Silvia Terziotti (Former Employee)
Science and Products
SPARROW model dataset for total suspended solids in North Carolina, including simulated stream loads SPARROW model dataset for total suspended solids in North Carolina, including simulated stream loads
To better understand the influence of human activities and natural processes on surface-water quality, the U.S. Geological Survey (USGS) developed the SPARROW (SPAtially Referenced Regressions On Watershed attributes) (Schwarz and others, 2006; Alexander and others, 2008) model. The framework is used to relate water-quality monitoring data to sources and watershed characteristics that...
Geomorphological Features of North Carolina Geomorphological Features of North Carolina
Three statewide datasets were compiled to provide information on the geomorphology for North Carolina. Geomorphology is commonly a missing element in many Earth-surface process models, thus it is essential to extract this missing information from available DEMs and use it to inform models and better understand the area of interest. For these threee datasets, information was extracted and...
Datasets and metadata for estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology Datasets and metadata for estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology
This USGS data release contains datasets, metadata, and figures associated with estimating nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology. There are three shapefiles with associated metadata and figures representing the shapefiles: Catchments_GWcontribN.shp: NHDPlus catchment estimates of groundwater contribution of...
Source and model output layers used for the prediction and display of the probability of elevated concentrations of redox-sensitive constituents in groundwater in the Fox-Wolf-Peshtigo watershed in Wisconsin and Michigan Source and model output layers used for the prediction and display of the probability of elevated concentrations of redox-sensitive constituents in groundwater in the Fox-Wolf-Peshtigo watershed in Wisconsin and Michigan
This USGS data release contains 1-kilometer resolution source-layer rasters used to predict redox conditions and contaminant concentrations in groundwater in the Fox-Wolf-Peshtigo watershed in Wisconsin and Michigan using random forest classification. The model output layers are 1-kilometer resolution rasters of the predicted probability of elevated concentrations of nitrate, iron, and...
Depth to 50 percent probability of oxic conditions, Chesapeake Bay Watershed Depth to 50 percent probability of oxic conditions, Chesapeake Bay Watershed
Defining the oxic-suboxic interface is often critical for determining pathways for nitrate transport in groundwater and to streams at the local scale. Defining this interface on a regional scale is complicated by the spatial variability of reaction rates. The probability of oxic groundwater in the Chesapeake Bay watershed was predicted by relating dissolved O2 concentrations in...
Data on annual total nitrogen loads and watershed characteristics used to develop a method to estimate the total nitrogen loads in small streams Data on annual total nitrogen loads and watershed characteristics used to develop a method to estimate the total nitrogen loads in small streams
This USGS Data Release represents the data used to develop multiple linear regression models for estimating the loads of total nitrogen in small streams. Recursive partitioning and random forest regression were used to assess 85 geospatial, environmental, and watershed variables across 636 small (less than 585 square kilometers) watersheds to determine which variables are fundamentally...
Filter Total Items: 36
Statistically extracted fundamental watershed variables for estimating the loads of total nitrogen in small streams Statistically extracted fundamental watershed variables for estimating the loads of total nitrogen in small streams
Accurate estimation of total nitrogen loads is essential for evaluating conditions in the aquatic environment. Extrapolation of estimates beyond measured streams will greatly expand our understanding of total nitrogen loading to streams. Recursive partitioning and random forest regression were used to assess 85 geospatial, environmental, and watershed variables across 636 small (
Authors
Scott C. Kronholm, Paul D. Capel, Silvia Terziotti
Predicting redox conditions in groundwater at a regional scale Predicting redox conditions in groundwater at a regional scale
Defining the oxic-suboxic interface is often critical for determining pathways for nitrate transport in groundwater and to streams at the local scale. Defining this interface on a regional scale is complicated by the spatial variability of reaction rates. The probability of oxic groundwater in the Chesapeake Bay watershed was predicted by relating dissolved O2 concentrations in...
Authors
Anthony J. Tesoriero, Silvia Terziotti, Daniel B. Abrams
A semi-automated tool for reducing the creation of false closed depressions from a filled LIDAR-derived digital elevation model A semi-automated tool for reducing the creation of false closed depressions from a filled LIDAR-derived digital elevation model
Closed depressions on the land surface can be identified by ‘filling’ a digital elevation model (DEM) and subtracting the filled model from the original DEM. However, automated methods suffer from artificial ‘dams’ where surface streams cross under bridges and through culverts. Removal of these false depressions from an elevation model is difficult due to the lack of bridge and culvert...
Authors
John Wall, Daniel H. Doctor, Silvia Terziotti
Simulating stream transport of nutrients in the eastern United States, 2002, using a spatially-referenced regression model and 1:100,000-scale hydrography Simulating stream transport of nutrients in the eastern United States, 2002, using a spatially-referenced regression model and 1:100,000-scale hydrography
Existing Spatially Referenced Regression on Watershed attributes (SPARROW) nutrient models for the northeastern and southeastern regions of the United States were recalibrated to achieve a hydrographically consistent model with which to assess nutrient sources and stream transport and investigate specific management questions about the effects of wetlands and atmospheric deposition on...
Authors
Anne B. Hoos, Richard B. Moore, Ana Maria Garcia, Gregory B. Noe, Silvia E. Terziotti, Craig M. Johnston, Robin L. Dennis
Relation of watershed setting and stream nutrient yields at selected sites in central and eastern North Carolina, 1997-2008 Relation of watershed setting and stream nutrient yields at selected sites in central and eastern North Carolina, 1997-2008
Data collected between 1997 and 2008 at 48 stream sites were used to characterize relations between watershed settings and stream nutrient yields throughout central and eastern North Carolina. The focus of the investigation was to identify environmental variables in watersheds that influence nutrient export for supporting the development and prioritization of management strategies for...
Authors
Stephen L. Harden, Thomas F. Cuffney, Silvia Terziotti, Katharine R. Kolb
Representation of regional urban development conditions using a watershed-based gradient study design Representation of regional urban development conditions using a watershed-based gradient study design
As part of the U.S. Geological Survey National Water-Quality Assessment Program, the effects of urbanization on stream ecosystems (EUSE) have been intensively investigated in nine metropolitan areas in the United States, including Boston, Massachusetts; Atlanta, Georgia; Birmingham, Alabama; Raleigh, North Carolina; Salt Lake City, Utah; Denver, Colorado; Dallas–Fort Worth, Texas...
Authors
Silvia Terziotti, Gerard McMahon, Amanda H. Bell
Science and Products
SPARROW model dataset for total suspended solids in North Carolina, including simulated stream loads SPARROW model dataset for total suspended solids in North Carolina, including simulated stream loads
To better understand the influence of human activities and natural processes on surface-water quality, the U.S. Geological Survey (USGS) developed the SPARROW (SPAtially Referenced Regressions On Watershed attributes) (Schwarz and others, 2006; Alexander and others, 2008) model. The framework is used to relate water-quality monitoring data to sources and watershed characteristics that...
Geomorphological Features of North Carolina Geomorphological Features of North Carolina
Three statewide datasets were compiled to provide information on the geomorphology for North Carolina. Geomorphology is commonly a missing element in many Earth-surface process models, thus it is essential to extract this missing information from available DEMs and use it to inform models and better understand the area of interest. For these threee datasets, information was extracted and...
Datasets and metadata for estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology Datasets and metadata for estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology
This USGS data release contains datasets, metadata, and figures associated with estimating nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology. There are three shapefiles with associated metadata and figures representing the shapefiles: Catchments_GWcontribN.shp: NHDPlus catchment estimates of groundwater contribution of...
Source and model output layers used for the prediction and display of the probability of elevated concentrations of redox-sensitive constituents in groundwater in the Fox-Wolf-Peshtigo watershed in Wisconsin and Michigan Source and model output layers used for the prediction and display of the probability of elevated concentrations of redox-sensitive constituents in groundwater in the Fox-Wolf-Peshtigo watershed in Wisconsin and Michigan
This USGS data release contains 1-kilometer resolution source-layer rasters used to predict redox conditions and contaminant concentrations in groundwater in the Fox-Wolf-Peshtigo watershed in Wisconsin and Michigan using random forest classification. The model output layers are 1-kilometer resolution rasters of the predicted probability of elevated concentrations of nitrate, iron, and...
Depth to 50 percent probability of oxic conditions, Chesapeake Bay Watershed Depth to 50 percent probability of oxic conditions, Chesapeake Bay Watershed
Defining the oxic-suboxic interface is often critical for determining pathways for nitrate transport in groundwater and to streams at the local scale. Defining this interface on a regional scale is complicated by the spatial variability of reaction rates. The probability of oxic groundwater in the Chesapeake Bay watershed was predicted by relating dissolved O2 concentrations in...
Data on annual total nitrogen loads and watershed characteristics used to develop a method to estimate the total nitrogen loads in small streams Data on annual total nitrogen loads and watershed characteristics used to develop a method to estimate the total nitrogen loads in small streams
This USGS Data Release represents the data used to develop multiple linear regression models for estimating the loads of total nitrogen in small streams. Recursive partitioning and random forest regression were used to assess 85 geospatial, environmental, and watershed variables across 636 small (less than 585 square kilometers) watersheds to determine which variables are fundamentally...
Filter Total Items: 36
Statistically extracted fundamental watershed variables for estimating the loads of total nitrogen in small streams Statistically extracted fundamental watershed variables for estimating the loads of total nitrogen in small streams
Accurate estimation of total nitrogen loads is essential for evaluating conditions in the aquatic environment. Extrapolation of estimates beyond measured streams will greatly expand our understanding of total nitrogen loading to streams. Recursive partitioning and random forest regression were used to assess 85 geospatial, environmental, and watershed variables across 636 small (
Authors
Scott C. Kronholm, Paul D. Capel, Silvia Terziotti
Predicting redox conditions in groundwater at a regional scale Predicting redox conditions in groundwater at a regional scale
Defining the oxic-suboxic interface is often critical for determining pathways for nitrate transport in groundwater and to streams at the local scale. Defining this interface on a regional scale is complicated by the spatial variability of reaction rates. The probability of oxic groundwater in the Chesapeake Bay watershed was predicted by relating dissolved O2 concentrations in...
Authors
Anthony J. Tesoriero, Silvia Terziotti, Daniel B. Abrams
A semi-automated tool for reducing the creation of false closed depressions from a filled LIDAR-derived digital elevation model A semi-automated tool for reducing the creation of false closed depressions from a filled LIDAR-derived digital elevation model
Closed depressions on the land surface can be identified by ‘filling’ a digital elevation model (DEM) and subtracting the filled model from the original DEM. However, automated methods suffer from artificial ‘dams’ where surface streams cross under bridges and through culverts. Removal of these false depressions from an elevation model is difficult due to the lack of bridge and culvert...
Authors
John Wall, Daniel H. Doctor, Silvia Terziotti
Simulating stream transport of nutrients in the eastern United States, 2002, using a spatially-referenced regression model and 1:100,000-scale hydrography Simulating stream transport of nutrients in the eastern United States, 2002, using a spatially-referenced regression model and 1:100,000-scale hydrography
Existing Spatially Referenced Regression on Watershed attributes (SPARROW) nutrient models for the northeastern and southeastern regions of the United States were recalibrated to achieve a hydrographically consistent model with which to assess nutrient sources and stream transport and investigate specific management questions about the effects of wetlands and atmospheric deposition on...
Authors
Anne B. Hoos, Richard B. Moore, Ana Maria Garcia, Gregory B. Noe, Silvia E. Terziotti, Craig M. Johnston, Robin L. Dennis
Relation of watershed setting and stream nutrient yields at selected sites in central and eastern North Carolina, 1997-2008 Relation of watershed setting and stream nutrient yields at selected sites in central and eastern North Carolina, 1997-2008
Data collected between 1997 and 2008 at 48 stream sites were used to characterize relations between watershed settings and stream nutrient yields throughout central and eastern North Carolina. The focus of the investigation was to identify environmental variables in watersheds that influence nutrient export for supporting the development and prioritization of management strategies for...
Authors
Stephen L. Harden, Thomas F. Cuffney, Silvia Terziotti, Katharine R. Kolb
Representation of regional urban development conditions using a watershed-based gradient study design Representation of regional urban development conditions using a watershed-based gradient study design
As part of the U.S. Geological Survey National Water-Quality Assessment Program, the effects of urbanization on stream ecosystems (EUSE) have been intensively investigated in nine metropolitan areas in the United States, including Boston, Massachusetts; Atlanta, Georgia; Birmingham, Alabama; Raleigh, North Carolina; Salt Lake City, Utah; Denver, Colorado; Dallas–Fort Worth, Texas...
Authors
Silvia Terziotti, Gerard McMahon, Amanda H. Bell