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At least 91 records · Page 5Linked to original sources
USGS2004

The influence of hook type, angler experience, and fish size on injury rates and the duration of capture in an Alaskan catch-and-release rainbow trout fishery

Owing to concerns about the high incidence of past hooking injuries in Alagnak River rainbow trout Oncorhynchus mykiss, fish were captured with spin- and fly-fishing gear with barbed and barbless circle and "J" hooks to determine gear types contributing to injury. Landing and hook removal times were measured for a portion of fish captured, and the anatomical hooking location, hooking scar locations, bleeding intensity, angler experience, and fish size were recorded for all captured fish. Approximately 62% of fish captured experienced at least one new hooking injury, and 29% of fish had at least one past hooking injury. Small fish sustained higher new injury and bleeding rates, but large fish had higher past injury rates. Injury rates were higher for barbed J hooks, barbed J hooks took longer to remove, and fish caught by spin-fishing were injured more frequently than fish caught by fly-fishing. Fewer fly-fishing-caught fish were injured using circle hooks, and circle hooks tended to hook fish in only one location, generally in the jaw. Barbed J hooks were more efficient at landing fish, and J hooks were more efficient at landing fish than circle hooks. Novice anglers injured proportionally more fish than experienced anglers, primarily during hook removal. Landing time was positively correlated with fish size, and experienced anglers took longer to land fish than novices because they captured larger fish. These results suggest that a reduction in hooking injuries may be achieved by using circle hooks as an alternative to J hooks and barbless J hooks to reduce injury and handling time, yet catch efficiency for both methods would be reduced. Although fish captured with barbless J hooks and circle hooks had fewer injuries, it is important to note that each hook type also caused significant injury, and angler education is recommended to promote proper hook removal techniques.

North American Journal of Fisheries Management↗
USGS2009

Assigning land use to supply wells for the statistical characterization of regional groundwater quality: Correlating urban land use and VOC occurrence

Many national and regional groundwater studies have correlated land use "near" a well, often using a 500 m radius circle, with water quality. However, the use of a 500 m circle may seem counterintuitive given that contributing areas are expected to extend up-gradient from wells, and not be circular in shape. The objective of this study was to evaluate if a 500 m circle is adequate for assigning land use to a well for the statistical correlation between urban land use and the occurrence of volatile organic compounds (VOCs). Land use and VOC data came from 277 supply wells in four study areas in California. Land use was computed using ten different-sized circles and wedges (250 m to 10 km in radius), and three different-sized "searchlights" (1-2 km in length). We define these shapes as contributing area surrogates (CASs), recognizing that a simple shape is at best a surrogate for the actual contributing area. The presence or absence of correlation between land use and the occurrence of VOCs was evaluated using Kendall's tau (??). Values of ?? were within 10% of one another for wedges and circles ranging in size from 500 m to 2 km, with correlations remaining statistically significant (p < 0.05) for all CAS sizes and shapes, suggesting that a 500 m circular CAS is adequate for assigning land use to a well. Additional evaluation indicated that urban land use is autocorrelated at distances ranging from 8 to 36 km. Thus, urban land use in a 500 m CAS is likely to be predictive of urban land use in the actual contributing area.

Journal of Hydrology↗
USGS2012

Landsat's international partners

Since the launch of the first Landsat satellite 40 years ago, International Cooperators (ICs) have formed a key strategic alliance with the U.S. Geological Survey (USGS) to not only engage in Landsat data downlink services but also to enable a foundation for scientific and technical collaboration. The map below shows the locations of all ground stations operated by the United States and IC ground station network for the direct downlink and distribution of Landsat 5 (L5) and Landsat 7 (L7) image data. The circles show the approximate area over which each station has the capability for direct reception of Landsat data. The red circles show the components of the L5 ground station network, the green circles show components of the L7 station network, and the dashed circles show stations with dual (L5 and L7) status. The yellow circles show L5 short-term ("campaign") stations that contribute to the USGS Landsat archive. Ground stations in South Dakota and Australia currently serve as the primary data capture facilities for the USGS Landsat Ground Network (LGN). The Landsat Ground Station (LGS) is located at the USGS Earth Resources Observation and Science (EROS) Center in Sioux Falls, South Dakota. The Alice Springs (ASN) ground station is located at the Geoscience Australia facility in Alice Springs, Australia. These sites receive the image data, via X-band Radio Frequency (RF) link, and the spacecraft housekeeping data, via S-band RF link. LGS also provides tracking services and a command link to the spacecrafts.

Argentina;Australia;Brazil;Canada;China;Germany;In↗
USGS2018

Geology and assessment of undiscovered oil and gas resources of the Tunguska Basin Province, 2008

The U.S. Geological Survey has evaluated the potential for undiscovered oil and gas resources of the Tunguska Basin Province as part of the Circum-Arctic Resource Appraisal (CARA). The Tunguska Basin Province includes an area of approximately 904,000 km 2 ; less than half the area of the province lies north of the Arctic Circle. The Tunguska Basin Province includes a large part of the Siberian craton and consists of several subbasins. The province is almost completely covered by Permian to Triassic volcanic rocks. Although some oil and gas fields have been discovered and produced in the province south of the Arctic Circle, no discoveries have been made north of the Arctic Circle as of 2008. The part of this province lying north of the Arctic Circle was evaluated for undiscovered, technically recoverable, conventional oil and gas resources. Because of a low geologic probability for the occurrence of significant oil and gas accumulations (50 million barrels of oil equivalent or more), the Tunguska Basin Province north of the Arctic Circle was not quantitatively assessed as part of CARA.

Tunguska Basin Province↗
USGS2012

An apparent shear zone trending north‐northwest across the Mojave Desert into Owens Valley, eastern California

Strain rates measured at four geodetic networks in eastern California situated between northern Owens Valley and the Transverse Ranges along a small circle drawn about the Pacific‐North America pole of rotation are remarkably consistent. Each exhibits 0.14 μrad/yr simple right‐lateral engineering‐shear‐strain accumulation across the local vertical plane tangent to the small circle. Local faults ( e.g. , Owens Valley, Garlock, Helendale) traversing these networks are not as closely aligned with the vertical planes of maximum shear‐strain accumulation as is the local tangent to the small circle. A fifth network slightly east of the small circle shows no significant strain accumulation. Thus, a shear zone trending N35° W from near the eastern end of the big bend of the San Andreas fault to northern Owens Valley is indicated by these data. This corresponds to the Eastern California shear zone proposed on geological evidence by Dokka and Travis. The shear zone carries ∼8 mm/yr of the Pacific‐North America relative plate motion from the San Andreas fault north‐northwest across the Mojave Desert into Owens Valley and the northern Basin and Range province. The shear zone observed at the surface may be a manifestation of a through‐going subcrustal fault.

California↗
USGS2017

Geology and assessment of undiscovered oil and gas resources of the Yukon Flats Basin Province, 2008

The hydrocarbon potential of the Yukon Flats Basin Province in Central Alaska was assessed in 2004 as part of an update to the National Oil and Gas Assessment. Three assessment units (AUs) were identified and assessed using a methodology somewhat different than that of the 2008 Circum-Arctic Resource Appraisal (CARA). An important difference in the methodology of the two assessments is that the 2004 assessment specified a minimum accumulation size of 0.5 million barrels of oil equivalent (MMBOE), whereas the 2008 CARA assessment specified a minimum size of 50 MMBOE. The 2004 assessment concluded that >95 percent of the estimated mean undiscovered oil and gas resources occur in a single AU, the Tertiary Sandstone AU. This is also the only AU of the three that extends north of the Arctic Circle. For the CARA project, the number of oil and gas accumulations in the 2004 assessment of the Tertiary Sandstone AU was re-evaluated in terms of the >50-MMBOE minimum accumulation size. By this analysis, and assuming the resource to be evenly distributed across the AU, 0.23 oil fields and 1.20 gas fields larger than 50 MMBOE are expected in the part of the AU north of the Arctic Circle. The geology suggests, however, that the area north of the Arctic Circle has a lower potential for oil and gas accumulations than the area to the south where the sedimentary section is thicker, larger volumes of hydrocarbons may have been generated, and potential structural traps are probably more abundant. Because of the low potential implied for the area of the AU north of the Arctic Circle, the Yukon Flats Tertiary Sandstone AU was not quantitatively assessed for the 2008 CARA.

Alaska↗
USGS1967

Ground-water conditions and geologic reconnaissance of the Upper Sevier River basin, Utah

The upper Sevier River basin is in south-central Utah and includes an area of about 2,400 .square miles of high plateaus and valleys. It comprises the entire Sevier River drainage basin above Kingston, including the East Fork Sevier River and its tributaries. The basin was investigated to determine general ground-water conditions, the interrelation of ground water and surface water, the effects of increasing the pumping of ground water, and the amount of ground water in storage. The basin includes four main valleys - Panguitch Valley, Circle Valley, East Fork Valley, and Grass Valley - which are drained by the Sevier River, the East Fork Sevier River, and Otter Creek. The plateaus surrounding the valleys consist of sedimentary and igneous rocks that range in age from Triassic to Quaternary. The valley fill, which is predominantly alluvial gravel, sand, silt, and clay, has a maximum thickness of more than 800 feet. The four main valleys constitute separate ground-water basins. East Fork Valley basin is divided into Emery Valley, Johns Valley, and Antimony subbasins, and Grass Valley basin is divided into Koosharem and Angle subbasins. Ground water occurs under both artesian and water-table conditions in all the basins and subbasins except Johns Valley, Emery Valley, and Angle subbasins, where water is only under water-table conditions. The water is under artesian pressure in beds of gravel and sand confined by overlying beds of silt and clay in the downstream parts of Panguitch Valley basin, Circle Valley basin, and Antimony subbasin, and in most of Koosharem subbasin. Along the sides and upstream ends of these basins, water is usually under water-table conditions. About 1 million acre-feet of ground water that is readily available to wells is stored in the gravel and sand of the upper 200 feet of saturated valley fill. About 570,000 acre-feet is stored in Panguitch Valley basin, about 210,000 in Circle Valley basin, about 6,000 in Emery Valley subbasin, about 90,000 in Johns Valley subbasin, about 36,000 in Antimony subbasin, about 90,000 in Koosharem subbasin, and about 60,000 in Angle subbasin. Additional water, although it is not readily available to wells, is stored in beds of silt and clay. Some ground water also is available in the bedrock underlying and surrounding the basins, although the bedrock formations generally are poor aquifers. The principal source of recharge to the valley fill in the upper Sevier River basin is infiltration from streams, canals, and irrigated fields. Some ground water also miles into the valley till from the bedrock surrounding the basins. The basin contains about 300 wells, most of which are less than 4 inches in diameter, are less than 250 feet deep, and are used for domestic purposes and stock watering. More than half the wells are flowing wells in Koosharem subbasin. Approximately 82,000 acre-feet of ground water was discharged in 1962 from the valley till. Springs discharged about 33,000 acre-feet, wells about 3,000, and drains about 3,000; and evapotranspiration from phreatophyte areas about 43,000 acre-feet. Springs in bedrock discharged an additional 75,000 acre-feet. Most of the water discharged by springs, wells, and drains was used for irrigation. The ground water in the basin generally is of good chemical quality. The water is excellent for irrigation and stock but is not as desirable for most domestic and industrial uses because of its hardness. The dissolved-solids content of the ground water generally increases slightly from the upstream end of the individual ground-water basins to. the downstream end owing mostly to repeated use of the water for irrigation. Surface water and ground water in the upper Sevier River basin are inter- connected, and the base flows of streams are affected by changes in ground- water levels. Increased pumping of ground water would result in (1) an increase in the recharge to the aquifers from surface-water sources or (2) a decrease in the discharge from streams, springs, flowing wells, and areas of phreatophytes or (3) a combination of these. About 43,000 acre-feet of ground water is now discharged annually by evapotranspiration from phreatophyte areas, and perhaps one-third of this loss, or about 14,000 acre-feet, could be salvaged by eliminating wet areas and phreatophytes. The areas where water could be salvaged are at the downstream ends of Panguitch Valley basin, Circle Valley basin, and Antimony subbasin. Most of the 14,000 acre-feet 'of water could be pumped from large-diameter wells or developed by properly designed drains without greatly affecting stream- flow and with only moderate effect on 'spring discharge. If the wells were properly located, the pumping would lower water levels and dry up wet areas where phreatophytes grow. Conjunctive use of ground water and surface water would facilitate the more efficient use of all water resources in the basin

Utah↗