Description: This data set contains points representing NHD hydrographic landmark features. The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the sream segments or reaches that comprise the nation's surface water drainage system. Medium resolution NHD is based on the content of the U.S. Geological Survey 1:100,000-scale Digital Line Graph (DLG) hydrography data, integrated with reach-related information from the U.S. Environmental Protection Agency Reach File Version 3.0 (RF3). More specifically, it contains reach codes for networked features and isolated lakes, flow direction, names, stream level, and centerline representations for areal water bodies. Reaches are also defined to represent water bodies and the approximate shorelines of the Great Lakes, the Atlantic and Pacific Oceans and the Gulf of Mexico. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee.
Description: Data available online through the Arkansas Spatial Data Infrastructure (ASDI) at http://gis.arkansas.gov. The subject file contains physical information on commercial facilities at the principal U.S. Coastal, Great Lakes and Inland Ports. The data is from the US Army Corps of Engineers. The data consists of listings of port area's waterfront facilities, including information on berthing, cranes, transit sheds, grain elevators, marine repair plants, fleeting areas, and docking and storage facilities. Collection of data is performed on a rotational basis to ensure on-site accuracy at each facility.
Description: This file contains the National Geodetic Survey (NGS) benchmark locations on the printed digital flood insurance map. The National Flood Hazard Layer (NFHL) data incorporates all Digital Flood Insurance Rate Map(DFIRM) databases published by FEMA, and any Letters Of Map Revision (LOMRs) that have been issued against those databases since their publication date. The DFIRM Database is the digital, geospatial version of the flood hazard information shown on the published paper Flood Insurance Rate Maps(FIRMs). The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual-chance flood event, and areas of minimal flood risk. The NFHL data are derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). The specifications for the horizontal control of DFIRM data are consistent with those required for mapping at a scale of 1:12,000. The NFHL data contain layers in the Standard DFIRM datasets except for S_Label_Pt and S_Label_Ld. The NFHL is available as State or US Territory data sets. Each State or Territory data set consists of all DFIRMs and corresponding LOMRs available on the publication date of the data set.
Definition Expression: N/A
Copyright Text: Acknowledgement of FEMA would be appreciated in products derived from these data.
Description: This data includes streams of Arkansas that have been designated as Impaired Waterbodies and have completed TMDLs (Total Maximum Daily Loads) for the listed pollutant pair(s) (Category 4a). It consists of a subset of the streams from the National Hydrography Dataset (NHD) Medium Resolution (1:100,000) Flowline. Category 4 is described as follows: One or more water quality standards not attained but does not require the development of a TMDL because: a. A TMDL has been completed for the listed parameter(s); b. Waters which are impaired by point source discharges and future permits restrictions are expected to correct the problem(s). c. Waters that currently do not meet an applicable water quality standard, but the impairment is not caused by a pollutant.
Description: This data includes streams of Arkansas that have been designated as Impaired Waterbodies (Category 5). It consists of a subset of the streams from the National Hydrography Dataset (NHD) Medium Resolution (1:100,000) Flowline. Category 5 is described as follows: The waterbody may be impaired, or one or more designated uses may not be attained. During the 2008 listing cycle, Waterbodies in Category 5 are placed in one of the following subcategories: a. Truly impaired; develop a TMDL or other corrective action(s) for the listed parameter. b. Waters currently not attaining standards, but may be de-listed with future revisions to Regulation No. 2, the state water quality standards; c. Waters in which the data is questionable because of QA/QC procedures and which require confirmation before a TMDL is scheduled; d. Waters which need data verification to confirm use impairment (additional sampling, biological assessment) before a TMDL is scheduled; e. Waters which are impaired by point source discharges and future permits restrictions are expected to correct the problem; f. These are waters that are not currently meeting a water quality standard. However, "the basis for not meeting an applicable water quality standard is not caused by a pollutant, but is attributed to other types of pollution" (EPA, 2005). g. Waterbodies added to ADEQ's list of Impaired Waterbodies by EPA.
Description: Drainage Ditches are the combination of the digitized line-work from AHTD's county maps that represent the individual Cartographer's interpretation of a Drainage Ditch from aerial photography.
Definition Expression: N/A
Copyright Text: In all cases, a credit line stating "Base Map Provided By The Mapping Section, Planning and Research Division, Arkansas State Highway and Transportation Department, In Cooperation With The U.S. Department of Transportation"
Description: Levees and Dikes are the combination of the digitized line-work from AHTD's county maps that represent the individual Cartographer's interpretation of a Levee or Dike from aerial photography.
Definition Expression: N/A
Copyright Text: In all cases, a credit line stating "Base Map Provided By The Mapping Section, Planning and Research Division, Arkansas State Highway and Transportation Department, In Cooperation With The U.S. Department of Transportation"
Description: This data set consist of routes that make up a linear surface water drainage network. The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the sream segments or reaches that comprise the nation's surface water drainage system. Medium resolution NHD is based on the content of the U.S. Geological Survey 1:100,000-scale Digital Line Graph (DLG) hydrography data, integrated with reach-related information from the U.S. Environmental Protection Agency Reach File Version 3.0 (RF3). More specifically, it contains reach codes for networked features and isolated lakes, flow direction, names, stream level, and centerline representations for areal water bodies. Reaches are also defined to represent water bodies and the approximate shorelines of the Great Lakes, the Atlantic and Pacific Oceans and the Gulf of Mexico. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee.
Description: This data set contains routes representing linear NHD hydrographic landmark features. The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the sream segments or reaches that comprise the nation's surface water drainage system. Medium resolution NHD is based on the content of the U.S. Geological Survey 1:100,000-scale Digital Line Graph (DLG) hydrography data, integrated with reach-related information from the U.S. Environmental Protection Agency Reach File Version 3.0 (RF3). More specifically, it contains reach codes for networked features and isolated lakes, flow direction, names, stream level, and centerline representations for areal water bodies. Reaches are also defined to represent water bodies and the approximate shorelines of the Great Lakes, the Atlantic and Pacific Oceans and the Gulf of Mexico. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee.
Description: This dataset consists of the medium-resolution NHD (National Hydrography Dataset), developed at 1:100,000 scale. This dataset was created using the NHDPlus tool, developed by Horizon Systems Corporation. The NHDPlus tool uses the Strahler method of Stream Order Classification. This method classifies streams based on where they lie in relation to other streams in a watershed.
Description: Swamps are the combination of the digitized line-work from AHTD's county maps that represent the individual Cartographer's interpretation of a swamp from aerial photography.
Definition Expression: N/A
Copyright Text: In all cases, a credit line stating "Base Map Provided By The Mapping Section, Planning and Research Division, Arkansas State Highway and Transportation Department, In Cooperation With The U.S. Department of Transportation"
Description: This dataset is derived from the High Resolution (1:24,000-scale) National Hydrography Dataset (NHD). The Arkansas Department of Environmental Quality uses this layer as their base water layer. This dataset includes the DEQ Reach column in the attribute table. DEQ reaches are referenced in the 303(d) list and 305(b) report.
Description: Data available online through the Arkansas Spatial Data Infrastructure (ASDI) at http://gis.arkansas.gov. The subject file represents the Arkansas portion of areas to be submerged derived from 1:100,000-scale (""intermediate-scale"") Digital Line Graph data created by the USGS. Digital Line Graph (DLG) data are digital representations of cartographic information. DLG's of map features are converted to digital form from maps and related sources. Intermediate-scale DLG data are derived from USGS 1:100,000-scale 30- by 60-minute quadrangle maps. If these maps are not available, Bureau of Land Management planimetric maps at a scale of 1:100,000 are used. Intermediate-scale DLG's are broken down into five categories: 1. Public Land survey, 2. boundaries, 3. transportation 4. hydrography, and 5. hypsography.
Description: This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit) 6th level for the State of Arkansas. This data set consists of geo-referenced digital data and associated attributes created in accordance with the "FGDC Proposal, Version 1.0 - Federal Standards For Delineation of Hydrologic Unit Boundaries 3/01/02"(http://www.ftw.nrcs.usda.gov/huc_data.html). Polygons are attributed with hydrologic unit codes for 4th level sub-basins, 5th level watersheds, 6th level subwatersheds, name, size, downstream hydrologic unit, type of watershed, non-contributing areas and flow modification. Arcs are attributed with the highest hydrologic unit code for each watershed, line source and a metadata reference file.
Definition Expression: N/A
Copyright Text: The dataset was created by the coordinated effort between multiple agencies including; Arkansas Natural Resources Commission (ANRC), USDA Arkansas, USDA Forest Service- Ozark-St. Francis National Forest, USGS Arkansas, USGS Utah, USGS Mississippi, Arkansas Game and Fish Commission, Arkansas Heritage Commission, Arkansas GIS User's Forum, Arkansas Department of Environmental Quality, Arkansas Geologic Commission, University of Arkansas at Monticello and University of Arkansas at Fayetteville. NRCS provided the oversight and did a major portion of the delineations and attribution in the eastern portion of the state and portions of the Upper White River area, as well as some areas along the middle and lower portions of the Arkansas side of the Mississippi. Over the past 1-1/2 years USGS in Arkansas as well as USGS in Utah have, under an agreement with NRCS and the State of Arkansas, completed the remainder of the states line work and attribution, appended the dataset together.
Description: This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit) 6th level for the State of Arkansas. This data set consists of geo-referenced digital data and associated attributes created in accordance with the "FGDC Proposal, Version 1.0 - Federal Standards For Delineation of Hydrologic Unit Boundaries 3/01/02"(http://www.ftw.nrcs.usda.gov/huc_data.html). Polygons are attributed with hydrologic unit codes for 4th level sub-basins, 5th level watersheds, 6th level subwatersheds, name, size, downstream hydrologic unit, type of watershed, non-contributing areas and flow modification. Arcs are attributed with the highest hydrologic unit code for each watershed, line source and a metadata reference file.
Definition Expression: N/A
Copyright Text: The dataset was created by the coordinated effort between multiple agencies including; Arkansas Natural Resources Commission (ANRC), USDA Arkansas, USDA Forest Service- Ozark-St. Francis National Forest, USGS Arkansas, USGS Utah, USGS Mississippi, Arkansas Game and Fish Commission, Arkansas Heritage Commission, Arkansas GIS User's Forum, Arkansas Department of Environmental Quality, Arkansas Geologic Commission, University of Arkansas at Monticello and University of Arkansas at Fayetteville. NRCS provided the oversight and did a major portion of the delineations and attribution in the eastern portion of the state and portions of the Upper White River area, as well as some areas along the middle and lower portions of the Arkansas side of the Mississippi. Over the past 1-1/2 years USGS in Arkansas as well as USGS in Utah have, under an agreement with NRCS and the State of Arkansas, completed the remainder of the states line work and attribution, appended the dataset together.
Description: This data includes lakes of Arkansas that have been designated as Impaired Waterbodies and have completed TMDLs (Total Maximum Daily Loads) for the listed pollutant pair(s) (Category 4a). It consists of a subset of the lakes from the National Hydrography Dataset (NHD) Medium Resolution (1:100,000) Flowline. Category 4 is described as follows: One or more water quality standards not attained but does not require the development of a TMDL because: a. A TMDL has been completed for the listed parameter(s); b. Waters which are impaired by point source discharges and future permits restrictions are expected to correct the problem(s). c. Waters that currently do not meet an applicable water quality standard, but the impairment is not caused by a pollutant.
Description: This data includes lakes of Arkansas that have been designated as Impaired Waterbodies (Category 5). It consists of a subset of the lakes from the National Hydrography Dataset (NHD) Medium Resolution (1:100,000) Flowline. Category 5 is described as follows: The waterbody may be impaired, or one or more designated uses may not be attained. During the 2008 listing cycle, Waterbodies in Category 5 are placed in one of the following subcategories: a. Truly impaired; develop a TMDL or other corrective action(s) for the listed parameter. b. Waters currently not attaining standards, but may be de-listed with future revisions to Regulation No. 2, the state water quality standards; c. Waters in which the data is questionable because of QA/QC procedures and which require confirmation before a TMDL is scheduled; d. Waters which need data verification to confirm use impairment (additional sampling, biological assessment) before a TMDL is scheduled; e. Waters which are impaired by point source discharges and future permits restrictions are expected to correct the problem; f. These are waters that are not currently meeting a water quality standard. However, "the basis for not meeting an applicable water quality standard is not caused by a pollutant, but is attributed to other types of pollution" (EPA, 2005). g. Waterbodies added to ADEQ's list of Impaired Waterbodies by EPA.
Description: This data set contains regions representing areal NHD hydrographic landmark features. The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the sream segments or reaches that comprise the nation's surface water drainage system. Medium resolution NHD is based on the content of the U.S. Geological Survey 1:100,000-scale Digital Line Graph (DLG) hydrography data, integrated with reach-related information from the U.S. Environmental Protection Agency Reach File Version 3.0 (RF3). More specifically, it contains reach codes for networked features and isolated lakes, flow direction, names, stream level, and centerline representations for areal water bodies. Reaches are also defined to represent water bodies and the approximate shorelines of the Great Lakes, the Atlantic and Pacific Oceans and the Gulf of Mexico. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee.
Description: This data set contains regions representing areal NHD hydrographic waterbody features. The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the sream segments or reaches that comprise the nation's surface water drainage system. Medium resolution NHD is based on the content of the U.S. Geological Survey 1:100,000-scale Digital Line Graph (DLG) hydrography data, integrated with reach-related information from the U.S. Environmental Protection Agency Reach File Version 3.0 (RF3). More specifically, it contains reach codes for networked features and isolated lakes, flow direction, names, stream level, and centerline representations for areal water bodies. Reaches are also defined to represent water bodies and the approximate shorelines of the Great Lakes, the Atlantic and Pacific Oceans and the Gulf of Mexico. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee.
Description: This is the Ozark - St. Francis National Forests Wild and Scenic River Cooridor polygon layer. In Apil 1992, Congress designated six Wild and Scenic Rivers on the Ozark - St. Francis National Forests. These rivers include: Big Piney Creek, the Buffalo River, Hurricane Creek, Mulberry River, North Sylamore Creek and Richland Creek. These areas include approximately 19,859 acres of the Ozark - St. Francis National Forests. This MA is unsuitable for timber prduction. The total miles of Wild and Scenic River designation is 162.5 miles.
Description: Data available online through GeoStor at http://www.geostor.arkansas.gov. The Q3 Flood Data are derived from the Flood Insurance Rate Maps (FIRMS) published by the Federal Emergency Management Agency (FEMA). The file is georeferenced to earth""s surface using geographic projection and decimal degree coordinate system. The specifications for the horizontal control of Q3 Flood Data files are consistent with those required for mapping at a scale of 1:24000.
Description: This data set is a complete digital hydrologic unit boundary layer to the Subwatershed (12-digit) 6th level for the State of Arkansas. This data set consists of geo-referenced digital data and associated attributes created in accordance with the "FGDC Proposal, Version 1.0 - Federal Standards For Delineation of Hydrologic Unit Boundaries 3/01/02"(http://www.ftw.nrcs.usda.gov/huc_data.html). Polygons are attributed with hydrologic unit codes for 4th level sub-basins, 5th level watersheds, 6th level subwatersheds, name, size, downstream hydrologic unit, type of watershed, non-contributing areas and flow modification. Arcs are attributed with the highest hydrologic unit code for each watershed, linesource and a metadata reference file.
Definition Expression: N/A
Copyright Text: The dataset was created by the coordinated effort between multiple agencies including; Arkansas Natural Resources Commission (ANRC), USDA Arkansas, USDA Forest Service- Ozark-St. Francis National Forest, USGS Arkansas, USGS Utah, USGS Mississippi, Arkansas Game and Fish Commission, Arkansas Heritage Commission, Arkansas GIS User's Forum, Arkansas Department of Environmental Quality, Arkansas Geologic Commission, University of Arkansas at Monticello and University of Arkansas at Fayetteville. NRCS provided the oversight and did a major portion of the delineations and attribution in the eastern portion of the state and portions of the Upper White River area, as well as some areas along the middle and lower portions of the Arkansas side of the Mississippi. Over the past 1-1/2 years USGS in Arkansas as well as USGS in Utah have, under an agreement with NRCS and the State of Arkansas, completed the remainder of the states line work and attribution, appended the dataset together.
Description: The Watershed Boundary Dataset (WBD) is a comprehensive aggregated collection of hydrologic unit data consistent with the national criteria for delineation and resolution. It defines the areal extent of surface water drainage to a point except in coastal or lake front areas where there could be multiple outlets as stated by the "Federal Standards and Procedures for the National Watershed Boundary Dataset (WBD)" “Standard” (http://pubs.usgs.gov/tm/11/a3/). Watershed boundaries are determined solely upon science-based hydrologic principles, not favoring any administrative boundaries or special projects, nor particular program or agency. This dataset represents the hydrologic unit boundaries to the 12-digit (6th level) for the entire United States. Some areas may also include additional subdivisions representing the 14- and 16-digit hydrologic unit (HU). At a minimum, the HUs are delineated at 1:24,000-scale in the conterminous United States, 1:25,000-scale in Hawaii, Pacific basin and the Caribbean, and 1:63,360-scale in Alaska, meeting the National Map Accuracy Standards (NMAS). Higher resolution boundaries are being developed where partners and data exist and will be incorporated back into the WBD. WBD data are delivered as a dataset of polygons and corresponding lines that define the boundary of the polygon. WBD polygon attributes include hydrologic unit codes (HUC), size (in the form of acres and square kilometers), name, downstream hydrologic unit code, type of watershed, non-contributing areas, and flow modifications. The HUC describes where the unit is in the country and the level of the unit. WBD line attributes contain the highest level of hydrologic unit for each boundary, line source information and flow modifications.
Definition Expression: N/A
Copyright Text: Funding for the Watershed Boundary Dataset (WBD) was provided by the USDA-NRCS, USGS and EPA along with other federal, state and local agenciesies. Representatives from many agencies contributed a substantial amount of time and salary towards quality review and updating of the dataset in order to meet the WBD Standards. Acknowledgment of the originating agencies would be appreciated in products derived from these data. See dataset specific metadata for further information
Description: The Watershed Boundary Dataset (WBD) is a comprehensive aggregated collection of hydrologic unit data consistent with the national criteria for delineation and resolution. It defines the areal extent of surface water drainage to a point except in coastal or lake front areas where there could be multiple outlets as stated by the "Federal Standards and Procedures for the National Watershed Boundary Dataset (WBD)" “Standard” (http://pubs.usgs.gov/tm/11/a3/). Watershed boundaries are determined solely upon science-based hydrologic principles, not favoring any administrative boundaries or special projects, nor particular program or agency. This dataset represents the hydrologic unit boundaries to the 12-digit (6th level) for the entire United States. Some areas may also include additional subdivisions representing the 14- and 16-digit hydrologic unit (HU). At a minimum, the HUs are delineated at 1:24,000-scale in the conterminous United States, 1:25,000-scale in Hawaii, Pacific basin and the Caribbean, and 1:63,360-scale in Alaska, meeting the National Map Accuracy Standards (NMAS). Higher resolution boundaries are being developed where partners and data exist and will be incorporated back into the WBD. WBD data are delivered as a dataset of polygons and corresponding lines that define the boundary of the polygon. WBD polygon attributes include hydrologic unit codes (HUC), size (in the form of acres and square kilometers), name, downstream hydrologic unit code, type of watershed, non-contributing areas, and flow modifications. The HUC describes where the unit is in the country and the level of the unit. WBD line attributes contain the highest level of hydrologic unit for each boundary, line source information and flow modifications.
Definition Expression: N/A
Copyright Text: Funding for the Watershed Boundary Dataset (WBD) was provided by the USDA-NRCS, USGS and EPA along with other federal, state and local agenciesies. Representatives from many agencies contributed a substantial amount of time and salary towards quality review and updating of the dataset in order to meet the WBD Standards. Acknowledgment of the originating agencies would be appreciated in products derived from these data. See dataset specific metadata for further information
Description: The Watershed Boundary Dataset (WBD) is a comprehensive aggregated collection of hydrologic unit data consistent with the national criteria for delineation and resolution. It defines the areal extent of surface water drainage to a point except in coastal or lake front areas where there could be multiple outlets as stated by the "Federal Standards and Procedures for the National Watershed Boundary Dataset (WBD)" “Standard” (http://pubs.usgs.gov/tm/11/a3/). Watershed boundaries are determined solely upon science-based hydrologic principles, not favoring any administrative boundaries or special projects, nor particular program or agency. This dataset represents the hydrologic unit boundaries to the 12-digit (6th level) for the entire United States. Some areas may also include additional subdivisions representing the 14- and 16-digit hydrologic unit (HU). At a minimum, the HUs are delineated at 1:24,000-scale in the conterminous United States, 1:25,000-scale in Hawaii, Pacific basin and the Caribbean, and 1:63,360-scale in Alaska, meeting the National Map Accuracy Standards (NMAS). Higher resolution boundaries are being developed where partners and data exist and will be incorporated back into the WBD. WBD data are delivered as a dataset of polygons and corresponding lines that define the boundary of the polygon. WBD polygon attributes include hydrologic unit codes (HUC), size (in the form of acres and square kilometers), name, downstream hydrologic unit code, type of watershed, non-contributing areas, and flow modifications. The HUC describes where the unit is in the country and the level of the unit. WBD line attributes contain the highest level of hydrologic unit for each boundary, line source information and flow modifications.
Definition Expression: N/A
Copyright Text: Funding for the Watershed Boundary Dataset (WBD) was provided by the USDA-NRCS, USGS and EPA along with other federal, state and local agenciesies. Representatives from many agencies contributed a substantial amount of time and salary towards quality review and updating of the dataset in order to meet the WBD Standards. Acknowledgment of the originating agencies would be appreciated in products derived from these data. See dataset specific metadata for further information
Description: This data includes streams of Arkansas that have been assessed as meeting their water quality standards and designated uses, and have completed TMDLs (Total Maximum Daily Loads) in place for a previously impaired pollutant pair(s) (Category 1b). It consists of a subset of the streams from the National Hydrography Dataset (NHD) Medium Resolution (1:100,000) Flowline. Category 1 is described as follows: Category 1. Attains all water quality standards for all designated uses; categorized by existence of a TMDL or not for one or more constituents:1a. Attaining water quality standards for all designated uses, no use is threatened. No TMDL exists for any constituents.1b. Attaining all water quality standards for all designated uses; however, a TMDL remains in place for one or more constituents.
Description: This data includes streams of Arkansas that have been assessed as Impaired Waterbodies and have alternative plans in place for the listed pollutant pair(s) (Category 4b). It consists of a subset of the streams from the National Hydrography Dataset (NHD) High Resolution (1:124,000) Flowline. Category 4b is described as follows: Category 4. Water quality standards are not attained for one or more designated uses but the development of a TMDL is not required because:Category 4b. Other pollution control requirements are expected to result in the attainment of the water quality standard
Description: This data includes streams of Arkansas that have been assessed as Impaired Waterbodies for the listed pollutant pair(s) (Category 5 alt). It consists of a subset of the streams from the National Hydrography Dataset (NHD) High Resolution (1:124,000) Flowline. Category 5 alt is described as follows: Category 5. The waterbody is impaired, or one or more water quality standards may not be attained. Category 5 alt Waters where alternative restoration approaches may be more immediately beneficial or practicable in achieving WQS than pursuing the TMDL approach in the near-term.
Description: This data includes lakes of Arkansas that have been assessed as Impaired Waterbodies for the listed pollutant pair(s) (Category 5 alt). It consists of a subset of the lakes from the Water Hydrography Tiger 2005V1.National Hydrography Dataset (NHD) High Resolution (1:124,000) Waterbody.Category 5 alt is described as follows: Category 5. The waterbody is impaired, or one or more water quality standards may not be attained. Category 5 alt Waters where alternative restoration approaches may be more immediately beneficial or practicable in achieving WQS than pursuing the TMDL approach in the near-term.