Suitability of the Dunes for Development

Stephen M. Dickson
Maine Geological Survey

Continuing natural movement of the beach and perhaps more abrupt shoreline changes caused by a major coastal storm or an acceleration of sea-level rise make some areas unsuitable for coastal development. Structures should be placed in locations which (1) have minimal interference with natural geologic processes and (2) are in areas with low risk from natural hazards. In addition, two books the Coastal Construction Manual and Living with the Coast of Maine, have recommendations for the design of buildings in coastal areas.

The Maine Natural Resources Protection Act (NRPA: Title 38 M.R.S.A., Section 480, 1995) requires that new coastal development will not unreasonably (1) interfere with the natural supply or movement of sand within or to the sand dune system; (2) cause or increase the flooding of the dunes or adjacent properties; (3) interfere with the natural flow of any surface or subsurface waters; (4) increase the erosion hazard to the sand dune system; or (5) inhibit the natural transfer of soil from the terrestrial to marine or freshwater environments. Additional NRPA restrictions on development concerning wildlife, water quality, recreation, etc. may apply to some dune areas.

The frontal dune is important for both storage of beach sand and protection of back dune areas during storms. Consequently, most coastal development in the frontal dune is restricted (for details see the DEP Sand Dune Rules). Seawalls prevent the natural exchange of sand between the frontal dune and beach and new seawalls are prohibited. In the back dunes, development is less restrictive due to the safety afforded by the frontal dune and slower rates of sand movement by geologic processes. Development is restricted anywhere in the dunes that will be threatened by shoreline erosion or by 0.9 m (3 ft) of sea-level rise during the next century.

References

Department of Environmental Protection, 1993, Coastal Sand Dune Rules - Chapter 355: Maine Department of Environmental Protection, Bureau of Land and Water Quality, 17 State House Station, Augusta, ME 04333-0017, 21 p.

Department of Environmental Protection, 1995, Natural Resources Protection Act (38MRSA, secs 480-A to 480-X): Maine Department of Environmental Protection, Bureau of Land and Water Quality, 17 State House Station, Augusta, ME 04333-0017, 26 p.

Federal Emergency Management Agency, 2011, Coastal Construction Manual (pdf), 4th edition, FEMA P-55.

Kelley, J.T., Kelley, A.R., and Pilkey, O.H., Sr., 1989, Living with the Coast of Maine: Duke University Press, Durham, North Carolina, 174 p., (Available from the Maine Geological Survey).


Last updated on April 23, 2012