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At least 325 records · Page 18Linked to original sources

Hydrologic and water-quality conditions in the lower Apalachicola-Chattahoochee-Flint and parts of the Aucilla-Suwannee-Ochlockonee River basins in Georgia and adjacent parts of Florida and Alabama during drought conditions, July 2011

As part of the U.S. Department of the Interior sustainable water strategy, WaterSMART, the U.S. Geological Survey documented hydrologic and water-quality conditions in the lower Apalachicola-Chattahoochee-Flint and western and central Aucilla-Suwannee-Ochlockonee River basins in Alabama, Florida, and Georgia during low-flow conditions in July 2011. Moderate-drought conditions prevailed in this area during early 2011 and worsened to exceptional by June, with cumulative rainfall departures from the 1981-2010 climate normals registering deficits ranging from 17 to 27 inches. As a result, groundwater levels and stream discharges measured below median daily levels throughout most of 2011. Water-quality field properties including temperature, dissolved oxygen, specific conductance, and pH were measured at selected surface-water sites. Record-low groundwater levels measured in 12 of 43 surficial aquifer wells and 128 of 312 Upper Floridan aquifer wells during July 2011 underscored the severity of drought conditions in the study area. Most wells recorded groundwater levels below the median daily statistic, and 7 surficial aquifer wells were dry. Groundwater-level measurements taken in July 2011 were used to determine the potentiometric surface of the Upper Floridan aquifer. Groundwater generally flows to the south and toward streams except in reaches where streams discharge to the aquifer. The degree of connection between the Upper Floridan aquifer and streams decreases east of the Flint River where thick overburden hydraulically separates the aquifer from stream interaction. Hydraulic separation of the Upper Floridan aquifer from streams located east of the Flint River is shown by stream-stage altitudes that differ from groundwater levels measured in close proximity to streams. Most streams located in the study area during 2011 exhibited below normal flows (streamflows less than the 25th percentile), substantiating the severity of drought conditions that year. Streamflow and springflow measured at 202 sites along 2,122 stream miles during July 20-24, 2011, identified about 286 miles of losing streams, about 1,230 miles of gaining streams, and about 606 miles of streams with no flow. Water-quality field properties measured at 123 stream and 5 spring sites during July 2011 yielded water temperatures ranging from 20.6 to 31.6 degrees Celsius, dissolved oxygen ranging from 0.47 to 9.98 milligrams per liter, specific conductance ranging from 13 to 834 microsiemens per centimeter at 25 degrees Celsius, and pH ranging from 3.6 to 8.03.

Alabama, Florida, Georgia↗

The Connecticut Streamflow and Sustainable Water Use Estimator—A decision-support tool to estimate water availability at ungaged stream locations in Connecticut

Freshwater streams in Connecticut are subject to many competing demands, including public water supply; agricultural, commercial, and industrial water use; and ecosystem and habitat needs. In recent years, drought has further stressed Connecticut’s water resources. To sustainably allocate and manage water resources among these competing uses, Federal, State, and local water-resource managers require data and modeling tools to estimate the water availability at a variety of temporal and spatial scales for planning purposes. The Connecticut Streamflow and Sustainable Water Use Estimator (CT SSWUE), developed by the U.S. Geological Survey in cooperation with the Connecticut Department of Energy and Environmental Protection, is a decision-support tool for estimating daily unaltered streamflow and sustainable water use at ungaged sites in Connecticut. The CT SSWUE estimates unaltered daily mean streamflow and water-use-adjusted streamflow for the period from October 1, 1960, to September 30, 2015, and the monthly sustainable net withdrawal at ungaged sites in Connecticut. Unaltered streamflow is the estimated daily mean streamflow in a drainage basin in the absence of any water withdrawals or wastewater discharges and with minimal human development. Sustainable net withdrawal is the maximum net withdrawal (withdrawal minus wastewater discharges) that can be drawn from a basin without critically depleting the water available through natural streamflow patterns. Sustainable net withdrawal is defined for this study as the difference between the unaltered daily mean streamflow and a user-defined target minimum streamflow. Weighted least squares and Tobit regression techniques were used to develop equations for estimating streamflow at ungaged sites at 19 streamflow quantiles with exceedance probabilities ranging from 0.005 to 99.995 percent. Regressions were based on streamflow quantiles and basin characteristics from 36 reference streamgages in and around Connecticut. Four basin characteristics—drainage area, mean of the soil permeability, mean of the average annual precipitation, and ratio of the length of streams that overlay sand and gravel deposits to the total length of streams in the basin—are used as explanatory variables in the equations. At an ungaged site, interpolation between the streamflow quantiles estimated from the regression equations produces a continuous flow-duration curve. A time series of daily mean streamflow at an ungaged site is then estimated by assuming that for each day, the streamflow quantile occurs on the same date at both a reference streamgage and the ungaged site. In a remove-one cross validation, estimated unaltered daily mean streamflow agreed well with observed values at reference streamgages, with a few exceptions. Nash Sutcliffe efficiency ranged from −0.43 to 0.97 with a median value of 0.88. The normalized root-mean-square error ranged from 16.6 to 120.4 percent with a median value of 34.5 percent. An empirical method for estimating 95-percent prediction intervals for unaltered daily and monthly mean streamflow was developed and tested by using the cross-validation data. Prediction intervals for unaltered daily mean streamflow at the cross-validation reference streamgages performed well in most cases. Gaged streamflow values from the cross-validation data fell within the prediction intervals a median 96.6 percent of the time for daily mean time series and 93.9 percent of the time for monthly mean time series. The CT SSWUE computes water-use-adjusted streamflow using spatially referenced water-use information provided by the Connecticut Department of Energy and Environmental Protection. Available water-use information included permitted and registered water withdrawals and permitted wastewater discharges during 1998 to 2015 for the Thames River Basin and central coastal drainage basins. Water-use information was incorporated into the U.S. Geological Survey StreamStats web application for Connecticut and can be used for computing water-use-adjusted streamflow and sustainable net withdrawal at selected points of interest. Altered daily streamflow is computed by applying average daily withdrawals and wastewater discharges to the water balance equation. Average daily surface water withdrawals and wastewater discharges are applied directly to the daily water balance equation. Time-lagged alterations on streamflow from groundwater withdrawals or wastewater discharges are estimated by using a response-coefficient method developed from results of previously published, calibrated groundwater models.

Connecticut↗

Characterization of peak streamflows and flooding in select areas of Pennsylvania from the remnants of Hurricane Ida, September 1–2, 2021

Pennsylvania experienced heavy rainfall on September 1 and 2, 2021, as the remnants of Hurricane Ida swept over parts of the State. Much of eastern and south-central Pennsylvania received 5 to 10 inches of rain, and most of the rainfall fell within little more than 6 hours. Southeastern Pennsylvania experienced widespread, substantial flooding, and the city of Philadelphia and surrounding areas were particularly affected by the flooding. U.S. Geological Survey (USGS) streamgages registered peak streamflows of record at 19 locations, and 52 locations experienced top 5 peak streamflows for the period of record and an annual exceedance probability estimate of at least 10 percent. During this September 2021 flood event, USGS personnel made over 60 streamflow measurements at streamgages in Pennsylvania using direct and indirect methods. Many of those streamflow measurements were made to verify or improve the accuracy, extent, or development of new stage-streamflow relations at streamgages operated by the USGS. After the floodwaters receded, USGS personnel identified and documented a total of 338 high-water marks in Pennsylvania, noting such things as their general description, location, height above land surface, and quality. Many of these high-water marks were used to create five flood-documentation maps for selected communities in southeastern Pennsylvania that experienced substantial flooding because of the remnants of Hurricane Ida. Digital datasets of the inundated areas, mapped boundaries, and water depth are available (Stuckey and Conlon, 2023).

Pennsylvania↗

Accuracy assessment of three-dimensional point cloud data collected with a scanning total station on Shinnecock Nation Tribal lands in Suffolk County, New York

A combined point cloud of about 85.6 million points was collected during 27 scans of a section of the western shoreline along the Shinnecock Peninsula of Suffolk County, New York, to document baseline geospatial conditions during July and October 2022 using a scanning total station. The three-dimensional accuracy of the combined point cloud is assessed to identify potential systematic error sources associated with the surveying equipment and the novel methodology used to collect and field-register (data are oriented and aligned in real time) point cloud data. The accuracy of the combined point cloud was assessed in terms of relative and absolute reference frames. Relative accuracy provides a measure of error within the local coordinate system and is determined by combining the uncertainty associated with the position of the scan station (the point being occupied by the scanning total station during the scan), the uncertainty associated with the position of the network control points, and the uncertainty associated with the laser of the scanning total station. Assessment of the absolute accuracy includes these three potential error sources combined with the uncertainty associated with the geodetic coordinates to which the local control network is referenced. The combined overall relative horizontal and vertical accuracy of the point cloud is 0.0156 and 0.0241 meter, respectively, at the 95 percent confidence level. The combined overall absolute horizontal and vertical accuracy of the point cloud is 0.0598 and 0.0733 meter, respectively, at the 95 percent confidence level.

New York↗

Decadal trends in the quality of groundwater used for public drinking-water supply in California, 2004–23, California Groundwater Ambient Monitoring and Assessment Program, Priority Basin Project

This study provides a comprehensive assessment of decadal changes in the quality of groundwater used for public drinking-water supply at 444 monitoring sites across California during 2004–23. We assessed decadal step trends in groundwater quality for 145 water-quality constituents and geochemical indicators statewide and across geographic and land-use based network groups. We evaluated the statistical significance of directional changes (predominant increase or decrease of constituent concentrations) and the magnitude of those changes across all network groups. Uranium showed the most widespread directional and high-magnitude increases of all constituents with regulatory benchmarks statewide, particularly in the agriculture-dominated Central Valley as well as urban-and desert-dominated regions of Southern California. Fluoride and perchlorate showed the most widespread directional and high-magnitude decreases of all constituents with regulatory benchmarks statewide, which were also most pronounced in Southern California. Although arsenic and nitrate did not often register significant directional changes across network groups, they showed widespread, high-magnitude changes in both directions (increase and decrease) at levels often exceeding 10 percent of respective regulatory benchmarks statewide. Triazine herbicides (atrazine and simazine) and the gasoline oxygenate methyl tert -butyl ether showed significant directional decreases statewide, but not at levels considered to be of high magnitude compared to respective regulatory benchmarks. We observed significant directional and high-magnitude increases of total dissolved solids statewide, which were most pronounced in agricultural areas. Analysis of explanatory geochemical indicators indicated that prevalent statewide increases of alkalinity and calcium were the predominant components of the observed statewide increases in total dissolved solids by mass. Widespread increases in groundwater alkalinity and calcium across agricultural and urban areas may be related, in part, to warm-season irrigation and other anthropogenic factors that have shifted soil weathering dynamics over the long term. Increasing alkalinity concentrations were related to increasing uranium concentrations, particularly in areas with aquifer materials derived from granitic rocks. Conversely, increasing calcium concentrations were related to decreasing fluoride concentrations, particularly in areas where fluoride occurred naturally at elevated concentrations. Decrease of perchlorate, triazine herbicides, and methyl tert -butyl ether are likely related to decreased anthropogenic source inputs over time and natural attenuation in aquifers.

California↗

Pesticides in the Lower Clackamas River Basin, Oregon, 2000-01

In 2000-01, the U. S. Geological Survey sampled the Clackamas River and its major lower-basin tributaries during storm runoff conditions for 86 dissolved pesticides and selected breakdown products. Twenty-seven compounds, including 18 herbicides, 7 insecticides, and 2 pesticide breakdown products, were detected in 18 stream samples. The most commonly detected pesticides, in decreasing frequency, included atrazine, simazine, diazinon, metolachlor, and diuron, which variously occurred in 46-92% of samples collected from the tributaries. Of these, atrazine, simazine, and metolachlor, plus six other compounds, also were detected in the main-stem Clackamas River. Pesticides were detected more frequently and at higher concentrations in the four lowermost tributaries (Deep, Richardson, Rock, and Sieben Creeks). In these streams, 12 to 18 pesticides were detected per stream in samples collected during spring and fall. Pesticides always occurred with at least one other pesticide, and about half of the samples, including one sample from the Clackamas River in October 2000, contained six or more pesticides. Nine pesticides, including the insecticide diazinon and the herbicides 2,4-D, atrazine, dichlobenil, diuron, imazaquin, metolachlor, simazine, and trifluralin, were detected in five water samples of Clackamas River water. No pesticides were detected in three samples of treated Clackamas River water used for drinking-water supply. Concentrations of six compounds--carbaryl, chlorpyrifos, diazinon, dieldrin, malathion, and the breakdown product of DDT (p,p'-DDE)--exceeded established or recommended criteria for the protection of aquatic life in some of the tributaries, sometimes for multiple pesticides in one sample. Identifying the sources of pesticides detected in the Clackamas River Basin is difficult because of the diverse land use in the basin and the multiple-use nature of many of the pesticides detected. Of the 25 parent compounds detected, 22 have agricultural uses, 23 have urban uses, 16 are applied to golf courses, 11 are applied along roads and other right-of-ways, and 5 have or had forestry applications. Because only a small fraction of the thousands of pesticide products registered for use in Oregon were tested for in this study, future monitoring could benefit from knowledge of what pesticides are applied so that potential problems can be identified and managed.

Water-Resources Investigations Report↗

Levels at streamflow gaging stations--A CD-ROM based training class

Streamgages record the elevation of the water surface above some reference surface, or datum. This datum is assumed to remain unchanged throughout the life of the gage. However, the elevation of gages and their supporting structures often change over time as a result of earthmovement, floods, ice, and debris. The surveying practice of leveling is used to establish datum for new gage structures and to check for vertical movement of those structures over time. Vertical changes in gage structures can affect stage-discharge relations and, thus, could result in incorrect discharge determinations. Datum checks are used to correct stage-discharge relations and allow the USGS to document gage datum throughout the life of a gage. This training presentation describes methods currently used by the U.S. Geological Survey to run levels at gaging stations. The presentation is narrated, but you control the pace of the presentation. If the computer you are using can view 'MPEG' videos you will be able to take advantage of videos found within the presentation. A test, found at the end of the presentation, can be taken to assess how well you understood the training material. The class is registered as class SW1307 with the National Training Center of the U.S. Geologcial Survey. The presentation was developed using Macromedia Director 8.5(1) and is contained in the file 'WRI-4002.exe', which should auto-launch after the CD-ROM is inserted in the PC. The program only runs on a windows-based personal computer (PC). A sound card and speakers are necessary to take advantage of the narration that accompanies the presentation. Text of narrations is provided, if you are unable to listen to the narrations. Instructions for installing and running the presentation are included in the file ' Intro.html'. The file 'Intro.html' is on the CD-ROM containing the presentation and is available from the presentation's help menu.

Water-Resources Investigations Report↗

Application of digital mapping technology to the display of hydrologic information; a proof-of-concept test in the Fox-Wolf River Basin, Wisconsin

The Fox-Wolf River basin in east-central Wisconsin was selected to test concepts for a water-resources information system using digital mapping technology. This basin of 16,800 sq km is typical of many areas in the country. Fifty digital data sets were included in the Fox-Wolf information system. Many data sets were digitized from 1:500,000 scale maps and overlays. Some thematic data were acquired from WATSTORE and other digital data files. All data were geometrically transformed into a Lambert Conformal Conic map projection and converted to a raster format with a 1-km resolution. The result of this preliminary processing was a group of spatially registered, digital data sets in map form. Parameter evaluation, areal stratification, data merging, and data integration were used to achieve the processing objectives and to obtain analysis results for the Fox-Wolf basin. Parameter evaluation includes the visual interpretation of single data sets and digital processing to obtain new derived data sets. In the areal stratification stage, masks were used to extract from one data set all features that are within a selected area on another data set. Most processing results were obtained by data merging. Merging is the combination of two or more data sets into a composite product, in which the contribution of each original data set is apparent and can be extracted from the composite. One processing result was also obtained by data integration. Integration is the combination of two or more data sets into a single new product, from which the original data cannot be separated or calculated. (USGS)

Water-Resources Investigations Report↗

Using a geographic information system and scanning technology to create high-resolution land-use data sets

A geographic information system (GIS) procedure was developed to compile low-altitude aerial photography, digitized data, and land-use data from U.S. Department of Agriculture Consolidated Farm Service Agency (CFSA) offices into a high-resolution (approximately 5 meters) land-use GIS data set. The aerial photography consisted of 35-mm slides which were scanned into tagged information file format (TIFF) images. These TIFF images were then imported into the GIS where they were registered into a geographically referenced coordinate system. Boundaries between land use were delineated from these GIS data sets using on-screen digitizing techniques. Crop types were determined using information obtained from the U.S. Department of Agriculture CFSA offices. Crop information not supplied by the CFSA was attributed by manual classification procedures. Automated methods to provide delineation of the field boundaries and land-use classification were investigated. It was determined that using these data sources, automated methods were less efficient and accurate than manual methods of delineating field boundaries and classifying land use.

Water-Resources Investigations Report↗

Geohydrology of the North Park area, Jackson County, Colorado

Increasing population in rural and suburban areas of Colorado is causing greater reliance on ground water as a source of domestic supply. In the primarily rural area of Jackson County, for example, the number of registered water wells increased from about 100 in 1972 to about 500 in 1995. Most of the new wells were drilled after 1988 and supply water to ranches and summer homes. In Jackson County, ground water is pumped from a series of shallow alluvial aquifers along principal stream valleys and from deeper, more extensive, bedrock aquifers. In much of the area, the alluvial aquifers are thin and can be dewatered by moderate water- level declines. Knowledge of the nature and extent of the alluvial and bedrock aquifers, the sources of recharge and discharge, and the effects of ground- water withdrawal on water levels in the aquifers is vital if management of the area's water resources is to ensure continued availability of a dependable water supply.

Colorado↗

Wet atmospheric deposition of pesticides in Minnesota, 1989-94

All of the rain samples during the growing season had detectable quantities of at least one pesticide, but most of the pesticides were only infrequently observed. The most frequently detected compounds were the herbicides alachlor, atrazine, cyanazine, and metolachlor, and in 1994, its first year of registration, acetochlor. Peak concentrations of most herbicides in rainfall occurred shortly after their application periods in the spring. Peak concentrations of most of the insecticides occurred later in the summer. The majority of the wet depositional flux of pesticides occurred between early May and October. The annual wet depositional flux of pesticides is 5 orders of magnitude less than is the "annual flux" normally applied on an agricultural field, although some of the pesticides in rain are deposited in areas far removed from agricultural fields. The annual variability in pesticide deposition can be explained by year-to-year differences in climate and pesticide use patterns. The one sampling site (Lamberton) that was in an area dominated by row crop agriculture showed a significantly greater annual flux than the other four sampling sites that were in areas of either urbanization or less intensive agricultural. Regional deposition, away from a local source, can be inferred from these four sites because they have annual pesticide fluxes that are very similar for any given year. The observation of agricultural pesticides (not registered for home and garden use) in rain and storm runoff in the urban area indicates their transport from areas of agricultural use. Urban areas may be the best locations for assessing changes in regional use and deposition of agricultural pesticides. The pesticide fluxes in the streams out of the small three watersheds was compared to the pesticide flux into the watersheds in rain. The data indicate that flux into the watersheds from the rain is generally much greater than the flux from the watersheds in the streams. Therefore, a large fraction of the pesticides deposited in rain is retained within the watersheds. For the urban area, this is on the order of 98 percent for the four most commonly observed herbicides in rain and runoff.

Minnesota↗

Distribution of major herbicides in ground water of the United States

Information on the concentrations and spatial distributions of pesticides and their transformation products, or degradates, in the hydrologic system is essential for managing pesticide use in both agricultural and nonagricultural settings to protect water resources. This report examines the occurrence of selected herbicides and their degradates in ground water, primarily on the basis of results from two large-scale, multistate investigations by the U.S. Geological Survey&mdash;the National Water-Quality Assessment (NAWQA) Program and the Midwest Pesticide Study (MWPS). The NAWQA pesticide data were derived from 2,227 sites (wells and springs) sampled in 20 major hydrologic basins across the United States from 1993 to 1995; the MWPS data were obtained from the sampling of 303 wells in a 12-state area of the northern midcontinent from 1991 to 1994. Data are presented for seven high-use herbicides: five of current interest to the U.S. Environmental Protection Agency for designing Pesticide Management Plans (atrazine, cyanazine, simazine, alachlor and metolachlor), a largely nonagricultural herbicide (prometon), and an agricultural herbicide first registered in 1994 for use in the United States (acetochlor). Six of the herbicides (all except acetochlor) were detected by the U.S. Geological Survey studies in shallow ground water&mdash;that is, ground water recharged within the past 10 years&mdash;in a variety of agricultural and nonagricultural settings, as well as in several aquifers that are sources of drinking-water supply. Acetochlor was not detected by the MWPS in the summer of 1994, but was detected in shallow ground water during the NAWQA Program by early 1995, and during another U.S. Geological Survey study in Iowa during the summers of 1995 and 1996. The acetochlor observations suggest that, in agreement with results from previous field studies, some pesticides may be detected in shallow ground water within 1 year following their application. In accord with the results from other largescale multistate studies of pesticides in ground water, more than 98 percent of the detections during the NAWQA and MWPS investigations were at concentrations of less than 1 microgram per liter. Consequently, water quality criteria for drinking water&mdash;that is, standards established to protect human health&mdash;were exceeded at fewer than 0.1 percent of the sites sampled by NAWQA (all of these exceedances involving atrazine alone) and at none of those sampled in 1992 by the MWPS. These criteria, however, may not accurately reflect the overall health risks associated with pesticide detections in water resources because they have been established only for a relatively small number of pesticides and they do not account for the additive or synergistic effects of mixtures, impacts on the health of aquatic ecosystems, or the effects of pesticide degradates. Among the sites sampled during the NAWQA and MWPS investigations, 19.7 and 13.8 percent, respectively, had detections of two or more of the herbicides of interest. Furthermore, for most of the herbicides for which degradates were examined, detection frequencies for major degradates were typically higher than for their respective parent compounds, particularly for the herbicides that are less persistent in aerobic soil. Frequencies of detection at or above 0.01 microgram per liter in shallow ground water beneath agricultural areas during the NAWQA study were significantly correlated with agricultural use in those areas for atrazine, cyanazine, alachlor, and metolachlor (P<0.05; Spearman rank correlations), but not for simazine (P>0.05). In urban areas, overall frequencies of detection of these five herbicides in shallow ground water were positively correlated with their total nonagricultural use nationwide (P=0.026; simple linear correlation). Multivariate statistical analysis indicated that frequencies of detection in shallow ground water beneath agricultural areas were positively correlated with half-lives for transformation in aerobic soil and agricultural use of the compounds (P&le;0.0001 for both parameters). Although frequencies of detection were not significantly correlated with their subsurface mobility (K oc ; P=0.19) or the median well depths of the sampled networks (P=0.72), the range of K oc values among the five herbicides and the range of well depths were limited.

Water-Resources Investigations Report↗

The Government Information Locator Service (GILS)

In coordination with the Information Infrastructure Task Force (IITF), the Office of Management and Budget (OMB) is promoting the establishment of an agency-based Government Information Locator Service (GILS) to help the public locate and access information throughout the Federal Government. This report presents a vision of how GILS will be implemented. Working primarily with OMB and the Locator Subgroup of the Interagency Working Group on Public Access, Eliot Christian of the US Geological Survey prepared this report under the auspices of the IITF Committee on Information Policy. This vision of GILS has also received extensive review by various Federal agencies and other interested parties, including some non-Federal organizations and by the general public through notices in both the Federal Register and the Commerce Business Daily and at a public meeting held in December, 1993. As part of the Federal role in the National Information Infrastructure, GILS will identify and describe information resources throughout the Federal government, and provide assistance in obtaining the information. It will be decentralized and will supplement other agency and commercial information dissemination mechanisms. The public will use GILS directly or through intermediaries, such as the Government Printing Office, the National Technical Information Service, the Federal depository libraries, other public libraries, and private sector information services. Direct users will have access to a GILS Core accessible on the Internet without charge. Intermediate access may include kiosks, "800 numbers", electronic mail, bulletin boards, fax, and off-line media such as floppy disks, CD-ROM, and printed works. GILS will use standard network technology and the American National Standards Institute Z39.50 standard for information search and retrieval so that information can be retrieved in a variety of ways. Direct users will eventually have access to many other Federal and non-Federal information resources, linkages to data systems, and electronic delivery of information products. Development of this report proceeded in tandem with a GILS Profile development project that produced an Implementors Agreement in the voluntary standards process. The National Institute of Standards and Technology is now establishing a Federal Information Processing Standard referencing the GILS Profile Implementors Agreement and making mandatory its application for Federal agencies establishing locators for government information. Existing law and policy, as articulated in OMB Circular A-130, the Records Disposal Act, and the Freedom of Information Act, require agencies to create and maintain an inventory of their information systems and information dissemination products. Although compliance with these requirements varies greatly, the incremental cost of making those inventories accessible through GILS is expected to be minimal. Accordingly, participation in establishing and maintaining GILS may be accomplished as a collective effort executed within existing funds and authorities. OMB will publish in 1994 a Bulletin following on Circular A-130 that will specify agency responsibilities in GILS and set implementation schedules. A process for ongoing evaluation will also be established to evaluate the degree to which GILS meets the information needs of the public.

Information Services and Use↗

Building loss in WUI disasters: Evaluating the core components of the wildland-urban interface definition

Accurate maps of the wildland–urban interface (WUI) are critical for the development of effective land management policies, conducting risk assessments, and the mitigation of wildfire risk. Most WUI maps identify areas at risk from wildfire by overlaying coarse-scale housing data with land cover or vegetation data. However, it is unclear how well the current WUI mapping methods capture the patterns of building loss. We quantified the building loss in WUI disasters, and then compared how well census-based and point-based WUI maps captured the building loss. We examined the building loss in both WUI and non-WUI land-use types, and in relation to the core components of the United States Federal Register WUI definition: housing density, vegetation cover, and proximity to large patches of wildland vegetation. We used building location data from 70 large fires in the conterminous United States, which cumulatively destroyed 54,000 buildings from 2000 through to 2018. We found that: (1) 86% and 97% of the building loss occurred in areas designated as WUI using the census-based and point-based methods, respectively; (2) 95% and 100% of all of the losses occurred within 100 m and 850 m of wildland vegetation, respectively; and (3) WUI components were the most predictive of building loss when measured at fine scales.

Fire↗

A land product characterization system for comparative analysis of satellite data and products

A Land Product Characterization System (LPCS) has been developed to provide land data and products to the community of individuals interested in validating space-based land products by comparing them with similar products available from other sensors or surface-based observations. The LPCS facilitates the application of global multi-satellite and in situ data for characterization and validation of higher-level, satellite-derived, land surface products (e.g., surface reflectance, normalized difference vegetation index, and land surface temperature). The LPCS includes data search, inventory, access, and analysis functions that will permit data to be easily identified, retrieved, co-registered, and compared statistically through a single interface. The system currently includes data and products available from Landsat 4 through 8, Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua, Suomi National Polar-Orbiting Partnership (S-NPP)/Joint Polar Satellite System (JPSS) Visible Infrared Imaging Radiometer Suite (VIIRS), and simulated data for the Geostationary Operational Environmental Satellite (GOES)-16 Advanced Baseline Imager (ABI). In addition to the future inclusion of in situ data, higher-level land products from the European Space Agency (ESA) Sentinel-2 and -3 series of satellites, and other high and medium resolution spatial sensors, will be included as available. When fully implemented, any of the sensor data or products included in the LPCS would be available for comparative analysis.

Remote Sensing↗

Accurate maps of reef-scale bathymetry with synchronized underwater cameras and GNSS

We investigate the utility of towed underwater camera systems with tightly coupled Global Navigation Satellite System (GNSS) positions to provide reef-scale bathymetric models with millimeter to centimeter resolutions and accuracies with Structure-from-Motion (SfM) photogrammetry. Successful development of these techniques would allow for detailed assessments of benthic conditions, including the accretion and erosion of reefs and adjacent sediment deposits, without the need for ground control points. We use a multi-camera system towed by a small vessel to map over 70,000 m 2 of complex shallow (2–8 m water depth) bedrock reef, boulder fields, and fine (sand and gravel) sediments of Lake Tahoe, California. We find that multiple synchronized cameras increase overall mapping coverage and allow for wider survey line spacing. The accuracy of the techniques was sub-millimeter for local length measurements less than a meter, and the bathymetric reproducibility was found to scale with the accuracy of GNSS (3–5 cm), although this could be improved to sub-centimeter with the inclusion of one or more co-registered, but unsurveyed, control points. For future applications, we provide guidance on conducting field operations, correcting underwater image color, and optimizing the SfM workflows. We conclude that a GNSS-coupled underwater camera array is a promising technique to map shallow reefs at high accuracy and resolution without ground control.

California↗

Safety of the molluscicide Zequanox (R) to nontarget macroinvertebrates Gammarus lacustris (Amphipoda: Gammaridae) and Hexagenia spp. (Ephemeroptera: Ephemeridae)

Zequanox® is a commercial formulation of the killed bacterium, Pseudomonas fluorescens (strain CL145A), that was developed to control dreissenid mussels. In 2014, Zequanox became the second product registered by the United States Environmental Protection Agency (USEPA) for use in open water environments as a molluscicide. Previous nontarget studies demonstrated the safety and selectivity of P. fluorescens CL154A, but the database on the toxicity of the formulation (Zequanox) is limited for macroinvertebrate taxa and exposure conditions. We evaluated the safety of Zequanox to the amphipod Gammarus lacustris lacustris , and nymphs of the burrowing mayfly, Hexagenia spp. at the maximum approved concentration (100 mg/L active ingredient, A.I.) and exposure duration (8 h). Survival of animals was assessed after 8 h of exposure and again at 24 and 96 h post-exposure. Histopathology of the digestive tract of control and treated animals was compared at 96 h post-exposure. The results showed no significant effect of Zequanox on survival of either species. Survival of G. lacustris exceeded 85% in all concentrations at all three sampling time points. Survival of Hexagenia spp. ranged from 71% (control) to 91% at 8 h, 89–93% at 24 h post-exposure, and 70–73% at 96 h post-exposure across all treatments. We saw no evidence of pathology in the visceral organs of treated animals. Our results indicate that application of Zequanox at the maximum approved concentration and exposure duration did not cause significant mortality or treatment-related histopathological changes to G. lacustris and Hexagenia spp.

Management of Biological Invasions↗

Effects of the biopesticide Zequanox® on reproduction and early development of the fathead minnow ( Pimephales promelas )

The biopesticide, Zequanox®, is registered for dreissenid mussel control in open water systems in the United States. Previous toxicity trials with nontarget organisms, including several young-of-the-year fish species and invertebrates, demonstrated selectivity of Zequanox for dreissenid mussels, but data are lacking on the treatment-related effects on reproduction and early life stage development of fish. The present study evaluated the effects of Zequanox on spawning and early life stages of the fathead minnow, Pimephales promelas , after exposure to the maximum approved concentration [100 mg active ingredient (AI)/L] and exposure duration (8h) for open water application. The results showed no significant treatment-related effect of Zequanox on survival, condition, or cumulative egg production (21 d) in adult fathead minnow. Eggs (≤24 h old) exposed to Zequanox developed to the eyed-stage at a similar rate to that of untreated eggs. Additionally, Zequanox did not have a significant effect on survival and growth (90 d) of newly hatched larvae (≤24-h old). Zequanox may be an option for control of dreissenid mussels in localized open water habitats where concerns exist regarding reproduction and recruitment of cyprinids and related species.

Management of Biological Invasions↗