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Level II scour analysis for Bridge 99 (LUDLVT01000099) on State Highway 99, crossing Branch Brook, Ludlow, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure LUDLVT01000099 on State Highway 100 crossing Branch Brook, Ludlow, 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 Green Mountain section of the New England physiographic province in central Vermont. The 15.7-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the channel banks are densely covered by trees and brush. The overbanks are primarily covered by field grasses. In the study area, Branch Brook has an incised, straight channel with a slope of approximately 0.003 ft/ft, an average channel top width of 73 ft and an average channel depth of 5 ft. The predominant channel bed materials are cobble and gravel with a median grain size (D 50 ) of 60.5 mm (0.198 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 13, 1995, indicated that the reach was stable. The State Highway 100 crossing of Branch Brook is a 84-ft-long, two-lane bridge consisting of one 82-foot steel-beam span (Vermont Agency of Transportation, written communication, March 13, 1995). The bridge is supported by vertical, concrete abutments. The abutments are set back from the channel edge and have a spill-through slope consisting of type-4 stone fill (median size less than 60 inches in diameter). The channel skew and the opening-skew-to-roadway is zero 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, 1995). 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 0.0 to 1.5 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 1.0 to 7.4 ft. The worst-case 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 others, 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↗

Characterization of surface-water quality based on real-time monitoring and regression analysis, Quivira National Wildlife Refuge, south-central Kansas, December 1998 through June 2001

Because of the considerable wildlife benefits offered by the Quivira National Wildlife Refuge in south-central Kansas, there is a desire to ensure suitable water quality. To assess the quality of water flowing from Rattlesnake Creek into the refuge, the U.S. Geological Survey collected periodic water samples from December 1998 through June 2001 and analyzed the samples for physical properties, dissolved solids, total suspended solids, suspended sediment, major ions, nutrients, metals, pesticides, and indicator bacteria. Concentrations of 10 of the 125 chemicals analyzed did not meet water-quality criteria to protect aquatic life and drinking water in a least one sample. These were pH, turbidity, dissolved oxygen, dissolved solids, sodium, chloride, phosphorus, total coliform bacteria, E. coli bacteria, and fecal coliform bacteria. No metal or pesticide concentrations exceeded water-quality criteria. Twenty-two of the 43 metals analyzed were not detected, and 36 of the 46 pesticides analyzed were not detected. Because dissolved solids, sodium, chloride, fecal coliform bacteria, and other chemicals that are a concern for the health and habitat of fish and wildlife at the refuge cannot be measured continuously, regression equations were developed from a comparison of the analytical results of periodic samples and in-stream monitor measurements of specific conductance, pH, water temperature, turbidity, and dissolved oxygen. A continuous record of estimated chemical concentrations was developed from continuously recorded in-stream measurements. Annual variation in water quality was evaluated by comparing 1999 and 2000 sample data- the 2 years for which complete data sets were available. Median concentrations of alkalinity, fluoride, nitrate, and fecal coliform bacteria were smaller or did not change from 1999 to 2000. Dissolved solids, total suspended solids, sodium, chloride, sulfate, total organic nitrogen, and total phosphorus had increases in median concentrations from 1999 to 2000. Increases in the median concentrations of the major ions were expected due to decreased rainfall in 2000 and very low streamflow late in the year. Increases for solids and nutrients may have been due to the unusually high streamflow in the early spring of 2000. This was the time of year when fields were tilled, exposing solids and nutrients that were transported with runoff to Rattlesnake Creek. Load estimates indicate the chemical mass transported into the refuge and can be used in the development of total maximum daily loads (as specified by the U.S. Environmental Protection Agency) for water-quality contaminants in Rattlesnake Creek. Load estimates also were used to evaluate seasonal variation in water quality. Seasonal variation was most pronounced in the estimates of nutrient loads, and most of the nutrient load transported to the refuge occurred during just a few periods of surface runoff in the spring and summer. This information may be used by resource managers to determine when water-diversion strategies would be most beneficial. Load estimates also were used to calculate yields, which are useful for site comparisons. The continuous and real-time nature of the record of estimated concentrations, loads, and yields may be important for resource managers, recreationalists, or others for evaluating water-diversion strategies, making water-use decisions, or assessing the environmental effects of chemicals in time to prevent adverse effects on fish or other aquatic life at the refuge.

Kansas↗

Multi-temporal mapping of a large, slow-moving earth flow for kinematic interpretation

Periodic movement of large, thick landslides on discrete basal surfaces produces modifications of the topographic surface, creates faults and folds, and influences the locations of springs, ponds, and streams (Baum, et al., 1993; Coe et al., 2009). The geometry of the basal-slip surface, which can be controlled by geological structures (e.g., fold axes, faults, etc.; Revellino et al., 2010; Grelle et al., 2011), and spatial variation in the rate of displacement, are responsible for differential deformation and kinematic segmentation of the landslide body. Thus, large landslides are often composed of several distinct kinematic elements. Each element represents a discrete kinematic domain within the main landslide that is broadly characterized by stretching (extension) of the upper part of the landslide and shortening (compression) near the landslide toe (Baum and Fleming, 1991; Guerriero et al., in review). On the basis of this knowledge, we used photo interpretive and GPS field mapping methods to map structures on the surface of the Montaguto earth flow in the Apennine Mountains of southern Italy at a scale of 1:6,000. (Guerriero et al., 2013a; Fig.1). The earth flow has been periodically active since at least 1954. The most extensive and destructive period of activity began on April 26, 2006, when an estimated 6 million m3 of material mobilized, covering and closing Italian National Road SS90, and damaging residential structures (Guerriero et al., 2013b). Our maps show the distribution and evolution of normal faults, thrust faults, strike-slip faults, flank ridges, and hydrological features at nine different dates (October, 1954; June, 1976; June, 1991; June, 2003; June, 2005; May, 2006; October, 2007; July, 2009; and March , 2010) between 1954 and 2010. Within the earth flow we recognized several kinematic elements and associated structures (Fig.2a). Within each kinematic element (e.g. the earth flow neck; Fig.2b), the flow velocity was highest in the middle, and lowest in the upper and lower parts. As the velocity of movement initiated and increased, stretching of the earth flow body induced the formation of normal faults. Conversely, decreasing velocity and shortening of the earth flow induced the formation of thrust faults. A zone with relatively few structures, bounded by strike-slip faults, was located between stretching and shortening areas. These kinematic elements indicate that the overall earth flow was actually composed of numerous linked internal earth flows, with each internal flow having a distinct pattern of structures representative of stretching and shortening (Guerriero et al., in review). These observations indicated that the spatial variation in movement velocity associated with each internal earth flow, mimicked the pattern of movement for the overall earth flow. That is, the earth flow displayed a self-similar pattern at different scales. Furthermore, the presence of other structures such as back-tilted surfaces, flank-ridges, and hydrological elements provide specific information about the shape of the basal topographic surface. Our multi-temporal maps provided a basis for interpretation of the long-term kinematic evolution of the earth flow and the influence of the basal-slip surface on the earth flow movement. Our maps showed that main faults remained stationary through time, despite extensive mobilization and movement of material. This observation indicated that the slip-surface has remained relatively stationary since at least 1954.

Conference Paper↗

Geochemical and generalized geologic map showing distribution and abundance of barium, arsenic, boron, and vanadium in stream sediments in the Chandalar Quadrangle, Alaska

This geochemical map shows the distribution and abundance of barium (Ba), arsenic (As), boron (B), and vanadium (V) in -80 mesh (177 micrometers) stream sediment samples in the Chandalar quadrangle, Alaska. The map is a part of a series of geochemical maps that together with the background information circular (Reiser and others, 1978) comprise the folio on the Chandalar quadrangle, Alaska. The data are plotted on a subdued base map showing the generalized geology, topography, and sample localities. Map symbols showing the ranges of metal values are indicated on the accompanying histograms and all values shown are considered anomalous. An explanation of sampling, preparation, analytical procedures, and geochemical raw data for all samples are discussed by O'Leary and others (1976). The -80 mesh (177 micrometers) stream sediment medium was used in this study because of the regional setting in the north-central Brooks Range. Given the rather restrictive time and manpower constraints the -80 mesh (177 micrometers) stream sediment combined with panned concentrates was determined to be the most economical and adequate medium in this case where clastic sediments are being derived from local bedrock. The study area is generally one of high relief with short fast-moving streams and broad glacial valleys. All samples were taken from active streams, as close to the center channel as possible. All sediments were considered to be locally derived. Care was taken, when sampling an obviously glaciated terrane, to sample above or upstream from morainal material, wherever possible. Most samples were taken in areas where bedrock was within 30 m of the sample site. Due to the poor sensitivity by spectrographic analysis for arsenic, 200 ppm (parts per million), all arsenic analyses were done by colorimetry.

Alaska↗

Effects of Glen Canyon Dam discharges on water velocity and temperatures at the confluence of the Colorado and Little Colorado Rivers and implications for habitat for young-of-year humpback chub (Gila cypha)

Water velocity and temperature are physical variables that affect the growth and survivorship of young-of-year (YOY) fishes. The Little Colorado River, a tributary to the Colorado River in Grand Canyon, is an important spawning ground and warmwater refuge for the endangered humpback chub (Gila cypha) from the colder mainstem Colorado River that is regulated by Glen Canyon Dam. The confluence area of the Little Colorado River and the Colorado River is a site where YOY humpback chub (size 30-90 mm) emerging from the Little Colorado River experience both colder temperatures and higher velocities associated with higher mainstem discharge. We used detailed surveying and mapping techniques in combination with YOY velocity and temperature preferenda (determined from field and lab studies) to compare the areal extent of available habitat for young fishes at the confluence area under four mainstem discharges (227, 368, 504, and 878 m3/s). Comparisons revealed that the areal extent of low-velocity, warm water at the confluence decreased when discharges exceeded 368 m3/s. Furthermore, mainstem fluctuations, depending on the rate of upramp, can affect velocity and temperature dynamics in the confluence area within several hours. The amount of daily fluctuations in discharge can result in the loss of approximately 1.8 hectares of habitat favorable to YOY humpback chub. Consequently, flow fluctuations and the accompanying changes in velocity and temperature at the confluence may diminish the recruitment potential of humpback chub that spawn in the tributary stream. This study illustrates the utility of multiple georeferenced data sources to provide critical information related to the influence of the timing and magnitude of discharge from Glen Canyon Dam on potential rearing environment at the confluence area of the Little Colorado River.

Arizona↗

Remote sensing and airborne geophysics in the assessment of natural aggregate resources

Natural aggregate made from crushed stone and deposits of sand and gravel is a vital element of the construction industry in the United States. Although natural aggregate is a high volume/low value commodity that is relatively abundant, new sources of aggregate are becoming increasingly difficult to find and develop because of rigid industry specifications, political considerations, development and transporation costs, and environmental concerns, especially in urban growth centers where much of the aggregate is used. As the demand for natural aggregate increases in response to urban growth and the repair and expansion of the national infrastructure, new sources of natural aggregate will be required. The USGS has recognized the necessity of developing the capability to assess the potential for natural aggregate sources on Federal lands; at present, no methodology exists for systematically describing and evaluating potential sources of natural aggregate. Because remote sensing and airborne geophysics can detect surface and nearsurface phenomena, these tools may useful for detecting and mapping potential sources of natural aggregate; however, before a methodology for applying these tools can be developed, it is necessary to understand the type, distribution, physical properties, and characteristics of natural aggregate deposits, as well as the problems that will be encountered in assessing their potential value. There are two primary sources of natural aggregate: (1) exposed or near-surface igneous, metamorphic, and sedimentary bedrock that can be crushed, and (2) deposits of sand and gravel that may be used directly or crushed and sized to meet specifications. In any particular area, the availability of bedrock suitable for crushing is a function of the geologic history of the area - the processes that formed, deformed, eroded and exposed the bedrock. Deposits of sand and gravel are primarily surficial deposits formed by the erosion, transportation by water and ice, and deposition of bedrock fragments. Consequently, most sand and gravel deposits are Tertiary or Quaternary in age and are most common in glaciated areas, alluvial basins, and along rivers and streams. The distribution of potential sources of natural aggregate in the United States is closely tied to physiography and the type of bedrock that occurs in an area. Using these criteria, the United States can be divided into 12 regions: western mountain ranges, alluvial basins, Columbia Plateau, Colorado Plateau and Wyoming basin, High Plains, nonglaciated central region, glaciated central region, Piedmont Blue Ridge region, glaciated northeastern and Superior uplands, Atlantic and Gulf coastal plain, Hawaiian Islands, and Alaska. Each region has similar types of natural aggregate sources within its boundary, although there may be wide variations in specific physical and chemical characteristics of the aggregates within a region. Conventional exploration for natural aggregate deposits has been largely a ground-based operation (field mapping, sampling, trenching and augering, resistivity), although aerial photos and topographic maps have been extensively used to target possible deposits for sampling and testing. Today, the exploration process also considers other factors such as the availability of the land, space and water supply for processing purposes, political and environmental factors, and distance from the market; exploration and planning cannot be separated. There are many physical properties and characteristics by which aggregate material is judged to be acceptable or unacceptable for specific applications; most of these properties and characteristics pertain only to individual aggregate particles and not to the bulk deposit. For example, properties of crushed stone aggregate particles such as thermal volume change, solubility, oxidation and hydration reactivity, and particle strength, among many others, are important consi

Open-File Report↗

Water-quality data analysis of the upper Gunnison River watershed, Colorado, 1989-99

Water-quality data from October 1969 to December 1999 for both surface water and ground water in the upper Gunnison River watershed were retrieved and compiled from the U.S. Geological Survey National Water Information System and the U.S. Environmental Protection Agency Storage and Retrieval databases. Analyses focused primarily on a subset of these data from October 1989 to December 1999. The upper Gunnison River watershed is located west of the Continental Divide in the Southern Rocky Mountains physiographic province. Surface-water-quality data were compiled for 482 sites in the upper Gunnison River watershed. Most values of surface-water temperature, dissolved oxygen, and pH were within Colorado Department of Public Health and Environment (CDPHE) in-stream standards. Calcium bicarbonate type water was the most spatially dominant water type in the basin. Nutrients were most commonly sampled along the Slate River and East River near Crested Butte and along the Gunnison River from the confluence of the East and Taylor Rivers to the western edge of the watershed. Median ammonia concentrations were low, with many concentrations less than laboratory reporting levels. All nitrate concentrations met the CDPHE in-stream standard of 10 milligrams per liter. More than 30 percent of stream sites with total phosphorus data (23 of 61 sites) had concentrations greater than the U.S. Environmental Protection Agency (USEPA) recommendation for controlling eutrophication. Ammonia concentrations at a site on the Slate River near Crested Butte had a statistically significant upward trend for the 1995–99 period. The Slate River near Crested Butte site is located immediately downstream from the towns of Crested Butte and Mount Crested Butte and may reflect recent population growth or other land-use changes. However, the rate of change of the trend is small (0.017 milligram per liter per year). Although a multiple comparison test showed nitrate concentrations were statistically different between agriculture and forest sites and between agriculture and urban land-use classified sites, median concentrations were low among all land-use settings. Median concentrations of total phosphorus were greatest in rangeland areas and least in urban areas. No significant differences were identified for median concentrations of total phosphorus in agriculture and forest land-use areas. Median concentrations of arsenic, lead, mercury, selenium, and silver were low or below reporting levels throughout the watershed. Aluminum, cadmium, copper, lead, manganese, and zinc concentrations were elevated near the town of Crested Butte and on Henson Creek upstream from Lake City, which may be explained by upstream areas of historical mining. Samples for six trace elements exceeded standards: cadmium, copper, lead, manganese, silver, and zinc. A downward trend (3 micrograms per liter per year) was identified for the dissolved iron concentration at a site on the Gunnison River at County Road 32 downstream from the city of Gunnison. Streambed-sediment samples from areas affected by historical mining also had elevated concentrations of some trace elements. Chlorophyll- a concentrations in samples from Blue Mesa Reservoir and streams in the Crested Butte and Gunnison areas were typical of unenriched to moderately enriched conditions. Median concentrations of 5-day biochemical oxygen demand concentrations for sites between Crested Butte and Blue Mesa Reservoir were less than 2 milligrams per liter. Occasional high (greater than 200 counts per 100 milliliters) concentrations for fecal coliform were determined at selected sites within the study area. However, median concentrations were less than 100 counts per 100 milliliters except for the Squaw Creek and Cimarron River areas in the western part of the watershed. Ground-water-quality data have been collected by the U.S. Geological Survey from 99 wells. Many wells were completed in aquifers composed of Holocene-age valley fill and alluvium. Most field properties were within the USEPA Secondary Drinking Water Regulations (SDWR) range for treated drinking water, except for 2 (of 40) pH samples. Calcium bicarbonate was the predominant water type in nearly all aquifers except for the aquifers composed of volcanic rock, which had more sodium and sulfate mixed water types. Wells with sulfate concentrations exceeding the SDWR of 250 milligrams per liter were completed in aquifers composed of volcanic rock near Lake City. Dissolution and oxidation of sulfide minerals in these aquifers may explain the elevated sulfate concentrations in ground water at these locations. Nutrient concentrations in ground water were generally low, and median concentrations for ammonia, nitrite, and dissolved phosphorus were below reporting levels. All nitrate concentrations in the samples were below the USEPA drinking-water maximum contaminant level of 10 mg/L. No statistical difference was found in nitrate concentrations among the four land-use classifications (agriculture, forest, rangeland, and urban). Trace elements in ground water were generally below the USEPA SDWR. Three iron samples exceeded the USEPA SDWR of 300 micrograms per liter at two wells located near the city of Gunnison and at a well south of the town of Powderhorn near the Cebolla River. Nine of 39 manganese samples exceeded the USEPA SDWR of 50 micrograms per liter and were collected from aquifers composed of Holocene-age valley fill and alluvium near Gunnison and Crested Butte and in one well near the Cebolla River. Radon gas is a natural radioactive decay product of uranium. All 39 radon samples collected from ground water in the watershed exceeded the proposed USEPA drinking-water maximum contaminant level of 300 picocuries per liter and ranged from 426 to 3,830 picocuries per liter.

Colorado↗

Influence of shell morphology on distributions of unionids in the upper Mississippi River

Attempts to predict the distribution of unionids from readily measurable microhabitat descriptors (i.e. water depth, current velocity, stream size, sediment type) have been largely unsuccessful, but certain biological and calculated hydraulic variables have recently shown some predictive power. We used historic and recent data on unionids (from 1987 to 2003) and hydraulic conditions at 438 sample locations over a 38-km reach of the Upper Mississippi River (Navigation Pool 8) to compare the distribution of unionids with different shell morphologies. We evaluated whether sculptured, thick-shelled (STK) species would be found in areas with higher velocity and shear stress, compared to nonsculptured, thin-shelled (NSTN) species. We used classification trees to model the presence and absence of STK and NSTN species to determine which variables were most likely to predict their distribution. Candidate predictor variables included sampling gear, field substrate, water depth (bathymetry), slope, velocity, shear stress and Froude number under low, moderate and high discharges. Our models predicted that STK mussels would occupy a larger portion of the total aquatic area in this reach of the river than NSTN mussels. However, our data demonstrated that NSTN species used areas of higher shear stress and velocity than STK species, but were also present in backwaters with low energy, thus rejecting our hypothesis. The presence of NSTN species over a wide range of shear stress and velocity was probably due to the wide array of life histories displayed within this guild. Overall, these results are consistent with the flow refuge concept in which unionids are more prevalent in areas with low to moderate hydraulic stresses, regardless of shell morphology, and demonstrate the importance of incorporating abiotic and biotic variables into predictive models.

Journal of Molluscan Studies↗

Element concentrations in soils and other surficial materials of Alaska

Mean concentrations of 35 elements, ash yields, and pH have been estimated for samples of sils and other unconsolidated surficial materials from 266 collection locations throughout Alaska. These background values can be applied to studies of environmental geochemistry and health, wildlife management, and soil-forming processes in cold climates and to computation of element abundances on a regional or worldwide scale. Limited data for an additoinal eight elements are also presented. Materials were collected using a one-way, three-level, analysis-of-variance samplling design in which collecting procedures were simplified for the convenience of the many volunteer field workers. The sample collectors were asked to avoid locations of known mineral deposits and obvious contamination, to take samples at a depth of about 20 cm where possible, and to take a replicate sample about 100 m distant from the first sample collected. With more than 60 percent of the samples replicated and 14 percent of the samples split for duplicate laboratory analyses, reliable estimates were made of the variability in element concentrations at two geographic scales and of the error associated with sample handling and laboratory procedures. Mean concentrations of most elements in surficial materials from the state of alaska correspond well with those reported in similar materials from the conterminous United STatess. Most element concentrations and ranges in samples of stream and lake sediments from Alaska, however, as reported in the literature, do not correspond well with those found in surficial materials of this study. This lack of correspondence is attributed to (1) a merger of two kinds ofsediments (stream and lake) for calculating means; (2) elimination from the sediment mean calculations of values below the limit of quantitative determination; (3) analytical methods different from those of the surficial materials study; and (4) most importantly, the inherent differences in chemistry of the materials. The distribution of variability in element concentrations o Alaskan surficial-material samples was, for most elements, largely among sampling locations, with only a samll part of the variability occurring between replicate samples at a location. The geochemical uniformity within sampling locations in Alaska is an expression of uniform geochemical cycling processes within small geographic areas. The concentration values for 35 elements in 266 samples were plotted on maps by symbols representing classes of concentration frequency distributions. These plotted symbols form patterns that may or may not be possible to interpret but nevertheless show differences that are observable at several geographical scales. The largest pattern is one generally low concentrations of many elements in materials from arctic and oceanic tundra regions, as contrasted to their often high concentrations in samples from interior and southeastern Alaska. The patttern for sodium isespecially pronounced. Intermediate-sized patterns are shown, for example, by the generally high values for magnesium and low values for silicon in the coastal forest region of southeastern Alaska. Many elements occur at low concentratoins in samples from the Alaskan peninsula and the Aleutian Islands. The degree of confidence in patterns of element abundance is expected to be in direct proportion to the number of samples included in the area. As the patterns become smaller, the probability increases that the patterns are not reproducible.

Alaska↗

Hydraulic Characteristics of Bedrock Constrictions and Evaluation of One- and Two-Dimensional Models of Flood Flow on the Big Lost River at the Idaho National Engineering and Environmental Laboratory, Idaho

A 1.9-mile reach of the Big Lost River, between the Idaho National Engineering and Environmental Laboratory (INEEL) diversion dam and the Pioneer diversion structures, was investigated to evaluate the effects of streambed erosion and bedrock constrictions on model predictions of water-surface elevations. Two one-dimensional (1-D) models, a fixed-bed surface-water flow model (HEC-RAS) and a movable-bed surface-water flow and sediment-transport model (HEC-6), were used to evaluate these effects. The results of these models were compared to the results of a two-dimensional (2-D) fixed-bed model [Transient Inundation 2-Dimensional (TRIM2D)] that had previously been used to predict water-surface elevations for peak flows with sufficient stage and stream power to erode floodplain terrain features (Holocene inset terraces referred to as BLR#6 and BLR#8) dated at 300 to 500 years old, and an unmodified Pleistocene surface (referred to as the saddle area) dated at 10,000 years old; and to extend the period of record at the Big Lost River streamflow-gaging station near Arco for flood-frequency analyses. The extended record was used to estimate the magnitude of the 100-year flood and the magnitude of floods with return periods as long as 10,000 years. In most cases, the fixed-bed TRIM2D model simulated higher water-surface elevations, shallower flow depths, higher flow velocities, and higher stream powers than the fixed-bed HEC-RAS and movable-bed HEC-6 models for the same peak flows. The HEC-RAS model required flow increases of 83 percent [100 to 183 cubic meters per second (m3/s)], and 45 percent (100 to 145 m3/s) to match TRIM2D simulations of water-surface elevations at two paleoindicator sites that were used to determine peak flows (100 m3/s) with an estimated return period of 300 to 500 years; and an increase of 13 percent (150 to 169 m3/s) to match TRIM2D water-surface elevations at the saddle area that was used to establish the peak flow (150 m3/s) of a paleoflood with a return period of 10,000 years. A field survey of the saddle area, however, indicated that the elevation of the lowest point on the saddle area was 1.2 feet higher than indicated on the 2-ft contour map that was used in the TRIM2D model. Because of this elevation discrepancy, HEC-RAS model simulations indicated that a peak flow of at least 210 m3/s would be needed to initiate flow across the 10,000-year old Pleistocene surface. HEC-6 modeling results indicated that to compensate for the effects of streambed scour, additional flow increases would be needed to match HEC-RAS and TRIM2D water-surface elevations along the upper and middle reaches of the river, and to compensate for sediment deposition, a slight decrease in flows would be needed to match HEC-RAS water-surface elevations along the lower reach of the river. Differences in simulated water-surface elevations between the TRIM2D and the HEC-RAS and HEC-6 models are attributed primarily to differences in topographic relief and to differences in the channel and floodplain geometries used in these models. Topographic differences were sufficiently large that it was not possible to isolate the effects of these differences on simulated water-surface elevations from those attributable to the effects of supercritical flow, streambed scour, and sediment deposition.

Scientific Investigations Report↗

Estimation of the effects of land use and groundwater withdrawals on streamflow for the Pomperaug River, Connecticut

A precipitation runoff model for the Pomperaug River watershed, Connecticut was developed to address issues of concern including the effect of development on streamflow and groundwater recharge, and the implications of water withdrawals on streamflow. The model was parameterized using a strategy that requires a minimum of calibration and optimization by establishing basic relations between the parameter value and physical characteristics of individual hydrologic response units (HRUs) that comprise the model. The strategy was devised so that the information needed can be obtained from Geographic Information System and other general databases for Connecticut. Simulation of groundwater recharge enabled evaluation of the temporal and spatial mapping of recharge variation across the watershed and the spatial effects of changes in land cover on base flow and surface runoff. The modeling indicated that over the course of a year, groundwater provides between 60 and 70 percent of flow in the Pomperaug River; the remainder is generated by more rapid flow through the shallow subsurface and runoff from impermeable surfaces and saturated ground. Groundwater is recharged primarily during periods of low evapotranspiration in the winter, spring, and fall. The largest amount of recharge occurs in the spring in response to snowmelt. During floods, the Weekeepeemee and Nonnewaug Rivers (tributaries that form the Pomperaug River) respond rapidly with little flood peak attenuation due to flood-plain storage. In the Pomperaug River, flood-plain storage is more important in attenuating floods; abandoned quarry ponds (O&G ponds) adjacent to the river provide substantial flood storage above specific river stages when flow from the river spills over the banks and fills the ponds. Discharge from the ponds also helps to sustain low flows in the Pomperaug River. Similarly, releases from the Bronson-Lockwood reservoir sustain flow in the Nonnewaug River and tend to offset the effect of groundwater withdrawals from a well field adjacent to the river during periods of natural low flow. The model indicated that under the current zoning, future development could reduce low flows by as much as 10 percent at the 99 percent exceedance level (99 percent of flows are greater than or equal to this flow), but would not substantially increase the highest flows. Simulation of projected and hypothetical development in the watershed shows, depending on how stormwater is managed, that between 10 and 20 percent effective impervious area in an HRU results in streamflow becoming dominated by the surface-runoff component. This shift from a groundwater-dominated system would likely result in substantial changes in water quality and instream habitat characteristics of the river. Base flow to streams in the Pomperaug River watershed is reduced by both increased impervious surface and increased groundwater withdrawals. For the watershed as a whole, increasing groundwater withdrawals have the potential for causing greater overall reductions in flow compared to increased development and impervious surfaces. Additionally, on the basis of groundwater-modeling simulations, the projected increase in development across the watershed and, to a lesser extent the increase in groundwater withdrawals, will increase the number of local losing reaches experiencing dry conditions and the duration of these dry periods. The location of the losing reaches tends to be in areas near the transition from the uplands to the valley bottoms that are filled with coarse glacial stratified deposits. The simulated increase in the duration and extent of localized dry stream reaches is most sensitive to local increase in impervious surface. Conversion of land from forest or developed land cover to pasture or agricultural land increases groundwater recharge and discharge to streams, while at the same time increasing overall streamflow (the opposite effect as increased impervious surface). These resu

Scientific Investigations Report↗

Cost-effectiveness of the stream-gaging program in North Carolina

This report documents the results of a study of the cost-effectiveness of the stream-gaging program in North Carolina. Data uses and funding sources are identified for the 146 gaging stations currently operated in North Carolina with a budget of $777,600 (1984). As a result of the study, eleven stations are nominated for discontinuance and five for conversion from recording to partial-record status. Large parts of North Carolina 's Coastal Plain are identified as having sparse streamflow data. This sparsity should be remedied as funds become available. Efforts should also be directed toward defining the efforts of drainage improvements on local hydrology and streamflow characteristics. The average standard error of streamflow records in North Carolina is 18.6 percent. This level of accuracy could be improved without increasing cost by increasing the frequency of field visits and streamflow measurements at stations with high standard errors and reducing the frequency at stations with low standard errors. A minimum budget of $762,000 is required to operate the 146-gage program. A budget less than this does not permit proper service and maintenance of the gages and recorders. At the minimum budget, and with the optimum allocation of field visits, the average standard error is 17.6 percent.

North Carolina↗

Larger larval sea lamprey (Petromyzon marinus) have longer survival times when exposed to the lampricide 3-trifluoromethyl-4-nitrophenol

Invasive sea lamprey ( Petromyzon marinus ) in the Laurentian Great Lakes have negatively impacted ecologically and economically important fishes for nearly a century. To mitigate these effects, the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is applied annually on a rotating basis to selected Great Lakes tributaries to kill larval lamprey before they become juveniles, out-migrate to the lakes, and parasitize other fishes. It has been hypothesized that larval size (e.g., mass, length) may affect survival time in response to TFM. To test this hypothesis, we conducted an experiment with 8611 larvae across four temporal replicates, in which TFM concentrations equivalent to those used in present-day stream treatments were applied for up to 18 h. When examining the survival times of larval lamprey exposed to TFM, we found a significant, positive relationship between length, mass, toxicity, and their interactions. For every 1 mm increase in total length, a corresponding increase by 1 g of mass reduced survival time by 0.4315 min [95 % CI: 0.5283–0.2992] and vice versa (i.e., the significant interaction between length and mass revealed that as larvae increase in mass, the survival benefit to being longer decreases, and vice versa). The changes in total length and mass of larval sea lamprey stored in ethanol for 4 months was also quantified. The observation that five larvae survived well past the 12-hour time window of a typical TFM field treatment highlights the need for continuous monitoring and the development of new control strategies to ensure the continued effective management of this invasive species.

Michigan↗

Reactive solute transport in streams: A surface complexation approach for trace metal sorption

A model for trace metals that considers in-stream transport, metal oxide precipitation-dissolution, and pH-dependent sorption is presented. Linkage between a surface complexation submodel and the stream transport equations provides a framework for modeling sorption onto static and/or dynamic surfaces. A static surface (e.g., an iron- oxide-coated streambed) is defined as a surface with a temporally constant solid concentration. Limited contact between solutes in the water column and the static surface is considered using a pseudokinetic approach. A dynamic surface (e.g., freshly precipitated metal oxides) has a temporally variable solid concentration and is in equilibrium with the water column. Transport and deposition of solute mass sorbed to the dynamic surface is represented in the stream transport equations that include precipitate settling. The model is applied to a pH-modification experiment in an acid mine drainage stream. Dissolved copper concentrations were depressed for a 3 hour period in response to the experimentally elevated pH. After passage of the pH front, copper was desorbed, and dissolved concentrations returned to ambient levels. Copper sorption is modeled by considering sorption to aged hydrous ferric oxide (HFO) on the streambed (static surface) and freshly precipitated HFO in the water column (dynamic surface). Comparison of parameter estimates with reported values suggests that naturally formed iron oxides may be more effective in removing trace metals than synthetic oxides used in laboratory studies. The model's ability to simulate pH, metal oxide precipitation-dissolution, and pH-dependent sorption provides a means of evaluating the complex interactions between trace metal chemistry and hydrologic transport at the field scale.

Water Resources Research↗

Environmental impacts of petroleum production: Fate of inorganic and organic chemicals in produced water from the Osage-Skiatook Petroleum Environmental Research sites, Osage County, Oklahoma

About 15 scientists from the U. S. Geological Survey, other Federal agencies and academia are involved in a multidisciplinary investigation to study the transport, fate, and natural attenuation of inorganic salts, trace metals, radionuclides and organic compounds present in produced water, and their impacts on soil, surface and ground water and the local ecosystem at the Osage-Skiatook Petroleum Environmental Research (OSPER) A and B sites, located in Osage County, OK. The Branstetter lease, OSPER B site, is typical of many aging petroleum fields in Osage County, which ranks among the top oil and gas producing counties in Oklahoma with close to 40,000 wells. Current production in Osage County is mainly from stripper wells (averaging ~2.8 bbls/d oil and >30 bbls/d brine) that are shallow, mostly 300-700 m in depth, and produce from several sandstones of Pennsylvanian age. About one hectare of land at the OSPER B site is affected by salt scarring, soil salinization and brine and petroleum contamination due to the leakage of produced water and associated hydrocarbons from two brine pits and due to accidental releases from active tank batteries. Eventually, the bulk of inorganic salts and some dissolved organic species in the released brine reach, directly or via the two local streams, the adjacent Skiatook Lake, a 4250-hectare reservoir that provides drinking water to the local communities and is a major recreational fishery. About 40 water samples were obtained from several oil wells at the B site and adjoining areas, the two brine pits, several brine pools and seeps in the impacted area, local streams, Skiatook Lake, and from about 20 boreholes (1-71 m deep), recently drilled and completed with slotted PVC tubing. Water level monitoring and additional sampling is continuing. Results to date show that the produced water is a high-salinity (~150,000 mg/L total dissolved solids) Na-Ca-Cl brine, with relatively high concentrations of Sr, Mg and NH4, but low amounts of SO4 and H2S. With the exception of Fe and Mn, the concentrations of trace metals are low, and the values of dissolved organics are relatively low. As the brine flows from the brine pits through the shallow eolian sand, colluvial and alluvial deposits to the streams and Skiatook Lake, it is diluted by infiltrating water from precipitation. Its chemical composition is modified by sorption, mineral precipitation/dissolution, transpiration, volatilization and oxidation/reduction reactions. Bacteria likely play an important role in many of these reactions.

Oklahoma↗

Distribution and abundance of gold in stream sediments and moraine debris, McCarthy quadrangle, Alaska

A geochemical survey was conducted in the McCarthy quadrangle Alaska, to identify areas containing anomalous concentrations of various metallic and nonmetallic elements. This study incorporates the results of analyses for gold from 764 stream sediment and glacial moraine debris samples collected in the quadrangle, and analyzed by the U.S. Geological Survey between 1961 and 1976 using atomic absorption spectrophotometry. No analytical results for gold are available for stream sediment samples from the White River area, located in the northeastern part of the quadrangle. The accompanying map shows the distribution and relative abundance of gold in stream sediment and glacial moraine debris samples. Geochemical analyses have been grouped and are represented by symbols on a base map, which includes topography and generalized geology. The range of analytical values and the symbol that represents it are shown on the histogram. Graphical representation of analytical values on the map permits easy observation of any large variation resulting from separate or duplicate samples collected at the same or nearby localites.

Alaska↗

Metolachlor metabolite (MESA) reveals agricultural nitrate-N fate and transport in Choptank River watershed

Over 50% of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on the index of biological integrity. The Choptank River estuary, a Bay tributary on the eastern shore, is one such waterway, where corn and soybean production in upland areas of the watershed contribute significant loads of nutrients and sediment to streams. We adopted a novel approach utilizing the relationship between the concentration of nitrate-N and the stable, water-soluble herbicide degradation product MESA {2-[2-ethyl-N-(1-methoxypropan-2-yl)-6-methylanilino]-2-oxoethanesulfonic acid} to distinguish between dilution and denitrification effects on the stream concentration of nitrate-N in agricultural subwatersheds. The ratio of mean nitrate-N concentration/(mean MESA concentration * 1000) for 15 subwatersheds was examined as a function of percent cropland on hydric soil. This inverse relationship (R 2 = 0.65, p < 0.001) takes into consideration not only dilution and denitrification of nitrate-N, but also the stream sampling bias of the croplands caused by extensive drainage ditch networks. MESA was also used to track nitrate-N concentrations within the estuary of the Choptank River. The relationship between nitrate-N and MESA concentrations in samples collected over three years was linear (0.95 ≤ R 2 ≤ 0.99) for all eight sampling dates except one where R 2 = 0.90. This very strong correlation indicates that nitrate-N was conserved in much of the Choptank River estuary, that dilution alone is responsible for the changes in nitrate-N and MESA concentrations, and more importantly nitrate-N loads are not reduced in the estuary prior to entering the Chesapeake Bay. Thus, a critical need exists to minimize nutrient export from agricultural production fields and to identify specific conservation practices to address the hydrologic conditions within each subwatershed. In well drained areas, removal of residual N within the cropland is most critical, and practices such as cover crops which sequester the residual N should be strongly encouraged. In poorly drained areas where denitrification can occur, wetland restoration and controlled drained structures that minimize ditch flow should be used to maximize denitrification.

Choptank River Watershed↗

Modeling soil porewater salinity response to drought in tidal freshwater forested wetlands

There is a growing concern about the adverse effects of saltwater intrusion via tidal rivers, streams and creeks into tidal freshwater forested wetlands (TFFW) due to sea‐level rise (SLR) and intense and extended drought events. However, the magnitude and duration of porewater salinity in exceedance of plant salinity stress threshold (2 practical salinity units, psu) and the controlling factors remain unclear. In this study, we developed a TFFW soil porewater salinity model, in which the feedback mechanisms between soil salinity and evapotranspiration and hydraulic conductivity were incorporated. We selected sites (upper, middle, lower tidal freshwater forest sites and oligohaline marsh site) along the coastal floodplains of two rivers, the Waccamaw River (SC, USA) and the Savannah River (GA and SC, USA), that represent landscape salinity gradients from tidal influence of the Atlantic Ocean. The model results agreed well with field measurements and revealed that with drought‐induced saltwater intrusion, the mean annual soil porewater salinity and duration of elevated soil porewater salinity (> 2 psu) increased significantly compared to the normal (non‐drought) condition, posing a threat to the health and ecosystem services of TFFW even in the absence of SLR. Model results also showed more severe salinity stress under drought for the lower forest sites along the two rivers, where soil salinity values have already been at or in exceedance of the 2 psu threshold.

Georgia, South Carolina↗