FEMA - 30685 - Flood high water mark in Missouri

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Radford High Water Mark sign Phillips WX4SNO

A high water mark is a point that represents the maximum rise of a body of water over land. Such a mark is often the result of a

flood A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...

, but high water marks may reflect an all-time high, an annual high (highest level to which water rose that year) or the high point for some other division of time. Knowledge of the high water mark for an area is useful in managing the development of that area, particularly in making preparations for flood surges. High water marks from floods have been measured for planning purposes since at least as far back as the civilizations of ancient

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

. It is a common practice to create a physical marker indicating one or more of the highest water marks for an area, usually with a line at the level to which the water rose, and a notation of the date on which this high water mark was set. This may be a free-standing flood level

sign A sign is an object, quality, event, or entity whose presence or occurrence indicates the probable presence or occurrence of something else. A natural sign bears a causal relation to its object—for instance, thunder is a sign of storm, or me ...

or other marker, or it may be affixed to a building or other structure that was standing at the time of the flood that set the mark. A high water mark is not necessarily an actual physical mark, but it is possible for water rising to a high point to leave a lasting physical impression such as floodwater staining. A landscape marking left by the high water mark of ordinary tidal action may be called a strandline and is typically composed of debris left by high tide. The area at the top of a

beach A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shel ...

where

debris Debris (, ) is rubble, wreckage, ruins, litter and discarded garbage/refuse/trash, scattered remains of something destroyed, or, as in geology, large rock fragments left by a melting glacier, etc. Depending on context, ''debris'' can refer to ...

is deposited is an example of this phenomenon. Where there are

tide Tides are the rise and fall of sea levels caused by the combined effects of the gravity, gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide t ...

s, this line is formed by the highest position of the tide, and moves up and down the beach on a fortnightly cycle. The debris is chiefly composed of rotting

seaweed Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...

, but can also include a large amount of

litter Litter consists of waste products that have been discarded incorrectly, without consent, at an unsuitable location. Litter can also be used as a verb; to litter means to drop and leave objects, often man-made, such as aluminum cans, paper cups, ...

, either from

ship A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...

s at sea or from

sewage Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewer system. Sewage consists of wastewater discharged from residenc ...

outflows.

Ecological significance

The strandline is an important

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

for a variety of

animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...

s. In parts of the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

sandhopper Talitridae is a family of amphipods. Terrestrial species are often referred to as landhoppers and beach dwellers are called sandhoppers or sand fleas. The name sand flea is misleading, though, because these talitrid amphipods are not siphonapter ...

s such as ''

Talitrus saltator ''Talitrus saltator'', a species of sand hopper, is a common amphipod crustacean of sandy coasts around Europe. The animal's typical "hopping" movement gives it its common name, and is produced by a flexion of the abdomen. In order to do this, ...

'' and the

seaweed fly Kelp fly is one common name of species of flies in a number of families of "true flies" or Diptera. They generally feed on stranded and rotting seaweed, particularly kelp in the wrack zone. When conditions are suitable they are very numerous and ...

Coelopa frigida ''Coelopa frigida'' is a species of seaweed fly or kelp fly. It is the most widely distributed species of seaweed fly. It can be found on most shorelines in the temperate Northern Hemisphere. Other species of seaweed flies include ''Coelopa nebul ...

'' are abundant in the rotting seaweed, and these invertebrates provide food for shore birds such as the rock pipit,

turnstone Turnstones are two bird species that comprise the genus ''Arenaria'' in the family Scolopacidae. They are closely related to calidrid sandpipers and might be considered members of the tribe Calidriini. The genus ''Arenaria'' was introduced by t ...

and

pied wagtail The white wagtail (''Motacilla alba'') is a small passerine bird in the family Motacillidae, which also includes pipits and longclaws. The species breeds in much of Europe and the Asian Palearctic and parts of North Africa. It has a toehold in ...

, and

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s such as brown hares,

foxes Foxes are small to medium-sized, omnivorous mammals belonging to several genera of the family Canidae. They have a flattened skull, upright, triangular ears, a pointed, slightly upturned snout, and a long bushy tail (or ''brush''). Twelve sp ...

vole Voles are small rodents that are relatives of lemmings and hamsters, but with a stouter body; a longer, hairy tail; a slightly rounder head; smaller eyes and ears; and differently formed molars (high-crowned with angular cusps instead of low-c ...

s and

mice A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

Legal significance

One kind of high water mark is the ordinary high water mark or average high water mark, 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 and is often being used to demarcate

property Property is a system of rights that gives people legal control of valuable things, and also refers to the valuable things themselves. Depending on the nature of the property, an owner of property may have the right to consume, alter, share, r ...

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 United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, the high water mark is also significant because the

United States Constitution The Constitution of the United States is the Supremacy Clause, supreme law of the United States, United States of America. It superseded the Articles of Confederation, the nation's first constitution, in 1789. Originally comprising seven ar ...

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 Clean Water Act (CWA) is the primary federal law in the United States governing water pollution. Its objective is to restore and maintain the chemical, physical, and biological integrity of the nation's waters; recognizing the responsibiliti ...

, 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 Rivers and Harbors Appropriation Act of 1899 is the oldest federal environmental law in the United States. The Act makes it a misdemeanor to discharge refuse matter of any kind into the navigable waters, or tributaries thereof, of the United S ...

, the OHWM defines the lateral limits of federal jurisdiction over traditional navigable waters of the US. The OHWM is used by the

United States Army Corps of Engineers , colors = , anniversaries = 16 June (Organization Day) , battles = , battles_label = Wars , website = , commander1 = ...

, the

United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...

, 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. In 2016, the Court of Appeals of Indiana ruled that land below the OHWM (as defined by common law) along Lake Michigan is held by the state in trust for public use. .

References

External links

{{wiktionary, high-water mark Surveying Beaches Hydrology Lakes Riparian zone Rivers Wetlands Vertical position

Ecological significance

Legal significance

See also

References

External links