were from one type of shrub community to another, and in areas with agriculture. Change estimates in these areas may be more difficult because of relatively low greenness values, and because of differences in soil moisture, sun-angle, and crop rotations among the dates of data collection. The potential for applying a satellite-based, greenness change approach to evaluate riparian ecosystem condition over broad geographic areas is also discussed.

Arizona↗
USGS2016

Low-flow characteristics for streams on the Islands of Kauaʻi, Oʻahu, Molokaʻi, Maui, and Hawaiʻi, State of Hawaiʻi

Statistical models were developed to estimate natural streamflow under low-flow conditions for streams with existing streamflow data at measurement sites on the Islands of Kauaʻi, O ʻ ahu, Moloka ʻ i, Maui, and Hawai ʻ i. Streamflow statistics used to describe the low-flow characteristics are flow-duration discharges that are equaled or exceeded between 50 and 95 percent of the time during the 30-year base period 1984–2013. Record-augmentation techniques were applied to develop statistical models relating concurrent streamflow data at the measurement sites and long-term data from nearby continuous-record streamflow-gaging stations that were in operation during the base period and were selected as index stations. Existing data and subsequent low-flow analyses of the available data help to identify streams in under-represented geographic areas and hydrogeologic settings where additional data collection is suggested. Low-flow duration discharges were estimated for 107 measurement sites (including long-term and short-term continuous-record streamflow-gaging stations, and partial-record stations) and 27 index stations. The adequacy of statistical models was evaluated with correlation coefficients and modified Nash-Sutcliff coefficients of efficiency, and a majority of the low-flow duration-discharge estimates are satisfactory based on these regression statistics. Molokaʻi and Hawaiʻi have the fewest number of measurement sites (that are not located on ephemeral stream reaches) at which flow-duration discharges were estimated, which can be partially explained by the limited number of index stations available on these islands that could be used for record augmentation. At measurement sites on some tributary streams, low-flow duration discharges could not be estimated because no adequate correlations could be developed with the index stations. These measurement sites are located on streams where duration-discharge estimates are available at long-term stations at other locations on the main stream channel to provide at least some definition of low-flow characteristics on that stream. In terms of general natural streamflow data availability, data are scarce in the leeward areas for all five islands as many leeward streams are dry or have minimal flow. Other under-represented areas include central Oʻahu, central Maui, and southeastern Maui.

Hawaiʻi↗
USGS2015

Final project memorandum: sea-level rise modeling handbook: resource guide for resource managers, engineers, and scientists

Coastal wetlands of the Southeastern United States are undergoing retreat and migration from increasing tidal inundation and saltwater intrusion attributed to climate variability and sea-level rise. Much of the literature describing potential sea-level rise projections and modeling predictions are found in peer-reviewed academic journals or government technical reports largely suited to reading by other Ph.D. scientists who are more familiar or engaged in the climate change debate. Various sea-level rise and coastal wetland models have been developed and applied of different designs and scales of spatial and temporal complexity for predicting habitat and environmental change that have not heretofore been synthesized to aid natural resource managers of their utility and limitations. Training sessions were conducted with Federal land managers with U.S. Fish and Wildlife Service, National Park Service, and NOAA National Estuarine Research Reserves as well as state partners and nongovernmental organizations across the northern Gulf Coast from Florida to Texas to educate and to evaluate user needs and understanding of concepts, data, and modeling tools for projecting sea-level rise and its impact on coastal habitats and wildlife. As a result, this handbook was constructed from these training and feedback sessions with coastal managers and biologists of published decision-support tools and simulation models for sea-level rise and climate change assessments. A simplified tabular context was developed listing the various kinds of decision-support tools and ecological models along with criteria to distinguish the source, scale, and quality of information input and geographic data sets, physical and biological constraints and relationships, datum characteristics of water and land elevation components, utility options for setting sea-level rise and climate change scenarios, and ease or difficulty of storing, displaying, or interpreting model output. The handbook is designed to be a primer to understanding sea-level rise and a practical synthesis of the current state of knowledge and modeling tools as a resource guide for DOl land management needs and facilitating Landscape Conservation Cooperative (LCC) research and conservation initiatives.

Conference Paper↗
USGS2000

Nutrient, suspended-sediment, and total suspended-solids data for surface water in the Great Salt Lake basins study unit, Utah, Idaho, and Wyoming, 1980-95

Selected nitrogen and phosphorus (nutrient), suspended-sediment and total suspended-solids surface-water data were compiled from January 1980 through December 1995 within the Great Salt Lake Basins National Water-Quality Assessment study unit, which extends from southeastern Idaho to west-central Utah and from Great Salt Lake to the Wasatch and western Uinta Mountains. The data were retrieved from the U.S. Geological Survey National Water Information System and the State of Utah, Department of Environmental Quality, Division of Water Quality database. The Division of Water Quality database includes data that are submitted to the U.S. Environmental Protection Agency STOrage and RETrieval system. Water-quality data included in this report were selected for surface-water sites (rivers, streams, and canals) that had three or more nutrient, suspended-sediment, or total suspended-solids analyses. Also, 33 percent or more of the measurements at a site had to include discharge, and, for non-U.S. Geological Survey sites, there had to be 2 or more years of data. Ancillary data for parameters such as water temperature, pH, specific conductance, streamflow (discharge), dissolved oxygen, biochemical oxygen demand, alkalinity, and turbidity also were compiled, as available. The compiled nutrient database contains 13,511 samples from 191 selected sites. The compiled suspended-sediment and total suspended-solids database contains 11,642 samples from 142 selected sites. For the nutrient database, the median (50th percentile) sample period for individual sites is 6 years, and the 75th percentile is 14 years. The median number of samples per site is 52 and the 75th percentile is 110 samples. For the suspended-sediment and total suspended-solids database, the median sample period for individual sites is 9 years, and the 75th percentile is 14 years. The median number of samples per site is 76 and the 75th percentile is 120 samples. The compiled historical data are being used in the basinwide sampling strategy to characterize the broad-scale geographic and seasonal water-quality conditions in relation to major contaminant sources and background conditions. Data for this report are stored on a compact disc.

Idaho, Utah, Wyoming↗
USGS2026

How hunters and non-hunters view barriers to allowing hunting access in an urban county

Barriers to allowing hunting of white-tailed deer ( Odocoileus virginianus ) on private land shape hunter recruitment, retention, and reactivation efficacy as well as the ability of wildlife management agencies to use hunting as a management tool. Understanding perceptions of these barriers is crucial in urbanizing landscapes where there are increased challenges to allowing hunting access, and deer may persist in relatively high numbers. We compared barriers to allowing hunting access on one’s property among hunters (n = 281) and non-hunters (n = 874) who did not have hunting occur on their property across urban, suburban, and rural groups in Durham County, North Carolina. (i.e., six groups). Rural landowners tended to perceive geographic barriers (e.g., property size) as less problematic than suburban and urban landowners, irrespective of personal participation in hunting, but landowners who hunted tended to view all barriers as less problematic than those who did not. Small property size, human population density, and housing density were viewed as important barriers to allowing hunting access for all groups, but suburban and urban non-hunters perceived the challenges as greater barriers compared to other groups. Conversely, the complexity of hunting regulations was viewed as a minor barrier to allowing hunting among all landowners. Safety concerns, not knowing other hunters, and disagreement with hunting as a practice showed the greatest contrasts between landowners who hunted and those who did not, with the latter group reporting the barriers as more important. Barriers to hunting identified in this study aligned with variables that predicted whether land is huntable (e.g., property size, housing density) in prior research. Our results indicate that developing public outreach highlighting hunting safety and creating landowner-hunter partnership programs may help facilitate hunting access in urbanizing areas.

North Carolina↗
USGS1952

Present and past ground-water conditions in the Morrison Formation in southwestern Colorado and southeastern Utah

Field and laboratory studies of ground-water conditions in the carnotite-bearing Morrison formation in southwestern Colorado and southeastern Utah were undertaken to determine possible relations between ground waters and the carnotite deposits. The ore-bearing sandstone consists of lenticular sandstone strata, interbedded within discontinuous layers of mudstone; these strata were deposited in a stream environment. The porosity and permeability of the ore-bearing sandstone in one area are relatively low, porosity averaging about 15 percent and permeability ranging between 30 and 3300 millidarcys. Permeability studies in this same area show that sandstone classed as favorable for ore is slightly more permeable than and has nearly twice the transmissibility of sandstone classed as semifavorable; outcrop studies also suggest a lower transmissibility for sandstone that is unfavorable. Samples of water from the ore-bearing and associated strata show considerable variation in chemical charter. These water samples are generally low in uranium, vanadium, copper, and lead, most samples containing less than 1 part per million (ppm) of each metal. General geologic relations suggest that ground-water movement probably was active through the ore-bearing strata during their deposition and shortly afterward. Movement during this time probably occurred largely through the more permeable sand strata and in the general direction of initial dip and stream flow. During Cretaceous time, when several thousand feet of marine sediments accumulated over the Morrison, the water contained in the ore-bearing strata probably was immobile or nearly so and was protected from escape or contamination. Following Tertiary deformation and erosion, active ground-water circulation no doubt was restored, but because of the low permeability and the lenticular character and therefore low transmissibility of the ore-bearing sandstone, ground-water movement probably was slow. Faulting probably also influenced the direction and rate of ground-water movement during Tertiary time. Movement and localization of ground water would permit the concentration of metal-bearing solutions during Salt Wash and early Brushy Basin time in the beds that now contain ore deposits. It is more difficult to explain the formation of these deposits, which have a wide geographic distribution at a restricted stratigraphic position, from solutions circulating through the rocks at a later date. Whatever mode of origin is used to explain the deposits, geologists almost without exception, agree that the metals were transported by solutions that have migrated through the sediments for considerable distances. For this reason, a study of the horizontal and vertical transmissibility characteristics of all exposed sedimentary formations on the Colorado Plateau is planned.

Colorado, Utah↗
USGS1998

Hydrology of Central Florida Lakes - A Primer

INTRODUCTION Lakes are among the most valued natural resources of central Florida. The landscape of central Florida is riddled with lakeswhen viewed from the air, it almost seems there is more water than land. Florida has more naturally formed lakes than other southeastern States, where many lakes are created by building dams across streams. The abundance of lakes on the Florida peninsula is a result of the geology and geologic history of the State. An estimated 7,800 lakes in Florida are greater than 1 acre in surface area. Of these, 35 percent are located in just four counties (fig. 1): Lake, Orange, Osceola, and Polk (Hughes, 1974b). Lakes add to the aesthetic and commercial value of the area and are used by many residents and visitors for fishing, boating, swimming, and other types of outdoor recreation. Lakes also are used for other purposes such as irrigation, flood control, water supply, and navigation. Residents and visitors commonly ask questions such as Whyare there so many lakes here?, Why is my lake drying up (or flooding)?, or Is my lake spring-fed? These questions indicate that the basic hydrology of lakes and the interaction of lakes with ground water and surface water are not well understood by the general population. Because of the importance of lakes to residents of central Florida and the many questions and misconceptions about lakes, this primer was prepared by the U.S. Geological Survey (USGS) in cooperation with the St. Johns River Water Management District and the South Florida Water Management District. The USGS has been collecting hydrologic data in central Florida since the 1920s, obtaining valuable information that has been used to better understand the hydrology of the water resources of central Florida, including lakes. In addition to data collection, as of 1994, the USGS had published 66 reports and maps on central Florida lakes (Garcia and Hoy, 1995). The main purpose of this primer is to describe the hydrology of lakes in central Florida, the interactions between lakes and ground- and surface-waters, and to describe how these interactions affect lake water levels. Included are descriptions of the basic geology and geomorphology of central Florida, origins of central Florida lakes, factors that affect lake water levels, lake water quality, and common methods of improving water quality. The geographic area discussed in this primer is approximate (fig. 1) and includes west and east-central Florida, extending from the Gulf of Mexico to the Atlantic Ocean coastlines, northward into Marion, Putnam, and Flagler Counties, and southward to Lake Okeechobee. The information presented here was obtained from the many publications available on lakes in central Florida, as well as from publications on Florida geology, hydrology, and primers on ground water, surface water, and water quality. Many publications are available that provide more detailed information on lake water quality, and this primer is not intended as an extensive treatise on that subject. The reader is referred to the reference section of this primer for sources of more detailed information on lake water quality. Lakes discussed in this report are identified in figure 2. Technical terms used in the report are shown in bold italics and are defined in the glossary. The classification of some water bodies as lakes is highly subjective. What one individual considers a lake another might consider a pond. Generally, any water- filled depression or group of depressions in the land surface could be considered a lake. Lakes differ from swamps or wetlands in the type and amount of vegetation, water depth, and some water-quality characteristics. Lakes typically have emergent vegetation along the shoreline with a large expanse of open water in the center. Swamps or wetlands, on the other hand, are characterized by a water surface interrupted by the emergence of many varieties of plant life, from saw grasses to cypress trees. Lakes may be na

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USGS2008

Mapping of Florida's coastal and marine resources: Setting priorities workshop

The importance of mapping habitats and bioregions as a means to improve resource management has become increasingly clear. Large areas of the waters surrounding Florida are unmapped or incompletely mapped, possibly hindering proper management and good decisionmaking. Mapping of these ecosystems is among the top priorities identified by the Florida Oceans and Coastal Council in their Annual Science Research Plan. However, lack of prioritization among the coastal and marine areas and lack of coordination of agency efforts impede efficient, cost–effective mapping. A workshop on Mapping of Florida’s Coastal and Marine Resources was sponsored by the U.S. Geological Survey (USGS), Florida Department of Environmental Protection (FDEP), and Southeastern Regional Partnership for Planning and Sustainability (SERPPAS). The workshop was held at the USGS Florida Integrated Science Center (FISC) in St. Petersburg, FL, on February 7-8, 2007. The workshop was designed to provide State, Federal, university, and non-governmental organizations (NGOs) the opportunity to discuss their existing data coverage and create a prioritization of areas for new mapping data in Florida. Specific goals of the workshop were multifold, including to: provide information to agencies on state-of-the-art technology for collecting data; inform participants of the ongoing mapping programs in waters off Florida; present the mapping needs and priorities of the State and Federal agencies and entities operating in Florida; work with State of Florida agencies to establish an overall priority for areas needing mapping; initiate discussion of a unified classification of habitat and bioregions; discuss and examine the need to standardize terminology and data collection/storage so that data, in particular habitat data, can be shared; identify opportunities for partnering and leveraging mapping efforts among agencies and entities; identify impediments and organizational gaps that hinder collection of data for mapping; seek innovative solutions to the primary obstacles identified; identify the steps needed to move mapping of Florida’s oceans and coasts forward, in preparation for a better coordinated, more cost-effective mapping program to allow State and Federal agencies to make better decisions on coastal-resource issues. Over 90 invited participants representing more than 30 State and Federal agencies, universities, NGOs, and private industries played a large role in the success of this two-day workshop. State of Florida agency participants created a ranked priority order for mapping 13 different regions around Florida. The data needed for each of the 13 priority regions were outlined. A matrix considering State and Federal priorities was created, utilizing input from all agencies. The matrix showed overlapping interests of the entities and will allow for partnering and leveraging of resources. The five most basic mapping needs were determined to be bathymetry, high-vertical resolution coastline for sea-level rise scenarios, shoreline change, subsurface geology, and benthic habitats at sufficient scale. There was a clear convergence on the need to coordinate mapping activities around the state. Suggestions for coordination included: creating a glossary of terms: a standard for specifying agency data-mapping needs; creating a geographic information officer (GIO) position or permanent organizing group to maintain communications established at this workshop and to maintain progress on the issues identified during the workshop. The person or group could develop a website, maintain a project-status matrix, develop a list of contacts, create links to legislative updates and links to funding sources; developing a web portal and one-stop/clearinghouse of data. There was general consensus on the need to adopt a single habitat classification system and a strategy to accommodate existing systems smoothly. Unresolved aspects of the systems warrant that a separate workshop would be needed to work out details. Participants recognized that the State priority list would necessarily be updated periodically. An annual review of priorities would facilitate information exchange, mapping activities updates, and re-allocation of funding among changing priorities. It was recognized that mapping of State waters would take billions of dollars and in light of tightening budgets there was need for processes that could be used to appropriate or leverage monies for mapping and reduce data-collection costs. Fourteen different avenues were explored. There was a clear consensus that the linking of public to private partnerships to support mapping was imperative, and ways to achieve this were discussed.

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USGS2007

Design and implementation of estimation-based monitoring programs for flora and fauna: A case study on the Cherokee National Forest

Science-based monitoring of biological resources is important for a greater understanding of ecological systems and for assessment of the target population using theoretic-based management approaches. When selecting variables to monitor, managers first need to carefully consider their objectives, the geographic and temporal scale at which they will operate, and the effort needed to implement the program. Generally, monitoring can be divided into two categories: index and inferential. Although index monitoring is usually easier to implement, analysis of index data requires strong assumptions about consistency in detection rates over time and space, and parameters are often biasednot accounting for detectability and spatial variation. In most cases, individuals are not always available for detection during sampling periods, and the entire area of interest cannot be sampled. Conversely, inferential monitoring is more rigorous because it is based on nearly unbiased estimators of spatial distribution. Thus, we recommend that detectability and spatial variation be considered for all monitoring programs that intend to make inferences about the target population or the area of interest. Application of these techniques is especially important for the monitoring of Threatened and Endangered (T&E) species because it is critical to determine if population size is increasing or decreasing with some level of certainty. Use of estimation-based methods and probability sampling will reduce many of the biases inherently associated with index data and provide meaningful information with respect to changes that occur in target populations. We incorporated inferential monitoring into protocols for T&E species spanning a wide range of taxa on the Cherokee National Forest in the Southern Appalachian Mountains. We review the various approaches employed for different taxa and discuss design issues, sampling strategies, data analysis, and the details of estimating detectability using site occupancy. These techniques provide a science-based approach for monitoring and can be of value to all resource managers responsible for management of T&E species.

Proceedings of the Annual Conference of the Southe↗