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At least 1,027 records · Page 57Linked to original sources
USGS2014

Improving groundwater predictions utilizing seasonal precipitation forecasts from general circulation models forced with sea surface temperature forecasts

Recent studies have found a significant association between climatic variability and basin hydroclimatology, particularly groundwater levels, over the southeast United States. The research reported in this paper evaluates the potential in developing 6-month-ahead groundwater-level forecasts based on the precipitation forecasts from ECHAM 4.5 General Circulation Model Forced with Sea Surface Temperature forecasts. Ten groundwater wells and nine streamgauges from the USGS Groundwater Climate Response Network and Hydro-Climatic Data Network were selected to represent groundwater and surface water flows, respectively, having minimal anthropogenic influences within the Flint River Basin in Georgia, United States. The writers employ two low-dimensional models [principle component regression (PCR) and canonical correlation analysis (CCA)] for predicting groundwater and streamflow at both seasonal and monthly timescales. Three modeling schemes are considered at the beginning of January to predict winter (January, February, and March) and spring (April, May, and June) streamflow and groundwater for the selected sites within the Flint River Basin. The first scheme (model 1) is a null model and is developed using PCR for every streamflow and groundwater site using previous 3-month observations (October, November, and December) available at that particular site as predictors. Modeling schemes 2 and 3 are developed using PCR and CCA, respectively, to evaluate the role of precipitation forecasts in improving monthly and seasonal groundwater predictions. Modeling scheme 3, which employs a CCA approach, is developed for each site by considering observed groundwater levels from nearby sites as predictands. The performance of these three schemes is evaluated using two metrics (correlation coefficient and relative RMS error) by developing groundwater-level forecasts based on leave-five-out cross-validation. Results from the research reported in this paper show that using precipitation forecasts in climate models improves the ability to predict the interannual variability of winter and spring streamflow and groundwater levels over the basin. However, significant conditional bias exists in all the three modeling schemes, which indicates the need to consider improved modeling schemes as well as the availability of longer time-series of observed hydroclimatic information over the basin.

Georgia↗
USGS2000

Effects of alternative Missouri River management plans on ground-water levels in the lower Missouri River flood plain

In 1998, the U.S. Army Corps of Engineers (USACE) proposed eight Alternative River Management Plans (ARMPs) for managing reservoir levels and water-release rates for the Missouri River. The plans include the Current Water Control Plan (CWCP), Conservation 18, 31, and 44 (C18, C31, and C44) that provide different levels of water conservation in the reservoirs during droughts, Fish and Wildlife 10, 15, and 20 (FW10, FW15, and FW20) that vary water-release rates to provide additional fish and wildlife benefits, and Mississippi River 66 (M66) that maintains a 66,000 cubic feet per second discharge at St. Louis to provide navigation support for the Mississippi River. Releases from Gavin?s Point Dam affect both the lower 1,305 kilometers of the Missouri River and ground-water levels in the lower Missouri River flood plain. Changes in the magnitude and timing of ground-water-level fluctuations in response to changes in river management could impact agriculture, urban development, and wetland hydrology along the lower Missouri River flood plain. This study compared simulated ground-water altitude and depth to ground water for the CWCP in the Missouri River alluvial aquifer near the Kansas City area between 1970 and 1980 with each ARMP, determined the average change in simulated ground-water level for selected river-stage flood pulses at selected distances from the river, and compared simulated flood pulse, ground-water responses with actual flood pulse, and ground-water responses measured in wells located at three sites along the lower Missouri River flood plain.For the model area, the percent total shallow ground-water area (depth to ground water less than 0.3048 meter) is similar for each ARMP because of overall similarities in river flow between ARMPs. The percent total shallow ground-water area for C18 is the most similar to CWCP followed by C31, M66, C44, FW10, FW15, and FW20. ARMPs C18, C31, C44, and M66 do not cause large changes in the percent shallow ground-water area when compared to CWCP. FW10 and FW15 each cause a spring increase and a summer decrease in the shallow ground-water area. FW20 has a larger spring increase in the shallow ground-water area, but the largest decrease is delayed into November. Analysis of daily changes between the ARMPs indicate large differences can exist in both duration and extent of shallow ground-water areas.A series of 12 flood pulses of 0.5-, 1-, and 3-meters in magnitude and 1-, 8-, 32-, and 128-days in duration were simulated using the ground-water flow model. A ground-water response factor (GWRF, defined as the change in ground-water level at a known distance from the river, at a specified time after the beginning of a flood pulse divided by the magnitude of the flood pulse) was determined daily for selected distances from the river. The GWRF multiplied by the magnitude of the flood pulse can be used to estimate the change in ground-water level at a known time after the beginning of a flood pulse for a known distance from the river. Flood-pulse simulation results indicate the relatively small impact on ground-water levels of small river-stage fluctuations of short duration as might occur daily or weekly. The larger impact on ground-water levels from larger river-stage increases of longer duration indicate the importance of river management flow releases, seasonal changes in river flow, and the effects of continuous high-river stage for long periods on ground-water levels of the lower Missouri River flood plain.A comparison of model results to well hydrographs from three areas along the lower Missouri River flood plain was used to determine how closely the simulated GWRFs matched the measured GWRFs for similar flood pulses and the transferability of GWRFs to other parts of the lower Missouri River flood plain. The comparison between the measured and simulated ground-water responses indicate that the simulated ground-water responses can provide a reasonable estimate of the ground-water resp

Water-Resources Investigations Report↗
USGS2010

Analysis of elevation changes detected from multi-temporal LiDAR surveys in forested landslide terrain in western Oregon

We examined elevation changes detected from two successive sets of Light Detection and Ranging (LiDAR) data in the northern Coast Range of Oregon. The first set of LiDAR data was acquired during leafon conditions and the second set during leaf-off conditions. We were able to successfully identify and map active landslides using a differential digital elevation model (DEM) created from the two LiDAR data sets, but this required the use of thresholds (0.50 and 0.75 m) to remove noise from the differential elevation data, visual pattern recognition of landslideinduced elevation changes, and supplemental QuickBird satellite imagery. After mapping, we field-verified 88 percent of the landslides that we had mapped with high confidence, but we could not detect active landslides with elevation changes of less than 0.50 m. Volumetric calculations showed that a total of about 18,100 m3 of material was missing from landslide areas, probably as a result of systematic negative elevation errors in the differential DEM and as a result of removal of material by erosion and transport. We also examined the accuracies of 285 leaf-off LiDAR elevations at four landslide sites using Global Positioning System and total station surveys. A comparison of LiDAR and survey data indicated an overall root mean square error of 0.50 m, a maximum error of 2.21 m, and a systematic error of 0.09 m. LiDAR ground-point densities were lowest in areas with young conifer forests and deciduous vegetation, which resulted in extensive interpolations of elevations in the leaf-on, bare-earth DEM. For optimal use of multi-temporal LiDAR data in forested areas, we recommend that all data sets be flown during leaf-off seasons.

Environmental & Engineering Geoscience↗
USGS2026

Morphodynamic controls on the performance of dune-based coastal flood mitigation under sea-level rise

Dune-based adaptation is increasingly used as a nature-based solution for coastal flood mitigation, yet many assessments rely on hydrodynamic-only approaches that treat beach and dune morphology as static, neglecting storm-driven erosion that can degrade dune performance during extreme events. This study develops a process-based modeling framework coupling extreme value analysis of regional wave climate with XBeach surfbeat simulations to evaluate coastal flooding, erosion, and dune performance across three time horizons (2025, 2055, 2085) and four storm return periods (5, 20, 50, and 100 years) at two contrasting sites in Santa Cruz County, California. At Santa Cruz Beach, flood extent increases at an accelerating rate with sea-level rise (SLR) for a given return period, while higher return period storms exhibit diminishing incremental increases under fixed SLR conditions. Storm-scale morphodynamic feedbacks reduce predicted flood extent by up to 32.4% through profile adjustment and nearshore bar formation. Dune effectiveness is strongly regime-dependent, reducing flooding by up to 60% under collision-regime conditions but declining rapidly as the system transitions toward overwash and inundation under stronger storms and late-century SLR. Comparison of static and erodible dune representations shows that flood estimates are not consistently conservative, with differences reaching up to 54.3% depending on storm intensity and time horizon. At Capitola Beach, limited accommodation space and water-level-dominated dynamics collectively constrain morphodynamic adjustment, render the site near its inundation capacity under present-day conditions, and result in near-complete dune collapse and limited flood mitigation across all scenarios. These findings highlight the importance of site-specific regime evaluation, process-based morphodynamic modeling, and adaptive management when assessing dune-based adaptation under rising sea levels.

California↗
USGS2002

Groundwater contamination downstream of a contaminant penetration site. I. Extension-expansion of the contaminant plume

This study concerns the possible use of boundary layer (BL) approach for the analysis and evaluation of contaminant transport in groundwater due to contaminant penetration into the groundwater aquifer through a site of limited size. The contaminant penetration may occur through either the upper (surface) or lower (bedrock) boundary of the aquifer. Two general cases of contaminant penetration mechanisms are considered: (1) the contaminant is transferred through an interface between a contaminating and freshwater fluid phases, and (2) the contaminant arrives at groundwater by leakage and percolation. For the purpose of BL evaluation the contaminant plume is divided into three different sections: (1) the penetration section, (2) the extension-expansion section, and (3) the spearhead section. In each section a different BL method approach yields simple analytical expressions for the description of the contaminant plume migration and contaminant transport. Previous studies of the BL method can be directly applied to the evaluation of contaminant transport at the contaminant penetration section. The present study extends those studies and concerns the contaminant transport in the two other sections, which are located downstream of the penetration section. This study shows that the contaminant concentration profiles in sections 2 and 3 incorporate two BLs: (1) an inner BL adjacent to the aquifer bottom or surface boundary, and (2) an outer BL, which develops above or below the inner one. The method developed in the present study has been applied to practical issues concerning salinity penetration into groundwater in south central Kansas.

Journal of Environmental Science and Health - Part↗
USGS2014

Summary of U.S. Geological Survey reports documenting flood profiles of streams in Iowa, 1963-2012

This report is part of an ongoing program that is publishing flood profiles of streams in Iowa. The program is managed by the U.S. Geological Survey in cooperation with the Iowa Department of Transportation and the Iowa Highway Research Board (Project HR-140). Information from flood profiles is used by engineers to analyze and design bridges, culverts, and roadways. This report summarizes 47 U.S. Geological Survey flood-profile reports that were published for streams in Iowa during a 50-year period from 1963 to 2012. Flood events profiled in the reports range from 1903 to 2010. Streams in Iowa that have been selected for the preparation of flood-profile reports typically have drainage areas of 100 square miles or greater, and the documented flood events have annual exceedance probabilities of less than 2 to 4 percent. This report summarizes flood-profile measurements, changes in flood-profile report content throughout the years, streams that were profiled in the reports, the occurrence of flood events profiled, and annual exceedance-probability estimates of observed flood events. To develop flood profiles for selected flood events for selected stream reaches, the U.S. Geological Survey measured high-water marks and river miles at selected locations. A total of 94 stream reaches have been profiled in U.S. Geological Survey flood-profile reports. Three rivers in Iowa have been profiled along the same stream reach for five different flood events and six rivers in Iowa have been profiled along the same stream reach for four different flood events. Floods were profiled for June flood events for 18 different years, followed by July flood events for 13 years, May flood events for 11 years, and April flood events for 9 years. Most of the flood-profile reports include estimates of annual exceedance probabilities of observed flood events at streamgages located along profiled stream reaches. Comparisons of 179 historic and updated annual exceedance-probability estimates indicate few differences that are considered substantial between the historic and updated estimates for the observed flood events. Overall, precise comparisons for 114 observed flood events indicate that updated annual exceedance probabilities have increased for most of the observed flood events compared to the historic annual exceedance probabilities. Multiple large flood events exceeding the 2-percent annual exceedance-probability discharge estimate occurred at 37 of 98 selected streamgages during 1960–2012. Five large flood events were recorded at two streamgages in Ames during 1990–2010 and four large flood events were recorded at four other streamgages during 1973–2010. Results of Kendall’s tau trend-analysis tests for 35 of 37 selected streamgages indicate that a statistically significant trend is not evident for the 1963–2012 period of record; nor is an overall clear positive or negative trend evident for the 37 streamgages.

Iowa↗
USGS2013

Sediment transport and deposition in the lower Missouri River during the 2011 flood

Floodwater in the Missouri River in 2011 originated in upper-basin regions and tributaries, and then travelled through a series of large flood-control reservoirs, setting records for total runoff volume entering all six Missouri River main-stem reservoirs. The flooding lasted as long as 3 months. The U.S Geological Survey (USGS) examined sediment transport and deposition in the lower Missouri River in 2011 to investigate how the geography of floodwater sources, in particular the decanting effects of the Missouri River main-stem reservoir system, coupled with the longitudinal characteristics of civil infrastructure and valley-bottom topography, affected sediment transport and deposition in this large, regulated river system. During the flood conditions in 2011, the USGS, in cooperation with the U.S. Army Corps of Engineers, monitored suspended-sediment transport at six primary streamgages along the length of the lower Missouri River. Measured suspended-sediment concentration (SSC) in the lower Missouri River varied from approximately 150 milligrams per liter (mg/L) to 2,000 mg/L from January 1 to September 30, 2011. Median SSC increased in the downstream direction from 355 mg/L at Sioux City, Iowa, to 490 mg/L at Hermann, Missouri. The highest SSCs were measured downstream from Omaha, Nebraska, in late February when snowmelt runoff from tributaries, which were draining zones of high-sediment production, was entering the lower Missouri River, and releases of water at Gavins Point Dam were small. The combination of dilute releases of water at Gavins Point Dam and low streamflows in lower Missouri River tributaries caused sustained lowering of SSC at all streamgages from early July through late August. Suspended-sediment ranged from 5 percent washload (PW; percent silt and clay) to as much as 98 percent in the lower Missouri River from January 1 to September 30, 2011. Median PW increased in the downstream direction from 24 percent at Sioux City, Iowa, to 78 percent at Hermann, Missouri. Measurements made in early January, when SSC was low, indicate that suspended sediment mostly was composed of bed material, but by mid-February, runoff from the plains caused PW to increase at most streamgages. Total suspended-sediment discharge (SSD) during water year 2011 at the selected streamgages in the lower Missouri River ranged from approximately 29 to 64 million tons. Total estimated SSD had the lowest exceedance frequencies in the reaches between Gavins Point Dam and Nebraska City, Nebraska, but exceedance frequencies increased substantially downstream. In 2011, total SSD with low exceedance frequencies were reported at Sioux City, Iowa, Omaha, Nebraska, and Nebraska City, Nebraska, despite moderate-to-high exceedance frequencies for annual average SSC, indicating that the duration of high-magnitude flooding was the primary driver of total SSD. Comparison of median SSC for samples from water year 2011 with samples in the 20 years prior indicated that median SSC for high-action streamflows (streamflows likely to produce a stage exceeding the National Weather Service’s “action stage”) in 2011 were lower than those typical for high-action streamflows. Multiple-comparison analysis indicated that median SSC values for low-action streamflows (streamflows likely to produce stages lower than the National Weather Service’s “action stage”) and high-action streamflows sampled in 2011 at 4 of 6 streamgages were not significantly distinguishable from median SSC values for low-action streamflows in the previous 20 years. Longitudinal comparison of streamflow and SSD exceedance frequencies for 2011 with corresponding frequencies for 2008 and 1993 indicated the important role of tributary contributions to total SSD in the lower Missouri River. In 1993 and 2008, tributaries were the primary source of floodwater in the lower Missouri River, which resulted in a 20-fold increase in total SSD from Sioux City, Iowa, to Hermann, Missouri. In 2011, releases at Gavins Point Dam were the primary source of floodwater in the lower Missouri River, and total SSD at Hermann, Missouri, was only twice that estimated for Sioux City, Iowa. Sand deposition was estimated using analysis of multispectral satellite imagery collected in October and November 2011. Distributions of sand in the flood plain of the lower Missouri River also were quantified in relation to distance from the banks of the main channel for seven discrete river segments bounded by Gavins Point Dam and selected downstream tributaries. The areal extent of overbank flooding and flood-plain sand deposits increased downstream from Sioux City, Iowa to a broad peak near Rulo, Nebraska, and then decreased to levels near the lower limit of quantification downstream from Kansas City, Missouri. Most of the flood plain inundation and sediment-deposition damage to agricultural fields was observed between river miles 480 and 700, where 2011 peak streamflows had low exceedance frequencies, and the lower Missouri River channel was less incised or had aggraded recently. As channel capacity increased in the downstream direction, the relative magnitude of the flood decreased downstream, and overbank flooding was less extensive. In the constricted reaches, flood-plain sand deposits mainly were observed in association with levee breaks.

Iowa, Kansas, Missouri, Montana, Nebraska, North D↗
USGS2013

Harmonizing multiple methods for reconstructing historical potential and reference evapotranspiration

Potential evapotranspiration (PET) and reference evapotranspiration (RET) data are usually critical components of hydrologic analysis. Many different equations are available to estimate PET and RET. Most of these equations, such as the Priestley-Taylor and Penman- Monteith methods, rely on detailed meteorological data collected at ground-based weather stations. Few weather stations collect enough data to estimate PET or RET using one of the more complex evapotranspiration equations. Currently, satellite data integrated with ground meteorological data are used with one of these evapotranspiration equations to accurately estimate PET and RET. However, earlier than the last few decades, historical reconstructions of PET and RET needed for many hydrologic analyses are limited by the paucity of satellite data and of some types of ground data. Air temperature stands out as the most generally available meteorological ground data type over the last century. Temperature-based approaches used with readily available historical temperature data offer the potential for long period-of-record PET and RET historical reconstructions. A challenge is the inconsistency between the more accurate, but more data intensive, methods appropriate for more recent periods and the less accurate, but less data intensive, methods appropriate to the more distant past. In this study, multiple methods are harmonized in a seamless reconstruction of historical PET and RET by quantifying and eliminating the biases of the simple Hargreaves-Samani method relative to the more complex and accurate Priestley-Taylor and Penman-Monteith methods. This harmonization process is used to generate long-term, internally consistent, spatiotemporal databases of PET and RET.

Florida↗
USGS2011

Anthropocene streams and base-level controls from historic dams in the unglaciated mid-Atlantic region, USA

Recently, widespread valley-bottom damming for water power was identified as a primary control on valley sedimentation in the mid-Atlantic US during the late seventeenth to early twentieth century. The timing of damming coincided with that of accelerated upland erosion during post-European settlement land-use change. In this paper, we examine the impact of local drops in base level on incision into historic reservoir sediment as thousands of ageing dams breach. Analysis of lidar and field data indicates that historic milldam building led to local base-level rises of 2–5 m (typical milldam height) and reduced valley slopes by half. Subsequent base-level fall with dam breaching led to an approximate doubling in slope, a significant base-level forcing. Case studies in forested, rural as well as agricultural and urban areas demonstrate that a breached dam can lead to stream incision, bank erosion and increased loads of suspended sediment, even with no change in land use. After dam breaching, key predictors of stream bank erosion include number of years since dam breach, proximity to a dam and dam height. One implication of this work is that conceptual models linking channel condition and sediment yield exclusively with modern upland land use are incomplete for valleys impacted by milldams. With no equivalent in the Holocene or late Pleistocene sedimentary record, modern incised stream-channel forms in the mid-Atlantic region represent a transient response to both base-level forcing and major changes in land use beginning centuries ago. Similar channel forms might also exist in other locales where historic milling was prevalent.

Delaware, Maryland, Newe Jersey, New York, Pennsyl↗
USGS2024

Special topic—Eruption plumes and clouds

Introduction Explosive eruptions create plumes of volcanic ash and gas that can rise more than 30,000 feet (9.1 kilometers [km]) above sea level within minutes of eruption onset. The resulting clouds disperse under prevailing winds and may cause hazardous conditions hundreds to thousands of kilometers from the volcano, including in international airspace. Rapid detection and characterization of explosive activity is vital to mitigate the wide-ranging effects of volcanic ash. Ashfall thicknesses as small as a millimeter or so on the ground can affect infrastructure, agriculture, and air quality, requiring extensive clean-up procedures (Schuster, 1981; Warrick and others, 1981, U.S. Geological Survey, 2022). Volcanic clouds also pose substantial threats to aircraft. Since 1953, 88 encounters between airplanes and ash clouds have been documented worldwide (International Civil Aviation Organization, 2015, appendix F), resulting in aircraft damage and, in 9 cases, engine failure (Guffanti and others, 2010). In 1982, two large passenger planes suffered complete engine failure owing to eruptions in Indonesia (Global Volcanism Program, 1982) and a similar incident occurred over Alaska in 1989 (Casadevall, 1994). In all three cases, they were able to restart some engine capability and land safely once they emerged from the ash clouds, although with substantial damage (Guffanti and others, 2010). The clear threat to aviation has led to establishment of nine Volcanic Ash Advisory Centers (VAAC) around the world to monitor and rapidly disseminate information about volcanic eruptions to the aviation community. U.S. Geological Survey (USGS) volcano observatories issue the Volcano Observatory Notice for Aviation that informs of preeruptive unrest or eruptive activity. When ash-producing eruptions do occur, volcano observatories work closely with their regional VAAC to ensure consistency and accuracy in eruption onset time, cloud altitude, ash production, and duration as reported in Volcanic Ash Advisories. Explosive volcanism in the United States and Commonwealth of the Northern Mariana Islands prompts 50–100 such advisories in any given year (table J1). This collaborative effort is greatly aided by USGS detection and monitoring of eruption clouds to ensure a timely and coordinated response. To support these efforts to provide guidance on ash transport and fallout, the USGS developed the Ash3d volcanic ash dispersion model ( https://vsc-ash.wr.usgs.gov/ash3d-gui ) (Schwaiger and others, 2012). Automated simulations are run daily by the USGS for volcanoes that are in elevated states of unrest, and in response mode when eruptions occur. During eruptions, the model output is provided to local National Weather Service Weather Forecast Offices to guide them in the issuance of their information products (such as special weather statements, ashfall advisories, or ashfall warnings), as well as to State and local governments and the public. Characterization of the eruption source is needed to estimate the parameters used to initialize the Ash3d model, and by the Anchorage and Washington VAACs to initialize other dispersion models that inform forecasts for the airborne volcanic cloud. The source parameters that can be provided by observation during an eruption include eruption start time, eruption cloud height over time, and eruption duration. Other, nonobservable source parameters, such as mass eruption rate and grain-size distribution, are based on empirical correlations and study of historical deposits. The goal is to provide a time series of cloud heights, mass eruption rates, and particle-size distributions that accurately reflects current conditions. When feasible, the USGS also provides guidance on the nature of ongoing eruptions and forecasts future activity using petrologic monitoring of collected tephra samples. The aims of providing accurate observable parameters are achieved through analysis of (1) near-real-time meteorological satellite data, (2) ground-based cameras (see of Flinders, A.F., Lowenstern, J.B., Coombs, M.L., and Poland, M.P., eds., Recommended capabilities and instrumentation for volcano monitoring in the United States: U.S. Geological Survey Scientific Investigations Report 2024–5062–G, 11 p., https://doi.org/10.3133/sir20245062g.">chapter G , this volume; Orr and others, 2024), (3) weather radar, (4) volcanic lightning detection, and (5) ground-based ash sensors and sampling. Explosive eruptions can be detected by a variety of geophysical monitoring, including infrasound (see of Flinders, A.F., Lowenstern, J.B., Coombs, M.L., and Poland, M.P., eds., Recommended capabilities and instrumentation for volcano monitoring in the United States: U.S. Geological Survey Scientific Investigations Report 2024–5062–C, 11 p., https://doi.org/10.3133/sir20245062c.">chapter C , this volume; Lyons and others, 2024) and seismicity (see of Flinders, A.F., Lowenstern, J.B., Coombs, M.L., and Poland, M.P., eds., Recommended capabilities and instrumentation for volcano monitoring in the United States: U.S. Geological Survey Scientific Investigations Report 2024–5062–B, 9 p., https://doi.org/10.3133/sir20245062b.">chapter B , this volume; Thelen and others, 2024). However, those methods cannot quantify the altitude, ash content, and dispersal dynamics of resulting volcanic clouds. Ideally, all available sources of monitoring data are synthesized to develop a coherent understanding of eruptive activity. The guidance summarized here provides a framework for characterizing volcanic clouds in the atmosphere and tracking the evolution of explosive eruption dynamics.

Scientific Investigations Report↗
USGS2008

Towards monitoring land-cover and land-use changes at a global scale: the global land survey 2005

Land cover is a critical component of the Earth system, infl uencing land-atmosphere interactions, greenhouse gas fl uxes, ecosystem health, and availability of food, fi ber, and energy for human populations. The recent Integrated Global Observations of Land (IGOL) report calls for the generation of maps documenting global land cover at resolutions between 10m and 30m at least every fi ve years (Townshend et al., in press). Moreover, despite 35 years of Landsat observations, there has not been a unifi ed global analysis of land-cover trends nor has there been a global assessment of land-cover change at Landsat-like resolution. Since the 1990s, the National Aeronautics and Space Administration (NASA) and the U.S. Geological Survey (USGS) have supported development of data sets based on global Landsat observations (Tucker et al., 2004). These land survey data sets, usually referred to as GeoCover ™, provide global, orthorectifi ed, typically cloud-free Landsat imagery centered on the years 1975, 1990, and 2000, with a preference for leaf-on conditions. Collectively, these data sets provided a consistent set of observations to assess land-cover changes at a decadal scale. These data are freely available via the Internet from the USGS Center for Earth Resources Observation and Science (EROS) (see http://earthexplorer.usgs.gov or http://glovis.usgs.gov). This has resulted in unprecedented downloads of data, which are widely used in scientifi c studies of land-cover change (e.g., Boone et al., 2007; Harris et al., 2005; Hilbert, 2006; Huang et al. 2007; Jantz et al., 2005, Kim et al., 2007; Leimgruber, 2005; Masek et al., 2006). NASA and USGS are continuing to support land-cover change research through the development of GLS2005 - an additional global Landsat assessment circa 20051 . Going beyond the earlier initiatives, this data set will establish a baseline for monitoring changes on a 5-year interval and will pave the way toward continuous global land-cover monitoring at Landsat-like resolution in the next decade.

Photogrammetric Engineering and Remote Sensing↗
USGS2017

Quantifying habitat benefits of channel reconfigurations on a highly regulated river system, Lower Missouri River, USA

We present a quantitative analysis of habitat availability in a highly regulated lowland river, comparing a restored reach with two reference reaches: an un-restored, channelized reach, and a least-altered reach. We evaluate the effects of channel modifications in terms of distributions of depth and velocity as well as distributions and availability of habitats thought to be supportive of an endangered fish, the pallid sturgeon ( Scaphirhynchus albus ). It has been hypothesized that hydraulic conditions that support food production and foraging may limit growth and survival of juvenile pallid sturgeon. To evaluate conditions that support these habitats, we constructed two-dimensional hydrodynamic models for the three study reaches, two located in the Lower Missouri River (channelized and restored reaches) and one in the Yellowstone River (least-altered reach). Comparability among the reaches was improved by scaling by bankfull discharge and bankfull channel area. The analysis shows that construction of side-channel chutes and increased floodplain connectivity increase the availability of foraging habitat, resulting in a system that is more similar to the reference reach on the Yellowstone River. The availability of food-producing habitat is low in all reaches at flows less than bankfull, but the two reaches in the Lower Missouri River – channelized and restored – display a threshold-like response as flows overtop channel banks, reflecting the persistent effects of channelization on hydraulics in the main channel. These high lateral gradients result in punctuated ecological events corresponding to flows in excess of bankfull discharge. This threshold effect in the restored reach remains distinct from that of the least-altered reference reach, where hydraulic changes are less abrupt and overbank flows more gradually inundate the adjacent floodplain. The habitat curves observed in the reference reach on the Yellowstone River may not be attainable within the channelized system on the Missouri River, but the documented hydraulic patterns can be used to inform ongoing channel modifications. Although scaling to bankfull dimensions and discharges provides a basis for comparing the three reaches, implementation of the reference reach concept was complicated by differences in flow-frequency distributions among sites. In particular, habitat availability in the least-altered Yellowstone River reach is affected by increased frequency of low-flow events (less than 0.5 times bankfull flow) and moderately high-flow events (greater than 1.5 times bankfull flow) compared to downstream reaches on the Lower Missouri River.

Lower Missouri River↗
USGS2014

Utilizing dimensional analysis with observed data to determine the significance of hydrodynamic solutions in coastal hydrology

In this paper, the authors present an analysis of the magnitude of the temporal and spatial acceleration (inertial) terms in the surface-water flow equations and determine the conditions under which these inertial terms have sufficient magnitude to be required in the computations. Data from two South Florida field sites are examined and the relative magnitudes of temporal acceleration, spatial acceleration, and the gravity and friction terms are compared. Parameters are derived by using dimensionless numbers and applied to quantify the significance of the hydrodynamic effects. The time series of the ratio of the inertial and gravity terms from field sites are presented and compared with both a simplified indicator parameter and a more complex parameter called the Hydrodynamic Significance Number (HSN). Two test-case models were developed by using the SWIFT2D hydrodynamic simulator to examine flow behavior with and without the inertial terms and compute the HSN. The first model represented one of the previously-mentioned field sites during gate operations of a structure-managed coastal canal. The second model was a synthetic test case illustrating the drainage of water down a sloped surface from an initial stage while under constant flow. The analyses indicate that the times of substantial hydrodynamic effects are sporadic but significant. The simplified indicator parameter correlates much better with the hydrodynamic effect magnitude for a constant width channel such as Miami Canal than at the non-uniform North River. Higher HSN values indicate flow situations where the inertial terms are large and need to be taken into account.

Florida↗
USGS2004

Simulation of ground-water flow, contributing recharge areas, and ground-water travel time in the Missouri River alluvial aquifer near Ft. Leavenworth, Kansas

The Missouri River alluvial aquifer near Ft. Leavenworth, Kansas, supplies all or part of the drinking water for Ft. Leavenworth; Leavenworth, Kansas; Weston, Missouri; and cooling water for the Kansas City Power and Light, Iatan Power Plant. Ground water at three sites within the alluvial aquifer near the Ft. Leavenworth well field is contaminated with trace metals and organic compounds and concerns have been raised about the potential contamination of drinking-water supplies. In 2001, the U.S. Geological Survey, U.S. Army Corps of Engineers, and the U.S. Army began a study of ground-water flow in the Missouri River alluvial aquifer near Ft. Leavenworth. Hydrogeologic data from 173 locations in the study area was used to construct a ground-water flow model (MODFLOW-2000) and particle-tracking program (MODPATH) to determine the direction and travel time of ground-water flow and contributing recharge areas for water-supply well fields within the alluvial aquifer. The modeled area is 28.6 kilometers by 32.6 kilometers and contains the entire study area. The model uses a uniform grid size of 100 meters by 100 meters and contains 372,944 cells in 4 layers, 286 columns, and 326 rows. The model represents the alluvial aquifer using four layers of variable thickness with no intervening confining layers. The model was calibrated to both quasi-steady-state and transient hydraulic head data collected during the study and ground-water flow was simulated for five well-pumping/river-stage scenarios. The model accuracy was calculated using the root mean square error between actual measurements of hydraulic head and model generated hydraulic head at the end of each model run. The accepted error for the model calibrations were below the maximum measurement errors. The error for the quasi-steady-state calibration was 0.82 meter; for the transient calibration it was 0.33 meter. The shape, size, and ground-water travel time within the contributing recharge area for each well or well field is affected by changes in river stage and pumping rates and by the location of the well or well field with respect to the major rivers, alluvial valley walls, and other pumping wells. The shapes of the simulated contributing recharge areas for the well fields in the study area are elongated in the upstream direction for all well-pumping/river-stage scenarios. The capture of ground water by the pumping wells as it moved downgradient toward the Missouri River caused the long up-valley extent of the contributing recharge areas. Recharge to the Iatan and Weston well fields primarily is from precipitation and surface runoff from the surrounding uplands because the contributing recharge area does not intersect the Missouri River for any well-pumping/river-stage scenarios. Recharge to the Leavenworth and Ft. Leavenworth well fields is from precipitation, surface runoff from the surrounding uplands, and the Missouri River because the contributing recharge area intersects these boundaries for all well-pumping/river-stage scenarios. Particle tracking analysis indicated ground water from the three contaminated sites was captured by the Ft. Leavenworth well field for all well-pumping/river-stage scenarios. Ground-water travel times to the Ft. Leavenworth well field for average well-pumping/river-stage scenario ranged from about 33 years for the closest contamination site to about 71 years for the farthest contamination site. Ground-water flow was induced below the Missouri River by the Ft. Leavenworth and Leavenworth well fields for all well-pumping/river-stage scenarios.

Scientific Investigations Report↗
USGS2018

Downstream fish passage guide walls: A hydraulic scale model analysis

Partial-depth guide walls are used to improve passage efficiency and reduce the delay of out-migrating anadromous fish species by guiding fish to a bypass route (i.e. weir, pipe, sluice gate) that circumvents the turbine intakes, where survival is usually lower. Evaluation and monitoring studies, however, indicate a high propensity for some fish to pass underneath, rather than along, the guide walls, compromising their effectiveness. In the present study we evaluated a range of guide wall structures to identify where/if the flow field shifts from sweeping (i.e. flow direction primarily along the wall and towards the bypass) to downward-dominant. Many migratory fish species, particularly juveniles, are known to drift with the flow and/or exhibit rheotactic behaviour during their migration. When these behaviours are present, fish follow the path of the flow field. Hence, maintaining a strong sweeping velocity in relation to the downward velocity along a guide wall is essential to successful fish guidance. Nine experiments were conducted to measure the three-dimensional velocity components upstream of a scale model guide wall set at a wide range of depths and angles to flow. Results demonstrated how each guide wall configuration affected the three-dimensional velocity components, and hence the downward and sweeping velocity, along the full length of the guide wall. In general, the velocities produced in the scale model were sweeping dominant near the water surface and either downward dominant or close to the transitional depth near the bottom of the guide wall. The primary exception to this shift from sweeping do downward flow was for the minimum guide wall angle tested in this study (15°). At 15° the flow pattern was fully sweeping dominant for every cross-section, indicating that a guide wall with a relatively small angle may be more likely to produce conditions favorable to efficient guidance. A critical next step is to evaluate the behaviour of migratory fish as they approach and swim along a guide wall in a controlled laboratory environment.

Ecological Engineering↗
USGS2017

Guidance documents: Continued support to improve operations of fish hatcheries and field sites to reduce the impact or prevent establishment of New Zealand Mudsnails and other invasive mollusks

This project tested and revised a risk assessment/management tool authored by Moffitt and Stockton designed to provide hatchery biologists and others a structure to measure risk and provide tools to control, prevent or eliminate invasive New Zealand mudsnails (NZMS) and other invasive mollusks in fish hatcheries and hatchery operations. The document has two parts: the risk assessment tool, and an appendix that summarizes options for control or management. The framework of the guidance document for risk assessment/hatchery tool combines approaches used by the Hazard Analysis and Critical Control Points (HACCP) process with those developed by the Commission for Environmental Cooperation (CEC), of Canada, Mexico, and the United States, in the Tri-National Risk Assessment Guidelines for Aquatic Alien Invasive Species. The framework approach for this attached first document assesses risk potential with two activities: probability of infestation and consequences of infestation. Each activity is treated equally to determine the risk potential. These two activities are divided into seven basic elements that utilize scientific, technical, and other relevant information in the process of the risk assessment. To determine the probability of infestation four steps are used that have scores reported or determined and averaged. This assessment follows a familiar HACCP process to assess pathways of entry, entry potential, colonization potential, spread potential. The economic, environmental and social consequences are considered as economic impact, environmental impact, and social and cultural influences. To test this document, the Principal Investigator worked to identify interested hatchery managers through contacts at regional aquaculture meetings, fish health meetings, and through the network of invasive species managers and scientists participating in the Western Regional Panel on Aquatic Nuisance Species and the 100th Meridian Initiative's Columbia River Basin Team, and the Western New Zealand Mudsnail Conference in Seattle. Targeted hatchery workshops were conducted with staff at Dworshak National Fish Hatchery Complex (ID), Similkameen Pond, Oroville WA, and Ringold Springs State Hatchery (WA). As a result of communications with hatchery staff, invasive species managers, and on site assessments of hatchery facilities, the document was modified and enhanced. Additional resources were added to keep it up to date. The result is a more simplified tool that can lead hatchery or management personnel through the process of risk assessment and provide an introduction to the risk management and communication process. In addition to the typical HACCP processes, this tool adds steps to rate and consider uncertainty and the weight of evidence regarding options and monitoring results . Uncertainty of outcome exists in most tools that can be used to control or prevent NZMS or other invasive mollusks from infesting an area. In additional this document emphasizes that specific control tools and plans must be tailored to each specific setting to consider the economic, environmental and social influences. From the testing and evaluation process, there was a strong recognition that a number of control and prevention tools previously suggested and reported in the literature from laboratory and small scale trials may not be compatible with regional and national regulations, economic constraints, social or cultural constraints, engineering or water chemistry characteristics of each facility. The options for control are summarized in the second document, Review of Control Measures for Hatcheries Infested with NZMS (Appendix A) that provides sources for additional resources and specific tools, and guidance regarding the feasibility and success of each approach. This tool also emphasizes that management plans need to be adaptive and incorporate oversight from professionals familiar with measuring risks of fish diseases, and treatments (e.g. the fish health practitioners and water quality and effluent management teams). Finally, with such a team, the adaptive management approach must be ongoing, and become a regular component of hatchery operations. Although it was the intent that this two part document would be included as part of the revised National Management and Control Plan for the NZMS proposed by the U.S. Fish and Wildlife Service (USFWS) and others, it is provided as a stand-alone document.

Cooperator Science Series↗
USGS2015

Shift in Global Tantalum Mine Production, 2000–2014

Introduction Tantalum has a unique set of properties that make it useful in a number of diverse applications. The ability of the metal to store and release electrical energy makes it ideally suited for use in certain types of capacitors that are widely used in modern electronics. Approximately 60 percent of global tantalum consumption is in the electronics industry. The ductility and corrosion resistance of the metal lends itself to application in the chemical processing industry, and its high melting point and high strength retention at elevated temperatures make it an important component of super alloys used in aircraft engines. As a major industrialized nation, the United States is a leading consumer of tantalum and tantalum-containing products. Domestic deposits typically are of low grade, and no tantalum has been recovered from mining activities in the United States since 1959. Consequently, the United States is nearly completely reliant on imports to meet its domestic consumption of tantalum for economic and national security needs. The recovery of tantalum from mine production is economically viable in only a few countries. Although developed countries dominated tantalum mine production in the early 2000s, production today is dominated by countries in the Great Lakes Region of Africa. There is concern that the sales of minerals, including columbite-tantalite or “coltan,” a mineral from which tantalum is derived, have helped finance rebel groups accused of violating human rights as part of the continuing armed conflict in the Democratic Republic of the Congo (DRC) and neighboring countries. These accusations have prompted the passage of legislation in the United States to curb the procurement of these mineral commodities, referred to as “conflict minerals,” from the DRC. Specifically, section 1502 of the 2010 Dodd-Frank Wall Street Reform and Consumer Protection Act (Public Law 111–203, 124 Stat. 2213–2218) requires companies that source tantalum, tin, tungsten, and gold (3TG) to perform due diligence on their supply chains to determine if the materials they use originate from the DRC or adjoining countries (defined as sharing a border with the DRC). The DRC, Rwanda, and surrounding countries are not globally significant sources of tin, tungsten, or gold, accounting for only about 2 percent of the mined world supply for each of these elements. The region has, however, evolved to become the world’s largest producer of mined tantalum. A further complication of the production of tantalum stems from the opacity of the tantalum market. Unlike most base and precious metals, tantalum concentrates are not publicly traded through commodities exchanges but are bought and sold through networks of dealers and on contract between producers and consumers, some of whom may not provide accurate statistical data concerning the amounts, origins, and destination of the concentrates. Some price data can be found in trade journals or in other publications; however, there are no recognized official set exchange prices for either concentrate or tantalum metal. Because price is determined by negotiation between buyer and seller, published prices for concentrate are probably not representative of global prices paid for concentrate. The development of a mine-to-market supply-chain analysis is complicated and difficult because many of the industry participants that produce, trade, and consume tantalum do not publish statistical information, contracts are long term between miners and buyers, and much of the industry is vertically integrated. As a result of these and other considerations, tantalum is considered by many to be a “critical” commodity. This fact sheet identifies and addresses the major geographic shifts in the source of mine production of tantalum which have occurred over the past 15 years, some of the factors that drove this shift, and some of the related consequences. One of the activities of the U.S. Geological Survey National Minerals Information Center (USGS-NMIC) is to analyze global supply chains and characterize major components of mineral and material flows from ore extraction through processing to first tier products. These analyses support the core mission of the USGS-NMIC as the Federal entity responsible for the collection, analysis, and dissemination of objective, unbiased, factual information on minerals essential to the U.S. economy and national security.

Fact Sheet↗
USGS2023

Climate change and the global redistribution of biodiversity: Substantial variation in empirical support for expected range shifts

Background Among the most widely predicted climate change-related impacts to biodiversity are geographic range shifts, whereby species shift their spatial distribution to track their climate niches. A series of commonly articulated hypotheses have emerged in the scientific literature suggesting species are expected to shift their distributions to higher latitudes, greater elevations, and deeper depths in response to rising temperatures associated with climate change. Yet, many species are not demonstrating range shifts consistent with these expectations. Here, we evaluate the impact of anthropogenic climate change (specifically, changes in temperature and precipitation) on species’ ranges, and assess whether expected range shifts are supported by the body of empirical evidence. Methods We conducted a Systematic Review, searching online databases and search engines in English. Studies were screened in a two-stage process (title/abstract review, followed by full-text review) to evaluate whether they met a list of eligibility criteria. Data coding, extraction, and study validity assessment was completed by a team of trained reviewers and each entry was validated by at least one secondary reviewer. We used logistic regression models to assess whether the direction of shift supported common range-shift expectations (i.e., shifts to higher latitudes and elevations, and deeper depths). We also estimated the magnitude of shifts for the subset of available range-shift data expressed in distance per time (i.e., km/decade). We accounted for methodological attributes at the study level as potential sources of variation. This allowed us to answer two questions: (1) are most species shifting in the direction we expect (i.e., each observation is assessed as support/fail to support our expectation); and (2) what is the average speed of range shifts? Review findings We found that less than half of all range-shift observations (46.60%) documented shifts towards higher latitudes, higher elevations, and greater marine depths, demonstrating significant variation in the empirical evidence for general range shift expectations. For the subset of studies looking at range shift rates, we found that species demonstrated significant average shifts towards higher latitudes (average = 11.8 km/dec) and higher elevations (average = 9 m/dec), although we failed to find significant evidence for shifts to greater marine depths. We found that methodological factors in individual range-shift studies had a significant impact on the reported direction and magnitude of shifts. Finally, we identified important variation across dimensions of range shifts (e.g., greater support for latitude and elevation shifts than depth), parameters (e.g., leading edge shifts faster than trailing edge for latitude), and taxonomic groups (e.g., faster latitudinal shifts for insects than plants). Conclusions Despite growing evidence that species are shifting their ranges in response to climate change, substantial variation exists in the extent to which definitively empirical observations confirm these expectations. Even though on average, rates of shift show significant movement to higher elevations and latitudes for many taxa, most species are not shifting in expected directions. Variation across dimensions and parameters of range shifts, as well as differences across taxonomic groups and variation driven by methodological factors, should be considered when assessing overall confidence in range-shift hypotheses. In order for managers to effectively plan for species redistribution, we need to better account for and predict which species will shift and by how much. The dataset produced for this analysis can be used for future research to explore additional hypotheses to better understand species range shifts.

Journal of Environmental Evidence↗