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Sedimentology of the Pennsylvanian and Permian Strathearn Formation, Northern Carlin Trend, Nevada; with a section on microfossil controls on age of the Strathearn Formation

Two framework-supported, poorly bedded conglomerate units of the middle Upper Pennsylvanian and middle Lower Permian Strathearn Formation belonging to the overlap assemblage of the Antler orogen are prominent in the northern Carlin trend. These horizons stratigraphically and temporally bracket thrust emplacement of a major allochthonous thrust plate of mainly quartzarenite of the Ordovician Vinini Formation. Lithologic and shape-ratio data from approximately 4,200 pebbles and cobbles at 17 sites as well as biostratigraphic data in the Strathearn, and their geologic implications, are included in this report. Conodont biofacies throughout the Strathearn Formation are normal marine and suggest middle shelf or deeper depositional environments. The conglomerate units roughly are similar in that they contain only chert and quartzarenite pebbles, but they differ in compositional proportions of the two lithologies. The relative proportion of quartzarenite pebbles increases sixfold in the middle Lower Permian upper conglomerate unit versus its content in the middle Upper Pennsylvanian lower unit, whereas chert pebbles predominate in both units. Various roundness categories of chert pebbles in both conglomerate units of the Strathearn show that the equant pebble class (B/A) = 1 clearly is represented strongly even in the subangular category, the lowest roundness categories for the pebbles. Thus, development of equant pebbles cannot be ascribed totally to a rounding process during predeposition transport. The equant character of many pebbles might, in part, be an original feature inherited from pre-erosion rock fractures and (or) bedding that control overall form of the fragments prior to their release to the transport environment. The allochthon of the Coyote thrust has been thrust above the lower conglomerate unit of the Strathearn during a regionally extensive contractional event in the late Paleozoic. The middle Lower Permian upper conglomerate unit, highest unit recognized in the Strathearn Formation, as well as similarly-aged dolomitic siltstone, onlap directly onto quartzarenite that comprises the allochthon of the Coyote thrust. The conglomerate units thus represent submarine fanglomerates whose quartz grains and quartzarenite fragments of variable roundness and shape were derived from a sedimentologically restored largely southeastward advancing late Paleozoic allochthonous lobe of mostly quartzarenite of the Ordovician Vinini Formation. Chert fragments in the conglomerates probably were derived mostly from Devonian Slaven Chert, including a widespread thick melange unit of the Slaven in the footwall of the Coyote thrust. Some chert pebbles may have been derived from the Ordovician Vinini Formation.

Nevada

Project Planning for Cougar Dam during 2010

Cougar Dam is a 158 m-tall, rock fill dam located about 63 km east of Springfield, Oregon. Completed in 1963, the dam is owned and operated by the U.S. Army Corps of Engineers (USACE). It impounds Cougar Reservoir, which is 9.7 km long, has a surface area of 518 ha, and is predominately used for flood control. The pool elevation typically ranges from a maximum conservation pool of 515 m (1,690 ft) National Geodetic Vertical Datum (NGVD) in summer to a minimum flood control elevation of 467 m (1,532 ft NGVD) in winter. The reservoir thermally stratifies in the summer, has an average depth of 37 m, and holds 153,500 acre-feet when full. Cougar Dam is located on the South Fork of the McKenzie River 7 km upstream from the mainstem McKenzie River, a tributary of the Willamette River. The McKenzie River Basin basin supports the largest remaining population of wild spawning spring Chinook salmon in the Willamette River Basin (National Oceanic and Atmospheric Administration; NOAA, 2008). Cougar Dam and others were collectively deemed to cause jeopardy to the sustainability of anadromous fish stocks in the Willamette River Basin (NOAA, 2008). Prior to dam construction, as many as 805 redds were observed in the South Fork of the McKenzie River (Willis and others, 1960) and it is estimated that 40 km of spawning habitat were lost when access was blocked after dam construction. The 2008 Willamette Biological Opinion (BIOP) requires improvements to operations and structures to reduce impacts on Upper Willamette River (UWR) Chinook salmon (Oncorhynchus tshawytscha) and UWR steelhead (O. mykiss; NOAA, 2008). In 2010, an adult fish collection facility was completed below Cougar Dam to collect returning adult salmon for transport to spawning habitats above the dam. Before that time, returning adult spring Chinook salmon were transported to upstream spawning areas as part of a trap-and-haul program with adults passed ranging annually from 0 to 1,038 (Taylor, 2000). The progeny of adult fish that are allowed to spawn above Cougar Dam move downstream into Cougar Reservoir in the spring. Under the BIOP, the USACE is required to provide downstream fish passage or operational alternatives at Cougar Dam by 2014. Currently, there is little information about the seasonal timing of reservoir entry of juvenile Chinook salmon and what habitats they and other fishes use in the reservoir. However, rotary screw traps placed in the outlet channel below the dam indicate peak juvenile passage coinciding with seasonally low pool elevation in mid December and late January. It is unknown whether juveniles upstream of Cougar Dam can be captured in large enough numbers for tagging and subsequent survival studies to proceed. These studies are needed to examine the feasibility of installing downstream fish passage structures at Cougar Dam to meet BIOP requirements. Therefore, the USACE contracted with the U.S. Geological Survey (USGS) to test the efficacy of using a mid-water trawl and lampara seine to capture fish in Cougar Reservoir on three consecutive days in the fall of 2010. These collection methods could potentially provide fish for feasibility and subsequent survival studies and as verification of fish targets in future active hydroacoustic surveys.

Oregon

Imagery

As part of CRMS, Digital Orthophoto Quarter Quadrangles (DOQQs) for the coastal region of Louisiana are created for years when coastwide land-water classifications are required. A DOQQ is a raster image in which displacement in the image caused by sensor orientation and terrain relief has been corrected. These images combine the image characteristics of a photo with the geometric qualities of a map. The DOQQs generated for this project consist of four components or spectral bands of information: blue, green, red and very-near infrared (VNIR). These images are referred to as Color Infrared (CIR) digital imagery. CRMS site-level assessments of land-water coverage will be based off of color-infrared photography acquired for coastal Louisiana and clipped to each 1-km2 CRMS-Wetlands site. Unless otherwise noted as a specific preliminary condition, all vegetation such as scrub-shrub, emergent vegetation, and forested areas will fall under the land classification, while open water, non-vegetated, regularly flooded mud flats, and aquatic vegetation beds will be characterized as water. CRMS imagery contracts are managed and issued by the United States Geological Survey (USGS) Wetland and Aquatic Research Center.

Louisiana

Bivalves

Bivalves are important as consumers of pelagic and demersal food resources. With sufficient biomass, they can compete with and, in some cases, outcompete other members of the pelagic food web for food resources such as phytoplankton and zooplankton. We include bivalves in the San Francisco Estuary (SFE) and Delta in the FLOAT MAST because they have been and continue to be an important member of the food web. Changes in the bivalves over the last 40 years have led us to hypothesize that bivalves may limit food resources for Delta Smelt and other pelagic fish species (Kimmerer and Thompson 2014, Sommer et al 2007). We will discuss the two bivalves with the largest biomass, the estuarine bivalve Potamocorbula amurensis (hereafter Potamocorbula ) and the freshwater bivalve Corbicula fluminea (hereafter Corbicula ). The distribution of these two species together covers the full range of salinities between the Golden Gate and the upstream reaches of the SR and SJR. The species overlap in the region of X2. Both species’ distributions expand or contract when the salinity distribution changes and do so in near synchrony with each other at a salinity of approximately 2. It is this interaction of both bivalves at their threshold levels of salinity within the ecologically sensitive low salinity zone (LSZ) in addition to their distribution in the rest of the system that determines each species effect on the food web.

California

Commerical Remote Sensing Data Contract

The U. S. Geological Survey's (USGS) Commercial Remote Sensing Data Contracts (CRSDCs) provide government agencies with access to a broad range of commercially available remotely sensed airborne and satellite data. These contracts were established to support The National Map partners, other Federal Civilian agency programs, and Department of Defense programs that require data for the United States and its territories. Experience shows that centralized procurement of remotely sensed data leads to considerable cost savings to the Federal government through volume discounts, reduction of redundant contract administrative costs, and avoidance of duplicate purchases. These contracts directly support the President's Commercial Remote Sensing Space Policy, signed in 2003, by providing a centralized mechanism for civil agencies to acquire commercial remote sensing products to support their mission needs in an efficient and coordinated way. CRSDC administration is provided by the USGS Mid-Continent Mapping Center in Rolla, Missouri.

Fact Sheet

Cooperative tectonic studies from seismic network in central Italy

The purpose of the subject contract work was to explore the possibility of tectonic research-work based on seismic data from a local network carried out as a cooperative effort between the Institute Nazionale di Geofisica (ING), Rome, and Columbia University (L-DGO), New York. This effort has been rather successful, and we hope to be able to continue this collaboration in the future.

Open-File Report

Final Report: Five years of monitoring reconstructed freshwater tidal wetlands in the urban Anacostia River (2000-2004)

The Anacostia River in Washington, D.C. USA consisted of over 809 hectares (2000 acres) of freshwater tidal wetlands before mandatory dredging removed most of them in the first half of the 20th century. Much of this13 kilometer (8 mile) reach was transferred to the National Park Service (NPS). Planning processes in the 1980?s envisioned a restoration (rejuvenation) of some wetlands for habitat, aesthetics, water quality and interpretative purposes. Subsequently, the U.S. Army Corps of Engineers in a cost share agreement with the District of Columbia reconstructed wetlands on NPS lands at Kenilworth - 12.5 hectares (1993), Kingman - 27 hectares (2000), a Fringe Marsh - 6.5 hectares (2003) and is currently constructing Heritage Marsh - 2.5 hectares (2005/2006). The USGS Patuxent Wildlife Research Center in conjunction with the University of Maryland Biological Engineering Department was contracted to conduct post-reconstruction monitoring (2000-2004) to document the relative success and progress of the Kingman Marsh reconstruction primarily based on vegetative response but also in conjunction with seed bank and soil characteristics. Results from Kingman were compared to Kenilworth Marsh (reconstructed 7 years prior), Dueling Creek Marsh (last best remaining freshwater tidal wetland bench in the urbanized Anacostia watershed) and Patuxent River Marsh (in a more natural adjacent watershed). Vegetation establishment was initially strong at Kingman, but declined rapidly as measured by cover, richness, diversity , etc. under grazing pressure from resident Canada geese and associated reduction in sediment levels. This decline did not occur at the other wetlands. The decline occurred despite a substantial seed bank that was sustained primarily be water born propagules. Soil development, as true for most juvenile wetlands, was slow with almost no organic matter accumulation. By 2004 only two of 7 planted species remained (mostly Peltandra virginica) at Kingman which did provide almost 50% of the approximately 1/3 total vegetation cover remaining.

Book

Discussion on remote sensing for aquatic monitoring

The special session on Remote Sensing for Aquatic Resource Monitoring concluded with an expert panel discussion. Panel members were Jennifer Bountry (hydraulic engineer, Bureau of Reclamation), Mimi D’Iorio (GIS analyst and database manager, National Oceanic and Atmospheric Administration), Russ Faux (president, Watershed Sciences, Inc.), Steve Lanigan (team leader, Aquatic and Riparian Effectiveness Monitoring Program, U.S. Forest Service), and Amar Nayegandhi (computer scientist, Jacobs Technology, contracted to U.S. Geological Survey). The panel was moderated by Ralph Haugerud (geologist, U.S. Geological Survey) and there were significant contributions from the audience. The dialogue is summarized below in question and answer format. This summary is followed by discussion of what we learned in the course of the special session and identification of some next steps for the Pacific Northwest aquatic monitoring community.

PNAMP Special Publication

An evaluation of selected extraordinary floods in the United States reported by the U.S. Geological Survey and implications for future advancement of flood science

Thirty flood peak discharges determine the envelope curve of maximum floods documented in the United States by the U.S. Geological Survey. These floods occurred from 1927 to 1978 and are extraordinary not just in their magnitude, but in their hydraulic and geomorphic characteristics. The reliability of the computed discharge of these extraordinary floods was reviewed and evaluated using current (2007) best practices. Of the 30 flood peak discharges investigated, only 7 were measured at daily streamflow-gaging stations that existed when the flood occurred, and 23 were measured at miscellaneous (ungaged) sites. Methods used to measure these 30 extraordinary flood peak discharges consisted of 21 slope-area measurements, 2 direct current-meter measurements, 1 culvert measurement, 1 rating-curve extension, and 1 interpolation and rating-curve extension. The remaining four peak discharges were measured using combinations of culvert, slope-area, flow-over-road, and contracted-opening measurements. The method of peak discharge determination for one flood is unknown. Changes to peak discharge or rating are recommended for 20 of the 30 flood peak discharges that were evaluated. Nine floods retained published peak discharges, but their ratings were downgraded. For two floods, both peak discharge and rating were corrected and revised. Peak discharges for five floods that are subject to significant uncertainty due to complex field and hydraulic conditions, were re-rated as estimates. This study resulted in 5 of the 30 peak discharges having revised values greater than about 10 percent different from the original published values. Peak discharges were smaller for three floods (North Fork Hubbard Creek, Texas; El Rancho Arroyo, New Mexico; South Fork Wailua River, Hawaii), and two peak discharges were revised upward (Lahontan Reservoir tributary, Nevada; Bronco Creek, Arizona). Two peak discharges were indeterminate because they were concluded to have been debris flows with peak discharges that were estimated by an inappropriate method (slope-area) (Big Creek near Waynesville, North Carolina; Day Creek near Etiwanda, California). Original field notes and records could not be found for three of the floods, however, some data (copies of original materials, records of reviews) were available for two of these floods. A rating was assigned to each of seven peak discharges that had no rating. Errors identified in the reviews include misidentified flow processes, incorrect drainage areas for very small basins, incorrect latitude and longitude, improper field methods, arithmetic mistakes in hand calculations, omission of measured high flows when developing rating curves, and typographical errors. Common problems include use of two-section slope-area measurements, poor site selection, uncertainties in Manning’s n -values, inadequate review, lost data files, and insufficient and inadequately described high-water marks. These floods also highlight the extreme difficulty in making indirect discharge measurements following extraordinary floods. Significantly, none of the indirect measurements are rated better than fair, which indicates the need to improve methodology to estimate peak discharge. Highly unsteady flow and resulting transient hydraulic phenomena, two-dimensional flow patterns, debris flows at streamflow-gaging stations, and the possibility of disconnected flow surfaces are examples of unresolved problems not well handled by current indirect discharge methodology. On the basis of a comprehensive review of 50,000 annual peak discharges and miscellaneous floods in California, problems with individual flood peak discharges would be expected to require a revision of discharge or rating curves at a rate no greater than about 0.10 percent of all floods. Many extraordinary floods create complex flow patterns and processes that cannot be adequately documented with quasi-steady, uniform one-dimensional analyses. These floods are most accurately described by multidimensional flow analysis. Within the U.S. Geological Survey, new approaches are needed to collect more accurate data for floods, particularly extraordinary floods. In recent years, significant progress has been made in instrumentation for making direct discharge measurements. During this same period, very little has been accomplished in advancing methods to improve indirect discharge measurements. Greater use of paleoflood hydrology could fill many shortcomings of U.S. Geological Survey flood science today, such as enhanced knowledge of flood frequency. Additional links among flood runoff, storm structure, and storm motion would provide more insight to flood hazards. Significant improvement in understanding flood processes and characteristics could be gained from linking radar rainfall estimation and hydrologic modeling. Additionally, more could be done to provide real-time flood-hazard warnings with linked rainfall/runoff and flow models. Several important recommendations are made to improve the flood-documentation capability of the U.S. Geological Survey. When very large discharges are measured by current meter or hydroacoustics, water-surface slope should be measured as well. This measurement would allow validation of roughness values that can significantly extend the discharge range of verified Manning’s n for 1-dimensional and 2-dimensional flow analyses. At least two of the floods investigated may have had flow so unstable that large waves affected the interpretation of high-water marks. Instability criteria should be considered for hydraulic analysis of large flows in high-gradient, smooth channels. The U.S. Geological Survey needs to modernize its toolbox of field and office practices for making future indirect discharge measurements. These practices could include, first and foremost, a new peak-flow file database that allows greater description and interpretation of flow events, such as stability criteria in high-gradient, smooth channels, debris flow documentation, and details of flood genesis (hurricane, snowmelt, rain-on-snow, dam failure, and the like). Other modernized practices could include (a) establishment of calibrated stream reaches in chronic flash flood basins to expedite indirect computation of flow; (b) development of process-based theoretical rating curves for streamflow-gaging stations; (c) adoption of step-backwater models as the standard surface-water modeling tool for U.S. Geological Survey field offices; (d) development and support for multidimensional flow models capable of describing flood characteristics in complex terrain and high-gradient channels; (e) greater use of the critical-depth method in appropriate locations; (f) deployment of non-contact instruments to directly measure large floods, rather than attempting to reconstruct them; (g) increased use of paleoflood hydrology; and (h) assurance that future collection of hydro-climatic data meets the needs of more robust watershed models.

Scientific Investigations Report

Borehole dilatometer installation, operation, and maintenance at sites in Hawaii

In response to concerns about the potential hazard of Mauna Loa volcano in Hawaii, the USGS began efforts in 1998 to add four high-resolution borehole sites. Located at these sites are; strainmeters, tiltmeters, seismometers, accelerometers and other instrumentation. These instruments are capable of providing continuous monitoring of the magma movement under Mauna Loa. Each site was planned to provide multi-parameter monitoring of volcanic activity. In June of 2000, a contract was let for the core drilling of three of these four sites. They are located at Hokukano (west side of Mauna Loa) above Captain Cook, Hawaii; at Mauna Loa Observatory (11,737 feet near the summit), and at Mauna Loa Strip Road (east side of Mauna Loa). Another site was chosen near Halema'uma u' and Kilauea's summit, in the Keller deep well. (See maps). The locations of these instruments are shown in Figure 1 with their latitude and longitude in Table 1. The purpose of this network is to monitor crustal deformation associated with volcanic intrusions and earthquakes on Mauna Loa and Kilauea volcanoes. This report describes the methods used to locate sites, install dilatometers, other instrumentation, and telemetry. We also provide a detailed description of the electronics used for signal amplification and telemetry, plus techniques used for instrument maintenance. Instrument sites were selected in regions of hard volcanic rock where the expected signals from magmatic activity were calculated to be a maximum and the probability of earthquakes with magnitude 4 or greater is large. At each location, an attempt was made to separate tectonic and volcanic signals from known noise sources for each instrument type.

Hawaii

Scour assessment at bridges from Flag Point to Million Dollar Bridge, Copper River Highway, Alaska

Twelve bridges are located along the Copper River Highway from Flag Point (Mile 27) to lhe Million Dollar Bridge (Mile 48). These bridges cross all or parts of the Copper River. Channel scour at these bridges was assessed by collecting and analyzing discharge and sediment data, analyzing aerial photography for eight different years, surveying and comparing cross sections, and utilizing scour equations. Between 1968 and 1992, scour occurring at Bridge 331 has formed two distinct channels at the bridge. The channel at Bridge 1187 has remained relatively unchanged between 1968 and 1992. During this same time period, the channel at Bridge 332 appears to have gradually filled. However, during the 1992 runoff season, the channel at this bridge scoured significantly, probably because of its unstable nature. The most significant scour has occurred at Bridge 342. A high-water period in 1981 probably shifted much of the flow of the Copper River through this bridge. As a result, severe contraction scour occurred which required major repairs to the bridge. During 1991 and 1992, the approach channel to Bridge 342 has been migrating, causing scour in the left side of the channel. Bed material at the Million Dollar Bridge consists of hard unweathered boulders nested in dense gravel. Because of this type of erosion-resistant material, no significant scour has occurred at this site. Contraction scour equations overestimated the mean depth of flow at Bridge 331 by 2.6 to 5.0 ft, but were within 1.0 ft of the mean depth of flow for Bridge 1187. The local scour equations generally overestimated local scour at both Bridge 331 and Bridge 1187. The accuracy of some equations was probably affected because water velocities could not be obtained upstream from the piers.

Water-Resources Investigations Report

Seismic-reflection records from a survey at the Rocky Mountain Arsenal near Denver, Colorado

During July 1966, after competitive bidding, a contract was awarded by the U.S. Geological Survey to GeoData Corporation and Geo Prospectors, Inc., both of Tulsa, Oklahoma, for 18 miles of continuous seismic-reflection profiling in the vicinity of a deep injection disposal well (IDW) at the Rocky Mountain Arsenal near Denver, Colorado. The purpose of this survey was to determine if structure exists in the 12,000-ft sedimentary section or in the Precambrian basement that might be related to the series of earthquakes that occurred in the area starting in the spring of 1962. A paper on the seismic-reflection profiling by Ben R. Rummerfield, A. Peter Olson, and D. B. Hoover (1968) reported the major conclusions of the survey.

Colorado

Streambed scour evaluations and conditions at selected bridge sites in Alaska, 2013–15

Streambed scour potential was evaluated at 52 river- and stream-spanning bridges in Alaska that lack a quantitative scour analysis or have unknown foundation details. All sites were evaluated for stream stability and long-term scour potential. Contraction scour and abutment scour were calculated for 52 bridges, and pier scour was calculated for 11 bridges that had piers. Vertical contraction (pressure flow) scour was calculated for sites where the modeled water surface was higher than the superstructure of the bridge. In most cases, hydraulic models of the 1- and 0.2-percent annual exceedance probability floods (also known as the 100- and 500-year floods, respectively) were used to derive hydraulic variables for the scour calculations. Alternate flood values were used in scour calculations for sites where smaller floods overtopped a bridge or where standard flood-frequency estimation techniques did not apply. Scour also was calculated for large recorded floods at 13 sites. Channel instability at 11 sites was related to human activities (in-channel mining, dredging, and channel relocation). Eight of the dredged sites are located on active unstable alluvial fans and were graded to protect infrastructure. The trend toward aggradation during major floods at these sites reduces confidence in scour estimates. Vertical contraction and pressure flow occurred during the 0.2-percent or smaller annual exceedance probability floods at eight sites. Contraction scour exceeded 5 feet (ft) at four sites, and total scour at piers (pier scour plus contraction scour) exceeded 5 ft at four sites. Debris accumulation increased calculated pier scour at six sites by an average of 2.4 ft. Total scour at abutments exceeded 5 ft at 10 sites. Scour estimates seemed excessive at two piers where equations did not account for channel armoring, and at four abutments where failure of the embankment and attendant channel widening would reduce scour.

Alaska

Water-Quality Data for Selected National Park Units within the Southern Colorado Plateau Network, Arizona, Utah, Colorado, and New Mexico, Water Years 2005 and 2006

The National Park Service initiated a Level 1 Water-Quality Inventory program to provide water-quality data to park managers so informed natural resource management decisions could be made. Level 1 water-quality data were collected by the U.S. Geological Survey Arizona Water Science Center at 57 sites in 13 National Park units located in the Southern Colorado Plateau Inventory and Monitoring network in water years 2005 and 2006. These data describe the current water-quality at selected sites within the park units and provide information for monitoring future trends. Water samples were collected three times at each type of site including wells, springs, seeps, tinajas, rivers, a lake, and an irrigation ditch. Field measurements were taken at each site and they included pH, specific conductance, temperature, barometric pressure, dissolved oxygen, alkalinity, turbidity, and discharge rates where applicable. Water samples collected were sent to the U.S. Geological Survey National Water Quality Laboratory and analyzed for major ions, trace elements, and nutrients. The National Water Quality Laboratory also analyzed selected samples for mercury and petroleum hydrocarbons. Additional samples at selected sites were collected and analyzed for cyanide, radiochemistry, and suspended sediment by U.S. Geological Survey contract labs. Fecal-indicator bacteria (Escherichia coli) were sampled for at selected sites as another indicator of water quality. Quality control for this study was achieved through proper training of field personnel, use of standard U.S. Geological Survey field and laboratory protocols, collection of sample blanks and replicates, and a thorough review of the water-quality analyses. Measured field pH ranged from 6.0 to 8.8, within normal range for springs and rivers, at most sites. Concentrations of dissolved solids ranged from 48 to 8,680 mg/L and the majority of samples had concentrations of dissolved solids below 900 mg/L. Trace-element concentrations at most sites were at or near the laboratory reporting levels. The highest overall trace-element concentrations were found at U.S. Highway 160 Spring near Park Entrance to Mesa Verde National Park. Concentrations of uranium in samples at all sites ranged from below the detection limit to 55.7 ?g/L. Water samples from selected sites were analyzed for total petroleum hydrocarbons and concentrations of total petroleum hydrocarbons were at or above the laboratory detection limit in samples at six National Park units. Ten sites were sampled for Escherichia coli and positive counts were found at 9 out of the ten sites, the highest colony counts were found at Chinle Creek at Chinle, AZ in Canyon de Chelly National Monument. Measured concentrations of dissolved ammonia, nitrite, and nitrate were at or near laboratory reporting levels at most sites; nitrate concentrations ranged from below the reporting limit (0.047 mg/L) to 9.77 mg/L. Samples that were analyzed for mercury had concentrations below or at the laboratory reporting level. Concentrations of cyanide were less than the laboratory reporting level for all samples except two, Spruce Tree House Spring in Mesa Verde National Park and Pine Tree Canyon Tinaja in Canyon de Chelly National Monument, which had average concentrations of .042 and .011 ?g/L respectively. Gross alpha/beta radioactivity counts were below the U.S. Environmental Protection Agency maximum contaminant level except for samples from Casa Chiquita Well  Middle at Chaco Culture National Historical Park which averaged 35 pCi/L. Suspended-sediment concentrations were variable and ranged from 10 to 150,000 mg/L.

Open-File Report

Desert wetlands—Archives of a wetter past

Scientists from the U.S. Geological Survey (USGS) are finding evidence of a much wetter past in the deserts of the American Southwest using a most unlikely source—wetlands. Wetlands form in arid environments where water tables approach or breach the ground surface. Often thought of as stagnant and unchanging, new evidence suggests that springs and wetlands responded dynamically to past episodes of abrupt climate change. Multiple cycles of deposition, erosion, and soil formation show that wetlands in the southwestern United States expanded and contracted many times during the past 35,000 years or so, before disappearing altogether as the last glacial period came to a close. USGS scientists are now studying the deposits to determine how closely conditions in the desert were tied to regional and global climate patterns in the past, and what it might mean for the fragile ecosystems in light of anticipated climate change in the future.

Nevada

Results of the second phase of the drought-disaster test-drilling program near Morristown, N.J.

The continued drought in northeastern New Jersey through the summer of 1966 with its attendant water-supply problems resulted in an extension of the drought-disaster test-drilling program originally requested by the Office of Emergency Planning on August 30, 1965. Authorization to continue test drilling was fiven by the Office of Emergency Planning on September 26, 1966, with the stipulation that all field work be complete by January 31, 1977. Contractural costs were paid by the Office of Emergency Planning, whereas personnel costs were shared by the U.S. Geological Survey and the New Jersey Department of Conservation and Economic Development, Division of Water Policy and Supply. The work undertaken in 1965 by the Geological Survey was "...to preform the necessary drilling and testing of wells to identify the extent and nature of a reserve ground-water source in the vicinity of the Passaic River near the northern New Jersey metropolitan area." Results of this first phase were made available in the fall of 1966 in Water Resources Circular 16 of the New Jersey Department of Conservation and Economic Development. Three of the five areas tested (figure 1)--two in Parsippany-Troy Hills Township (areas 2 and 4) and one in East Hanover Township (area 1), Morris County--proved capable of providing an aggregate sustained yield of 7.5 million gallons daily (mgd) from wells constructed in sand and gravel deposits. Because significant supplies of ground water for emergency use were located in the first phase of the exploratory test-drilling program, it was though desirable to extend the originally planned studies so as to obtain maximum practicable information on emergency supplies. During this second phase of the investigation, drilling was conducted in 16 sites in Chatham, Madison, and Florham Park Boroughs and in Hanover and East Hanover Townships, Morris County. (See figure 2.) The drilling in Hanover and East Hanover Townships, and part of the drilling done in Florham Park was to explore the availability of large undeveloped ground-water supplies. Drilling in Chatham, Madison, and Florham Park Boroughs was done primarily to determine the extent and continuity of buried valley-fill aquifers, so that a full evaluation of the effects of pumpage from other areas on these already heavily pumped areas could be made. In addition, it was anticipated that the drilling could help in defining the feasibility of artificial recharge of the heavily pumped areas and in the determination of the prospective method of recharge and points of emplacement. Arrangements for easements with landowners, preparation of specifications for well drilling and seismic work, and supervision of well drilling and seismic contracts were all performed by the New Jersey District, Water Resources Division of the Geological Survey. Prior to the test drilling, seismic exploration under contract with Alpine Geophysical Associates of Norwood, N. J. was conducted at five locations in the Chatham-Madison-Florham Park area and at one place in Parsippany-Troy Hills Township. The seismic work was done to determine the most favorable location for a test well at several potential test-well sites and to help in the interpretation of subsurface geology between test sites. Contracts for the drilling of the test holes were awarded during November and drilling commences on November 30. Kaye Well drilling, Inc. of Jackson, N. J. was the recipient of a contract for eight of the test holes, and a second contract was awarded to Rinbrand Well Drilling Co., Inc. of Glen Rock, N. J.--also for eight test holes. Acknowledgment is due to the many public officials of Chatham, Madison, Florham Park, Morristown, and East Hanover Township as well as officials of the Braidburn Corporation and Esso Research and Engineering Co., who cooperated by making their lands available for exploration.

New Jersey

Size of the California Brown Pelican Metapopulation During a Non-El Nino Year

Overall, we estimated a total metapopulation within the geographical range of the California brown pelican subspecies (Pelecanus occidentalis californicus) as about 70,680 ? 2,640 breeding pairs (mean ? SD). Little change in at least three decades is indicated in the total metapopulation south of the Southern California Bight (SCB) subpopulation, but significant improvements in the breeding subpopulation size in the SCB reported elsewhere, support the present high numbers observed in this northernmost subpopulation. The largest breeding aggregation within the entire range (consisting of three immediately adjacent sub-colonies), at the San Lorenzo Archipelago, consisted of about 17,225 breeding pairs, or about 24.4% of the metapopulation in 2006. Other, smaller colonies are no less important, however, although each subpopulation defined by us seemed to have a single or small number of large 'core' breeding colonies, plus many smaller colonies (for example, in 2006, one colony consisted of only 2 breeding pairs). Small colonies (< about 70 nests) comprised about 35.6% of the total occupied colonies, but only about 0.87% of the total estimated numbers (values corrected for detectability). The modal colony-size throughout the range was much smaller (about 230 to 1,300 breeding pairs, depending on subpopulation), indicating that small, scattered colonies and sub-colonies, especially on the range peripheries, function in brown pelican population dynamics and are no less important from a conservation viewpoint. These smaller breeding colonies probably represent some colonies of antiquity, but also range expansions and contractions that occur within the typically-defined metapopulation, and local manifestations of source-sink phenomena. Given such dynamics, even unoccupied islands within the range in 2006 have conservation importance from the viewpoint of such dynamics as potential alternate nesting sites. Natural variations in the estimated population levels seem to be related to the natural cycles of El Ni?o/Southern Oscillation (ENSO) phenomena where very low breeding populations (as low as no nesting in many areas) might be expected to occur in these same areas censused in 2006 at least 40% of the time. From the 2006 aerial survey, extensive commercial and sport-fishing activity, resort/tourist developments and associated human activities along the coastal areas and at offshore islands, and extensive aquacultural (and to a lesser degree, agricultural) developments seen from the Rio Colorado Delta region, Sonora, south at least through San Blas, Nayarit (the southern terminus of our 2006 aerial survey) may result in substantial loss of breeding habitat. Juvenile (young of the 2005 breeding season) plus subadult brown pelicans comprised 28.1% ? 0.33% (mean ? 95% CI) of the total numbers in age-ratio samples. Thus, our overall metapopulation estimate for P. o. californicus in 2006 was 195,900 ? 7,225 individuals.

Open-File Report

Level II scour analysis for Bridge 17 (NEWHTH00200017) on Town Highway 20, crossing Little Otter Creek, New Haven, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure NEWHTH00200017 on Town Highway 20 crossing Little Otter Creek, New Haven, 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). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Champlain section of the St. Lawrence Valley physiographic province in west-central Vermont. The 10.8-mi 2 drainage area is in a predominantly rural and wetland basin. In the vicinity of the study site, the surface cover is shrubland on the downstream right overbank. The surface cover of the downstream left overbank, the upstream right overbank and the upstream left overbank is wetland and pasture. In the study area, Little Otter Creek has a meandering channel with a slope of approximately 0.0007 ft/ft, an average channel top width of 97 ft and an average bank height of 5 ft. The channel bed material ranges from silt and clay to cobble. Medium sized silt and clay is the channel material upstream of the approach cross-section and downstream of the exit cross-section. The median grain size (D 50 ) of the silt and clay channel bed material is 1.52 mm (0.005 ft), which was used for contraction and abutment scour computations. From the approach cross-section, under the bridge, and to the exit cross-section, stone fill is the channel bed material. The median grain size (D 50 ) of the stone fill channel bed material is 95.7 mm (0.314 ft). The stone fill median grain size was used solely for armoring computations. The geomorphic assessment at the time of the Level I and Level II site visit on June 11, 1996, indicated that the reach was stable. The Town Highway 20 crossing of Little Otter Creek is a 32-ft-long, two-lane bridge consisting of a 28-ft steel-beam span (Vermont Agency of Transportation, written communication, December 15, 1995). The opening length of the structure parallel to the bridge face is 24.9 ft. The bridge is supported by almost vertical, concrete abutments. The channel is skewed approximately 15 degrees to the opening while the opening-skew-toroadway is zero degrees. The scour countermeasures at the site consisted of type-1 stone fill (less than 12 inches diameter) along the left and right abutments, as well as along the upstream left and right banks. Type-2 stone fill (less than 36 inches diameter) was present along the downstream right bank. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at 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 depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 9.7 to 13.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 6.9 to 7.9 ft. Right abutment scour ranged from 10.5 to 11.8 ft. The worst-case left and right abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

Vermont