Hydrological code: Difference between revisions

Revision as of 10:07, 8 October 2018

Revision as of 14:40, 29 September 2019

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[[Image:Huc region-edit.png|thumb|right|The 21 top-level 2-digit "region" hydrologic unit boundaries. The names are as follows: 01 New England, 02 Mid-Atlantic, 03 South Atlantic-Gulf, 04 Great Lakes, 05 Ohio, 06 Tennessee, 07 Upper Mississippi, 08 Lower Mississippi, 09 Souris-Red-Rainy, 10 Missouri, 11 Arkansas-White-Red, 12 Texas-Gulf, 13 Rio Grande, 14 Upper Colorado, 15 Lower Colorado, 16 Great Basin, 17 Pacific Northwest, 18 California, 19 Alaska, 20 Hawaii, 21 Caribbean.]]

The regions (1st level hydrologic units) are geographic areas that contain either the [[Drainage basin|drainage area]] of a major river, such as the Missouri region, or the combined drainage areas of a series of rivers, such as the Texas–Gulf region. Each subregion includes the area drained by a river system, a [[Reach (geography)|reach]] of a river and its tributaries in that reach, a [[Endorheic basin|closed basin]] or basins, or a group of streams forming a coastal drainage area.<ref name=HUmaps>{{cite web |title= Hydrologic Unit Maps, U.S. Geological Survey Water-Supply Paper 2294 |last1= Seaber |first1= Paul R. |last2= Kapinos |first2= F. Paul |last3= Knapp |first3= George L. |publisher= [[United States Geological Survey]] |url= http://pubs.usgs.gov/wsp/wsp2294/pdf/wsp_2294.pdf |accessdate= 3 November 2010}}</ref> Regions receive a two-digit code. The following levels are designated by the addition of another two digits.<ref>{{cite web|url=https://www.nrcs.usda.gov/programs/rwa/Watershed_HU_HUC_WatershedApproach_defined_6-18-07.pdf |title=Watersheds, Hydrologic Units, Hydrologic Unit Codes, Watershed Approach, and Rapid Watershed Assessments |publisher=[[USDA]] |accessdate=2010-10-27 |deadurlurl-status=yes dead|archiveurl=https://web.archive.org/web/20101012233329/http://www.nrcs.usda.gov/programs/rwa/Watershed_HU_HUC_WatershedApproach_defined_6-18-07.pdf |archivedate=2010-10-12 |df= }}</ref>

[[Image:HUC subregions.png|thumb|right|A map of the "subregion hydrologic unit boundaries. Note this updated map updates boundaries to include the ocean as well as the portions of the basins that cross international boundaries.]]

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* {{cite web |url= http://www.dcr.virginia.gov/soil_and_water/hu.shtml |title= Hydrologic Unit Geography |publisher= Virginia Department of Conservation & Recreation |accessdate= 21 November 2010}}

* {{cite web |url= http://ccm.jrc.ec.europa.eu |title= CCM2 Catchments and Rivers of Europe |publisher= Joint Research Center of the European Commission |accessdate= 13 September 2012}}

* {{cite web|url=http://193.178.1.168/River_Coding_Review.pdf |title=Review of Existing River Coding Systems |publisher=European Coding Systems WFD GIS Working Group |accessdate=29 September 2014 |deadurlurl-status=yes dead|archiveurl=https://web.archive.org/web/20070121122717/http://193.178.1.168/River_Coding_Review.pdf |archivedate=January 21, 2007 }}

[[Category:Hydrology]]