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At least 919 records · Page 51Linked to original sources

USGS2022

Air, land, and water variables associated with the first appearance and current spatial distribution of toxic Prymnesium parvum blooms in reservoirs of the Southern Great Plains, USA

This study examined the association of air, land, and water variables with the first historical occurrence and current distribution of toxic Prymnesium parvum blooms in reservoirs of the Brazos River and Colorado River, Texas (USA). One impacted and one reference reservoir were selected per basin. Land cover and use variables were estimated for the whole watershed (WW) and a 0.5-km zone on either side of streams (near field, NF). Variables were expressed in annual values. Principal component and trend analyses were used to determine (1) differences in environmental conditions before and after the 2001 onset of toxic blooms in impacted reservoirs (study period, 1992–2017), and (2) traits that uniquely discriminate impacted from reference reservoirs (2001–2017). Of thirty-three variables examined, two positively aligned with the reoccurring appearance of blooms in impacted reservoirs (air CO 2 and herbicide Glyphosate) and another two negatively aligned (insecticides Terbufos and Malathion). Glyphosate use was observed throughout the study period but a turning point for an upward trend occurred near the year of first bloom occurrence. While the relevance of the decreased use of insecticides is uncertain, prior experimental studies reported that increasing concentrations of air CO 2 and water Glyphosate can enhance P. parvum growth. Consistent with prior findings, impacted reservoirs were of higher salinity than reference reservoirs. In addition, their watersheds had far lower wetland cover at NF and WW scales. The value of wetlands in reducing harmful algal bloom incidence by reducing nutrient inputs has been previously recognized, but wetlands can also capture pesticides. Therefore, a diminished wetland cover could magnify Glyphosate loads flowing into impacted reservoirs. These observations are consistent with a scenario where rising levels of air CO 2 and Glyphosate use contributed to the establishment of P. parvum blooms in reservoirs of relatively high salinity and minimal wetland cover over their watersheds.

Texas↗

USGS2017

Depth of the vadose zone controls aquifer biogeochemical conditions and extent of anthropogenic nitrogen removal

We investigated biogeochemical conditions and watershed features controlling the extent of nitrate removal through microbial dinitrogen (N 2 ) production within the surficial glacial aquifer located on the north and south shores of Long Island, NY, USA. The extent of N 2 production differs within portions of the aquifer, with greatest N 2 production observed at the south shore of Long Island where the vadose zone is thinnest, while limited N 2 production occurred under the thick vadose zones on the north shore. In areas with a shallow water table and thin vadose zone, low oxygen concentrations and sufficient DOC concentrations are conducive to N 2 production. Results support the hypothesis that in aquifers without a significant supply of sediment-bound reducing potential, vadose zone thickness exerts an important control of the extent of N 2 production. Since quantification of excess N 2 relies on knowledge of equilibrium N 2 concentration at recharge, calculated based on temperature at recharge, we further identify several features, such as land use and cover, seasonality of recharge, and climate change that should be considered to refine estimation of recharge temperature, its deviation from mean annual air temperature, and resulting deviation from expected equilibrium gas concentrations.

Water Research↗

USGS2001

The Landsat 7 mission: terrestrial research and applications for the 21st century

The Landsat Earth observation approach introduced in 1972 created a new way of monitoring land cover and land use globally. The Landsat 7 mission, successfully launched on April 15, 1999, continues those observations and demonstrates significant progress in precise numerical radiometry, spectral differentiation, and seasonally repetitive monitoring. Substantial improvements in calibration procedures, both prior to launch and during normal operations, have also been made to ensure long-term stability in the acquired spectral radiometry. Landsat 7 data acquisitions are being driven by a long-term data acquisition plan that was designed to ensure that substantially cloud-free, seasonal coverage would be recorded and archived in the US for all land areas of the globe. NASA competitively selected a Landsat Science Team, consisting of representatives from US universities and government agencies, to exploit the Landsat 7 record for global change research. This team is addressing the technical and analytical means to process and analyze the core of this observation record, and for the first time in the history of the Landsat mission, the technical and operational aspects of the mission are being driven by the goals of the US science community. The expected outcome of these efforts is a rapid improvement in understanding the Earth system, as well as conceptual knowledge that will underpin significant advancements in the application of this technology for commercial, operational, educational, and research purposes. Pathways to achieve effective Landsat continuity in the early decades of the 21st century are also being given careful attention, and there is no question that the lessons learned from the Landsat 7 mission will strongly influence these next-generation sensor systems.

Remote Sensing of Environment↗

USGS2004

Urbanization impacts on the structure and function of forested wetlands

The exponential increase in population has fueled a significant demographic shift: 60% of the Earth's population will live in urban areas by 2030. While this population growth is significant in its magnitude, the ecological footprint of natural resource consumption and use required to sustain urban populations is even greater. The land use and cover changes accompanying urbanization (increasing human habitation coupled with resource consumption and extensive landscape modification) impacts natural ecosystems at multiple spatial scales. Because they generally occupy lower landscape positions and are linked to other ecosystems through hydrologic connections, the cascading effects of habitat alteration on watershed hydrology and nutrient cycling are particularly detrimental to wetland ecosystems. I reviewed literature relevant to these effects of urbanization on the structure and function of forested wetlands. Hydrologic changes caused by habitat fragmentation generally reduce species richness and abundance of plants, macroinvertebrates, amphibians, and birds with greater numbers of invasives and exotics. Reduction in soil saturation and lowered water tables result in greater nitrogen mineralization and nitrification in urban wetlands with higher probability of NO − 3 export from the watershed. Depressional forested wetlands in urban areas can function as important sinks for sediments, nutrients, and metals. As urban ecosystems become the predominant human condition, there is a critical need for data specific to urban forested wetlands in order to better understand the role of these ecosystems on the landscape.

Urban Ecosystems↗

USGS2009

Quantifying the spatial details of carbon sequestration potential and performance

Upscaling the spatial and temporal changes of carbon stocks and fluxes from sites to regions is challenging owing to the spatial and temporal variances and covariance of driving variables and the uncertainties in both the model and the input data. Although various modeling approaches have been developed to facilitate the upscaling process, few deal with error transfer from model input to output, and error propagation in time and space. The author has developed the General Ensemble Biogeochemical Modelling System (GEMS) for upscaling carbon stocks and fluxes from sites to regions with measures of uncertainty. This chapter describes the GEMS model, its application to regional- and larger-scale areas, and the new results that demonstrate the challenges of upscaling. GEMS relies on site-scale biogeochemical models to simulate carbon dynamics at the site scale. The spatial deployment of the site-scale model in GEMS is based on the spatial and temporal joint frequency distribution of major driving variables (e.g., land cover and land use change, climate, soils, disturbances, and management). At the site scale, GEMS uses stochastic ensemble simulations to incorporate input uncertainty to quantify uncertainty transfer from input to output, and to identify trends in both input data and simulation results. It permits one to simulate the range of possible permutations of input values and identify the trends and variance in both the input data and results. Using data assimilation techniques, GEMS simulations can be constrained by field and satellite observations, including estimates of net primary production (NPP) from the Moderate Resolution Imaging Spectroradiometer (MODIS), grain yield and cropping practices, and forest inventories. The modeling philosophy embedded in GEMS makes it ideal for assimilating information with various uncertainties to support estimating the spatial details of carbon sequestration potential as well as dynamic monitoring of the performance of carbon sequestration activities over large areas. As a case study, GEMS is applied to simulate the spatial and temporal details of carbon sources, sinks, and uncertainty in the Ridge and Valley ecoregion in the eastern United States

Book chapter↗

USGS2024

Changes in landscape and climate in Mexico and Texas reveal small effects on migratory habitat of monarch butterflies (Danaus plexippus)

The decline of the iconic monarch butterfly ( Danaus plexippus ) in North America has motivated research on the impacts of land use and land cover (LULC) change and climate variability on monarch habitat and population dynamics. We investigated spring and fall trends in LULC, milkweed and nectar resources over a 20-year period, and ~ 30 years of climate variables in Mexico and Texas, U.S. This region supports spring breeding, and spring and fall migration during the annual life cycle of the monarch. We estimated a − 2.9% decline in milkweed in Texas, but little to no change in Mexico. Fall and spring nectar resources declined < 1% in both study extents. Vegetation greenness increased in the fall and spring in Mexico while the other climate variables did not change in both Mexico and Texas. Monarch habitat in Mexico and Texas appears relatively more intact than in the midwestern, agricultural landscapes of the U.S. Given the relatively modest observed changes in nectar and milkweed, the relatively stable climate conditions, and increased vegetation greenness in Mexico, it seems unlikely that habitat loss (quantity or quality) in Mexico and Texas has caused large declines in population size or survival during migration.

Scientific Reports↗

USGS2011

Estimation of volumetric runoff coefficients for Texas watersheds using land-use and rainfall-runoff data

The rational method for peak discharge ( Q p "> Q p ) estimation was introduced in the 1880s. Although the rational method is considered simplistic, it remains an effective method for estimating peak discharge for small watersheds. The runoff coefficient ( C "> C ) is a key parameter for the rational method and can be estimated in various ways. Literature-based C "> C values ( C lit "> C lit ) are listed for different land-use/land cover (two words, no hyphen) (LULC) conditions in various design manuals and textbooks; however, these C lit "> C lit values were developed with little basis on observed rainfall and runoff data. In this paper, C lit "> C lit values were derived for 90 watersheds in Texas by using LULC data for 1992 and 2001; the C lit "> C lit values derived from the two data sets were essentially the same. Also for this study, volumetric runoff coefficients ( C v "> C v ) were estimated by using observed rainfall and runoff depths from more than 1,600 events observed in the watersheds. Watershed-median and watershed-average C v "> C v values were computed, and both are consistent with data from the National Urban Runoff Program. In addition, C v "> C v values were estimated by using rank-ordered pairs of rainfall and runoff depths (i.e., frequency matching). As anticipated, C "> C values derived by all three methods (literature based, event totals, and frequency matching) consistently had larger values for developed watersheds than for undeveloped watersheds. Two regression equations of C v "> C v versus percent impervious area were developed and combined into a single equation that can be used to rapidly estimate C v "> C v values for similar Texas watersheds.

Texas↗

USGS2019

Modeling the morphological response of a barrier island to Hurricane Matthew

Surge and wave forcing from Hurricane Matthew caused a breach south of Matanzas Inlet (FL, USA) on a complex barrier island, including sandy dunes, hard structures (residential buildings and a highway), wetlands, and the US Intracoastal Waterway. In this paper, the skill of the XBeach model to predict hurricane-induced barrier island overwash, dune erosion, and breaching is demonstrated. The location of the breach is predicted correctly if bottom roughness based on land cover is used to calculate bed shear stresses. While the dunes are initially lowered by wave attack and surge from the ocean side, the main driver for breach formation is the water level difference between the back-barrier and nearshore, causing an ocean-directed outflow of water after the peak of the storm.

Florida↗

USGS2003

Geographic analysis and monitoring at the United States Geological Survey

The Geographic Analysis and Monitoring (GAM) Program of the U.S. Geological Survey assesses the Nation's land surface at a variety of spatial and temporal scales to understand the rates, causes, and consequences of natural and human-induced processes and their interactions that affect the landscape over time. The program plays an important role in developing National Map tools and application. The GAM is a science and synthesis program that not only assesses the rates of changes to the Earth's land surface, but also provides reports on the status and trends of the Nation's land resources on a periodic basis, produces a land-use and land- cover database for the periodically updated map and data set-the Geographic Face of the Nation, and conducts research leading to improved understanding and knowledge about geographic processes. Scientific investigations provide comprehensive information needed to understand the environmental, resource, and economic consequences of landscape change. These analyses responds to the needs of resource managers and offers the American public baseline information to help them understand the dynamic nature of our national landscape and to anticipate the opportunities and consequences of our actions.

Cartography and Geographic Information Science↗

USGS2005

Correlates of vernal pool occurrence in the Massachusetts USA, landscape

Vernal pool wetlands are at risk of destruction across the northeast United States, due in part to their diminutive size and short hydroperiolds. These characteristics make it difficult to locate vernal pool habitats in the landscape during much of the year, and no efficient method exists for predicting their occurrence. A logistic regression procedure was used to identify large-scale variables that influence the presence of a potential vernal pool, including surficial geology, land use and land cover, soil classification, topography, precipitation, and surficial hydrologic features. The model was validated with locations of field-verified vernal pools. The model demonstrated that the probability of potential vernal pool occurrence is positively related to slope, negatively related to till/bedrock surficial geology, and negatively related to the proportion of cropland, urban/commercial, and high density residential development in the landscape. The relationship between vernal pool occurrence and large-scale variables suggests that these habitats do not occur at random in the landscape, and thus, protection in situ should be considered.

Massachusetts↗

USGS2005

1970's Land use data refined with 2000 population data to indicate new residential development for the conterminous United States

This data set represents U.S. Geological Survey (USGS) historical Land Use and Land Cover (LULC) from the 1970's that has been refined with 2000 population density at the block group level to indicate new residential development representative of the early 2000's. Any area having a population density of at least 1,000 people per square mile had been re-classified as "urban" land in this data set.

Report↗

USGS2005

1970's Land use data refined with 1990 population data to indicate new residential development for the conterminous United States

This data set represents U.S. Geological Survey (USGS) historical Land Use and Land Cover (LULC) from the 1970's that has been refined with 1990 population density at the block group level to indicate new residential development representative of the 1990's. Any area having a population density of at least 1,000 people per square mile had been re-classified as "urban" land in this data set.

Report↗

USGS1986

Applications of U.S. Geological Survey digital cartographic products, 1979-1983

The U.S. Geological Survey prepares and distributes fundamental, multipurpose cartographic data to a wide range of users throughout the United States. Recognizing that traditional cartographic procedures will eventually be replaced by digital techniques, the USGS is now actively developing computer-based methods to produce digital cartographic products. The digital cartographic products currently being developed parallel the traditional map-based information but have the advantage that they can be used in a computer environment. The digital cartographic products include: 1) digital elevation models (DEM's), 2) digital land use and land cover data, and 3) digital line graphs (DLG's). In addition, digital terrain tapes (DTT's) that were developed by the Defense Mapping Agency are currently available through the USGS. As with conventional map products, the digital products are suitable for efficient application to a variety of problems.

Bulletin↗

USGS1995

Automated feature extraction and classification from image sources

The U.S. Department of the Interior, U.S. Geological Survey (USGS), and Unisys Corporation have completed a cooperative research and development agreement (CRADA) to explore automated feature extraction and classification from image sources. The CRADA helped the USGS define the spectral and spatial resolution characteristics of airborne and satellite imaging sensors necessary to meet base cartographic and land use and land cover feature classification requirements and help develop future automated geographic and cartographic data production capabilities. The USGS is seeking a new commercial partner to continue automated feature extraction and classification research and development.

Fact Sheet↗

USGS2007

Climate Change Research at USGS Center for Earth Resources Observation and Science (EROS)

Research and development projects at EROS apply unique resources to support the USGS mission of developing understanding, monitoring, and modeling of climate variability and change and their human, physical, and biological impacts. Remote sensing resources, both new and archived, form the core of our ability to determine changes in the state or condition of the Earth’s surface and its dynamic landscape and ecosystem processes. This rich resource provides powerful biophysical information for local to global areas. Archival data form the basis for assessing human and climate impacts on the land surface, trends of land use, and an understanding of climate and management impacts. Biophysical information from satellite data is assimilated into quantitative models that allow all disciplines of the USGS to understand impacts on ecosystem processes. Major processes and problems we address include: carbon fluxes, hydrological processes, albedo changes and regional climates, mangroves and wetland protection of coastal environments, natural and manmade hazards (e.g., fire and drought), ecosystem change and succession, land use and land cover change, and more. The integration of remote sensing, modeling, and multidisciplinary approaches fosters international scientific leadership across all disciplines for the USGS.

Fact Sheet↗

USGS2009

The National Map - Orthoimagery

Orthorectified digital aerial photographs and satellite images of 1-meter (m) pixel resolution or finer make up the orthoimagery component of The National Map. The process of orthorectification removes feature displacements and scale variations caused by terrain relief and sensor geometry. The result is a combination of the image characteristics of an aerial photograph or satellite image and the geometric qualities of a map. These attributes allow users to: *Measure distance *Calculate areas *Determine shapes of features *Calculate directions *Determine accurate coordinates *Determine land cover and use *Perform change detection *Update maps The standard digital orthoimage is a 1-m or finer resolution, natural color or color infra-red product. Most are now produced as GeoTIFFs and accompanied by a Federal Geographic Data Committee (FGDC)-compliant metadata file. The primary source for 1-m data is the National Agriculture Imagery Program (NAIP) leaf-on imagery. The U.S. Geological Survey (USGS) utilizes NAIP imagery as the image layer on its 'Digital- Map' - a new generation of USGS topographic maps (http://nationalmap.gov/digital_map). However, many Federal, State, and local governments and organizations require finer resolutions to meet a myriad of needs. Most of these images are leaf-off, natural-color products at resolutions of 1-foot (ft) or finer.

Fact Sheet↗

USGS2016

Community exposure to potential climate-driven changes to coastal-inundation hazards for six communities in Essex County, Massachusetts

Introduction Understanding if and how community exposure to coastal hazards may change over time is crucial information for coastal managers tasked with developing climate adaptation plans. This report summarizes estimates of population and asset exposure to coastal-inundation hazards associated with sea-level-rise and storm scenarios in six coastal communities of the Great Marsh region of Essex County, Massachusetts. This U.S. Geological Survey (USGS) analysis was conducted in collaboration with National Wildlife Federation (NWF) representatives, who are working with local stakeholders to develop local climate adaptation plans for the Towns of Salisbury, Newbury, Rowley, Ipswich, and Essex and the City of Newburyport (hereafter referred to as communities). Community exposure was characterized by integrating various community indicators (land cover and land use, population, economic assets, critical facilities, and infrastructure) with coastal-hazard zones that estimate inundation extents and water depth for three time periods. Estimates of community exposure are based on the presence of people, businesses, and assets in hazard zones that are calculated from geospatial datasets using geographic-information-system (GIS) tools. Results are based on current distributions of people and assets in hazard zones and do not take into account projections of human population, asset, or land-use changes over time. Results are not loss estimates based on engineering analysis or field surveys for any particular facility and do not take into account aspects of individual and household preparedness before an extreme event, adaptive capacity of a community during an event, or long-term resilience of individuals and communities after an event. Potential losses would match reported inventories only if all residents, business owners, public managers, and elected officials were unaware of what to do if warned of an imminent threat, failed to take protective measures during an extreme event, or failed to implement any long-term strategies to mitigate potential impacts. This analysis is intended to serve as a foundation for additional risk-related studies, plans, and mitigation efforts that are tailored to local needs. After a summary of the geospatial methods used in the analysis, results are organized by community so that local officials can easily use them in their local adaptation planning efforts.

Massachusetts↗

USGS2013

Assessment of macroinvertebrate communities in adjacent urban stream basins, Kansas City, Missouri, metropolitan area, 2007 through 2011

Macroinvertebrates were collected as part of two separate urban water-quality studies from adjacent basins, the Blue River Basin (Kansas City, Missouri), the Little Blue River and Rock Creek Basins (Independence, Missouri), and their tributaries. Consistent collection and processing procedures between the studies allowed for statistical comparisons. Seven Blue River Basin sites, nine Little Blue River Basin sites, including Rock Creek, and two rural sites representative of Missouri ecological drainage units and the area’s ecoregions were used in the analysis. Different factors or levels of urban intensity may affect the basins and macroinvertebrate community metrics differently, even though both basins are substantially developed above their downstream streamgages (Blue River, 65 percent; Little Blue River, 52 percent). The Blue River has no flood control reservoirs and receives wastewater effluent and stormflow from a combined sewer system. The Little Blue River has flood control reservoirs, receives no wastewater effluent, and has a separate stormwater sewer system. Analysis of macroinvertebrate community structure with pollution-tolerance metrics and water-quality parameters indicated differences between the Blue River Basin and the Little Blue River Basin. A four-metric score (total taxa richness, Ephemeroptera plus Plecoptera plus Trichoptera taxa richness, Macroinvertebrate Biotic Index, and Shannon Diversity Index) for richest-targeted habitat was used to calculate a Stream Condition Index (SCI) in order to evaluate the aquatic-life status of the streams. About 80 percent of all samples combined were determined to be less than fully biologically supporting, and about 11 percent of spring samples were fully biologically supporting. No sites within the Blue River Basin had a fully supporting score. The aquatic-life status scores for the Little Blue River and its tributaries were higher (indicating more optimal conditions) than for the Blue River and its tributaries. Fall samples scored higher than spring samples. However, fall samples were collected at the Little Blue River Basin and rural sites only. The Little Blue River sites scored higher for fall samples than spring samples; about 39 percent fully biologically supporting and 61 percent partially biologically supporting; more similar to the rural comparison sites, 40 percent fully biologically supporting and 60 percent partially biologically supporting. The SCI was compared to other multimetric indices with more or other component metrics to determine if the SCI effectively described differences among sites. Environmental variables (streamflow, water quality, land use, impervious cover, and population density) were used in statistical analyses to evaluate relations to macroinvertebrate metrics. Multimetric indices (MMIs) were modeled using step regression with a simple urban intensity index (SUII) based on percentage of impervious cover, population density, and forest cover in a 30-meter stream-buffer zone, and two were selected for further analysis. Three other multimetric indices composed of metrics common to local and national studies show results similar to the two modeled MMIs. A common Benthic Index of Biotic Integrity (R 2 equals 0.71) developed for a national study had the highest correlation with urban intensity as measured with the SUII, followed by a modeled 6-metric index (R 2 equals 0.61). The other MMIs and the SCI explained less than a half of the variability in macroinvertebrate communities in relation to the SUII. Wastewater-treatment plant discharges during base flow, which elevated specific conductance and nutrient concentrations, combined sewer overflows, and nonpoint sources likely contributed to water-quality impairment and lower aquatic-life status at the Blue River Basin sites. Releases from upstream reservoirs to the Little Blue River likely decreased specific conductance, suspended-sediment, and dissolved constituent concentrations and may have benefitted water quality and aquatic life of main-stem sites. Chloride concentrations in base-flow samples, attributable to winter road salt application, had the highest correlation with the SUII (Spearman’s ρ equals 0.87), were negatively correlated with the SCI (Spearman’s ρ equals -0.53) and several pollution sensitive Ephemeroptera plus Plecoptera plus Trichoptera abundance and percent richness metrics, and were positively correlated with pollution tolerant Oligochaeta abundance and percent richness metrics. Study results show that the easily calculated SUII and the selected modeled multimetric indices are effective for comparing urban basins and for evaluation of water quality in the Kansas City metropolitan area.

Missouri↗