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At least 613 records · Page 34Linked to original sources
USGS1996

Level II scour analysis for Bridge 34 (BRIDTH00050034) on Town Highway 005, crossing North Branch Ottauquechee River, Bridgewater, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure BRIDTH00050034 on town highway 5 crossing the North Branch Ottauquechee River, Bridgewater, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge available from VTAOT files was compiled prior to conducting Level I and Level II analyses and can be found in Appendix D. The site is in the Green Mountain physiographic division of central Vermont in the town of Bridgewater. The 5.45-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, left and right banks are forested. Upstream of bridge 34, Town Highway 5 runs parallel to the right bank and DS of the bridge, parallel to the left bank. In the study area, the North Branch Ottauquechee River has an incised channel with a slope of approximately 0.015 ft/ft, an average channel top width of 32 ft and an average channel depth of 7 ft. The predominant channel bed material is sand and gravel (D 50 is 105 mm or 0.345 ft). The geomorphic assessment at the time of the Level I and Level II site visit on November 3, 1994, indicated that the reach was stable. The town highway 31 crossing of Lilliesville Brook is a 41-ft-long, one-lane bridge consisting of one 39-foot steel-beam span with a timber deck (Vermont Agency of Transportation, written commun., August 24, 1994). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 35 degrees to the opening while the opening-skew-to-roadway is 0 degrees. Scour protection measures in place at the site were type-1 stone fill (less than 12 inches diameter) at the downstream left wingwall, left abutment, and upstream and downstream sides of the left road embankment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8.

Vermont↗
USGS2017

Reducing risk where tectonic plates collide—U.S. Geological Survey subduction zone science plan

The U.S. Geological Survey (USGS) serves the Nation by providing reliable scientific information and tools to build resilience in communities exposed to subduction zone earthquakes, tsunamis, landslides, and volcanic eruptions. Improving the application of USGS science to successfully reduce risk from these events relies on whole community efforts, with continuing partnerships among scientists and stakeholders, including researchers from universities, other government labs and private industry, land-use planners, engineers, policy-makers, emergency managers and responders, business owners, insurance providers, the media, and the general public. Motivated by recent technological advances and increased awareness of our growing vulnerability to subduction-zone hazards, the USGS is uniquely positioned to take a major step forward in the science it conducts and products it provides, building on its tradition of using long-term monitoring and research to develop effective products for hazard mitigation. This science plan provides a blueprint both for prioritizing USGS science activities and for delineating USGS interests and potential participation in subduction zone science supported by its partners. The activities in this plan address many USGS stakeholder needs: High-fidelity tools and user-tailored information that facilitate increasingly more targeted, neighborhood-scale decisions to mitigate risks more cost-effectively and ensure post-event operability. Such tools may include maps, tables, and simulated earthquake ground-motion records conveying shaking intensity and frequency. These facilitate the prioritization of retrofitting of vulnerable infrastructure; Information to guide local land-use and response planning to minimize development in likely hazardous zones (for example, databases, maps, and scenario documents to guide evacuation route planning in communities near volcanoes, along coastlines vulnerable to tsunamis, and built on landslide-prone terrain); New tools to assess the potential for cascading hazards, such as landslides, tsunamis, coastal changes, and flooding caused by earthquakes or volcanic eruptions; Geospatial models of permanent, widespread land- and sea-level changes that may occur in the immediate aftermath of great ( M ≥8.0) subduction zone earthquakes; Strong partnerships between scientists and public safety providers for effective decision making during periods of elevated hazard and risk; Accurate forecasts of far-reaching hazards (for example, ash clouds, tsunamis) to avert catastrophes and unnecessary disruptions in air and sea transportation; Aftershock forecasts to guide decisions about when and where to re-enter, repair, or rebuild buildings and infrastructure, for all types of subduction zone earthquakes.

Circular↗
USGS1995

The Alaska Mineral Resource Assessment Program: Background information to accompany geologic and mineral-resource maps of the Killik River 1°x3° quadrangle, northern Alaska

This report summarizes results of integrated geological, geochemical, and geophysical field and laboratory studies conducted by the U.S. Geological Survey in the Killik River 1°x3° quadrangle, Brooks Range, northern Alaska. These studies were designed to provide an assessment of the mineral resources of the quadrangle. The geological and geochemical data were the primary sources of information used to assess the mineral-resource potential of the quadrangle. The presence of permissive host rocks and favorable geochemical signatures in stream- and lake-sediment and (or) heavy-mineral-concentrate samples were used to infer the potential for undiscovered resources of minerals in deposits of different types. The Killik River quadrangle may contain undiscovered resources of preciousand base-metals (principally lead, silver, and zinc) in veins and breccias hosted by Devonian and Mississippian clastic sedimentary rocks or in stratiform massive sulfide deposits hosted primarily by Mississippian and Pennsylvanian sedimentary rocks. Resources of barium, phosphate, and manganese may be present in Mississippian to Jurassic sedimentary rocks. Cretaceous fluvial sedimentary rocks in the northern part of the quadrangle are permissive hosts for uranium deposits, as well as for placer deposits of heavy minerals such as gold and chromite; however, geochemical data suggest that the potential for deposits of this type is low. Numerous coal beds are present in the Cretaceous rocks throughout the northern part of the quadrangle, but the limited thickness and lateral extent of most of the beds reduce their resource potential. Although the southern third of the quadrangle has no potential for petroleum resources, there is potential in the northern two-thirds.

Alaska↗
USGS1996

Level II scour analysis for Bridge 6 (IRASTH00050006) on Town Highway 5, crossing the Black River, Irasburg, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure IRASTH00050006 on town highway 5 crossing the Black River, Irasburg, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge available from VTAOT files were compiled prior to conducting Level I and Level II analyses and can be found in Appendix D. The site is in the New England Upland physiographic province of north-central Vermont. The 91.1-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the left and right banks are forested and a residence is located on the downstream left overbank. In the study area, the Black River has an incised, sinuous channel with a slope of approximately 0.05 ft/ft, an average channel top width of 116 ft and an average bank-full channel depth of 2.8 ft. The predominant channel bed material is cobble (D 50 is 240 mm or 0.789 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 4, 1994, indicated that the reach was stable. The town highway 5 crossing of the Black River is a 70-ft-long, two-lane bridge consisting of one 65-foot clear span (Vermont Agency of Transportation, written commun., August 2, 1994). The bridge is supported by vertical, concrete abutments with wingwalls. There is also a retaining wall along the upstream side of the road embankments. The channel is skewed approximately 20 degrees to the opening while the opening-skew-to-roadway is 15 degrees. A scour hole 3.0 ft deeper than the mean thalweg depth was observed along the right abutment. The scour hole was 27 feet long, 15 feet wide, and was 2.5 feet below the abutment footing at the time of the Level I assessment. This right abutment had numerous cracks and had settled. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8.

Vermont↗
USGS1993

International strategic minerals inventory summary report; niobium (columbium) and tantalum

Major world resources of niobium and tantalum are described in this summary report of information in the International Strategic Minerals Inventory (ISMI). ISMI is a cooperative data-collection effort of earth-science and mineral-resource agencies in Australia, Canada, the Federal Republic of Germany, the Republic of South Africa, the United Kingdom, and the United States of America. Part I of this report presents an overview of the resources and potential supply of niobium and tantalum based on inventory information; Part II contains tables of both geologic and mineral-resource information and includes production data collected by ISMI participants. Niobium is used principally as an alloying element in special steels and superalloys, and tantalum is used mainly in electronics. Minerals in the columbite-tantalite series are principal ore minerals of niobium and tantalum. Pyrochlore is a principal source of niobium. These minerals are found in carbonatite, certain rocks in alkaline igneous complexes, pegmatite, and placer deposits. ISMI estimates show that there are over 7 million metric tons of niobium and almost 0.5 million metric tons of tantalum in known deposits, outside of China and the former Soviet Union, for which reliable estimates have been made. Brazilian deposits, followed by Canadian deposits, contain by far the largest source of niobium. Tantalum production is spread widely among several countries, and Brazil and Canada are the most significant of these producers. Brazil's position is further strengthened by potential byproduct columbite from tin mining. Present economically exploitable resources of niobium appear to be sufficient for the near future, but Brazil will continue to be the predominant world supplier of ferrocolumbium. Tantalum, a byproduct of tin production, has been captive to the fluctuations of that market, but resources in pegmatite in Canada and Australia make it likely that future increases in the present modest demand will be met.

Circular↗
USGS2015

Field-based description of rhyolite lava flows of the Calico Hills Formation, Nevada National Security Site, Nevada

Contaminants introduced into the subsurface of Pahute Mesa, Nevada National Security Site, by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas at Pahute Mesa and into the accessible environment is greatest by groundwater transport through fractured volcanic rocks. The 12.9 Ma (mega-annums, million years) Calico Hills Formation, which consists of a mixture of rhyolite lava flows and intercalated nonwelded and bedded tuff and pyroclastic flow deposits, occurs in two areas of the Nevada National Security Site. One area is north of the Rainier Mesa caldera, buried beneath Pahute Mesa, and serves as a heterogeneous volcanic-rock aquifer but is only available to study through drilling and is not described in this report. A second accumulation of the formation is south of the Rainier Mesa caldera and is exposed in outcrop along the western boundary of the Nevada National Security Site at the Calico Hills near Yucca Mountain. These outcrops expose in three dimensions an interlayered sequence of tuff and lava flows similar to those intercepted in the subsurface beneath Pahute Mesa. Field description and geologic mapping of these exposures described lithostratigraphic variations within lava flows and assisted in, or at least corroborated, conceptualization of the rhyolite lava-bearing parts of the formation. In the area south of the Rainier Mesa caldera, surface exposures and nearby subsurface equivalents were studied through compilation of geologic maps, new field mapping, subsurface information from boreholes, and data extracted from three-dimensional geologic framework models. Rhyolite lava flows within the Calico Hills Formation are described in terms of lithostratigraphic variations established for rhyolite lava flows in other volcanic fields. In general, the flows consist of a core of crystallized, flow-banded rhyolite lava, surrounded by a carapace of obsidian, commonly mantled by blocky, pumiceous rhyolite lava and flow breccia. Rhyolite lava flows were correlated and mapped on the basis of distinctive appearance in outcrop, stratigraphic sequence, and the presence of stratigraphic markers. Pyroclastic deposits that are spatially, temporally, and genetically related to the rhyolite lava flows consist of a series of intercalated pyroclastic flows, bedded ash-fall, and reworked tuff that have varying amounts of pumice and volcanic rock clasts. In the area south of the Rainier Mesa caldera, surface and subsurface geologic data are combined to interpret the overall thickness of the Calico Hills Formation and the proportion of lava flow lithology across the study area. The formation is at least 500 meters (m) thick and contains the greatest proportion of rhyolite lava flow to the northeast of Yucca Mountain in the lower part of Fortymile Canyon. The formation thins to the south and southwest where it is between 50 and 200 m thick beneath Yucca Mountain and contains no rhyolite lavas. Geologic mapping and field-based correlation of individual lava flows allow for the interpretation of the thickness and extent of specific flows and the location of their source areas. The most extensive flows have widths from 2 to 3 kilometers (km) and lengths of at least 5–6 km. Lava flow thickness varies from 150 to 250 m above interpreted source vents to between 30 and 80 m in more distal locations. Rhyolite lavas have length-to-height ratios of 10:1 or greater and, in one instance, a length-to-width ratio of 2:1 or greater, implying a tongue-shaped geometry instead of circular domes or tabular bodies. Although geologic mapping did not identify any physical feature that could be positively identified as a vent, lava flow thickness and the size of clasts in subjacent pyroclastic deposits suggest that primary vent areas for at least some of the flows in the study area are on the east side of Fortymile Canyon, to the northeast of Yucca Mountain.

Nevada↗
USGS2005

Geography for a Changing World - A science strategy for the geographic research of the U.S. Geological Survey, 2005-2015

This report presents a science strategy for the geographic research of the U.S. Geological Survey (USGS) for the years 2005-2015. The common thread running through the vision, mission, and science goals presented in the plan is that USGS geographers will provide national leadership to understand coupled human-environmental systems in the face of land change and will deliver pertinent information to decisionmakers on the vulnerability and resilience of these systems. We define land change science as the study of the human and environment dynamics that give rise to changed land use, cover, and surface form. A number of realities shape the strategic context of this plan: The Department of Interior Strategic Plan focuses on meeting society’s resource needs and sustaining the Nation’s life support systems, underscoring the importance of characterizing and understanding coupled human-environmental systems. In redefining its mission in the mid-1990s, the USGS envisions itself as an integrated natural science and information agency. The USGS will assume a national leadership role in the use of science to develop knowledge about the web of relations that couple biophysical and human systems and translate this knowledge into unbiased, reliable information that meets important societal information needs. The following trends will influence USGS geography-oriented science activities over the next decade. Most of the emerging earth science issues that the USGS will address are geographic phenomena. A growing international concern for aligning society’s development activities with environmental limits has led to an articulation of a science agenda associated with global environmental change, vulnerability, and resilience. Earth science investigations have evolved toward the study of very large areas, and the resulting huge volumes of data are challenging to manage and understand. Finally, scientists and the public face the challenge of gaining intelligent insights about geographic and environmental processes from these data, with the ultimate goal of guiding resource-management decisions. The first four science goals in the plan support understanding the human and environmental dynamics of land change. Each science goal has an associated set of strategic actions to achieve the goal. These goals and actions are consistent with national science priorities and the Department of Interior and USGS missions, take advantage of existing expertise, and lead to the strengthening of critical geographic research capacities that do not exist in other USGS disciplines.

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USGS1992

The Alaska Mineral Resource Assessment Program: Background information to accompany geologic and mineral-resource maps of the Cordova and Middleton Island quadrangles, southern Alaska

This report summarizes recent results of integrated geological, geochemical, and geophysical field and laboratory studies conducted by the U.S. Geological Survey in the Cordova and Middleton Island 1°x3° quadrangles of coastal southern Alaska. Published open-file reports and maps accompanied by descriptive and interpretative texts, tables, diagrams, and pertinent references provide background information for a mineral-resource assessment of the two quadrangles. Mines in the Cordova and Middleton Island quadrangles produced copper and byproduct gold and silver in the first three decades of the 20th century. The quadrangles may contain potentially significant undiscovered resources of precious and base metals (gold, silver, copper, zinc, and lead) in veins and massive sulfide deposits hosted by Cretaceous and Paleogene sedimentary and volcanic rocks. Resources of manganese also may be present in the Paleogene rocks; uranium resources may be present in Eocene granitic rocks; and placer gold may be present in beach sands near the mouth of the Copper River, in alluvial sands within the canyons of the Copper River, and in smaller alluvial deposits underlain by rocks of the Valdez Group. Significant coal resources are present in the Bering River area, but difficult access and structural complexities have discouraged development. Investigation of numerous oil and gas seeps near Katalla in the eastern part of the area led to the discovery of a small, shallow field from which oil was produced between 1902 and 1933. The field has been inactive since, and subsequent exploration and drilling onshore near Katalla in the 1960's and offshore near Middleton Island on the outer continental shelf in the 1970's and 1980's was not successful.

Alaska↗
USGS1996

Level II scour analysis for Bridge 40 (BETHTH00230040) on Town Highway 23, crossing Gilead Brook, Bethel, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure BETHTH00230040 on town highway 23 crossing Gilead Brook, Bethel, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from VTAOT files, was compiled prior to conducting the Level I and Level II analyses and can be found in Appendix D. The site is in the Green Mountain physiographic province of central Vermont in the town of Bethel. The 10.2-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the banks have moderately dense woody vegetation coverage. In the study area, the Gilead Brook has an incised, sinuous channel downstream of the site and a meandering channel upstream, with narrow flood plains and a slope of approximately 0.015 ft/ft, an average channel top width of 47.0 ft and an average channel depth of 2.75 ft. The predominant channel bed materials are gravel and cobble (D 50 is 94.8 mm or 0.311 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 14, 1994, indicated that the reach was laterally unstable. The town highway 23 crossing of Gilead Brook is a 37-ft-long, one-lane bridge consisting of one 34-foot span steel-stringer type superstructure (Vermont Agency of Transportation, written commun., August 24, 1994). The bridge is supported by vertical, concrete abutments with concrete wingwalls. The channel is skewed 25 degrees to the opening and the opening-skew-to-roadway is zero degrees. A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the downstream right wingwall during the Level I assessment. The scour protection measures at the site were type-2 stone fill (less than 36 inches diameter) on the upstream and downstream right roadway embankments, at the extreme upstream and downstream ends of the upstream and downstream right wingwalls, and along the entire base length of the downstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8.

Vermont↗
USGS1996

Level II scour analysis for Bridge 34 (RANDTH00660034) on Town Highway 66, crossing Second Branch White River, Randolph, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure RANDTH00660034 on town highway 66 crossing the Second Branch White River, Randolph, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge available from VTAOT files was compiled prior to conducting Level I and Level II analyses and can be found in Appendix D. The site is in the Green Mountain physiographic division of central Vermont in the town of Randolph. The 51.3-mi 2 drainage area is in a predominantly rural basin. In the vicinity of the study site, the left and right banks are covered by fields with some brush on the upstream left and downstream right banks and with row crops on the downstream left overbank. In the study area, the Second Branch White River has a sinuous channel with a slope of approximately 0.002 ft/ft, an average channel top width of 60 ft and an average channel depth of 7 ft. The predominant channel bed material is sand (D 50 is 1.34 mm or 0.0044 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 11, 1994, indicated that the reach was laterally unstable. Channel scour is evident along the left half of the channel from about 30 feet upstream to about 20 feet downstream of the bridge. There is a cut bank with block failures along the left bank upstream of the bridge further indicating instability of the stream reach. The town highway 66 crossing of the Second Branch White Riveris a 57-ft-long, one-lane covered bridge consisting of one 45-foot span (Vermont Agency of Transportation, written communication, July 29, 1994). The bridge is supported by vertical, concrete abutments with one wingwall on the upstream left side. The base of the left abutment was protected by type-1 stone fill (less than 12 inches diameter). The channel is skewed approximately 40 degrees to the opening while the opening-skew-to-roadway is 45 degrees. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Total scour at a highway crossing is comprised of three components: 1) long-term aggradation or degradation; 2) contraction scour (due to reduction in flow area caused by a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute scour depths for contraction and local scour and a summary of the results follows. Contraction scour for all modelled flows ranged from 6.3 ft to 7.8 ft and the worst-case contraction scour occurred at the 100-year discharge. Abutment scour ranged from 7.9 ft to 20.3 ft and the worst-case abutment scour occurred at the 500-year discharge. Scour depths and depths to armoring are summarized on p. 14 in the section titled “Scour Results”. Scour elevations, based on the calculated depths are presented in tables 1 and 2; a graph of the scour elevations is presented in figure 8 Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. For all scour presented in this report, “the scour depths adopted [by VTAOT] may differ from the equation values based on engineering judgement” (Richardson and others, 1993, p. 21, 27). It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1993, p. 48). Many factors, including historical performance during flood events, the geomorphic assessment, and the results of the hydraulic analyses, must be considered to properly assess the validity of abutment scour results.

Vermont↗
USGS1996

Level II scour analysis for Bridge 25 (ALBATH00250030) on Town Highway 25, crossing the Black River, Albany, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure ALBATH00250030 on town highway 25 crossing the Black River, Albany, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge available from VTAOT files were compiled prior to conducting Level I and Level II analyses and can be found in Appendix D. The site is in the New England Upland physiographic province of north-central Vermont in the town of Albany. The 58.8-mi 2 drainage area is in a rural, forested basin. In the vicinity of the study site, the banks have predominantly grass vegetation coverage with a few shrubs. In the study area, the Black River has a non-incised, highly meandering channel with a slope of approximately 0.0005 ft/ft, an average channel top width of 56 ft and an average channel depth of 4 ft. The predominant channel bed material is fine sand (D 50 is 1.68 mm or 0.00551 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 5, 1995, indicated that the reach was laterally unstable. The town highway 25 crossing of the Black River is a 42-ft-long, one-lane bridge consisting of one 40-foot span steel-beam superstructure with a timber deck (Vermont Agency of Transportation, written commun., August 3, 1994). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is not skewed to the opening and the opening-skew-to-roadway is zero degrees. A scour hole 0.5 ft deeper than the mean thalweg depth was observed along mid-channel from 40 feet upstream to about 10 feet under the bridge during the Level I assessment. The left abutment is slightly undermined at the downstream end. The only scour protection measures at the site were sparse type-1 stone fill (less than 12 inches diameter) on the upstream right road embankment, along the left and right abutments, and along the upstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices  D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8.

Vermont↗
USGS1996

Level II scour analysis for Bridge 27 (BRIDTH00490027) on Town Highway 049, crossing Broad Brook, Bridgewater, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure BRIDTH00490027 on town highway 49 crossing Broad Brook, Bridgewater, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge available from VTAOT files was compiled prior to conducting Level I and Level II analyses and can be found in Appendix D. The site is in the Green Mountain physiographic province of central Vermont in the town of Bridgewater. The 13.9-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the left and right banks are pasture with moderate tree cover on the immediate banks. Upstream of bridge 27, a gravel road runs parallel to the left bank. In the study area, the Broad Brook has an incised channel with a slope of approximately 0.007 ft/ft, an average channel top width of 54 ft and an average channel depth of 4 ft. The predominant channel bed materials are gravel and cobble with a D 50 (median diameter) of 77.9 mm or 0.256 ft. The geomorphic assessment at the time of the Level I and Level II site visit on November 9, 1994, indicated that the reach was stable. The town highway 49 crossing of the Broad Brook is a 32-ft-long, one-lane bridge consisting of one 31-ft steel-beam span (Vermont Agency of Transportation, written commun., August 24, 1994). The bridge is supported by vertical, concrete abutments with wingwalls. The left abutment is noted as settled due to previous undermining. Type-2 (less than 3 ft diameter) stone fill protects the upstream left and right wingwalls, the downstream right wingwall, the right abutment, the upstream right road embankment, and the downstream left and right road embankments. Type-3 (less than 4 ft diameter) stone fill protects the downstream left wingwall, but it’s condition was reported as slumping. The channel is skewed approximately 10 degrees to the opening; the opening-skew-to-roadway is also 10 degrees. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8.

Vermont↗
USGS1996

Level II scour analysis for Bridge 57 (BRIDTH00650057) on Town Highway 65, crossing Broad Brook, Bridgewater, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure BRIDTH00650057 on Town Highway 65 crossing Broad Brook, Bridgewater, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge, available from VTAOT files, was compiled prior to conducting Level I and Level II analyses and can be found in Appendix D. The site is in the Green Mountain physiographic province of central Vermont in the town of Bridgewater. The 26.9-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the US left bank is forested; DS left bank is shrub and brushland; US right bank is lawn and the DS right bank has very little vegetation and is largely coincident with the Ottauquechee River. In the study area, Broad Brook has an incised channel with a slope of approximately 0.0067 ft/ft, an average channel top width of 60 ft and an average channel depth of 3 ft. The predominant channel bed material is gravel (D 50 is 46.2 mm or 0.151 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 25, 1994, indicated that the reach was stable. The Town Highway 65 crossing of Broad Brook is a 47-ft-long, one-lane bridge consisting of one 44-ft steel-beam span with a timber deck, supported by vertical concrete abutments with wingwalls on the upstream and downstream sides (Vermont Agency of Transportation, written commun., August, 1994). The US right wingwall and road approach is protected by stone fill. The US and DS right wingwalls and the right abutment are reported as having 1.0 to 1.5 ft of scour at the time of the Level one assessment on 10/25/94. Erosion from road wash affects all road approach embankments. Broad Brook flows into the Ottauquechee River approximately 30 ft downstream of the bridge. The channel approach to the bridge is straight with the bridge skewed 20 degrees to flow and the opening skew-to-roadway is 0 degrees. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Total scour at a highway crossing is comprised of three components: 1) long-term aggradation or degradation; 2) contraction scour (due to reduction in flow area caused by a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute scour depths for contraction and local scour and a summary of the results follows. Contraction scour for all modelled flows ranged from 0.4 ft to 1.5 ft and the worst-case contraction scour occurred at the incipient overtopping discharge. Abutment scour ranged from 6.0 ft to 14.6 ft and the worst-case abutment scour occurred at the 100-year discharge. Scour depths and depths to armoring are summarized on p. 14 in the section titled “Scour Results”. Scour elevations, based on the calculated depths are presented in tables 1 and 2; a graph of the scour elevations is presented in figure 8 Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. For all scour presented in this report, “the scour depths adopted [by VTAOT] may differ from the equation values based on engineering judgement” (Richardson and others, 1993, p. 21, 27). It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1993, p. 48). Many factors, including historical performance during flood events, the geomorphic assessment, and the results of the hydraulic analyses, must be considered to properly assess the validity of abutment scour results.

Vermont↗
USGS1996

Level II scour analysis for Bridge 22 (CRAFTH00180022) on Town Highway 18, crossing Black River, Craftsbury, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure CRAFTH00180022 on town highway 18 crossing the Black River, Craftsbury, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). A Level I study is included in Appendix E of this report. A Level I study provides a qualitative geomorphic characterization of the study site. Information on the bridge, available from VTAOT files, was compiled prior to conducting Level I and Level II analyses and can be found in Appendix D. The site is in the New England Upland physiographic province of north-central Vermont in the town of Craftsbury. The 41.6-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the banks and floodplains are pasture and have no woody vegetation coverage. In the study area, the Black River is not incised, has a meandering channel with a slope of approximately 0.0004 ft/ft, an average channel top width of 66 ft, and an average channel depth of 3 ft. The predominant channel bed material is sand (D 50 is 0.148 mm or 0.000487 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 13, 1995, indicated that the reach was laterally unstable. The town highway 18 crossing of the Black Riveris a 60-ft-long, one-lane bridge consisting of one 55-foot clear-span riveted through-girder type structure with a timber deck (Vermont Agency of Transportation, written commun., August 3, 1994). The bridge is supported by concrete abutments with no wingwalls. The bridge skew is approximately 5 degrees and there is no opening-skew-to-roadway. A scour hole 3 ft deeper than the mean thalweg depth was observed 35 ft downstream of the bridge during the Level I assessment. There is also approximately 2 ft of channel scour upstream of the bridge. There is type-one (less than 12 in diameter) protection on both abutments that may act, in part, as spill-through abutments; the material however is partially made up of the remnants of older log-cribbing abutments, when the bridge length was significantly less than the current structure. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E. Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of the scour depths is presented in figure 8.

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USGS2024

U.S. Geological Survey data strategy 2023–33

The U.S. Geological Survey (USGS) has long recognized the strategic importance and value of well-managed data assets as an integral component of scientific integrity and foundational to the advancement of scientific research, decision making, and public safety. The USGS investment in the science lifecycle, including collection of unbiased data assets, interpretation, peer review, interpretive publications, and data release, ultimately contributes to the transparency and availability of science. Foundational Government directives and laws, such as the Foundations for Evidence-Based Policymaking Act of 2018 (Public Law 115–435, 132 Stat. 5529) as well as Executive Order 13642, “Making Open and Machine Readable the New Default for Government Information,” provide a framework for addressing strategic data management. The USGS Data Strategy builds on that framework by outlining high-level goals and objectives that serve as a long-term, decadal guide toward achieving a broad, data-focused vision. Benefits of the USGS Data Strategy are many. The USGS will contribute to open science by increasing efficiencies in the consistent management of valuable data assets; driving innovation that results in modernized capabilities to ensure data are analysis ready; increasing data skills across the Bureau to enhance workforce data literacy; broadening capacity to understand and address needs of stakeholders; and measuring progress in producing findable, accessible, interoperable, and reusable (FAIR) data products. The major goals and objectives of the USGS Data Strategy promote maximizing the utility of USGS data based on stakeholder needs, promoting data innovation, coordinating common data practices, modernizing our USGS enterprise data architecture, and enhancing our data-centric culture. The goals and objectives in the strategy align with other Bureau strategic plans, guidance, and directives from the Department of the Interior and the Federal Government. This strategy is a key component to strengthen the Bureau’s data ecosystem to ensure a relevant, long-term capacity that supports internal needs and achieves its scientific mission in the most efficient and effective manner.

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USGS2020

Communicating hazards—A social science review to meet U.S. Geological Survey needs

This report is for U.S. Geological Survey (USGS)—and any other—hazard scientists who want to improve the understanding and use of their scientific information, particularly by non-experts. In order for people to use science, they need to understand it. The highly technical, specialized nature of scientific information makes that difficult, particularly when few scientists are trained to communicate with people outside their fields. These issues are of special importance to the USGS because it has many users who are not scientists and because it develops and applies hazard science to help protect the safety, security, and economic well-being of our Nation. In 2010, the Science Application for Risk Reduction group at the USGS discovered the Center for Research on Environmental Decisions (CRED) guide, “The Psychology of Climate Change Communication.” Ever since, a growing number of USGS staff who need to communicate about hazards have used that guide and have asked CRED for a companion report dedicated to hazard communication to harness knowledge from more than 50 years of social science research. In 2016, the USGS and CRED launched a collaboration to develop that companion report. Ultimately, a CRED hazard communication guide would be a Columbia University publication with a wide focus and would include many hazards that are outside the USGS purview. This report is a first step and concentrates strictly on hazard communication needs at the USGS. To identify those needs and tailor this effort to USGS hazard communication priorities, this collaboration began with telephone interviews and an online survey of USGS staff. This report is the result; it summarizes social science research and experience in the areas of hazard communication that USGS participants deemed most important to include.

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USGS2014

The National Climate Change and Wildlife Science Center annual report for 2013

In 2008, Congress created the National Climate Change and Wildlife Science Center (NCCWSC) within the U.S. Geological Survey (USGS). The center was formed to respond to the demands of natural resource managers for rigorous scientific information and effective tools for assessing and responding to climate change. Located at the USGS National Headquarters in Reston, Va., the NCCWSC has invested more than $93 million (through FY13) in cutting-edge climate change research and, in response to Secretarial Order No. 3289, established and is managing eight regional Department of Interior (DOI) Climate Science Centers (CSCs). In 2013: The DOI CSCs awarded nearly $7 million in funding to universities and other partners for climate and land-use change research. The scientific work of the NCCWSC-CSC enterprise moved toward projects that focus on ‘Science Infrastructure and Capacity Building’ and ‘Thematic Science’. A permanent director, David Helweg, Ph.D., was hired for the Pacific Islands CSC (PI CSC), completing the CSC leadership team. Staff scientists were hired at the Alaska (AK), Northeast (NE), and Southeast (SE) CSCs. Each of the eight CSCs completed the formation of regional Stakeholder Advisory Committees (SACs) and a national advisory committee (ACCCNRS) was created to oversee the NCCWSC-CSC enterprise. NCCWSC staff worked on creating a searchable public database on climate change vulnerability assessments. NCCWSC scientists authored articles in a special issue of the Ecological Society of America’s journal Frontiers in Ecology and the Environment, which was devoted to an assessment of climate change effects on biodiversity and ecosystems, and the consequences for people. Learn more about these achievements in The National Climate Change and Wildlife Science Center Annual Report for 2013 .

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USGS1983

Summary of workshops concerning regional seismic source zones of parts of the conterminous United States, convened by the U.S. Geological Survey, 1979-1980, Golden, Colorado

Workshops were convened by the U.S. Geological Survey to obtain the latest information and concepts relative to defining seismic source zones for five regions of the United States. The zones, with some modifications, have been used in preparation of new national probabilistic ground motion hazard maps by the U.S. Geological Survey. The five regions addressed are the Great Basin, the Northern Rocky Mountains, the Southern Rocky Mountains, the Central Interior, and the northeastern United States. Discussions at the workshops focussed on possible temporal and spatial variations of seismicity within the regions, latest ages of surface-fault displacements, most recent uplift or subsidence, geologic structural provinces as they relate to seismicity, and speculation on earthquake causes. Within the Great Basin region, the zones conform to areas characterized by a predominance of faults that have certain ages of latest surface displacements. In the Northern and Southern Rocky Mountain regions, zones primarily conform to distinctive structural terrane. In the Central Interior, primary emphasis was placed on an interpretation of the areal distribution of historic seismicity, although geophysical studies in the Reelfoot rift area provided data for defining zones in the New Madrid earthquake area. An interpretation of the historic seismicity also provided the basis for drawing the zones of the New England region. Estimates of earthquake maximum magnitudes and of recurrence times for these earthquakes are given for most of the zones and are based on either geologic data or opinion.

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