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Water & Shorelines > Shoreline & coastal management > Shoreline management > Shoreline Management Act > Shoreline Management Act jurisdiction > Ordinary high water mark

Ordinary high water mark

Under Washington's Shoreline Management Act, the ordinary high water mark (OHWM) is defined as a biological vegetation mark. For locations where the OHWM cannot be found, our Shoreline Master Program guidelines include default elevation lines for tidal and fresh water shorelines. 

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Definition

The ordinary high water mark is defined as:
"That mark that will be found by examining the bed and banks and ascertaining where the presence and action of waters are so common and usual, and so long continued in all ordinary years, as to mark upon the soil a character distinct from that of the abutting upland, in respect to vegetation as that condition exists on June 1, 1971, as it may naturally change thereafter, or at it may change thereafter in accordance with permits issued by a local government or the Department of Ecology.

"Provided, that in any area where the ordinary high water mark cannot be found, the ordinary high water mark adjoining salt water shall be the line of mean higher high tide and the ordinary high water mark adjoining fresh water shall be the line of mean high water."
In relation to extreme high and extreme low water, the position of the OHWM varies from site to site and changes through time due to a number of factors including:
Shoreline cross-section showing extreme high water mark, ordinary high water mark, and extreme low water mark in relation to vegetation and distance from shore.

Ordinary high water mark in relationship to extreme high and extreme low water marks.

  • Accretion
  • Activities of beavers and other animals and organisms
  • Consistency of pool elevations
  • Erosion
  • Groundwater
  • Land-use changes
  • Presence of peat
  • Soils
  • Stormwater runoff
  • Substrates
  • Waves
  • Wind

Related links


Contact information

Central Regional Office:
Chelan, Douglas, and Okanogan counties
Andrea Jedel
andrea.jedel@ecy.wa.gov
509-454-4260

Benton, Kittitas, Klickitat, and Yakima counties
Lori White
lori.white@ecy.wa.gov
509-575-2616
 
Eastern Regional Office:
Stevens county
Jeremy Sikes
jeremy.sikes@ecy.wa.gov
509-329-3426

Ferry, Grant, Lincoln, Pend Oreille, and Spokane counties
Jacob McCann
jacob.mccann@ecy.wa.gov
509-329-3426

Adams, Asotin, Columbia, Garfield, Franklin, Walla Walla, and Whitman counties
Hallie Ladd
hallie.ladd@ecy.wa.gov
509-329-3474
 
Northwest Regional Office:
King, San Juan, Skagit, and Snohomish counties
Doug Gresham
doug.gresham@ecy.wa.gov
425-649-7199

Island, Kitsap, and Whatcom counties
Diane Hennessey
diane.hennessey@ecy.wa.gov
425-649-4447
 
Southwest Regional Office:
Clallam, Grays Harbor, Jefferson, Mason, and Pacific counties
Rick Mraz
richard.mraz@ecy.wa.gov
360-407-6221

Clark, Cowlitz, Skamania, and Wahkiakum counties
Rebecca Rothwell
rebecca.rothwell@ecy.wa.gov
360-407-7273

Lewis, Pierce, and Thurston counties
Zach Meyer
zachary.meyer@ecy.wa.gov
360-407-6167