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Silvia Terziotti

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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 affect the fate and transport of constituents to receiving surface-water bodies. The core of the model consists of using a nonlinear-regression equation to describe the non-conservative transport of contaminants from point and nonpoint sources on land to rivers, lakes and estuaries through the stream and river network. In North Carolina,...
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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 important to the estimation of annual loads of total nitrogen. These data support the following publication: Kronholm, S.C., Capel, P.D., and Terziotti, Silvia, 2016, Statistically extracted fundamental watershed variables for estimating the loads of total nitrogen in small streams: Environmental Modeling and Assessment, 10 p., http://dx.doi.org/10.1007/s10666-016-9525-3.
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Indicators of Hydrologic Alteration in North Carolina Catchments: Small Ponds and Artificial Drainage
Alterations to stream hydrology, which include changes in stream geomorphology, are primary impacts of anthropogenic disruption. In North Carolina, hydrological alterations lead to environmental impacts through degraded ecosystems and water quality. In collaboration with the North Carolina Department of Environmental Quality, Division of Mitigation Services (DMS), the USGS South Atlantic Water Science Center datasets are proxy measurements of the extent of altered hydrology in riverine systems across the State of North Carolina. The datasets consist of an inventory and characterization of small scale (mostly agricultural) ponds and artificial drainages, which are both significant hydrologic modifications in the...
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Reactive nitrogen is transported from the atmosphere to the landscape as wet and dry deposition that contributes to annual nitrogen loads to the Chesapeake Bay. Estimates of atmospheric inorganic nitrogen deposition to the Chesapeake Bay watershed during 1950 to 2050 are presented, and are based on field measurements, model simulations, statistical relations, and surrogate constituents used for estimates. Wet atmospheric nitrogen deposition has generally been quantified from weekly precipitation sample collections, whereas dry atmospheric nitrogen deposition has been simulated by a model at an hourly time step.
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Note: this data release has been deprecated. Please see new data release here: https://doi.org/10.5066/P9IGSRCV. Artificial drainage has major ecosystem impacts through the development of extensive ditch networks that reduce storage and induce large-scale vegetation changes. This has been a widespread practice of water table management for agriculture in Eastern North Carolina. However, these features are challenging to identify because the structure has been determined by non-natural factors. A dataset of open ditches was processed by calculating terrain (also, positive) openness – a value based on a line-of-sight approach to measure the surrounding eight zenith angles as viewed above the landscape surface. The...
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