12 Mar 2021

National Hydrography Dataset (Waterbody)

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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.

12 Mar 2021

Hydrography – Rivers & Streams

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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.

12 Mar 2021

National Wetlands Inventory (NWI), 2018

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The National Wetlands Inventory (NWI) provides detailed information on the characteristics and distribution of wetlands in the United States. This update incorporates many changes, including the representation of wetland areas for intermittent streams.

12 Mar 2021

Army Corps Enbankments

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This layer displays United States Army Core of Engineers surveyed Embankments. The USACE defines an Embankment as the area of a floodplain from which flood water is excluded by the levee system. For more information about USACE data, visit the National Levee Database here .

12 Mar 2021

Army Corps Floodwalls

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This layer displays United States Army Core of Engineers surveyed Floodwalls. The USACE defines an Floodwall as a structure erected to protect areas from high river stages. For more information about USACE data, visit the National Levee Database here .

12 Mar 2021

Army Corps Leveed Areas

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This layer displays United States Army Core of Engineers surveyed Leveed Areas. The USACE defines a Levee Areas as the area of a floodplain from which flood water is excluded by the levee system. For more information about USACE data, visit the National Levee Database here .

12 Mar 2021

Toxic Release Inventory by County

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This layer displays the amount of toxic releases based on the Environmental Protection Agency (EPA) Toxics Release Inventory (TRI), a national program which tracks the management of over 650 toxic chemicals that pose a threat to human health and the environment. Facilities must report how each chemical is managed through recycling, energy recovery, treatment, and releases to the environment. A “release” of a chemical means that it is emitted to the air or water, or placed in some type of land disposal. The information submitted by facilities to the EPA and states is compiled annually as the Toxics Release Inventory or TRI, and is stored in a publicly accessible database ( Envirofacts. For more information, please visit the EPA Toxics Release Inventory web page.

12 Mar 2021

Safe Drinking Water Information System Sites

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This layer displays the locations of a subset of the Environmental Protection Agency (EPA) Safe Drinking Water Information System (SDWIS) sites. The SDWIS contains information about public water systems and their violations of EPA’s drinking water regulations. Data can be accessed through the EPA’s Clip N Ship map application. For more information, please visit the Safe Drinking Water Information System web page.

12 Mar 2021

National Hydrography Dataset (NHD) Flowline

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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.

12 Mar 2021

Hydrography – Rivers & Streams

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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.