Watershed Creation

Watershed Creation

• 1.
  State of Alaska Watershed and Stream Hydrography Enhanced Datasets (AWSHED) Project
• 2.
  Project Background andDetailsPrior to the completion of this project, the State of Alaska had defined watersheds to the 4th Level sub-basin level. The Alaska Geospatial Data Committee (AGDC) and the Alaska state government expressed a need to further refine this scale to a watershed (5th level) and sub-watershed (6th level) system. These Watersheds and sub-watersheds would be Delineated and certified into the national Watershed Boundary Dataset (WBD), thus leading to Increased capabilities for watershed modeling and sharing of aquatic resources information in Alaska.
• 3.
  The following isa visual illustration of the process of watershed and sub-watershed delineation that took place.
• 4.
  ALASKA REGION (LEVEL 1)
• 5.
  SUB-REGION (LEVEL 2)
• 6.
  BASIN (LEVEL 3)
• 7.
  SUB-BASIN (LEVEL 4)
• 8.
  SUB-BASIN (LEVEL 4)
• 9.
  DELINEATE 5TH LEVELWATERSHEDS ALONG THE UPLAND CONTOURS FROM THE MOST DOWNSTREAM POINT
• 10.
  REPEAT LAST STEPFOR NEXT WATERSHED
• 11.
  AND REPEAT AGAIN
• 12.
  UNTIL THE SUB-BASINIS COMPLETELY DIVIDED INTO WATERSHEDS
• 13.
  NOW INPUT ATTRIBUTEDATA4th level HUC No.5th level HUC No.Downstream 5th level HUC No.
• 14.
  NOW DIVIDE THE5TH LEVEL WATERSHEDS INTO 6TH LEVEL SUB-WATERSHEDS ALONG THE UPLAND CONTOURS FROM THE MOST DOWNSTREAM POINT
• 18.
  UNTIL THE WATERSHEDIS COMPLETELY DIVIDED INTO SUB-WATERSHEDS
• 19.
  NOW INPUT ATTRIBUTEDATA FOR THE SUB-WATERSHEDS5th level HUC No.6th level HUC No.
• 20.
  NOW INPUT ATTRIBUTEDATADownstream 5th level HUC No.
• 21.
  At time ofcompletion over 1000 fully named and numbered watersheds were created and almost 15,000 sub-watersheds.Futher documentation on this project can be found at http://agdc.usgs.gov/hydro/