Learn more about beaches & dunes

barrier beach system

pocket beach

Beaches occupy only about two percent or 75 miles of Maine’s coastline. Sand beaches, which account for less than 40 of the 75 miles, are most common along the southern coast between Kittery and Cape Elizabeth, although several stretches of sandy beach occur in midcoast Maine near the mouth of the Kennebec River, and elsewhere as small pocket beaches bound by bedrock headlands. Many pocket beaches do not have an extensive back-barrier marsh system. Other beaches are made up of gravel, cobble, or boulders.

Beaches provide a natural buffer from storm events, and serve as critical habitat for wildlife and plants. Beach-related tourism and recreation contribute significantly to the state’s economy.

Beaches and dunes are extremely dynamic features, changing in response to waves, wind, and tides. Beaches and dunes in Maine experience different kinds of erosion, from seasonal changes and short-term, storm-induced sand loss to long-term erosion and inlet migration.

Erosion of Maine's beaches and dunes

Coastal erosion and associated flooding from storm events can damage property and infrastructure. Erosion also compromises the ability of beaches protect neighboring property, provide habitat for plants and wildlife, and accomodate recreation and attract tourism.

 

Erosion problems in Maine are generally caused by a persistent rise in sea level, storms, changes in sand availability, and the construction of jetties and seawalls.

10% of Maine’s beaches are highly erosional, disappearing at a rate of more than two feet per year. Some of these beaches have seawalls along the frontal dune, while few have no seawalls. Most are in need of beach replenishment to replace eroded sand. Many of these shorelines have no beach for about half of the tidal cycle.

50% of Maine’s beaches are moderately erosional, with erosion rates of one to two feet per year. Along some of these beaches where seawalls are present, the seawalls are regularly overtopped during winter coastal storms, and a limited number of seawalls have been undermined during severe coastal storms. In some areas, local overtopping occurs once or twice a year in winter, but is usually restricted to limited areas of beachfront properties. Natural beaches in this category have chronic dune scarps (steep drop-offs) and frontal dune erosion. Some beaches have exposed gravel berms and limited recreational opportunities at high tide.

About 40% of southern Maine beaches are only slightly erosional.

Maine Geological Survey prepared a table that generalizes the status of many of southern Maine’s beaches. This information is taken directly from Appendix B of the Protecting Maine’s Beaches for the Future (2006) report. This table is meant to provide more information about the general characteristics of some of Maine’s beaches, including development status, beach replenishment history, shoreline armoring status, shoreline change status, and public ownership.

Seasonal changes

Typically, beaches and dunes undergo a seasonal transformation from a “summer” beach to a "winter" beach. A summer beach has a wide, well-developed berm often with a vegetated dune where American beach grass grows seaward onto the berm. A winter beach is lower, may not have a berm, and often shows signs of loss of beach grass.

 

Winter Beach: As storms and wave heights (along with a general change in wave and wind direction) increase during the fall and winter months, beach berms and sometimes the dunes erode in response, lowering the beach as sand is pulled offshore from the upper portions of the beach and deposited in protective offshore sandbars. The result is typically a flatter, more concave beach shape. The sandbars that form offshore in winter help protect the beach by causing waves to break farther offshore.

Summer Beach: In the late spring and early summer months, smaller, calmer waves dominate, and sand slowly returns to the beach and berm, and the beach and dunes typically recover, as long as sediment is not lost offshore. The key to this equilibrium is the berm, which is the part of the beach that changes most during the seasonal cycle.

 

(Above: Seasonal changes in the beach at Kinney Shores in Saco.)

Short-term (storm-induced) erosion

One large storm or a series of storms can cause significant beach and dune erosion. Storm erosion follows a similar but more rapid pattern than seasonal erosion. Damaging storms usually occur in the fall, winter, or early spring months when the “seasonal” beach profile is already relatively lean in shape. Changes seen at the beach are similar to the seasonal changes, with lowering of the beach and extensive loss of the berm. In addition, storm damage usually causes extensive dune erosion, scarping, or complete loss of the frontal dune.

Storm recovery follows a similar process of the seasonal beach, with offshore sandbars providing protection, and slow, gradual build up of the berm in response to smaller waves. This can occur in the course of one season, but may take a year or more. Dune recovery is a much slower process which involves dune vegetation re-establishing, wind transport of sand, and other processes. It can take several seasons to several years or more for a dune to recover naturally from a large storm event.

 

Long-term erosion

Almost all of Maine’s beaches are "transgressing," or moving landward in response to coastal storms and gradual sea-level rise at a rate of about an inch per decade. This landward migration of the beach and dune system is like the motion of a tank tread; the beach basically migrates over itself in response to storms and sea-level rise.

Long-term erosion is considered permanent erosion that occurs over decades due to numerous factors:

• Structures like jetties prevent sand from being transported to the beach.
• Upstream dams on rivers prevent sand from reaching the beach;
• Tidal river dynamics force sand into deltas that serve as sediment sinks or traps.
• Sea-level rise or storm-related erosion occurs faster than the rate of sand deposited on the beach.

 

The photo to the left shows Scarborough Beach after the Patriots' Day Storm in 2007, when the beach "washed over" into the dunes.

 

 

 

 

A sure sign of beach and dune transgression is the continual presence of stumps or peat (marsh) deposits in the surf zone; these materials are from historic backbarrier marsh and forested uplands that became covered by sand and then exposed, as in this photo of Ferry Beach in Scarborough.
 

 

 

 

 

Inlet erosion

Some of the fastest changing shorelines are found adjacent to tidal inlets, which meander and change shape. Inlets can move unexpectedly one way or another in response to storms, or can migrate in a single direction continuously.

Some inlets migrate in a single direction for a certain amount of time until they reach a point where they jump back to their original starting places.

A great example of this phenomenon is the Morse River at Popham Beach State Park in Phippsburg. The channel of the Morse River migrated dramatically to the northeast over the past few decades, eroding large stretches of Popham Beach. A dramatic course change in 2010 opened a new channel to the west, adjacent to bedrock headlands.

At some inlets that have been stablized by jetties, nearby beach erosion can still occur due to sediment movement associated with ebb-or flood-tidal delta formation. For example, Western Beach in Scarborough, adjacent to the Scarborough River, has undergone extensive erosion due to tidal river dynamics. The beach received nourishment in 2005, but has continued to erode at very high rates along the majority of its stretch, evidenced by the net shoreline movement of the high water line, measured by Maine Geological Survey from 2005-2009.

 

 

Do nothing

Doing nothing is sometimes considered last, after other more expensive and intensive options have been undertaken with no success. But doing nothing is typically the least costly alternative and does not require permitting, unless erosion causes damage to property or infrastructure. The do-nothing alternative takes into account the level of risk you are willing to accept in conjunction with the expected uses of your property.

The “do nothing” alternative makes the most sense if there aren’t any structures on your property, in areas of critical habitat, or on beaches where erosion is minimal and a structure is located far away from the eroding shoreline, and a defined erosion rate has been determined (in consultation with local experts).

Move back to avoid the hazard

Avoiding existing or potential hazards as much as possible is usually a property owner's most efficient and cost-effective response. This is especially true when siting new development, as structures can be built as far away (landward) from the hazard as possible.

To ensure safety of an existing structure that is being threatened by erosion or flooding, a property owner can move up or move back:

Relocating a structure out of the hazardous area, typically in a landward direction, can be very effective in minimizing the hazard, but it can be expensive. Costs vary from several thousand dollars to tens of thousands of dollars, and are based on the existing foundation of the structure, size of the structure, topography and geology, and distance the structure may need to be moved. Consultation with a local contractor is suggested, and local and state permits may be needed. Relocation of a structure can also be constrained by the size of a property and any applicable setbacks, such as from other existing structures or roadways, and you may need to request a variance from local setback ordinances. Also consider significant habitat resources or environmentally sensitive areas, which are usually identified by municipal or state regulations.

Move up by elevating structures

Case Study:
Move Up and Move Back

Existing structures that are threatened with coastal flooding or erosion often can be moved up. If you are located in a flood zone, your town may require that the lowest structural part of your house be a minimum of one foot above the base flood elevation (this is typically the minimum standard).

If your structure is older and has been flooded and does not meet current standards, or any time you are doing substantial improvements to your structure, consider the cost of elevating the structure using a flow-through foundation or a pile foundation, especially if structure improvements meet or exceed 50% of the value of the structure.

Flow-through foundations are typically block or poured cement foundations with adequate spacing for floodwaters to flow through the foundation without damaging the supports. These structures are acceptable in the A-zone areas of back dune environments that are not considered to be Erosion Hazard Areas.	Pile foundations are typically used in more active flooding areas along open ocean coastlines, and provide much more open space for floodwaters to travel through. Piles are required in the frontal dune and in areas of the back dune classified as Erosion Hazard Areas.

The concept behind both foundation types is that water, sediment, and debris travel through the foundation, instead of applying pressure and lateral force to the foundation which can cause structural failure. Both foundation types can significantly reduce potential flood damage to a structure.

In some areas, fill can be added below a foundation to increase the elevation of the structure to meet floodplain standards. This technique is not recommended, as it can result in potential increased flood hazard impacts to adjacent properties.

Many of the state requirements regarding elevation of structures, including a review of techniques, are outlined in Chapter 5 of the Maine Floodplain Management Handbook. Your town may have additional requirements that meet or exceed minimum state standards. Contact your local Code Enforcement Officer for more information.

You may also want to review the FEMA Coastal Construction Manual and the FEMA Home Builder’s Guide to Coastal Construction Technical Fact Sheets. The Coastal Construction Manual is available as a CD or in print copy by calling FEMA Publications Distribution Facility at 1-800-480-2520, and should also be available for review at your local town office or public library.

Refer to Chapter 305 (Permit by Rule), Chapter 310 (Wetlands) and Chapter 355 (Coastal Sand Dune Rules) for additional requirements relating to impacts to coastal sand dunes associated with elevating structures.

If you consider elevating your structure, think about making other improvements to make your home more storm and flood resilient. Also, consider elevating your structure over and above the elevation required by your floodplain ordinance, in order to take into account expected rates of sea-level rise and higher future floodplain elevations. The State of Maine has adopted an expected rise in sea level of 2 feet over the next 100 years.

Design and build new structures appropriately

Construction techniques that are appropriate to coastal areas involve not only siting of the structure and support structures, including septic, utilities, etc., but also design and building techniques that can withstand hazards and potential land, wind, and water forces associated with the dynamic coastal zone.

Things to consider:

• The construction footprint, given applicable setbacks for sensitive areas;
• The extent of grading needed to achieve a stable building footprint;
• The level of engineering required address erosion or flooding; and
• Potential physical forces such as water and wind.
• Be neighborly. Think about potential impacts on your neighbor’s property that may result from an activity on your property. At the same time, it may make sense to work with adjacent property owners if a common goal is found or regional approach is being adopted to deal with certain hazards.

Some of the best and most comprehensive resources available regarding proper coastal construction techniques are the FEMA Coastal Construction Manual and the FEMA Home Builder’s Guide to Coastal Construction Technical Fact Sheets. The Coastal Construction Manual is available as a CD or in print copy by calling FEMA Publications Distribution Facility at 1-800-480-2520, and should also be available for review at your local town office or public library.

Protect, enhance, or construct dunes

Case Study:
Dune Restoration

Dunes contain a reservoir of sand that is released to the beach during storms, providing a natural buffer from storm damage. Preserving or enhancing dune systems can help protect coastal property, especially in areas with low or moderate erosion. Sand dunes are dynamic features and will erode or move landward over time. Any dune preservation, enhancement, or reconstruction activities need to keep in mind that the landform is mobile.

Protecting Dunes: For areas with existing dunes and low erosion rates, simply preserving dunes might be all that is needed to help maintain protection from storms. Other options include planting dune grass, erecting fencing, building dune paths and walkovers. 

Constructing Dunes: Property owners can work together to increase or create dunes as a protective measure. Teaming with your neighbors can help defray construction costs, and create a more storm-resistant dune. Dune construction requires, at a minimum, a Permit by Rule finding from the Maine DEP, though larger projects may require an individual permit. Dune activities are limited by specific timing windows, mostly related to seasonality of plants and threatened or endangered species such as least terns or piping plovers. Most activities are restricted to the periods from March 1 to April 1, or from October 1 to November 15. Refer to the Natural Resources Protection Act for more information specific to certain types of activities that could impact threatened or endangered species such as piping plovers. If these species are present, it's likely you have been made aware of this. In these cases, consultation with state and federal wildlife agencies will be needed before action can be taken.

Further guidance regarding dune construction, fencing, and management is provided by the Maine DEP in a technical guide on dune management and construction. Additional resources are provided in the references section.

Plant vegetation on the dune

Vegetation traps and stabilizes sand on the dune. In areas with low long-term erosion rates, building taller or wider dunes can increase protection against storms.

In some cases on beaches and dunes, actions you might take could impact threatened or endangered species such as piping plovers. If these species are present, it's likely you've been made aware of this. In these cases, consultation with state and federal wildlife agencies will be needed before action can be taken. 

Dune planting typically uses species of vegetation that are native to the coastal sand dune system. In Maine, this includes American beach grass (Ammophila breviligulata), which is the dominant dune species. Other common species include:

Coastal panicgrass (Panicum amarum)
Seaside goldenrod (Solidago sempervirens)
Beach pea(Lathyrus japonicus)
Northern bayberry (Morella pensylvanica)
Rugosa rose (Rosa rugosa) Rosa rugosa, also known as rugosa rose, beach rose, or Japanese rose, is native to Asia and was introduced to the United States as a garden and landscape ornamental around 1845. It soon escaped from cultivation and naturalized to the New England coast, where it is now a characteristic feature of seaside Maine. Its ability to spread rapidly and shade out native plants has earned Rosa rugosa an invasive designation in some states, and it is not recommended as a species to introduce to a dune system. For dunes where Rosa rugosa is already present, steps should be taken to prevent it from spreading, such as pulling up, weed whacking, mowing, and cutting back new growth.

American beach grass is normally planted in late winter while the plants are still dormant. The grass can be planted using the broom stick method: insert a broomstick 8 inches deep into the sand, and place 2 sprigs of grass in each hole. American beach grass is typically planted in staggered rows at 12-18 inch spacings, depending on the application. The plants can be fertilized easily with dried seaweed from the nearby beach.
 
American beach grass can be ordered from one of the following locations:

• Pierson Nurseries, Biddeford, ME
• Cape Coastal Nursery, MA
• Great Meadows Nursery, MA
• Quansett Nurseries, Inc., MA
• Church’s Beachgrass & Nursery, Cape May, NJ
• Octoraro Native Plant Nursery, PA
• Cape Farms, Inc., DE

Phragmites australis, also known as common reed, is considered an invasive plant by the State of Maine and should not be planted or allowed to spread.

A good resource regarding plants is the USDA Natural Resources Conservation Service Cape May Plant Materials Center which maintain numerous resources for information on Coastal and Shoreline Restoration and Protection.
 

Erect fencing

Open fencing (posts with string) can help limit foot traffic within dunes and other sensitive areas, but does little to help trap sand within the dune. Installing open fencing usually does not require a permit.

Sand/snow fencing (wooden slats/pickets with wire) can help trap sediment adjacent to the dune system. If the opening between pickets/slats is at least 4 inches wide, or at least double the width of the picket, whichever is greater, a permit is not needed; all other fencing will require a permit from Maine DEP.

Cobble trapping fences may be installed where cobble regularly washes over a seawall and threatens private structures. These fences are permitted only in specific areas adjacent to cobble or gravel beaches and have developed areas between the building and the beach (such as lawn). Specific standards relating to these fences are included in Natural Resources Protection Act Chapter 305, 16C.

Be neighborly. Think about potential impacts on your neighbor’s property that may result from an activity on your property. At the same time, it may make sense to work with adjacent property owners if a common goal is found or regional approach is being adopted to deal with certain hazards.

In some cases on beaches and dunes, actions you might take could impact threatened or endangered species such as piping plovers. If these species are present, it's likely you have been made aware of this. In these cases, consultation with state and federal wildlife agencies will be needed before action can be taken.

Build paths and walkovers

Paths: Dunes can lose their protective cover of vegetation along fot paths where people access the beach.  Over time, these paths can act as conduits for floodwaters, wave runup, and overwash.

A path that curves or zig-zags near the seaward edge of the dune can slow erosion and flooding in the back dune. The main turn of the path should occur near the crest of the dune. Path rerouting will likely require a permit-by-rule from the Maine DEP since it impacts dune vegetation.

Dune walkovers: To protect dunes from foot-traffic that can contribute to erosion, elevated walkways or bridges can be constructed perpendicular to the natural sand dune. Temporary structures may be in place for up to 7 months of the year.

Both temporary and permanent walkovers would likely require full permitting from the Maine DEP under the Coastal Sand Dune Rules.

In Maine, no specific guidance is provided by the DEP for construction of walkovers in terms of elevation, slat spacing, or design; dune walkovers are reviewed on a case-by-case basis. Maine DEP suggests contacting their southern Maine regional office to set up a pre-application conference if such a structure is proposed. Usually, walkovers are elevated off the surface of the dune about three feet, with sufficient spacing between individual slats so that dune grass can receive needed sunlight. Most are constructed with handrails and steps, or if used for public access, ADA-compatible ramps. Typically, they must be less than 10 feet wide for public use, and less than 4 feet wide for private use.

Several guides for construction guidance are available from other states, including Florida and Texas, and the FEMA Coastal Construction ManualVolume III, Appendix I.

Nourish or "scrape" the beach

Beach scraping uses mechanical equipment to scrape sand from the lower part of the beach up to or just below the sand dune. Beach scraping is only a temporary measure to try to protect upland property during a storm. A Maine DEP permit is required for beach scraping, and additional restrictions may be imposed in terms of timing (typically between April 1 and September 1) by the Maine Department of Inland Fisheries and Wildlife.

Beach nourishment is defined as the artificial addition of sand, gravel or other similar natural material to a beach or subtidal area adjacent to a beach and is governed by the Coastal Sand Dune Rules.

Beach nourishment can be an effective, temporary response to coastal erosion, though it tends to be costly, and its effectiveness is generally short-lived (5 years or less), especially in areas with high erosion rates. Generally, there are two sources of material in Maine that have been used for beach nourishment:

1. “beneficial reuse” of dredged material, usually in conjunction with a federal (US Army Corps of Engineers) dredging project of navigable waterways; and
2. upland sourcing of material, typically from a gravel pit, where trucks are used to transport material from an upland source to the beach.

Generally, if the US Army Corps dredges a project and the material is considered to be clean, beach-compatible sand, the 

beneficial reuse of dredged materials as beach nourishment is encouraged. If beach nourishment is considered to be a least 

cost alternative for disposal of the dredged material, the costs of dredging and material placement are borne by the federal government. If not, some cost-matching by a local sponsor (typically the receiving community) is required for the Corps to proceed with a project.

Private beach nourishment projects using dredged material – either from an adjacent river channel or other offshore source – have not been undertaken in Maine. One of the reasons for this is cost: finding, dredging, and transporting material can run between $10-20 per cubic yard of sand, depending on source and its proximity to the nourishment site.

Rebuild or enhance a seawall

No new seawalls may be constructed along Maine’s beaches or sand dune system. The Maine Geological Survey estimates that about half of Maine’s sandy beaches are armored with “hard” engineering structures like seawalls that limit the natural ability of beach and dune systems to move in response to storm events and maintain themselves by exchanging sediment.

In an emergency, a property owner can make temporary fixes to an existing seawall to protect private infrastructure from storm damage. The specific activities are outlined in the Natural Resources Protection Act (Title 38 Section 480-W) .

Be neighborly. Think about potential impacts on your neighbor’s property that may result from an activity on your property. At the same time, it may make sense to work with adjacent property owners if a common goal is found or regional approach is being adopted to deal with certain hazards.

Rebuild after severe storm damage

If a seawall protecting property is damaged, a coastal property owner may replace or repair the seawall in-kind and in-place (i.e., same materials, same dimensions as the previously existing structure) with a Permit by Rule. Seawall repair or reconstruction requires a survey plan prepared by a licensed engineer, surveyor, or geologist.

If a property owner proposes to change their seawall in some way, a full permit through the Coastal Sand Dune Rules (Chapter 355) would be required. A seawall located farther landward, sloped, or both, is potentially less damaging to the beach and dunes.

Be neighborly. Think about potential impacts on your neighbor’s property that may result from an activity on your property. At the same time, it may make sense to work with adjacent property owners if a common goal is found or regional approach is being adopted to deal with certain hazards.

Case Study:
Move Up and Move Back

Learn more about bluffs & rocky shores

Most of the Maine coastline is rocky, and erosion isn’t a major problem. But 40% or 1,400 miles of coast have loose or “unconsolidated” rock, clay, sand, or gravel bluffs that slope steeply down to just above the high tide line and are easily eroded.

Bluffs form where the rising sea has encountered piles of sediment left behind by the glaciers during or soon after the last Ice Age. Storms, coastal floods, waves, and tides all work to remove bluff sediments and redistribute them in the coastal zone. Bluff stability varies based on the frequency of waves and storms and whether or not the base of the bluff is protected by a wetland or marsh. Bluffs will continue to erode and move landward due to rising sea levels.

Bluff erosion and stability

As a bluff erodes, the top edge moves landward. This is a natural process that becomes a hazard when it threatens buildings or other developed property. Bluff erosion rates will vary from year to year, much like the weather. Even a steep bluff may remain unchanged for many years, or slump a large amount of sediment once every few years. Fine silt and clay eroded from bluffs may end up on mud flats or salt marshes at the base of the bluff, helping to reduce wave energy and slow the overall rate of bluff erosion. Eroded sand and gravel become part of the beach at the base of the bluff, helping to stabilize the shoreline.

A Highly Unstable Bluff is near vertical or very steep with little vegetation and lots of exposed, loose sediment. Fallen trees and displaced chunks of sediment are common on the bluff face and at the base of the bluff.
An Unstable Bluff is steep to gently sloping and mostly covered by shrubs with a few bare spots. Bent and tilting trees may be present.
A Stable Bluff has a gentle slope with continuous cover of grass, shrubs or mature trees, and a wide zone of ledge or sediment at its base. Over time, stable bluffs can become unstable due to natural changes or human activities.

Common types of landslides in Maine

Rotational slide results in a concave surface.
Translational slide moves along a roughly planar surface with little rotation or backward tilting.
Rockfalls happen when masses of rocks or boulders become detached from steep slopes or cliffs and move abruptly downhill.
Debris flow is a rapid mass movement of loose soil, rock, organic matter, and water as a slurry that flows downslope.
Earthflow is a viscous flow of fine-grained materials that have been saturated with water.
Creep is the imperceptibly slow, steady, downward movement of slope-forming soil or rock. The bluff changes shape but doesn’t fall apart.

 The different types of landslides featured here are from US Geological Survey.

 

Do nothing

Doing nothing is sometimes considered last, after other more expensive and intensive options have been undertaken with no success. But doing nothing is typically the least costly alternative and does not require permitting, unless erosion causes damage to property or infrastructure. The do-nothing alternative takes into account the level of risk you are willing to accept in conjunction with the expected uses of your property.

The “do nothing” alternative makes the most sense if there aren’t any structures on your property, or if a structure is located far away from the eroding bluff or landslide site, and the bluff has an identified and steady erosion rate (determined in consultation with local experts). Owners of coastal property along eroding bluffs or near landslide-prone areas should check their insurance coverage for provisions related to loss due to landslides or shoreline erosion.

Move back to avoid the hazard

Avoiding existing or potential hazards as much as possible is usually the most efficient and cost-effective response, especially when siting new development.

One of the most effective ways to ensure safety of an existing structure that is being threatened by erosion or landslides is to relocate the structure out of the hazardous area, typically in a landward direction. Although moving back can be very effective in minimizing the hazard, it can be expensive. Costs vary from several thousand dollars to tens of thousands of dollars, and are based on the existing foundation of the structure, size of the structure, topography and geology, and distance the structure may need to be moved. Consultation with a local contractor is suggested, and local and state permits may be needed. Relocation of a structure can also be constrained by the size of a property and any applicable setbacks, such as from other existing structures or roadways.

As much as is practical with your building considerations, consider moving back and moving up to avoid some hazards. Consideration should also be given to significant habitat resources or environmentally sensitive areas, which are usually identified by municipal or state regulations.

Design and build new structures appropriately

Construction techniques that are appropriate to coastal areas involve not only siting of the structure and support structures, including septic, utilities, etc., but also design and building techniques that can withstand hazards and potential land, wind, and water forces associated with the dynamic coastal zone.

Things to consider:

• The construction footprint, given applicable setbacks for sensitive areas;
• The extent of grading needed to achieve a stable building footprint;
• The level of engineering required address erosion or landslides; and
• Potential physical forces such as water and wind.
• Be neighborly. Think about potential impacts on your neighbor’s property that may result from an activity on your property. At the same time, it may make sense to work with adjacent property owners if a common goal is found or regional approach is being adopted to deal with certain hazards.

Some of the best and most comprehensive resources available regarding proper coastal construction techniques are the FEMA Coastal Construction Manual and the FEMA Home Builder’s Guide to Coastal Construction Technical Fact Sheets. The Coastal Construction Manual is available as a CD or in print copy by calling FEMA Publications Distribution Facility at 1-800-480-2520, and should also be available for review at your local town office or public library.

Stabilize the bluff with engineered structures (rip-rap, seawalls, etc.)

Shoreline engineering in the form of seawalls, rip-rap, or other solid structures is sometimes used to reduce wave erosion at the toe of a bluff. In some settings, engineering can increase the rate of beach or tidal flat erosion, undermining engineering and weakening the base of the bluff. When coastal engineering ends along a shoreline, “end effect” erosion can cause worse erosion on adjacent properties. Engineering alone cannot prevent some large landslides. In general, human activities that increase the amount or rate of natural processes may, in various ways, contribute to landslide risk.

Eroding bluffs sometimes can be stabilized solely at the base or along the entire bluff surface using a single technique or combination of tree rafts, wattles, geotextile fabrics, rip-rap, or gabion structures. The costs associated with bluff stabilization can be quite high, depending on the size and project design specifications. Permitting may be required for not only the actual activity, but also for staging or seasonal use of equipment, especially if it occurs from the seaward side of the project and is within the “coastal wetland” or below highest annual tide. The guide to Maine Erosion and Sediment Control Best Management Practices, contains stabilization techniques applicable to coastal bluff and landslide sites, including:

• land grading and slope protection
• use of geotextile fabric
• stabilizing slopes with rip-rap
• stabilizing slopes with gabions (rock-filled wire baskets)
• stabilizing streambanks

Be neighborly. Think about potential impacts on your neighbor’s property that may result from an activity on your property. At the same time, it may make sense to work with adjacent property owners if a common goal is found or regional approach is being adopted to deal with certain hazards.

Additional resources regarding slope stabilization are provided by the US Army Corps of Engineers Coastal and Hydraulics Laboratory.
 

Stabilize the bluff by planting vegetation

Planting vegetation can help stabilize slightly or moderately eroding bluffs. Vegetation tends to remove ground water, strengthen soil with roots, and lessen the impact of heavy rain on the bluff face.

The Washington Department of Ecology's guide on vegetative planting techniques contains many techniques applicable to Maine, though plant species will be different. The Maine Natural Areas Program's Natural Landscapes of Maine: A Guide to Natural Communities and Ecosystems provides guidance on existing dominant vegetative species in different landscapes in Maine. A database of plant communities located at coastal headlands can be used as general guidance. The University of Maine Cooperative Extension has compiled a listing of native plant species in Maine. For additional information on bluff-appropriate vegetation species and techniques in Maine, consult with local garden centers and landscape architects.

Clearing vegetation from the bluff face can increase erosion, creating a steeper bluff that is more prone to landslide. Removal of vegetation within a shoreland zone to enhance a view may require a permit from the Maine DEP and/or your city or town.

Improve drainage on bluffs

Adequate drainage can be a key factor in bluff stability. Actions that increase surface water flow to a bluff face, such as watering lawns or grading slopes, add to natural drainage processes destabilizing the bluff face. Saturating the ground with water adds weight to the top of the bluff and can weaken muddy soils, both of which can increase the risk of a landslide. Surface water, collected by roofs, driveways, paths, and lawns, flows toward and down the bluff face. Walkways down the face of a bluff can concentrate surface water flow. Both surface and ground water above a bluff can be supplied by pipes, culverts, surface drains, and septic systems. Increased water below ground can weaken a bluff and contribute to internal weakness that leads to a landslide. Greater seepage of water out of the bluff face can also increase the risk.

Drainage can be maintained or improved by installing surface and subsurface drainage devices within and adjacent to potentially unstable slopes. Surface contours can be designed to drain water away from a bluff, which can reduce infiltration to ground water beneath a bluff face. Some examples of techniques used for controlling surface and subsurface drainage along bluffs are well summarized by the California Coastal Commission.

Reducing the overall slope or overhang by grading the bluff to a lower angle can decrease erosion and landslide hazard risk. Some slopes can be stabilized by terraces.

Stabilize rocky shores with seawalls or rip-rap

New seawalls are not permitted if they will adversely affect beaches and dunes. As sea level continues to rise in Maine, there may be places where waves regularly wash up the rocky shore and cause erosion of upland soil. Currently, no clear statutory or rule language exists for seawalls outside of the coastal sand dune system. Existing seawalls located along a rocky shore or on ledge may potentially be expanded in terms of their height with an appropriate permit on a case-by-case basis, if regular flooding and overtopping and subsequent erosion can be proven. The use of rip-rap on a rocky shore may be permitted by the DEP.

Rebuilding after a landslide or severe storm damage

Text for this section is under development.

Learn more about coastal wetlands

The Maine coast contains approximately 19,500 acres of wetland, more than any other New England state, New York, or Canadian province in the Gulf of Maine. Marsh types vary along the coast due to different geology and tidal ranges, from extensive back-barrier marshes in southern Maine to river-fringing tidal marshes and pocket wetlands in central and eastern Maine.

Much of the information in this section is from the extremely comprehensive guide, Maine Citizen’s Guide to Evaluating, Restoring, and Managing Tidal Marshes. Other sources for information on Maine’s salt marshes include Maine Salt Marshes: Their Function, Values, and Restoration and Salt Marshes in the Gulf of Maine, Human Impacts, Habitat Restoration and Long-Term Change Analysis.

Marsh System Types

Marsh systems in Maine can generally be classified into three different types based on their overall geomorphology and shape. 

Back-Barrier Marshes	Finger Marshes	Fringe Marshes
Located adjacent to barrier beaches, with direct access to the ocean through tidal inlets. Usually dominated by high marsh.	Long marshes along tidal channels. The area of high marsh is large compared to size of the channel.	Marshes on the edges of protected shorelines in estuarine coves and rivers, or at the toe of eroding bluffs. With less area of high marsh and bordered by mud flats, fringe marshes are strongly influenced by erosion from ice and waves.

 

Do nothing

Doing nothing is sometimes considered last, after other more expensive and intensive options have been undertaken with no success. But doing nothing is typically the least costly alternative and does not require permitting, unless erosion causes damage to property or infrastructure. The do-nothing alternative takes into account the level of risk you are willing to accept in conjunction with the expected uses of your property.

The “do nothing” alternative makes the most sense if there aren’t any structures on your property, in areas of critical habitat, or in areas where erosion is minimal and a structure is located far away from the wetland.

Expect wetland boundaries to change. The nature and location of coastal wetlands may change in the future with increasing elevation of the highest annual tide due to sea-level rise. (See the Maine Geological Survey mapping efforts for sea-level rise in southern Maine.)

Move back to avoid the hazard

Avoiding wetlands and their associated hazards as much as possible is usually the most efficient and cost effective response, especially when siting new development.

One of the most effective ways to ensure safety of an existing structure that is being threatened by erosion or flooding is to relocate the structure out of the hazardous area. Although moving back can be very effective in minimizing the hazard, it can be expensive. Costs vary from several thousand dollars to tens of thousands of dollars, and are based on the existing foundation of the structure, size of the structure, topography and geology, and distance the structure may need to be moved. Consultation with a local contractor is suggested, and local and state permits may be needed. Relocation of a structure can also be constrained by the size of a property and any applicable setbacks, such as from other existing structures or roadways.

Another method is to elevate a structure over and above certain base flood elevation standards.

As much as is practical with your building considerations, consider moving back and moving up to avoid some hazards. Consideration should also be given to significant habitat resources or environmentally sensitive areas, which are usually identified by municipal or state regulations.
 

Move up by elevating structures

Existing structures that are threatened with coastal flooding or erosion often can be moved up. If you are located in a flood zone, you may be required by your town’s floodplain management ordinance to have the lowest structural part of your house be a minimum of one foot above the base flood elevation (this is typically the minimum standard).

If your structure is older and has been flooded and does not meet current standards, or any time you are doing substantial improvements to your structure, consider the cost of elevating the structure using a flow-through foundation or a pile foundation, especially if structure improvements meet or exceed 50% of the value of the structure.

Flow-through foundations are typically block or poured cement foundations with adequate spacing for floodwaters to flow through the foundation without damaging the supports. These structures are acceptable in the A-zone areas of back dune environments that are not considered to be Erosion Hazard Areas.	Pile foundations are typically used in more active flooding areas along open ocean coastlines, and provide much more open space for floodwaters to travel through. Piles are required in the frontal dune and in areas of the back dune classified as Erosion Hazard Areas.

The concept behind both these foundation types is that water, sediment, and debris can travel through the foundation, thus not applying significant pressure and lateral force to the foundation which can cause structural failure. Both applications can significantly reduce potential flood damage to a structure.

You will likely need a permit from your local municipality, in addition to Maine DEP, to elevate your structure. Federal permits from the US Army Corps of Engineers and US EPA may be required if impacts to navigable waters or discharges into waters of the United States occurs. Check with your local Code Enforcement Office or the Maine DEP for more information.

Many of the state requirements regarding elevation of structures, including a review of techniques, are outlined in Chapter 5 of the Maine Floodplain Management Handbook. Your town may have additional requirements that meet or exceed minimum state standards. Contact your local Code Enforcement Officer for more information. You may also want to review the FEMA Coastal Construction Manual and the FEMA Home Builder’s Guide to Coastal Construction Technical Fact Sheets.  The Construction Manual is available as a CD or in print copy by calling FEMA Publications Distribution Facility at 1-800-480-2520, and should also be available for review at your local town office or public library.

If you consider elevating your structure, think about making other improvements to make your home more storm and flood resilient. Also, consider elevating your structure over and above the elevation required by your floodplain ordinance, in order to take into account expected rates of sea-level rise and higher future floodplain elevations.

Design and build new structures appropriately

Construction techniques that are appropriate to coastal areas involve not only siting of the structure and support structures, including septic, utilities, etc., but also design and building techniques that can withstand hazards and potential land, wind, and water forces associated with the dynamic coastal zone.

Things to consider:

• The construction footprint, given applicable setbacks for sensitive areas;
• The extent of grading needed to achieve a stable building footprint;
• The level of engineering required address erosion or flooding; and
• Potential physical forces such as water and wind.

Some of the best and most comprehensive resources available regarding proper coastal construction techniques are the FEMA Coastal Construction Manual and the FEMA Home Builder’s Guide to Coastal Construction Technical Fact Sheets. The Construction Manual is available as a CD or in print copy by calling FEMA Publications Distribution Facility at 1-800-480-2520, and should also be available for review at your local town office or public library.

Maintain a buffer next to the wetland

Keeping a healthy, diverse, vegetated upland buffer adjacent to a coastal wetland can lessen erosion and protect property. Without a buffer, development disturbs the fringing marsh boundary. Fertilizer usage can degrade marsh vegetation and allow colonization by invasive species. If you live on or near a coastal wetland, try to maintain, to the maximum width practicable, a naturally vegetated, woody upland buffer between the “developed” (planted lawn or infrastructure) portion of your property, and adjacent coastal wetlands. Other things you can do include:

• Enhance the width of existing buffers with native vegetation;
• Minimize disturbances adjacent to coastal wetlands;
• Limit planting and maintenance of lawns and subsequent usage of nitrogen-rich fertilizers;
• Remove invasive species within the buffer, especially common reed (Phragmites australis);
• Limit the amount of unnatural freshwater runoff directed into coastal wetlands from the adjacent uplands.

A great general resource for buffer management is from the Save the Bay Narragansett Bay Backyards on the Bay Yard Care Guide for the Coastal Homeowner.

Case Study:
Marsh Buffer

Plant or restore wetlands

Planted marshes are generally considered to be one of the most cost-effective and environmentally desirable erosion-control approaches. Fringing marshes protect adjacent uplands by gradually dissipating wave energy, absorbing the force of breaking waves, and stabilizing the soft, underlying soil. Planting marsh grass—which you can do yourself—has been particularly effective where previous marshes were destroyed by dredging and filling. Marshes can be created or restored by increasing tidal flow.

Marsh planting is most effective in areas that are sheltered from the wind and where waves and boat wakes are not a major problem. A marsh fringe at least 10 feet wide is necessary for erosion control, but 20 feet or more is preferred. If the marsh is not established continuously along the shoreline, erosion can continue on the unprotected areas. In some cases, two or more planting attempts may be required for the marsh to take hold. From a regulatory standpoint, marsh creation or restoration will likely require permitting on several levels (local, state, and federal). From the state standpoint, permits from Maine DEP will be required.

North Carolina's Shoreline Erosion Control Using Marsh Vegetation and Low-Cost Structures provides a good outline for how to plant and create a new coastal wetland. Similarly, the North Carolina Coastal Federation Erosion Control: Non-Structural Alternatives, A Shorefront Property Owner’s Guide provides some good guidance for marsh plantings. The techniques and species discussed in these guides are applicable to Maine’s marsh systems. Tidal bank protection using vegetative plantings is also outlined by the Maine DEP under their Maine Erosion and Sediment Control Best Management Practices (scroll down to Site Specific Applications of BMPs, Sand Dune and Tidal Bank Protection).

Commonly used grasses include species native to Maine salt marshes, such as saltmeadow hay (Spartina patens) and smooth cordgrass (Spartina alterniflora). Planting elevations can vary but can be determined by observing the elevations of healthy native marshes nearby. Marsh grasses may be purchased from specialized commercial nurseries (or can be potentially transplanted from existing marshes with a permit).

Phragmites australis, also known as common reed, is considered an invasive plant by the State of Maine and should not be planted or allowed to spread.

Increasing tidal flow into marsh areas by removing or replacing inadequately functioning road culverts can help facilitate the natural proliferation of marsh plants. Adequate tidal flushing is required for marsh growth, and also helps eliminate invasive species that are not salt-tolerant. Note that permits are likely required from Maine DEP and the US Army Corps of Engineers for work associated with road culverts.

Much of the above marsh restoration information was adapted from Managing Erosion on Estuarine Shorelines, which was prepared for estuarine shorelines in North Carolina. However, much of the information and techniques outlined transfer to Maine’s marshes. Additional online resources regarding techniques that provide good guidance for marsh restoration and creation include Maine Salt Marshes: Their Function, Values, and Restoration and Salt Marshes in the Gulf of Maine, Human Impacts, Habitat Restoration and Long-Term Change Analysis.

Add rip-rap or bulkheads to wetlands

Although not generally recommended because it limits coastal wetland migration and the transfer of sediment from uplands, rip-rap can be placed in or adjacent to a coastal wetland to protect property within 100 feet of an eroding bank, as long as the wetland does not have mudflats or salt marsh vegetation, or is within the Coastal Sand Dune System (Chapter 305, 8, A, (1)-(6). Otherwise, an individual permit will likely be required from Maine DEP in order to pursue bank stabilization that impacts coastal wetlands. Rip-rap best management practices for placement and construction techniques are available from Maine DEP.

The placement of a bulkhead adjacent to a coastal wetland will require permitting from Maine DEP. Like rip-rap, bulkheads limit the landward migration of wetlands, and cut off the natural transfer of sediment from eroding banks into the wetland. However, in some cases, their placement might be a necessity.

Some good sources for using bulkheads and rip-rap adjacent to marshes include the North Carolina Coastal Federation Erosion Control: Non-Structural Alternatives, A Shorefront Property Owner’s Guide, Shoreline Erosion Control Using Marsh Vegetation and Low-Cost Structures, and Maine DEP’s guide for the use of gabions.

Rebuilding after severe storm damage

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