State of Alaska Watershed and Stream Hydrography Enhanced Datasets (AWSHED) Project

Project Background and Details

Prior 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.

The following is a visual illustration of the process of watershed and sub-watershed delineation that took place.

ALASKA REGION (LEVEL 1)

SUB-REGION (LEVEL 2)

BASIN (LEVEL 3)

SUB-BASIN (LEVEL 4)

SUB-BASIN (LEVEL 4)

DELINEATE 5TH LEVEL WATERSHEDS ALONG THE UPLAND CONTOURS FROM THE MOST DOWNSTREAM POINT

REPEAT LAST STEP FOR NEXT WATERSHED

AND REPEAT AGAIN

UNTIL THE SUB-BASIN IS COMPLETELY DIVIDED INTO WATERSHEDS

NOW INPUT ATTRIBUTE DATA

4th level HUC No.

5th level HUC No.

Downstream 5th level HUC No.

NOW DIVIDE THE 5TH LEVEL WATERSHEDS INTO 6TH LEVEL SUB-WATERSHEDS ALONG THE UPLAND CONTOURS FROM THE MOST DOWNSTREAM POINT

UNTIL THE WATERSHED IS COMPLETELY DIVIDED INTO SUB-WATERSHEDS

NOW INPUT ATTRIBUTE DATA FOR THE SUB-WATERSHEDS

5th level HUC No.

6th level HUC No.

Downstream 5th level HUC No.

NOW INPUT ATTRIBUTE DATA

At time of completion 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/