Facilities that Discharge to Water Point

This layer displays a point layer depicting Facilities that Discharge to Water indexed to NHDPlus version 2.1. National Pollutant Discharge Elimination System (NPDES) is used by EPA programs, regions, states, and water programs for monitoring water quality. Discharge of pollutants into waters of the United States is regulated under the NPDES, a mandated provision of the Clean Water Act. To assist with the regulation process, state and federal regulators use an information management system called the Integrated Compliance Information System (ICIS-NPDES). ICIS-NPDES stores data about NPDES facilities, permits, compliance status, and enforcement activities. ICIS-NPDES replaces the legacy Permit Compliance System (PCS). The NPDES permit program addresses water pollution by regulating point sources that discharge pollutants to waters of the United States.

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Water Monitoring Locations

This layer displays GIS data from EPA Office of Water STORET Warehouse. Reach indexed NPDES locations comprise two basic types: facilities and pipes. For a given NPDES permit, the program may have locational information on the facility alone or specific pipe outfalls.

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EPA RSEI Score, 2021

This layer displays RSEI score by county. A RSEI Score is a unitless value that accounts for the size of the chemical release, the fate and transport of the chemical through the environment, the size and location of the exposed population, and the chemical’s toxicity. RSEI scores are designed to be compared to each other. A RSEI Score 10 times higher than another RSEI Score suggests that the potential for risk is 10 times higher. Relatively small releases may lead to high RSEI Scores if the toxicity weight is particularly high or if the estimated exposed population is large. Conversely, large releases may lead to low RSEI Scores if the toxicity weight is low or if the estimated exposed population is small. A low RSEI Score indicates low potential concern from reported TRI releases, but other kinds of environmental risk may also be present, including pollution from mobile sources like cars and trucks, hazardous waste, and unreported releases from facilities.

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Estimated Pesticide Use by County

This layer shows the estimated agricultural use of pesticide compounds for counties in the contiguous lower 48 states. Total pesticide use was calculated per area and for area in agricultural land. Additional layers for glyphosate, metolachlor, atrazine, acetochlor, 2,4-D were also calculated and available in the maproom as separate layers!

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EPA RSEI Score, 2019

This layer displays RSEI score by county. A RSEI Score is a unitless value that accounts for the size of the chemical release, the fate and transport of the chemical through the environment, the size and location of the exposed population, and the chemical’s toxicity. RSEI scores are designed to be compared to each other. A RSEI Score 10 times higher than another RSEI Score suggests that the potential for risk is 10 times higher. Relatively small releases may lead to high RSEI Scores if the toxicity weight is particularly high or if the estimated exposed population is large. Conversely, large releases may lead to low RSEI Scores if the toxicity weight is low or if the estimated exposed population is small. A low RSEI Score indicates low potential concern from reported TRI releases, but other kinds of environmental risk may also be present, including pollution from mobile sources like cars and trucks, hazardous waste, and unreported releases from facilities.

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Hydrography – Rivers & Streams

Hydrography depicts surface water, including rivers and streams, lakes and ponds, canals, coastlines, and many other water features. The Hydrography layer combines two data sets: the 2021 National Map Hydrographic Geodatabase (1:1,000,000 scale) for small to medium scales, and the 2016 National Hydrography Datataset (NHD) (1:24,000 scale) for large scale mapping. Hydrography is depicted in two layers. Rivers & Streams depicts linear hydrography, including rivers, streams, canals, pipes, and artificial paths (line networks through larger water bodies). Waterbodies includes area hydrography, including larger rivers, lakes, ponds, seas, bays, estuaries, etc.

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National Hydrography Dataset (NHD) Flowline

The National Hydrography Dataset (NHD) is used to portray surface water. The NHD represents the drainage network with features such as rivers, streams, canals, lakes, ponds, coastline, etc. The principal components of the NHD are:

  • NHDFlowline: This is the fundamental flow network consisting predominantly of stream/river and artificial path vector features. It represents the spatial geometry, carries the attributes, models the water flow, and contains linear referencing measures for locating events on the network. Additional NHDFlowline features are canal/ditch, pipeline, connector, underground conduit, and coastline.
  • NHDArea: This feature class contains many additional features of water polygons. One of the more important is the stream/river feature. It represents the aerial extent of the water in a wide stream/river with a basic set of attributes. They typically contain NHDFlowline artificial paths that are used to model the stream/river. Artificial path carries the critical attributes of the stream/river, whereas NHDArea represents the geometric extent.
  • NHDWaterbody: Basic waterbodies such as lake/pond features are represented here. They portray the spatial geometry and the attributes of the feature. These water polygons may contain NHDFlowline artificial paths to allow the representation of water flow. Other NHDWaterbody features are swamp/marsh, reservoir, playa, estuary, and ice mass.
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Hydrography – Rivers & Streams

Hydrography depicts surface water, including rivers and streams, lakes and ponds, canals, coastlines, and many other water features. The Hydrography layer combines two data sets: the 2014 National Map Hydrographic Geodatabase (1:1,000,000 scale) for small to medium scales, and the 2016 National Hydrography Datataset (NHD) (1:24,000 scale) for large scale mapping. Hydrography is depicted in two layers. Rivers & Streams depicts linear hydrography, including rivers, streams, canals, pipes, and artificial paths (line networks through larger water bodies). Waterbodies dipicts area hydrography, including larger rivers, lakes, ponds, seas, bays, estuaries, etc.

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