Oregon Department of Fish and Wildlife

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Columbia River Estuary

Bathymetric and Topographic Surveys

 

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T-Sheets Extent
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Historic hydrographic (H-sheets) and topographic (T-sheets) surveys adjacent to the river channel were conducted by the National Geodetic Survey , formerly the U.S. Coast and Geodetic Survey.  Hydrographic surveys maps were cartographically combined with the topographic survey maps to produce Nautical Charts for river navigation.  Topographic surveys contain shoreline delineation, structures, and habitat in the adjacent floodplain.  The extent of the floodplain surveyed appeared to vary depending on the surveyor or the area.  No bathymetric data was provided on the topographic survey maps.  However, shallow water detail was superior in the hydrographic survey maps, so for that reason the hydrographic maps were included in this project.

Click images to see a larger version

T-shee7.gif (68289 bytes)Topographic Survey Maps (T-sheets)

Scale: 1:10,000
Vertical Datum: 
Horizontal Datum: US Standard or North American Datum
Shoreline Delineation: MHW - mean high water

Purpose: Shoreline delineation, topography

Bathyc8.gif (15089 bytes)

Nautical Chart

commonly referred to as U.S. Coastal Survey Maps 

Scale: 1:40,000
Vertical Datum: 
Horizontal Datum: US Standard or North American Datum
Shoreline Delineation:  MLLW - mean lower low water
wpe1.jpg (14911 bytes) Hydrographic Survey maps (H-sheets)
Scale: 1:10,000
Vertical Datum: 
Horizontal Datum: 
Shoreline Delineation: MHHW - mean higher high water
Purpose: Navigation