| az_huc5_83 - 5th level (10 digit) hydrologic unit codes (hucs) | |
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Data format: ArcInfo Coverage File or table name: az_watshed_5 Coordinate system: Universal Transverse Mercator Theme keywords: HUC, Hydrologic Units, Hydrologic Unit Code, Region, Subregion, Basin, Subbasin, Watershed, Watershed Boundaries, boundaries, WBD, Watershed Boundary Dataset, HUA, Hydrologic Units Area |
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Abstract:
This data set is a complete digital hydrologic unit boundary layer to the 5th level for the State of Arizona. 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 1st through 5th levels of hydrologic units, 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. |
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Metadata elements shown with blue text are defined in the Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). Elements shown with green text are defined in the ESRI Profile of the CSDGM. Elements shown with a green asterisk (*) will be automatically updated by ArcCatalog. ArcCatalog adds hints indicating which FGDC elements are mandatory; these are shown with gray text.
This data set is a complete digital hydrologic unit boundary layer to the 5th level for the State of Arizona. 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 1st through 5th levels of hydrologic units, 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.
The hydrologic unit boundaries provide a uniquely identified and uniform method of subdividing large drainage areas. The smaller sized watersheds are useful for numerous application programs supported by a variety of local, State, and Federal Agencies. This data set is intended to be used as a tool for water-resource management and planning activities, particularly for site-specific and localized studies requiring a level of detail provided by large-scale map information. The dataset will be appended to a larger seamless nationally consistant geospatial database as other states complete their portion of the Watershed Boundary Dataset.
Outlet methodology: Outlet points were chosen by first choosing as many full stream reaches tributaries to the main stem as possible (classic watersheds). Outlets are then attempted adjacent to these classic watersheds on the main stem. Any remaining watersheds are then chosen in accordance to the next best available option. See "Process Step" for further information.
Publication date of sources
The distributor shall not be held liable for improper or incorrect use of this data, based on the description of appropriate/inappropriate uses described in this metadata document. It is strongly recommended that this data is directly acquired from the distributor and not indirectly through other sources which may have changed the data in some way. These data should not be used at scales greater than 1:24,000 for the purpose of identifying hydrographic watershed boundary feature locations. United States Department of Agriculture-Natural Resources Conservation Service should be acknowledged as the data source in products derived from these data. The Watershed Boundary Dataset is public information and may be interpreted by all organizations, agencies, units of government, or others based on needs; however, they are responsible for the appropriate application of the data. Federal, State, or local regulatory bodies are not to reassign to the Natural Resources Conservation Service any authority for the decisions they make. The Natural Resources Conservation Service will not perform any evaluations of these maps or purposes related solely to State or local regulatory programs. Photographic or digital enlargement of these maps to scales greater than that at which they were originally delineated can result in misrepresentation of the data. If enlarged, the maps will not include the fine detail that would be appropriate for mapping at the small scale. Digital data files are periodically updated. Files are dated, and users are responsible for obtaining the latest version of the data from the source distributor.
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Funding for the Arizona Watershed Boundary Dataset (WBD) was provided by the Natural Resources Conservation Service, Forest Service, and Bureau of Land Management. Representatives from these and other organizations also contributed a substantial amount of time and salary towards quality review of the dataset.
There are no unclosed polygons, intersections without nodes, or polygons without labels or with more than one label. Arc/Info's topological correction program CLEAN was used to correct intersections without nodes, identify unclosed polygons and remove duplicate lines with the same beginning and ending nodes. All sliver and wedge polygons were removed manually in ArcEdit.
All fields for all polygons in the .pat are attributed except for HU_8_DS and HU_10_DS. These will be attributed at a later date. NCONTRB_A is only attributed if the polygon is a 100% closed area. Otherwise the NCONTRB_A field will have a 0 value, even if it is partially or even mostly non-contributing. All fields for the lines in the .aat are attributed except hu_level. This field in the .aat will attributed at a later date. The lines adjacent to the universal polygon may be attributed with a 0. These cannot be attributed until the adjacent states complete their linework at which point the highest level of hydrologic unit can be determined.
The WBD was produced using Enhanced Digital Raster Graphics (DRG-e's) digital images as source map. Data completeness for DRG files reflect content of the source graphic and may therefore be reflected in the completeness and accuracy of the WBD. The map was digitized from USGS 1:24,000-scale digital raster graphic base maps, with an inherited error of +/- 40 feet according to USGS National Map Accuracy Standards. Digitized line locations were held to the +/- 40 foot accuracy standards by ensuring that all lines were within a 12 meter buffer of where visual interpretion put the actual boundary. Any lines outside the buffer were corrected. It is estimated that the errors detected were less than 10%. It should be noted that while general rules of hydrology were used (i.e. water flows downhill), the location of boundaries is still somewhat subjective as the 1:24,000-scale DRG-e do not always provide enough information for identifying the location of the boundaries. In these instances group consensus was used. Please refer to the methods section for more details on watershed delineation rules. Unquantifiable errors may be associated with coordinate shift. The default was used for all other ArcEdit tolerances except fuzzy tolerance which was set to .05 meters, and dangle which was set to 0. As with the original DRGs, DRG-e is cast in the Universal Transverse Mercator projection and is referenced to the NAD27 datum. When the DRG-e's are used in the NAD83 datum the alternate world files only approximate the NAD83 by shifting the coordinates of the imagery. The total error introduced using this shift is less than 2 meters for all DRG-e imagery.
Source Contribution map delineation and field verify.
Process description: Level 5 (10 digit) watersheds were delineated within a nested hierarchical structure using the existing Level 4 (8 digit) watershed delineation as a starting framework. The 11-digit code was reduced to 10 digits to conform to the new Federal Standards for the Delineation of Hydrologic Units Boundaries, by dropping the zero in the last position. The typical size of a level 5 watershed is 40,000 to 250,000 acres. Only those watersheds that show some unique cultural, physical, or logical significance were included in the data. The order of precedence for establishing the outlet point of a watershed is: (1) at the outlet of a lake or pond; (2) at a confluence for a full stream reach forming classic watershed; (3) at the adjacent point to (2); (4) at some topographic feature, such as a natural gap in topography; (5) at a dam or stream gauging station.
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Dataset moved.
Dataset copied.
Internal feature number.
ESRI
Feature geometry.
ESRI
Internal node number for the beginning of an arc (from-node).
ESRI
Internal node number for the end of an arc (to-node).
ESRI
Internal node number for the left polygon.
ESRI
Internal node number for the right polygon.
ESRI
Length of feature in internal units.
ESRI
Internal feature number.
ESRI
User-defined feature number.
ESRI
Hydrologic Unit level.
Line spatial data source.
Metadata ID number.
Internal feature number.
ESRI
Feature geometry.
ESRI
Area of feature in internal units squared.
ESRI
Perimeter of feature in internal units.
ESRI
Internal feature number.
ESRI
User-defined feature number.
ESRI
Region code (2 digit).
Subregion code (2 digit).
Basin code (2 digit).
Subbasin code (2 digit).
Watershed code (2 digit).
Region code (2 digit).
Region name.
Subregion code (4 digit).
Subregion name.
Basin code (6 digit).
Basin name.
Subbasin code (8 digit).
Subbasin name.
Watershed code (10 digit).
Watershed name.
Watershed acreage.
Watershed area in square miles.
States in which the watershed resides.
Non-Contributing acreage (only for 100% NC watersheds, otherwise 0).
Downstream subbasin.
Subbasin modification(s).
Subbasin type.
Downstream watershed.
Watershed modification(s).
Watershed type.
This data set is a complete digital hydrologic unit boundary layer to the 5th level for the State of Arizona. 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 1st through 5th levels of hydrologic units, 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.
This is a description of attributes by field from the Federal Standards for Delineation of Hydrologic Unit Boundaries. 1) Polygon attributes Huc_8 : Eight Digit Hydrologic Unit Code A unique 8-digit code from the USGS map series "Hydrologic Unit Maps". The same number was used in every record that pertains to a subwatershed that resides within the same 8-digit sub-basin. Numbers were assigned in an upstream to downstream fashion. Where no downstream/upstream relationship could be determined numbers were assigned in a clockwise fashion. Huc_10: Ten Digit Hydrologic Unit Code This field provides a unique 10-digit code for each watershed. This same number was used in every record that pertains to a subwatershed that resides within the same 10-digit watershed. Numbers were assigned in an upstream to downstream fashion. Where no downstream/upstream relationship could be determined numbers were assigned in a clockwise fashion. Acres: Acres Area of subwatershed including non-contributing areas calculated to acres as a whole number, no decimals. The "Acres" field was calculated from the "Area" field. States: States The "States" field includes the names of all state(s) that the subwatershed falls within. The 2-digit postal abbreviation in upper case and in alphabetical order was used, separated with a comma. Ncontrb_a: Non-Contributing Area Drainage areas that do not flow toward the outlet of any hydrologic unit are considered non-contributing. If a non-contributing area is on the boundary between two or more hydrologic units, the non-contributing area is associated with the hydrologic unit adjacent to the low point on the boundary. This attribute should be the total of the non-contributing areas within a hydrologic unit calculated in acres. Hu_10_ds: Fifth Level Downstream Hydrologic Unit Code This field has the 10-digit code of the 5th level hydrologic unit that is receiving the majority of the flow from the watershed that the 6th level HU falls within. Outlets created by ditching or other artificial drainage were not considered for this field. If an HU flows into an ocean or the Gulf of Mexico, this field was populated with "OCEAN" and if a HU flows into one of the Great Lakes the term "LAKE" was used. If a HU flows across international borders, "CANADA" or "MEXICO" was used depending on which country the HU drains into. If an HU is a closed basin, then the term "CLOSED BASIN" was used. Hu_10_name: Fifth Level Hydrologic Unit Name This field used officially recognized names only. This field was populated by following the directions in subsection 6.3 "Watershed and Subwatershed Naming Protocol". The name used to attribute the watershed was used only once within a 4th level unit. Hu_10_mod: Fifth Level Hydrologic Unit Modifications This field identifies any type of modifications to natural overland flow that alters the location of the hydrologic unit boundary for a 10-digit watershed. This field shows the most significant to least significant modification(s) to the watershed boundary. One or more of the following abbreviations was used. SC - Stormwater Canal ID - Irrigation Ditch IT - Interbasin Transfer BC - Barge Canal SD - Stormwater Ditch PD - Pipe Diversion CD - Channel Diversion NC - Non-Contributing KA - Karst LE - Levee NM - No Modifications OC - Overflow Channel DM - Dam at outlet or HU boundary OT - Other Hu_10_type: Fifth Level Hydrologic Unit Type This field was populated with the hydrologic unit type from the list provided that most closely identifies the watershed. S - "Standard" hydrologic unit - Any land HU with drainage flowing to a single outlet point, excluding non-contributing areas. This includes areas or small triangular wedges between adjacent HU's that remain after classic hydrologic units are delineated. Some examples include "true", "classic", "composite", and "remnant" hydrologic units. C - "Closed Basin" hydrologic unit - A drainage area that is 100% non-contributing. This means all surface flow is internal, no overland flow leaves the hydrologic unit through the outlet point. F - "Frontal" hydrologic unit - Areas along the coastline of lakes, oceans, bays, etc. that have more than one outlet. These HU's are predominantly land with some water areas at or near the outlet(s). W - "Water" hydrologic unit - Hydrologic units that are predominantly water with adjacent land areas, ex. lake, easturies, harbors. I - "Island" hydrologic unit - A hydrologic unit that is one or more islands and adjacent water out to the toe of the shore face. U - "Unclassified" hydrologic unit - A hydrologic unit that can't be defined or doesn't fit into one of the types that have been listed. 2) Line attributes Hu_level: Hydrologic Unit Level This field provides the means to create cartographically pleasing maps. This field is populated with the highest hydrologic unit level (smallest number) for the line (arc) represented by the record. The attribute was recorded using numbers 1 through 6 representing each level with 1 being the highest and 6 the lowest level. An example would be if a line represents a region, subregion, basin, subbasin, watershed, and subwatershed boundary, then this cell was populated with a 1 (Region). Below is a list of numbers used for each level. Level Digit# Name 1 2 Region 2 4 Subregion 3 6 Basin 4 8 Subbasin 5 10 Watershed 6 12 Subwatershed Linesource: Line Spatial Data Source The Linesource indicates the base map source(s) used to delineate at 1:24,000 scale. The field was populated using one of the standardized code(s) listed below. If more than one code was used, then a comma was used to separate the codes. TOPO24 - Delineation from hardcopy 1:24,000 scale topographic maps TOPO25 - Delineation from hardcopy 1:25,000 topgraphic maps, only Alaska and Caribbean TOPO63 - Delineation from hardcopy 1:63,360 topographic maps, only Alaska and Caribbean DRG24 - Delineation from 1:24,000 scale Digital Raster Graphics DRG25 - Delineation from 1:25,000 Digital Raster Graphics, only Alaska and Caribbean DRG63 - Delineation from 1:63,360 Digital Raster Graphics, only Alaska and Caribbean DEM10 - Derived from 10 meter Digital Elevation Model DEM30 - Derived from 30 meter Digital Elevation Model NED30 - Derived from 30 meter National Elevation Dateset Model EDNA30 - (formally NED-H), derived from 30 meter Elevation Derivatives for National Applications BATH"scale" (ex. BATH24) - Interpreted from NOAA 1:24,000 scale bathymetric data HYPSO"scale" (ex. HYPSO24)- Delineated from 1:24,000 scale contour data ORTHO"scale" (ex. ORTHO12) - Interpreted from 1:12,000 scale Ortho-imagery DEDEM10 - Drainage enforced 10 meter Digital Elevation Model DEDEM30 - Drainage enforced 30 meter Digital Elevation Model GPS - Derived from Global Positioning System LIDAR - Derived from LIDAR IFSAR - Derived from IFSAR data OTH - Other UNK - Unknown All other reference and source maps not listed should be noted in the metadata. Meta_id: Metadata ID Number The Metadata ID is a code that identifies which metadata file applies to the arc. In most cases there is only one metadata file. However, in some cases more than one metadata file was used to identify different groups and/or procedures used to produce the lines. The metadata ID is a 4-character code starting with the 2-letter state postal code, followed by a 2-digit sequence number. For example "OK01", "ID02", etc
Federal Standard for Delineation of Hydrologic Unit Boundaries
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please e-mail with data requests.
The distributor shall not be held liable for improper or incorrect use of this data, based on the description of appropriate/inappropriate uses described in this metadata document. It is strongly recommended that this data is directly acquired from the distributor and not indirectly through other sources which may have changed the data in some way. These data should not be used at scales greater than 1:24,000 for the purpose of identifying hydrographic watershed boundary feature locations in Arizona. The Natural Resources Conservation Service makes no claims for the data's suitability for other purposes. The Natural Resources Conservation Service should be acknowledged as the data source in products derived from these data. The Watershed Boundary Dataset is public information and may be interpreted by all organizations, agencies, units of government, or others based on needs; however, they are responsible for the appropriate application of the data. Federal, State, or local regulatory bodies are not to reassign the boundaries authorized by the Natural Resources Conservation Service. The Natural Resources Conservation Service will not perform any evaluations of these maps or purposes related solely to State or local regulatory programs. Photographic or digital enlargement of these maps to scales greater than that at which they were originally delineated can result in misrepresentation of the data. If enlarged, the maps will not include the fine detail that would be appropriate for mapping at the small scale. Digital data files are periodically updated. Files are dated, and users are responsible for obtaining the latest version of the data from the source distributor.
.e00 & .zip
Contact GIS Specialist for product information and ordering instructions or connect to http://www.blm.gov/az/gis/index.htm
3003 N. Central Ave., Suite 800