Marine Conservation Agreements
A Practitioner's Toolkit
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Submerged Lands

The term submerged lands is primarily used in the United States to describe lands lying below the high tide line or high water mark.1 The accompanying figure depicts the terms used by different countries, sources, and states to describe lands lying below the high tide line.

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General Terms

   

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United Kingdom

In the United Kingdom, the area between the Mean High Water (MHW) and Mean Low Water (MLW) is referred to as the foreshore while the area below the MLW is referred to as the seabed.

United States - Federal Submerged Lands Act

The U.S. Federal Submerged Lands Act (SLA) (download pdf, 176k) surprisingly does not define submerged lands. Instead the SLA defines lands beneath navigable waters as “...all lands permanently or periodically covered by tidal waters up to but not above the line of Mean High Tide (MHT) and seaward to a line three geographical miles distant from the coast line.” As a result, the SLA implies that submerged lands and lands beneath navigable waters are the same.

United States - Putting the Public Trust Doctrine to Work

The renowned publication Putting the Public Trust Doctrine to Work (Sade et al. 1997) is used by many national organizations, federal agencies, and state agencies as a guide to public trust-related issues on public trust lands, which submerged lands are normally considered. Submerged lands are defined within this publication as lands below the Ordinary Low Tide (OLT). It also defines tidelands as land between the Ordinary High Tide (OHT) and the Ordinary Low Tide.

Alabama

Along Alabama's coast, submerged lands are those lands lying between the Mean High Tide (MHT) line and the three-mile seaward extent of the state's jurisdictional limit.

Alaska

In Alaska, the land area between the Mean High Tide (MHT) and the Mean Low Tide (MLT) is referred to as tidelands while the land area between the MLT and the seaward extent of the state jurisdictional limit is referred to as submerged lands.

California

In California, tidelands are those lands that lie between the Mean High Tide (MHT) and the Mean Low Tide (MLT) while submerged lands are those lands that lie between the MLT and the three-mile seaward extent of the state's jurisdictional limit.

Connecticut

The terms submerged lands and tidelands are both used in Connecticut to mean lands lying water ward of the Mean High Water (MHW) line in tidal, coastal, or navigable waters of the state. This area is defined as public beach in the Connecticut Coastal Management Act.

Delaware

In Delaware, tidelands are those lands lying between the Mean High Water (MHW) line and Mean Low Water (MLW) line while submerged lands are those lands lying between the MLW line and three-mile seaward extent of the state's jurisdictional limit. Together, tidelands and submerged lands are referred to as sub aqueous lands.

Florida

Florida's submerged lands include all lands lying water ward of the Ordinary (or mean) High Water (OHW) line.

Georgia

Georgia's coastal submerged lands extend from the Ordinary High Water (OHW) mark to three nautical miles offshore.

Hawaii

Submerged lands in Hawaii include all lands lying between the upper reaches of the waves on the shore and the seaward extent of the state's jurisdictional limits.

Louisiana

Louisiana refers to its submerged lands as navigable water bottoms. Navigable water bottoms within the Gulf of Mexico and the arms of the sea generally start at the seashore, which begins on the landward side at the highest tide of winter or the Ordinary High Water (OHW) line (there is some question as to which line is the official ownership line as the OHW line is likely to be more landward than the highest tide of winter line). In bays, navigable water bottoms begin at the OHW line.

Maine

In Maine, submerged lands include lands lying below the Mean Low Water (MLW) line and extending seaward three nautical miles. Presumably, inter tidal areas lie between the Mean High Water (MHW) and MLW lines.

Maryland

In Maryland, tidal wetlands means any land under the navigable waters of the state below the Mean High Tide (MHT), affected by the regular rise and fall of the tide.

Massachusetts

Massachusetts generally refers to the area between the Mean High Water (MHW) and the Historic Low Water (HLW) as the inter tidal zone or tidal flats. The area lying between the HLW and the seaward extent of state jurisdiction (usually three nautical miles, including all of Cape Cod and Massachusetts Bays) is called submerged lands. Collectively, the inter tidal zone and submerged lands make up tidelands, which is the most common term used to refer to these areas.

Mississippi

Mississippi calls the land between the Mean Low Tide (MLT) and Mean High Tide (MHT) tidelands, and the land below MLT submerged lands (or submerged water bottoms).

North Carolina

As a general matter, most lands seaward of the Mean High Tide (MHT) line are referred to as public trust lands or, on occasion, as sovereignty lands.

New Hampshire

The state of New Hampshire does not commonly use the term submerged lands. Instead, public tidal or coastal waters is used to describe all waters subject to the ebb and flow of the tide, including the Great Bay Estuary and the associated tidal rivers. The term tidal flat is used to describe a relatively level landform composed of unconsolidated mineral and organic sediments, usually continuous with the shore, and that is alternately flooded and exposed by the tides, presumably the inter tidal area between a Low Water (LW) and High Water (HW) line. It is unclear if there is a specific term used to describe the area lying below the low water line.

New Jersey

The state of New Jersey uses the terms tidelands or riparian lands to describe areas under state waters up to the Mean High Tide (MHT) line.

New York

The State of New York refers to submerged lands as lands under water, which begin at the Mean High Water (MHW) line and extend seaward three nautical miles into the Atlantic Ocean, Long Island Sound, and other navigable bays.

Oregon

The state of Oregon uses two terms to describe areas lying between the high water line and jurisdictional limit of the state: submerged lands and submersible lands. Submerged lands are those lands lying below the Ordinary Low Water (OLW) line of all... tidally influenced waters... normally extending seaward three nautical miles. Submersible lands are those lands lying between the Ordinary High Water (OHW) line and the OLW line of all... tidally influenced waters.

Pennsylvania

In Pennsylvania, submerged lands include waters and permanently or periodically inundated lands, including lands in the beds of navigable lakes and rivers and beds of streams. Submerged lands generally extend only as far landward as the Low Water Mark (LWM) and as far from shore as the boundaries of other states and nations. It is unclear what term is used to describe the inter tidal area lying between the LWM and the High Water Mark (HWM).

Rhode Island

The terms used to describe the lands lying below the mean high water line in Rhode Island can be confusing. Rhode Island refers to the lands lying between the Mean High Water (MHW) line and the seaward extent of the state's jurisdictional limit (three nautical miles) as tidal lands. However, the terms submerged lands and tidelands are also used to describe this area. The term submersible lands is used to describe the area lying between the MHW line and the Mean Low Water (MLW) line while sub tidal lands and submerged lands can be used interchangeably to describe the area lying between the MLW line and the seaward extent of the state's jurisdictional limit.

South Carolina

In South Carolina tidelands include all areas below the Mean High Tide (MHT) line. The area between MHT and the Mean Low Tide (MLT) are considered inter tidal lands while submerged lands include areas lying below the MLT.

Texas

Submerged lands along the Texas coast generally include any lands lying between the Mean High Tide (MHT) line and the seaward extent of the state's jurisdictional limit, which lies nine nautical miles offshore.

Virginia

In Virginia, submerged lands or submerged bottoms are those lands lying between the Mean Low Water (MLW) mark and the seaward extent of the state's jurisdictional limit, three nautical miles offshore. However, the terms sub aqueous lands and sub aqueous bottoms are used most frequently to describe these areas, while the term bottomlands is rarely used. Some form of all of these terms can be found in Virginia's legal code. Tidal wetlands is the term used to describe lands between the Mean High Water (MHW) mark and the MLW mark.

Washington State

In Washington State the term aquatic lands is used somewhat synonymously with submerged lands. While the term submerged lands is not legally defined in Washington State, aquatic lands is defined in state statute as all tidelands... and the beds of navigable waters. Tidelands are defined as the shores of navigable tidal waters... between the line of Ordinary High Tide (OHT) and the line of Extreme Low Tide (ELT). Beds of navigable waters, or bed lands, lie below the ELT.

 
Show general terms
Countries
U.S. States
Mississippi
New Hampshire
California New Jersey
Connecticut New York
Delaware North Carolina
Florida Oregon
Georgia Pennsylvania
Hawaii Rhode Island
Louisiana South Carolina
Maine Texas
Maryland Virginia
Massachusetts Washington State

A Complex Term in the U.S.

The term submerged lands is complex and often confusing as there is little standardized application of submerged lands in the U.S. For example, a major federal law (the Submerged Lands Act) and a renowned publication (Putting the Public Trust Doctrine to Work, Sade et al., 1997) are inconsistent in their use of the term as are many individual states.

U.S. State Submerged Lands

In general, U.S. state submerged lands (along ocean coasts) are considered those lands lying between the high or low tide line of a state and the seaward jurisdictional limit of the state, which is normally three nautical miles (except for Texas, Florida, and Puerto Rico within the Gulf of Mexico where the seaward jurisdictional limit is nine nautical miles).

Several issues complicate the use of the term submerged lands:

  1. States do not always use the term submerged lands. Instead, states use various and often inconsistent terms, such as aquatic lands, tidelands, water bottoms, and underwater lands (among other terms), to describe areas below the high tide line.
  2. States often, but not always, use different terms to describe subsets of areas that lie below the high tide line. States may refer to areas close to shore differently than areas further offshore. States may also refer to areas within estuaries and bays differently than areas along the open coast.
  3. Many states use different terms and measurements to describe the landward extent of submerged lands, such as the wash up line, extreme high tide line, or mean high water mark (and several different combinations and variations of the aforementioned terms).
  4. Some states are considered high-water states2 and others are considered low-water states3. In high-water states, the submerged lands are typically thought to extend landward to a state-defined high water line while in low-water states the submerged lands are typically thought to extend landward only to a state-defined low water line. This does not mean, however, that state ownership always or only extends to the high or low water line (further discussion on this can be found within Public Ownership).

U.S. Federal Submerged Lands

U.S. Federal submerged lands are considered those lands starting at the seaward extent of states' jurisdictional limits and extending further seaward to the extent of the U.S. Federal Exclusive Economic Zone (200 nautical miles).

Sub tidal and Inter tidal Lands

The terms inter tidal lands and sub tidal lands are used somewhat consistently throughout the United States. These terms are more descriptive and functional, as opposed to legal, in nature when compared to submerged lands. In general, inter tidal lands are considered those lands lying between the high tide and low tide while sub tidal lands are considered those lands lying below the low tide.

 

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1 Since the focus of this toolkit is on ocean and related coastal conservation, further discussion on submerged, inter tidal, and sub tidal lands will be limited to application of the terms to saltwater areas.

2 High-water states include: Alabama, Alaska, California, Connecticut, Florida, Georgia, Hawaii, Louisiana, Maryland, Mississippi, New Jersey, New York, North Carolina, Oregon, Rhode Island, South Carolina, Texas, and Washington State.

3 Low-water states include: Delaware, Massachusetts, Maine, New Hampshire, and Virginia.

 

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