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Access, Lateral

Right to walk or otherwise move along a shore, once someone has reached the shore.

Access, Perpendicular

Legally permissible means of reaching the shore from dry land.

Access Point

Place where anyone may legally gain access to the shore; usually a park, the end of a public street, or a public path. A place where perpendicular access is provided.


One of three general pathways by which society can respond to rising sea level or shoreline erosion, in which no effort is made at shore protection while human activities continue to occupy an increasingly wet environment. This approach is most common for a small rise in sea level that does not warrant the major investments or relocations necessitated by the retreat and shore protection pathways.


1. Gradual and imperceptible advance of a shoreline into the sea. 2. Legal doctrine under which property lines that follow the shoreline move with the changing shore when that change is gradual and imperceptible, whether the shore erodes or accretes. 3.  Wetland Accretion.

Affirmative Easement

 See easement.


See shoreline armoring.

Astronomical Tides

Tides that result from gravitational forces of the moon and sun on ocean waters.

Average High Water Mark

1. In this report, the average upper reach of the waves during all the high tides over the course of the year.  2.  The average position of the wet/dry line along a sandy beach.  3. The upper reach of the waves during a day with average seas and the average high tide.


1.  Loss or gain of lands bordering on the seashore by sudden or violent action of the elements, perceptible while in progress, or caused by human activities.  Often refers to the sudden and rapid change in the course and channel of a boundary river. 2. Legal doctrine under which property lines that follow the shoreline do not move with the changing shore, when that change is sudden and perceptible.

Barrier Island

Long, narrow coastal landform composed of sand that is essentially parallel to the shore and usually separated by wetlands; protects inland areas from ocean waves and storms.

Barrier Island Migration

Whole-scale movement of a barrier island or barrier spit in response to sea level rise, changes in sediment supply, storm surges or waves, or some combination of these factors.

Barrier Island Raising

Combination of beachfill and grade elevation in the area landward of the beach. The landward portion is rarely elevated as a large-scale operation. Individual lot owners sometimes import fill to raise their lots, especially if the lots are prone to flooding.


Unconsolidated material that covers a gently sloping zone, typically with a concave profile, extending landward from the low water line to the place where there is a definite change in material or physiographic form (such as a cliff), or to the line of permanent vegetation (usually the effective limit of the highest storm waves); a shore of a body of water, formed and washed by waves or tides, usually covered by sand or gravel and lacking a bare rocky surface.

Beach Nourishment

Addition of sand, usually dredged from offshore, to an eroding shoreline to enlarge or create a beach area, offering both temporary shore protection and recreational opportunities. Putting sand where there is none necessarily raises the elevation, but engineered beaches can be designed to have a volume and height that a natural beach would never attain. Also known as “beachfill” and “sand replenishment.”


Elevated landform, such as a cliff, composed of partially consolidated and unconsolidated sediments, typically sands, gravel, and/or clays.


Offshore structure (such as a wall or jetty) that, by breaking the force of the waves, protects a harbor, anchorage, beach, or shore area.


Vertical wall along the shore designed either to create a vertical shore for navigation purposes, or to prevent erosion in areas with minor wave action.

Buyer Resistance

Reluctance of a potential purchaser to pay what a product is worth for reasons that appear to be based on intuition or emotion rather than a rational assessment of the product’s value. The requirement that the price be discounted because of a feature by an amount far in excess of any reasonable expectation of the cost of that feature, e.g., requiring a price discount of $1,000 because of a clause that may require a payment of $500.

Civil Law

A system of law derived from Roman Law as codified by the Institutes of Justinian.  The civil law governs most of Europe, and South America, other than former British Colonies, as well as parts of Asia and Africa.   Unlike common law, judges do not make law under the civil system.  In the United States, Louisiana is the only state that (partially) follows the civil law today.  But some land grants conform to the civil law rather than the common law, in states that were once ruled by France or Spain.  In particular, the public trust extended farther inland under the civil law than the common law.

Coastal Zone

Area extending from the ocean inland across the region directly influenced by marine processes.

Common Law

The system of law developed by English judges and adopted by most states, based on precedent and case law, in which judges make decisions on specific cases, generally on matters where no statute clearly applies, and each judge attempts to rule in a manner consistent with how previous courts have addressed similar facts.

Conservation Easement.

A negative easement in gross whose restrictions promote conservation. Ownership is generally limited to government agencies and qualified nonprofit land trusts.

Contour Interval

Difference in elevations of adjacent contours on a topographic map. The smaller the contour interval, the more precise the map.

Covenant Running with the Land

Agreement concerning use of a parcel of land between an owner of the parcel and an owner of a nearby parcel, which binds and benefits successive owners of both parcels as if each had made the agreement. Unless otherwise specified, covenant running with the land means legal covenant running with the land for which the remedy for a violation would be an award of damages. Often a given agreement is also an equitable covenant running with the land, also known as an equitable servitude.

Defeasible Estate

Complete ownership of land that is capable of terminating upon the occurrence of an event.

Design Sea Level

The sea level at which a rolling easement based on sea level changes ownership.


Wall generally of earthen materials designed to prevent permanent inundation of lands below sea level, tidal flooding of lands between sea level and spring high water, or storm-surge flooding of the coastal floodplain.

Dominant Estate

Land whose owner benefits from an easement.

Dredge and Fill

Process used extensively before the 1970s to elevate estuarine shorelines to a height that allows construction of homes. Commonly known as lagoon development, channels are dredged through tidal wetlands to allow small boat navigation, and dredge spoil is placed on the remaining marsh to raise the marsh high enough to allow development. Also known as “canal estates.”

Dry Beach

1.  In legal writing, the portion of a beach landward of mean high water   2.  In geological writing, the portion of a beach landward of the wet/dry line or upper limit of wave runup.


Landform characterized by accumulation of wind-blown sand, often vegetated, along the coast.


Right to enter land possessed by someone else and make limited use of that land (such as walk, fish, change the grade elevation, or drain water). Also known as affirmative easement.


1.  In this primer, to lie a short distance seaward beyond the boundary line, either by advancing beyond the boundary, or be remaining in place while the boundary line moved inland.  2. To advance a short distance beyond the normal boundary line.

Easement Holder

Party who owns the rights in an easement, such as a conservation easement. Typically the landowner conveys a conservation easement to a holder. In this report, however, the term usually means rolling easement holder, which has a broader meaning. See rolling easement holder and dominant estate.

Easement in Gross

Easement (usually an affirmative easement) that allows someone (called either the dominant tenant or the easement holder) to make use of land owned by another (the servient estate) unrelated to any land the dominant tenant may own.

Equitable Covenant Running with the Land

See equitable servitude.

Equitable Servitude

Agreement concerning use of a parcel of land between an owner of the parcel and an owner of a nearby parcel, which binds and benefits successive owners of both parcels as if each had made the agreement. An equitable servitude is similar to a legal covenant, except that it entitles the benefited land to an equitable remedy, such as an injunction to honor the terms of the covenant. A negative equitable servitude (which limits one owner’s use of this land) is similar to negative easement, except that courts recognize only a few types of negative easements, whereas they allow parties to restrict almost any type of land use in an equitable servitude.


Loss of sediment, sometimes indicated by the landward retreat of a shoreline indicator such as the water line, berm crest, or vegetation line. The loss occurs when sediments are entrained into the water column and transported from the source.

Erosion-Based Setback

Setback equal to an estimated annual erosion rate multiplied by a number of years set by statute or regulation (e.g., 30 years).

Estate for Years

Ownership of land that terminates after a given period of time. When a grantor conveys an estate for years, the interest he retains is known as a reversion.

Eustatic Sea-Level Rise

Changes in global sea level relative to a vertical datum. Eustatic changes represent global sea level. The causes include ice sheet melting, increasing temperature of surface waters, and increasing volume of seafloor due to tectonic processes.


Interest in land, usually an easement or a parcel of land in fee simple absolute, that a government agency requires a private landowner to convey to the government as a condition for a permit.

Executory Interest

Future interest in land that entitles owner to possession for the first time, when an event occurs that ends the possibility of reverter or fee simple subject to condition subsequent owned by someone else.  For example, a deed that says “O grants Blueacre to A and his heirs for so long as sea level is less than one meter above the NAVD, and then to B” would give a fee simple determinable to A and an executory interest in Blueacre to B. The legal difference between a possibility of reverter (or power of termination) and an executory interest is that neither the owner of an executory interest nor his heirs ever owned Blueacre, whereas the owner a possibility of reverter (or a power of termination) or his heirs owned Blueacre at one time.

Fee Simple Absolute

Ownership of the entire set of rights in land forever. A deed that says “O grants Blueacre to A and his heirs” conveys to A fee simple absolute in Blueacre.

Fee Simple Determinable

Ownership of the entire set of rights in land with the potential to last forever but which is subject to a limitation, which would cause the estate to end. The limitation is generally the end of the circumstances that motivated the owner to obtain this interest in land (e.g. the railroad closes or the sea rises enough to threaten the property).  A deed that says “O grants Blueacre to A and his heirs for so long as sea level is less than one meter above the NAVD” conveys a fee simple determinable to A unless and until sea level rises one meter above NAVD, after which point Blueacre reverts to O or his heirs. O retains a possibility of reverter.

Fee Simple Subject to Condition Subsequent

Ownership of the entire set of rights in land with the potential to last forever but which ends if a particular condition occurs, provided the original grantor exercises his power of termination.  A deed that says “O grants Blueacre to A and his heirs, but if a seawall is built on Blueacre, O has a power of termination” conveys a fee simple subject to a condition subsequent. If a seawall is built on the property, O has the power to terminate the estate by going to court.  The condition is generally an action by the owner contrary to the original agreement under which the land was transferred.  Courts have often viewed the resulting transfer of possession as unreasonably punitive.

Flag Lot

Parcel with no true front yard, whose only frontage along the street is for the driveway. A flag lot often has a shape that looks like a flag (the site for the home and most of the yard) on a pole (the driveway).

Future Interest in Land

Future and possibly contingent right to a fee simple absolute that entitles one to take possession at some date in the future or upon the occurrence of an event (e.g. when the sea rises to a specified level).

Global Sea Level Rise

Worldwide average rise in mean sea level.

Grade Elevation

Adding sand, gravel, or soil to elevate a land surface.


Engineering structure perpendicular to the coast, used to accumulate littoral sand by interrupting alongshore transport processes. A groin is often constructed of concrete, timbers, steel, or rock.

In Gross

See easement in gross.


Privately owned land within a publicly owned park, wildlife refuge, or other natural area.


Permanent flooding of dry lands when the sea level rises.


In this report, someone whose property interest in a particular parcel entitles her to current possession.    The landowner may be the holder of a defeasible estate, an estate for years, or fee simple absolute subject to a conservation easement.

Land Trust

Private charitable organization that works to conserve land by acquiring and managing conservation lands or conservation easements.


Wall generally of earthen materials designed to prevent riverine flooding after periods of great rainfall.

Life Estate

Ownership of land that terminates when someone dies.  When a grantor conveys a life estate, the interest he retains is known as a “reversion”.  Generally, the person whose death triggers the reversion owns the life estate. If he sells the life estate to someone else, it is known as a “life estate par autre vie.”


Relating to a tidal shoreline.

Living Shoreline

Type of shore protection that retains some or all of the environmental characteristics of a natural shoreline.


Low-lying vegetated wetlands that generally are found between mean sea level and spring high water, or areas that are flooded at least a few times each month. Salt marshes occur in protected environments, such as behind barriers. Salt-tolerant plants colonize salt marshes.

Mean High Tide Line

General term that refers to whichever measure of mean high water applies. This term is used in Texas, where land conveyances before 1840 extended to mean higher high water, but land grants thereafter extended down to mean high water. In Texas , this line refers to the elevation contour along the beach whose elevation is the same as mean high tide, which is considerably seaward of where the waves wash at high tide.

Mean High Water

Tidal datum. The average height of all high water heights observed over a 19-year period.

Mean Higher High Water

Tidal datum. The average height of the higher of two daily high tides observed over a 19-year period. This measure is often used along the Gulf of Mexico, where one of the high tides each day is much higher than the other high tide. Along most of the U.S. Atlantic coast, by contrast, the two daily high tides reach similar heights.

Mean Low Water

Tidal datum. The average height of all low water heights observed over a 19-year period.

Mean Sea Level

Average water level position measured over a 19-year period that takes into account natural tidal oscillations. Often computed by the arithmetic mean of observed hourly heights over a 19-year period. Local mean sea level is determined relative to the local land at a tide station. Global mean sea level is the average level of the global ocean.


Level area of fine silt and clay along a shore alternately covered or uncovered by the tide or covered by shallow water.

Negative Easement

Right to prevent the owner of land from doing something on her land that she would otherwise have the right to do.

Nanotidal Wetlands

Wetlands that are irregularly flooded by wind-generated tides in estuaries with little or no astronomical tides. These wetlands are often classified as nontidal wetlands, but like tidal wetlands, their frequency of inundation is controlled directly by sea level.

Nontidal Wetlands

Wetlands that are not flooded by tides.


In this report, the Atlantic, Pacific, and Arctic Oceans; the Gulf of Mexico, and other bodies of water with large waves.

Ordinary High Water Mark

Demarcation between the publicly owned land along the water and privately owned land. Generally based on mean high water, the definition varies by state. Along beaches with significant waves, it may be based on the line of vegetation, the water mark caused by wave runup, surveys of the elevation of mean high water, or other procedures.  Along flat waters, it is the same as the average high water mark.

Possibility of Reverter

Future interest in land that entitles the owner to re-possess the land if and when a specific event occurs.  That event is also the limitation that ends the preceding fee simple determinable occurs. A possibility of reverter is automatically created when the owner of a fee simple absolute conveys a fee simple determinable.

Power of Termination

Future interest in land that entitles the owner to go to court to re-possess the land if and when a particular condition occurs, which is specified in the conveyance of a fee simple subject to condition subsequent. A power of termination is automatically created when the owner of a fee simple absolute conveys a fee simple determinable subject to condition subsequent.

Privity of Estate, Horizontal

Situation in which the original parties of a covenant shared some interest in the land that is the subject of the covenant, or the covenant is created as part of the subdivision process when both owners can trace their titles back to a common owner of a larger parcel that included their respective parcels.

Privity of Estate, Vertical

Situation in which the present owner of a parcel that is benefited or burdened by a covenant owns the entire estate that was owned by the original party that made the agreement, to whom the owner traces his title.

Public Trust Doctrine

Legal principle derived from English common law. The essence is that the waters of the state are a public resource owned by and available to all citizens equally for the purposes of navigation, hunting, fowling, and fishing, and that this trust is not invalidated by private ownership of the underlying land.

Relative Sea Level Rise

Rate of sea level change measured with respect to a specified vertical datum relative to the land, which may also be changing elevation over time.

Recorded Rolling Easement

1.  A rolling easement recorded in the local land records office.  2. Any property interest designed to prevent shore protection or ensure that a property boundary or right of access migrates inland.  3.  A conservation easement, affirmative easement, covenant, future interest in land, or ambulatory boundary designed to ensure that a property boundary or right of access migrates inland.


Slow and imperceptible advance of the shoreline resulting from falling sea level, as distinct from the deposit of sediment, which is known as accretion.


One of three general pathways by which society can respond to rising sea level or shoreline erosion, in which human activities move inland to make way for the landward migration of wetlands, beaches, open water, and public rights associated with the shore and tidal waters.


Sloped facing of stone, concrete, etc., built to protect a scarp, embankment, or shore structure against erosion by waves or currents.

Rolling Conservation Easement

1. Conservation easement that both restricts construction and other land use with the purpose of maintaining existing conservation value of land, and prohibits shore protection, i.e., a standard conservation easement combined with a shoreline migration conservation easement. 2. Conservation easement with boundaries that migrate as a result of changing environmental conditions or forest practices. 3. A shoreline migration conservation easement. This report uses the first definition.

Rolling Design Boundary

Shoreline (or a line that generally follows the shore) that defines the landward boundary of certain rights or restrictions in a rolling easement. The most common examples are the dune vegetation line, spring high water (upper edge of tidal wetlands) mean high water, mean low water, and a given distance inland (e.g., 100 feet) from any of those boundaries.

Rolling Easement

1. Regulation or an interest in land in which a property owner’s interest in preventing real estate from eroding or being submerged yields to the public or environmental interest in allowing wetlands, beaches, or access along the shore to migrate inland.  2.  An interest in land along the shore whose inland boundary migrates inland as the shore erodes.  3.  In Texas, an easement along the shore whose inland boundary migrates inland or seaward as the shore erodes or accretes.

There is generally a rolling design boundary seaward of which the restrictions apply, such as the dune vegetation line. At a minimum, a rolling easement prohibits hard shore protection and other structures that prevent the landward edge of wetlands or beaches from migrating inland or block public access along the shore. A rolling easement may also require removal of preexisting buildings as they become nonconforming structures seaward of the rolling design boundary. Along estuaries, a rolling easement may also prohibit grade elevation of dry land, which would tend to squeeze wetlands.

Rolling Easement Holder

Person, land trust, or government agency that owns the property rights from a rolling easement or has the legal power to enforce it. The rolling easement holder could be a local planning department or land use regulatory agency (in the case of rolling easement zoning), a state regulatory agency (in the case of state regulations prohibiting shore protection), the state agency responsible for managing public trust lands (in the case of a rolling easement that derives from the public trust doctrine of common law), a government agency that acquires conservation easements (in the case of a recorded rolling easement that had been conveyed to a government agency), a qualified land trust (in the case of a rolling easement that had been acquired by a land trust), or a nearby landowner (in the case of a covenant, equitable servitude, or affirmative easement with a rolling boundary).

Rolling Easement Zoning

Land use zoning that prohibits shore protection in some zones.

Running with the Land

See covenant running with the land.

Sand Dunes

Mounds or ridges of sand. They are formed from sand that is transported and deposited by the wind.

Sand Replenishment

See beach nourishment.

Safety Valve

1.  A provision in a regulation or recorded property interest that limits the potential harm to the property owner.  2.  In this report, a provision that the rolling easement will not require the removal of the home before a specified date, even the land is submerged more rapidly than expected.

Sea Level Rise

In this report, relative sea level rise. In other contexts, the term may refer to global sea level rise.


Structure separating land and water areas, primarily designed to prevent erosion and other damage from wave action.

Servient Estate

Land that is burdened by an easement.


Requirement that construction be located a minimum distance inland from tidal wetlands, tidal water, the primary dune line, or some other definition of the shore.


Narrow strip of land in immediate contact with the sea, including the zone between high and low water lines. A shore of unconsolidated material is usually called a beach. (In common parlance, “shore” may refer to an entire coastal community; but that meaning is not used in this report.)

Shoreline migration conservation easement

Conservation easement whose sole restriction is to make a property subject to a rolling easement.

Shoreline migration easement

See shoreline migration conservation easement.

Shore Retreat

1. Migration of a shoreline toward higher ground away from deeper water, whether through direct inundation from higher relative sea level or shoreline erosion. 2. One of three general pathways by which society can respond to rising sea level and other processes that cause the shoreline to migrate inland. See retreat.


Intersection of a specified plane of water with the shore or beach. The line delineating the shoreline on National Ocean Service nautical charts and surveys approximates the mean high water line.

Shoreline Armoring

Placement of fixed engineering structures, typically rock or concrete, on or along the shoreline to mitigate the effects of coastal erosion and protect structures. These structures include seawalls, revetments, bulkheads, and rip-rap (loose boulders).

Shore Protection

1. Activity that protects land from inundation, erosion, or storm-induced flooding, generally either through shoreline armoring or soft shore protection. 2. One of three general pathways by which society can respond to rising sea level and other processes that increase the risk for flooding and coastal erosion through use of shore protection measures, such as shoreline armoring, beach nourishment, or grade elevation.

Soft Shore Protection

Method of shore protection that prevents erosion through use of materials similar to those already found in a given location, e.g., adding sand to an eroding beach, planting vegetation whose roots will retain soils along the shore, and elevating the surface grade of dry land.

Special Exception

Land use permitted within a given zone, provided that an administrative fact finder is satisfied that specific conditions are met.

Spring High Water

Average height of the high water during semi-monthly times of spring tides (full and new moons).

Submerge Date

1. The day the rolling design boundary migrates inland of a given building or parcel of land subject to a rolling easement.  2. In the case of a rolling easement structured as a future interest in land, the day that the property reverts from the landowner to the owner of the future interest.

Submerged Land

1. Land that is below the water all of the time or on a regular basis. 2. In this report, tidelands plus the bottoms of bays and other estuaries, as well as the ocean floor along the coast.


1. In this report, the conversion of dry land to wetland or open water through either shoreline erosion or inundation. 2. In the case of a rolling easement, the occurrence of the submerge date.   3. A rise in sea level or sinking of the land surface so that areas that were formerly dry land become intertidal or open water.  4.  Inundation.


An action by a government that diminishes an owner’s property rights enough to require compensation under the 5th Amendment of the U.S. Constitution.

Tidal Inlet

Opening in the shoreline through which water penetrates the land, thereby providing a connection between the ocean and bays, lagoons, marsh, and tidal creek systems. The main channel of a tidal inlet is maintained by tidal currents.

Tidal Range

Vertical difference between normal high and low tides often computed as the elevation difference between mean high water and mean low water. Spring tide range is the elevation difference between spring high water and spring low water.

Tidal Wetlands

Wetlands that are flooded by high tides and exposed at low tides. In some contexts, this term refers to vegetated wetlands (e.g., marshes and swamps) but not non-vegetated wetlands such as tidal mudflats and beaches. In other contexts, it may refer to both vegetated and non-vegetated wetlands.


The sum of all property rights to a particular parcel owned by a particular owner.


Lands that are flooded during ordinary high water and hence available to the public under the public trust doctrine. They include beaches, vegetated wetlands, mudflats, salt flats, and rocky intertidal areas.

TLC (The Land Conservancy)

An example land trust that accepts conservation easements in coastal communities.

Transfer Title

To convey all of one’s property rights in a particular parcel to someone else.  A title transfer conveys only what the transferor owns, which may be less than fee simple absolute.


An exemption to a local land use rule granted to an applicant because of hardship or because the enforcement of the rule might violate a statute or constitutional provision.

Wetland Accretion

Process by which tidal wetlands keep pace with rising sea level through peat formation and the accumulation of sediment, so that the land level rises at approximately the same rate as the sea rises.  Also known as “vertical accretion”.

Wetland Migration

Process by which tidal wetlands adjust to rising sea level by advancing inland into areas previously above the ebb and flow of the tides.


A system of regulating the use of land based on dividing a jurisdiction into several zones, each of which has different allowed land uses.

Go Back9.4  After the land is submerged
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This page contains a section from: James G. Titus, Rolling Easements, U.S. Environmental Protection Agency. EPA‑430‑R‑11‑001 (2011). The report was originally published by EPA's Climate Ready Estuary Program in June 2011. The full report (PDF, 176 pp., 7 MB) is also available from the EPA web site.

For additional reports focused on the implications of rising sea level, go to Sea Level Rise Reports.

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