Content deleted Content added
m Task 18 (cosmetic): eval 13 templates: del empty params (5×); hyphenate params (14×); |
Mdoughty332 (talk | contribs) No edit summary |
||
Line 76:
The boundaries of the hydrologic units usually correspond to drainage basins with some exceptions; for example, subregion 1711, called "Puget Sound", includes all U.S. drainage into not only Puget Sound but also the [[Strait of Georgia]], [[Strait of Juan de Fuca]], and the [[Fraser River]].<ref>{{cite web |url= http://wa.water.usgs.gov/data/wuse/huc.names.txt |title= List Hydrologic Unit Codes (HUCs) - USGS Washington |publisher= [[USGS]] |access-date= 19 July 2011}}</ref> Also, region and subregion boundaries end at the U.S. international boundary.<ref name=HUmaps/>
=== Delineation ===
In general, hydrologic units were delineated such that all surface drainage within each unit converges at a single outlet point—a type of hydrologic unit called a "classic hydrological unit". It was not always possible to delineated units in this way while adhering to the size and subdivision standards of the system. There are several "non-classic" types of drainage areas, each requiring special criteria for delineation and subdivision.<ref name="WBDstandard" />
"Remnant areas" occur along coasts where individual streams are too small for the given subdivision type. Such remnants were combined into a single unit if they were adjacent and could be combined. These "composite" units are called "frontal units". They are non-classic because they have more than one outlet.<ref name=WBDstandard/>
| |||