Strandline - Legal Significance

Legal Significance

One kind of high water mark is the ordinary high water mark or average high water mark, which is the high water mark that can be expected to be produced by a body of water in non-flood conditions. The ordinary high water mark may have legal significance, often being used to demarcate property boundaries. The ordinary high water mark has also been used for other legal demarcations. For example, a 1651 analysis of laws passed by the English Parliament notes that for persons granted the title Admiral of the English Seas, "the Admirals power extended even to the high water mark, and into the main streams".

In the United States, the high water mark is also significant because the United States Constitution gives Congress the authority to legislate for waterways, and the high water mark is used to determine the geographic extent of that authority. Federal regulations (33 CFR 328.3(e)) define the "ordinary high water mark" (OHWM) as "that line on the shore established by the fluctuations of water and indicated by physical characteristics such as a clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding areas. For the purposes of Section 404 of the Clean Water Act, the OHWM defines the lateral limits of Federal jurisdiction over non-tidal water bodies, in the absence of adjacent wetlands. For the purposes of Sections 9 and 10 of the Rivers and Harbors Act of 1899, the OHWM defines the lateral limits of Federal jurisdiction over traditional navigable waters of the U.S. The OHWM is used by the U.S. Army Corps of Engineers, the U.S. Environmental Protection Agency, and other Federal agencies to determine the geographical extent of their regulatory programs. Likewise, many states use similar definitions of the OHWM for the purposes of their own regulatory programs.