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USGS2015

Regional regression equations to estimate peak-flow frequency at sites in North Dakota using data through 2009

Annual peak-flow frequency data from 231 U.S. Geological Survey streamflow-gaging stations in North Dakota and parts of Montana, South Dakota, and Minnesota, with 10 or more years of unregulated peak-flow record, were used to develop regional regression equations for exceedance probabilities of 0.5, 0.20, 0.10, 0.04, 0.02, 0.01, and 0.002 using generalized least-squares techniques. Updated peak-flow frequency estimates for 262 streamflow-gaging stations were developed using data through 2009 and log-Pearson Type III procedures outlined by the Hydrology Subcommittee of the Interagency Advisory Committee on Water Data. An average generalized skew coefficient was determined for three hydrologic zones in North Dakota. A StreamStats web application was developed to estimate basin characteristics for the regional regression equation analysis. Methods for estimating a weighted peak-flow frequency for gaged sites and ungaged sites are presented.

North Dakota↗

USGS2015

Initial characterization of the groundwater system near the Lower Colorado Water Supply Project, Imperial Valley, California

In 2009, the U.S. Geological Survey, in cooperation with the city of Needles, began a study of the hydrogeology along the All-American Canal, which conveys water from the Colorado River to the Imperial Valley. The focus of this study was to gain a better understanding of the effect of lining the All-American Canal, and other management actions, on future total dissolved solids concentrations in groundwater pumped by Lower Colorado Water Supply Project wells that is delivered to the All-American Canal. The study included the compilation and evaluation of previously published hydrogeologic and geochemical information, establishment of a groundwater-elevation and groundwater-quality monitoring network, results of monitoring groundwater elevations and groundwater quality from 2009 to 2011, site-specific hydrologic investigations of the Lower Colorado Water Supply Project area, examination of groundwater salinity by depth by using time-domain electromagnetic surveys, and monitoring of groundwater-storage change by using microgravity methods. Prior to the completion of the All-American Canal in 1940, groundwater in the study area flowed from east to west, and groundwater was recharged primarily by underflow from the Colorado River Valley. After construction of the All-American Canal, groundwater elevations were altered in the study area as seepage of Colorado River water from the All-American Canal and other canals became the dominant recharge source. By 2005, groundwater elevations had increased by as much as 50–70 feet along the All-American Canal. Superimposed on the east-to-west groundwater gradient was groundwater movement away from the All-American Canal to the north and, most likely, to the south into Mexico. After lining the All-American Canal, from 2007 to 2010, groundwater elevations declined as seepage from the All-American Canal decreased. Between 2005 (the last complete groundwater-elevation survey prior to lining the All-American Canal) and 2011, groundwater elevations declined 20–40 feet along the All-American Canal and as much as 40–45 feet in the vicinity of Lower Colorado Water Supply Project pumping wells. Water-quality and isotope data were used to differentiate historically recharged groundwater from groundwater more recently recharged by seepage of Colorado River surface water from the All-American Canal. Prior to the completion of the All-American Canal in 1940, groundwater in the southern part of the study area was primarily sodium-chloride/sulfate type water that had relatively low total dissolved solids concentrations (500–820 milligrams per liter). During 2007–11, groundwater in the southern part of the study area, near the All-American Canal, ranged from sodium-chloride type water to mixed-cation-sulfate type water that had total dissolved solids concentrations generally less than 879 milligrams per liter. The stable-isotopic signature of groundwater near the All-American Canal sampled in 2009–11 indicated inputs of Colorado River water that had been affected by evaporation, and radioactive isotopes indicated that a substantial fraction of water had been recharged recently, within the past 60 years. This contrasted with historically recharged groundwater near the All-American Canal, which had higher sodium and chloride concentrations, and lower calcium and sulfate concentrations, than recent recharge from the All-American Canal. Groundwater at a distance from the All-American Canal, in the East Mesa, Algodones Dunes, Pilot Knob Mesa, and Cargo Muchacho Mountains piedmont, was found to have higher total dissolved solids concentrations (generally greater than 1,000 milligrams per liter) than recently recharged groundwater near the All-American Canal. Time-domain electromagnetic data indicated that low-salinity groundwater was present down to about 377 feet below land surface near the All-American Canal; groundwater salinity at depth increased with distance north from the All-American Canal. Groundwater several miles or more from the canal also did not contain tritium and had a residence time on the order of thousands to tens of thousands of years. The groundwater in the piedmont of the Cargo Muchacho Mountains had a distinctly light stable-isotopic signature indicative of recharge by runoff from local precipitation, whereas the stable isotopic signature of groundwater in the East Mesa and the Algodones Dunes indicated a mixture of local precipitation and historic Colorado River recharge sources. During and after lining the All-American Canal (2007–11), groundwater elevations in the Lower Colorado Water Supply Project area declined, while total dissolved solids concentrations remained relatively constant. The total dissolved solids concentrations in well LCWSP-2 ranged from 650 to 800 milligrams per liter during this study. Depth-specific water-quality and isotope sampling at well LCWSP-2 indicated the groundwater pumped from the deeper part of the screened interval (240–280 feet below land surface) contained a greater proportion of historical groundwater than the groundwater pumped from the shallower part of the screened interval (350–385 feet below land surface). Age-tracer data at well LCWSP-2 indicated that all depths of the screened interval had received recent recharge from seepage of Colorado River water from the All-American Canal.

California↗

USGS2025

Hydrogeology and groundwater quality in the Snake River alluvial aquifer at Jackson Hole Airport, Wyoming, 2011–20

The Snake River alluvial aquifer underlying the Jackson Hole Airport (JHA) in northwest Wyoming is an important source of water used for domestic, commercial, and irrigation purposes by the airport and nearby residents. The U.S. Geological Survey, in response to previously identified water-quality concerns in the area, monitored and evaluated changes in hydrogeologic characteristics and groundwater-quality conditions of the alluvial aquifer during 2011–20. During that period, the Jackson Hole Airport made several changes that potentially improved water quality at and downgradient from the airport. Well, water level, and hydrogeologic data were collected from the alluvial aquifer to identify hydrogeologic characteristic and groundwater quality changes. Additionally, results of statistical tests were applied to water-quality results to evaluate trends in selected physical properties and constituent concentrations with time. The trends of those data show that water quality did improve overall during the study period compared to previously collected data. Presumably, these trends are in response to the changes in the aircraft deicing/anti-icing fluid (ADAF) formulation used by the JHA, the many JHA infrastructure improvements made during 2011–20, the degradation of existing ADAFs in subsurface soils and groundwater, or some combination of these possibilities.

Wyoming↗

USGS2022

Using paleoecological data to inform decision making: A deep-time perspective

Latest climate models project conditions for the end of this century that are generally outside of the human experience. These future conditions affect the resilience and sustainability of ecosystems, alter biogeographic zones, and impact biodiversity. Deep-time records of paleoclimate provide insight into the climate system over millions of years and provide examples of conditions very different from the present day, and in some cases similar to model projections for the future. In addition, the deep-time paleoecologic and sedimentologic archives provide insight into how species and habitats responded to past climate conditions. Thus, paleoclimatology provides essential context for the scientific understanding of climate change needed to inform resource management policy decisions. The Pliocene Epoch (5.3–2.6 Ma) is the most recent deep-time interval with relevance to future global warming. Analysis of marine sediments using a combination of paleoecology, biomarkers, and geochemistry indicates a global mean annual temperature for the Late Pliocene (3.6–2.6 Ma) ∼3°C warmer than the preindustrial. However, the inability of state-of-the-art climate models to capture some key regional features of Pliocene warming implies future projections using these same models may not span the full range of plausible future climate conditions. We use the Late Pliocene as one example of a deep-time interval relevant to management of biodiversity and ecosystems in a changing world. Pliocene reconstructed sea surface temperatures are used to drive a marine ecosystem model for the North Atlantic Ocean. Given that boundary conditions for the Late Pliocene are roughly analogous to present day, driving the marine ecosystem model with Late Pliocene paleoenvironmental conditions allows policymakers to consider a future ocean state and associated fisheries impacts independent of climate models, informed directly by paleoclimate information.

Frontiers in Ecology and Evolution↗

USGS2011

Using models for the optimization of hydrologic monitoring

Hydrologists are often asked what kind of monitoring network can most effectively support science-based water-resources management decisions. Currently (2011), hydrologic monitoring locations often are selected by addressing observation gaps in the existing network or non-science issues such as site access. A model might then be calibrated to available data and applied to a prediction of interest (regardless of how well-suited that model is for the prediction). However, modeling tools are available that can inform which locations and types of data provide the most 'bang for the buck' for a specified prediction. Put another way, the hydrologist can determine which observation data most reduce the model uncertainty around a specified prediction. An advantage of such an approach is the maximization of limited monitoring resources because it focuses on the difference in prediction uncertainty with or without additional collection of field data. Data worth can be calculated either through the addition of new data or subtraction of existing information by reducing monitoring efforts (Beven, 1993). The latter generally is not widely requested as there is explicit recognition that the worth calculated is fundamentally dependent on the prediction specified. If a water manager needs a new prediction, the benefits of reducing the scope of a monitoring effort, based on an old prediction, may be erased by the loss of information important for the new prediction. This fact sheet focuses on the worth or value of new data collection by quantifying the reduction in prediction uncertainty achieved be adding a monitoring observation. This calculation of worth can be performed for multiple potential locations (and types) of observations, which then can be ranked for their effectiveness for reducing uncertainty around the specified prediction. This is implemented using a Bayesian approach with the PREDUNC utility in the parameter estimation software suite PEST (Doherty, 2010). The techniques briefly described earlier are described in detail in a U.S. Geological Survey Scientific Investigations Report available on the Internet (Fienen and others, 2010; http://pubs.usgs.gov/sir/2010/5159/). This fact sheet presents a synopsis of the techniques as applied to a synthetic model based on a model constructed using properties from the Lake Michigan Basin (Hoard, 2010).

Fact Sheet↗

USGS2014

SAHM:VisTrails (Software for Assisted Habitat Modeling for VisTrails): training course

VisTrails is an open-source management and scientific workflow system designed to integrate the best of both scientific workflow and scientific visualization systems. Developers can extend the functionality of the VisTrails system by creating custom modules for bundled VisTrails packages. The Invasive Species Science Branch of the U.S. Geological Survey (USGS) Fort Collins Science Center (FORT) and the U.S. Department of the Interior’s North Central Climate Science Center have teamed up to develop and implement such a module—the Software for Assisted Habitat Modeling (SAHM). SAHM expedites habitat modeling and helps maintain a record of the various input data, the steps before and after processing, and the modeling options incorporated in the construction of an ecological response model. There are four main advantages to using the SAHM:VisTrails combined package for species distribution modeling: (1) formalization and tractable recording of the entire modeling process; (2) easier collaboration through a common modeling framework; (3) a user-friendly graphical interface to manage file input, model runs, and output; and (4) extensibility to incorporate future and additional modeling routines and tools. In order to meet increased interest in the SAHM:VisTrails package, the FORT offers a training course twice a year. The course includes a combination of lecture, hands-on work, and discussion. Please join us and other ecological modelers to learn the capabilities of the SAHM:VisTrails package.

Fact Sheet↗

USGS2026

Monitoring changes in Landsat thermal features in urban and non-urban interfaces from 1986 to 2023 in two international urban centers: Implications for climate and global issues

Rapid urbanization is reshaping thermal environments worldwide, with the strongest impacts occurring at the interface between urban and non-urban areas. Impervious surfaces, as key indicators of urban expansion, are critical for monitoring urban growth and assessing surface urban heat island (SUHI) effects. Land use and land cover change (LULCC) provides an essential link between urban dynamics and their environmental and societal consequences. Here, we integrated the U.S. Geological Survey (USGS) Climate Global Issues (CGI) Land Cover Product with Landsat thermal time-series to investigate SUHI evolution in two contrasting metropolitan regions: Wuhan, China, and Brasília, Brazil. Using data spanning 1986–2023, we analyzed the relationships between land cover, Landsat-based land surface temperature (LST), and SUHI intensity, and identified persistent thermal hotspots. Results demonstrate that the land cover data utilized increases the accuracy of impervious surface mapping along urban–rural gradients. Average SUHI intensities were 3.4 °C in Wuhan and 3.3 °C in Brasília, with statistically significant warming trends of 0.04 °C/year and 0.01 °C/year, respectively. Maximum temperature proved to be a robust indicator of SUHI intensification, capturing long-term upward trends. Our findings highlight the important role of urban land cover dynamics in shaping temporal SUHI variability and hotspot emergence. This prototype framework demonstrates the scientific and policy value of combining long-term land cover monitoring information with satellite thermal monitoring to quantify and track SUHI at city scale, supporting sustainable urban planning and climate adaptation strategies.

Remote Sensing↗

USGS2023

Metagenomic mapping of cyanobacteria and potential cyanotoxin producing taxa in large rivers of the United States

Cyanobacteria and cyanotoxin producing cyanobacterial blooms are a trending focus of current research. Many studies focus on bloom events in lentic environments such as lakes or ponds. Comparatively few studies have explored lotic environments and fewer still have examined the cyanobacterial communities and potential cyanotoxin producers during ambient, non-bloom conditions. Here we used a metagenomics-based approach to profile non-bloom microbial communities and cyanobacteria in 12 major U.S. rivers at multiple time points during the summer months of 2019. Our data show that U.S. rivers possess microbial communities that are taxonomically rich, yet largely consistent across geographic location and time. Within these communities, cyanobacteria often comprise significant portions and frequently include multiple species with known cyanotoxin producing strains. We further characterized these potential cyanotoxin producing taxa by deep sequencing amplicons of the microcystin E ( mcyE ) gene. We found that rivers containing the highest levels of potential cyanotoxin producing cyanobacteria consistently possess taxa with the genetic potential for cyanotoxin production and that, among these taxa, the predominant genus of origin for the mcyE gene is Microcystis . Combined, these data provide a unique perspective on cyanobacteria and potential cyanotoxin producing taxa that exist in large rivers across the U.S. and can be used to better understand the ambient conditions that may precede bloom events in lotic freshwater ecosystems.

Scientific Reports↗

USGS2011

Bedrock geologic map of the Seward Peninsula, Alaska, and accompanying conodont data

This 1:500,000-scale geologic map depicts the bedrock geology of Seward Peninsula, western Alaska, on the North American side of the Bering Strait. The map encompasses all of the Teller, Nome, Solomon, and Bendeleben 1:250,000-scale quadrangles, and parts of the Shishmaref, Kotzebue, Candle, and Norton Bay 1:250,000-scale quadrangles (sh. 1; sh. 2). The geologic map is presented on Sheet 1. The pamphlet includes an introductory text, detailed unit descriptions, tables of geochronologic data, and an appendix containing conodont (microfossil) data and a text explaining those data. Sheet 2 shows metamorphic and tectonic units, conodont color alteration indices, key metamorphic minerals, and locations of geochronology samples listed in the pamphlet. The map area covers 74,000 km 2 , an area slightly larger than West Virginia or Ireland.

Alaska↗

USGS2012

Storage capacity and sedimentation trends of Lago Garzas, Puerto Rico, 1996-2007

Lago Garzas is located in west-central Puerto Rico, about 3.5 kilometers southwest of the town of Adjuntas, in the confluence of the Río Vacas and three other unnamed tributaries (fig. 1). The dam is owned and operated by the Puerto Rico Electric Power Authority (PREPA), and was constructed in 1943 for hydroelectric power generation and municipal water use along the southern coast. The dam is a semi-hydraulic earthfill embankment lined with boulders, and has a height of 61.57 meters, a top width of 9.14 meters, a base width of 365.76 meters, and a crest length of 227.37 meters; State Road PR-518 crosses the top of the dam. A morning-glory-type spillway is located near the west abutment of the dam at an elevation of 736.12 meters above mean sea level (Puerto Rico Water Resources Authority, 1969). Figure 2 shows an aerial photograph of the Lago Garzas earthfill dam and the morning-glory spillway section. Additional information and operational procedures are provided in Soler-López and others (1999). During July 17-18, 2007, the U.S. Geological Survey (USGS) Caribbean Water Science Center, in cooperation with the Puerto Rico Aqueduct and Sewer Authority, conducted a bathymetric survey of Lago Garzas to update the reservoir storage capacity and update the reservoir sedimentation rate by comparing the 2007 data with the previous 1996 bathymetric survey results. The purpose of this report is to describe and document the USGS sedimentation survey conducted at Lago Garzas during July 2007, including the methods used to update the reservoir storage capacity, sedimentation rates, and areas of substantial sediment accumulation since 1996.

Lago Garzas Basin Area↗

USGS2005

Modeling hydrodynamics, temperature, and water quality in Henry Hagg Lake, Oregon, 2000-03

The two-dimensional model CE-QUAL-W2 was used to simulate hydrodynamics, temperature, and water quality in Henry Hagg Lake, Oregon, for the years 2000 through 2003. Input data included lake bathymetry, meteorologic conditions, tributary inflows, tributary temperature and water quality, and lake outflows. Calibrated constituents included lake hydrodynamics, water temperature, orthophosphate, total phosphorus, ammonia, algae, chlorophyll a, zooplankton, and dissolved oxygen. Other simulated constituents included nitrate, dissolved and particulate organic matter, dissolved solids, and suspended sediment. Two algal groups (blue-green algae, and all other algae) were included in the model to simulate the lake’s algal communities. Measured lake stage data were used to calibrate the lake's water balance; calibration of water temperature and water quality relied upon vertical profile data taken in the deepest part of the lake near the dam. The model initially was calibrated with data from 2000-01 and tested with data from 2002-03. Sensitivity tests were performed to examine the response of the model to specific parameters and coefficients, including the light-extinction coefficient, wind speed, tributary inflows of phosphorus, nitrogen and organic matter, sediment oxygen demand, algal growth rates, and zooplankton feeding preference factors.

Oregon↗

USGS2005

Water quality and ground-water/surface-water interactions along the John River near Anaktuvuk Pass, Alaska, 2002-2003

The headwaters of the John River are located near the village of Anaktuvuk Pass in the central Brooks Range of interior Alaska . With the recent construction of a water -supply system and a wastewater-treatment plant, most homes in Anaktuvuk Pass now have modern water and wastewater systems. The effluent from the treatment plant discharges into a settling pond near a tributary of the John River . The headwaters of the John River are adjacent to Gates of the Arctic National Park and Preserve, and the John River is a designated Wild River . Due to the concern about possible water - quality effects from the wastewater effluent, the hydrology of the John River near Anaktuvuk Pass was studied from 2002 through 2003 . Three streams form the John River at Anaktuvuk Pass : Contact Creek, Giant Creek, and the John River Tributary. These streams drain areas of 90.3 km (super 2) , 120 km (super 2) , and 4.6 km (super 2) , respectively. Water - quality data collected from these streams from 2002 -03 indicate that the waters are a calcium-bicarbonate type and that Giant Creek adds a sulfate component to the John River. The highest concentrations of bicarbonate, calcium, sodium, sulfate, and nitrate were found at the John River Tributary below the wastewater-treatment lagoon. These concentrations have little effect on the water quality of the John River because the flow of the John River Tributary is only about 2 percent of the John River flow. To better understand the ground-water/surface-water interactions of the upper John River, a numerical groundwater-flow model of the headwater area of the John River was constructed. Processes that occur during spring break-up, such as thawing of the active layer and the frost table and the resulting changes of storage capacity of the aquifer, were difficult to measure and simulate. Application and accuracy of the model is limited by the lack of specific hydrogeologic data both spatially and temporally. However, during the mid-winter and open-water periods, the model provided acceptable results and was coupled with a particle-movement model to simulate the movement and possible extent of conservative particles from the wastewater-treatment-plant lagoon.

Scientific Investigations Report↗

USGS2011

Geomorphology and bank erosion of the Matanuska River, southcentral Alaska

Bank erosion along the Matanuska River, a braided, glacial river in southcentral Alaska, has damaged or threatened houses, roadways, and public facilities for decades. Mapping of river geomorphology and bank characteristics for a 65-mile study area from the Matanuska Glacier to the river mouth provided erodibility information that was assessed along with 1949-2006 erosion to establish erosion hazard data. Braid plain margins were delineated from 1949, 1962, and 2006 orthophotographs to provide detailed measurements of erosion. Bank material and height and geomorphic features within the Matanuska River valley (primarily terraces and tributary fans) were mapped in a Geographic Information System (GIS) from orthophotographs and field observations to provide categories of erodibility and extent of the erodible corridor. The braid plain expanded 861 acres between 1949 and 2006. Erosion in the highest category ranged from 225 to 1,043 feet at reaches of bank an average of 0.5 mile long, affecting 8 percent of the banks but accounting for 64 percent of the erosion. Correlation of erosion to measurable predictor variables was limited to bank height and material. Streamflow statistics, such as peak streamflow or mean annual streamflow, were not clearly linked to erosion, which can occur during the prolonged period of summer high flows where channels are adjacent to an erodible braid plain margin. The historical braid plain, which includes vegetated braid plain bars and islands and active channels, was identified as the greatest riverine hazard area on the basis of its historical occupation. In 2006, the historical braid plain was an average of 15 years old, as determined from the estimated age of vegetation visible in orthophotographs. Bank erosion hazards at the braid plain margins can be mapped by combining bank material, bank height, and geomorphology data. Bedrock bluffs at least 10 feet high (31 percent of the braid plain margins) present no erosion hazard. At unconsolidated banks (63 percent of the braid plain margins), erosion hazards are great and the distinction in hazards between banks of varying height or geomorphology is slight.

Alaska↗

USGS2013

Estimates of the volume of water in five coal aquifers, Northern Cheyenne Indian Reservation, southeastern Montana

The Tongue River Member of the Tertiary Fort Union Formation is the primary source of groundwater in the Northern Cheyenne Indian Reservation in southeastern Montana. Coal beds within this formation generally contain the most laterally extensive aquifers in much of the reservation. The U.S. Geological Survey, in cooperation with the Northern Cheyenne Tribe, conducted a study to estimate the volume of water in five coal aquifers. This report presents estimates of the volume of water in five coal aquifers in the eastern and southern parts of the Northern Cheyenne Indian Reservation: the Canyon, Wall, Pawnee, Knobloch, and Flowers-Goodale coal beds in the Tongue River Member of the Tertiary Fort Union Formation. Only conservative estimates of the volume of water in these coal aquifers are presented. The volume of water in the Canyon coal was estimated to range from about 10,400 acre-feet (75 percent saturated) to 3,450 acre-feet (25 percent saturated). The volume of water in the Wall coal was estimated to range from about 14,200 acre-feet (100 percent saturated) to 3,560 acre-feet (25 percent saturated). The volume of water in the Pawnee coal was estimated to range from about 9,440 acre-feet (100 percent saturated) to 2,360 acre-feet (25 percent saturated). The volume of water in the Knobloch coal was estimated to range from about 38,700 acre-feet (100 percent saturated) to 9,680 acre-feet (25 percent saturated). The volume of water in the Flowers-Goodale coal was estimated to be about 35,800 acre-feet (100 percent saturated). Sufficient data are needed to accurately characterize coal-bed horizontal and vertical variability, which is highly complex both locally and regionally. Where data points are widely spaced, the reliability of estimates of the volume of coal beds is decreased. Additionally, reliable estimates of the volume of water in coal aquifers depend heavily on data about water levels and data about coal-aquifer characteristics. Because the data needed to define the volume of water were sparse, only conservative estimates of the volume of water in the five coal aquifers are presented in this report. These estimates need to be used with caution and mindfulness of the uncertainty associated with them.

Montana↗

USGS2013

Hydrogeologic framework, arsenic distribution, and groundwater geochemistry of the glacial-sediment aquifer at the Auburn Road landfill superfund site, Londonderry, New Hampshire

Leachate continues to be generated from landfills at the Auburn Road Landfill Superfund Site in Londonderry, New Hampshire. Impermeable caps on the three landfills at the site inhibit direct infiltration of precipitation; however, high water-table conditions allow groundwater to interact with landfill materials from below, creating leachate and ultimately reducing conditions in downgradient groundwater. Reducing conditions can facilitate arsenic transport by allowing it to stay in solution or by liberating arsenic adsorbed to surfaces and from geologic sources, such as glacial sediments and bedrock. The site occupies a 180-acre parcel of land containing streams, ponds, wetlands, and former gravel pits located in glacial sediment. Four areas, totaling 14 acres, including three landfills and one septage lagoon, were used for waste disposal. The site was closed in 1980 after volatile organic compounds associated with industrial waste dumping were detected. The site was added to the U.S. Environmental Protection Agency National Priority List in 1982, and the landfills were capped in 1996. Although volatile organic compound concentrations in groundwater have declined substantially, some measurable concentrations remain. Temporally variable and persistent elevated arsenic concentrations have been measured in groundwater affected by the landfill leachate. Microbial consumption of carbon found in leachate is a driver of reducing conditions that liberate arsenic at the site. In addition to sources of carbon in landfill leachate, wetland areas throughout the site also could contribute carbon to groundwater, but it is currently unknown if any of the wetland areas have downward or reversing gradients that could allow the infiltration of surface water to groundwater. Red-stained sediments and water indicate iron-rich groundwater discharge to surface water and are also associated with elevated concentrations of arsenic in sediment and groundwater. Ironrich groundwater seeps have been observed in the wetland, streams, and pond downgradient of the landfills. Piezometers were installed in some of these locations to confirm groundwater discharge, measure vertical-flow gradients, and to provide a way to sample the discharging groundwater. Understanding the movement of leachate in groundwater is complicated by the presence of preferential flow paths through aquifer materials with differing hydraulic properties; these preferential flow paths can affect rates of recharge, geochemical conditions, and contaminant fluxes. In areas adjacent to the three capped landfills, infiltration of precipitation containing oxygenated water through permeable deltaic sediments in the former gravel pit area causes increases in dissolved oxygen concentrations and decreases in arsenic concentrations. Layered deltaic sediments produce anisotropic hydraulic characteristics and zones of high hydraulic conductivity. The glacial-sediment aquifer also includes glaciolacustrine sediments that have low permeability and limit infiltration at the surface Discharge of leachate-affected groundwater may be limited in areas of organic muck on the bottom of Whispering Pines Pond because the muck may act as a semiconfining layer. Geophysical survey results were used to identify several areas with continuous beds of muck and an underlying highresistivity layer on top of a layer of low resistivity that may represent leachate-affected groundwater. The high-resistivity layer is likely groundwater associated with oxygenated recharge, which would cause arsenic to adsorb onto aquifer sediments and reduce concentrations of dissolved arsenic in groundwater. Surface and borehole geophysical data collected in 2011 were used to identify potentially high-permeability or contaminated zones in the aquifer (preferential flowpaths) as well as low-permeability zones that may promote contamination through back diffusion. Some groundwater in parts of the glacial-sediment aquifer where the leachate plumes were present had low electrical resistivity, low dissolved oxygen, and high concentrations of arsenic. Low-resistivity zones in the underlying bedrock were associated with fractures that also may contain leachate. Although surveying the fractured bedrock was not a specific objective of this study, the results suggest that such a survey would help to determine if leachate and associated concentrations of arsenic are migrating downward into the fractured-bedrock-aquifer system. An uncalibrated, one-dimensional, reactive-transport model was used to assess several conditions that affect arsenic mobility. The results indicate that reductive dissolution and desorption from glacial sediments control dissolved arsenic concentrations. Parameter sensitivity analysis was used to identify key data that are needed in order to accurately assess the time required for arsenic concentrations to fall to levels below the maximum contaminant level at the site. Quantifying this time will require accurate characterization of carbon, sediment-surface sorption sites, and groundwater fluxes at the site.

New Hampshire↗

USGS2018

UFINCH: A method for simulating unit and daily flows in networks of channels described by NHDPlus using continuous flow data at U.S. Geological Survey streamgages

The UFINCH (Unit Flows In Networks of Channels) computer application can be used to simulate daily and unit flows in networks of streams based on geospatial data in the National Hydrography Dataset NHDPlus (with value added attributes), and U.S. Geoogical Survey daily streamflow data from a downstream (or base) streamgage. Among streamflow augmentation methods, UFINCH has the unique capability to estimate time series of flows from a single base (downstream) streamgage to many upstream reaches, while conserving flows within the basin. UFINCH also provides a simple statistical model to adjust simulated flows to better match continuous flows from data at an upstream streamgage. Parameters of the statistical model are estimated using overlapping periods of record at the two streamgages, but the adjustment can be applied to all years of record available at the base streamgage. This report describes the main features of UFINCH and presents results from a sample application. Interactive graphical user interfaces and automated geographical information processing facilitate flow-data retrievals provide an intuitive environment for efficient and effective generation of flow information in a network. UFINCH is coded in the Matlab programming language and can be run in the Matlab programming environment, with supporting statistical, optimization, and mapping toolboxes, or from compiled code on a Microsoft Windows computer.

Scientific Investigations Report↗

USGS2021

Multilevel groundwater monitoring of hydraulic head, water temperature, and chemical constituents in the eastern Snake River Plain aquifer, Idaho National Laboratory, Idaho, 2014–18

Radiochemical and chemical wastewater discharged to infiltration ponds and disposal wells since the early 1950s at the Idaho National Laboratory (INL), southeastern Idaho, has affected the water quality of the eastern Snake River Plain (ESRP) aquifer. In 2006, the U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, added a multilevel well-monitoring network to their ongoing monitoring program to begin describing the vertical movement and distribution of the chemical constituents in the ESRP aquifer. The multilevel monitoring system (MLMS) at the INL has been ongoing since 2006, and this report summarizes data collected during 2014–18 from 11 multilevel monitoring wells. Hydraulic head (head) and groundwater temperature data were collected, including 177 measurements from hydraulically isolated depth intervals from 448.0 to 1,377.6 feet below land surface. One port (port 3) within well USGS 134 was not monitored owing to a valve failure . Note: This is a partial abstract.

Idaho↗

USGS2023

Comparison of turbidity sensors at U.S. Geological Survey supergages in Indiana from November 2018 to December 2021

Beginning in September 2010, the U.S. Geological Survey installed continuous water-quality monitors at several streamgages across Indiana as part of a network of supergages to meet cooperator information needs. Two types (or models) of water-quality monitors deployed at each site measured and recorded water temperature, dissolved oxygen, specific conductance, pH, and turbidity every 15 minutes during the study period. Associated discrete water samples were collected at regular intervals and analyzed for concentrations of suspended sediment and total phosphorus. Surrogate regression models were developed between the continuously measured turbidity values and turbidity values in the associated samples to compute continuous concentrations and loads of suspended sediment and total phosphorus. Starting in November 2018, the original extended deployment system monitors were replaced with the newest model of multiparameter water-quality monitors and were equipped with turbidity smart sensors because the older monitors were phased out of production. The updated monitor and smart sensor yield different but relatable turbidity values. Turbidity data collected concurrently by the two sensors from November 2018 to December 2021 were compared and analyzed to quantify the relation between them at six supergage sites in northwestern Indiana and one site in the town of Zionsville in central Indiana. Ordinary least squares regression was used to calculate site-specific conversion factors so that turbidity data from the newer monitors can be used in published surrogate models based on the older monitor data. Regression analyses explained approximately 98 percent of the variation in turbidity readings between the two sensors. From these analyses, conversion factors were developed that may be applied to older turbidity readings to calculate near real-time concentrations of phosphorus and suspended sediment.

Indiana↗