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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 freshwater 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 and Okanogan counties
Mike Locatelli
Michael.locatelli@ecy.wa.gov
509-379-4541

Benton, Kittitas, and Yakima counties
Ryan Anderson
ryan.anderson@ecy.wa.gov
509-379-1917

Douglas and Klickitat counties
Heather Durkee
Heather.Durkee@ecy.wa.gov
509-379-4530

 
Eastern Regional Office:
Adams, Grant, Lincoln, & Whitman counties
Jake Madewell
Jake.Madewell@ecy.wa.gov
509-437-0255

Asotin, Columbia, Franklin, Garfield, Spokane, and Walla Walla counties
Mindi Sheer
Mindi.Sheer@ecy.wa.gov
509-601-9546

Ferry, Pend Oreille, & Stevens counties
Ryan McNair
Ryan.McNair@ecy.wa.gov
509-309-5547
 
Northwest Regional Office:
King County
Leah Beckett
leah.beckett@ecy.wa.gov
425-324-5590

Neil Molstad
neil.molstad@ecy.wa.gov
425-389-5549

Snohomish county
Doug Gresham
doug.gresham@ecy.wa.gov
425-429-1846

Island county
Leah Beckett
leah.beckett@ecy.wa.gov
425-324-5590

Kitsap county
Neil Molstad
neil.molstad@ecy.wa.gov
425-389-5549

Whatcom, San Juan, and Skagit Counties
Chris Luerkens
chris.luerkens@ecy.wa.gov
360-410-4807

Southwest Regional Office:
Clallam, Jefferson, and Thurston counties
Lizzie Carp
lizzie.carp@ecy.wa.gov
564-200-4184


Pacific, Grays Harbor, and Lewis counties
Zach Meyer
zach.meyer@ecy.wa.gov
360-481-9885

Clark, Cowlitz, and Skamania counties
Meghan Flounlacker
Meghan.Flounlacker@ecy.wa.gov
360-210-2783

Pierce, Mason, and Wahkiakum counties
Brook Swensen
Brook.swensen@ecy.wa.gov
564-999-1749