Engineers and Surveyors in the Design Process
The design of coastal structures often have complex geology, drainage issues, structural conditions and wave climates that require careful consideration, planning and design which can benefit from the expertise of professional engineers and surveyors. Failure of an erosion control structure, even over a period of years, may result in loss of additional upland, threaten existing buildings and result in damage to adjacent properties. The repair of a failed structure may be as expensive as the original construction.
Professional Engineers (PE) and Licensed Land Surveyors (LS) certify that the design work is prepared with direct supervisory control, according to the best professional standards in a manner that is protective of public welfare and property.
The planning of a project also requires a field survey. The LS is best suited to provide the critical site information needed by the PE for design including existing site contours, the location, dimensions and elevations of structures and the offshore bathymetry. A surveyor determines the boundary of the upland parcel and the partition lines for littoral rights extending into the waterbody. If a submerged land lease is needed, an LS prepares a metes and bounds description and plat. These products can only be prepared by a New York Licensed Land Surveyor.
Effects on Adjacent or Nearby Properties
The design objective for all shore structures is to minimize changes to wave energy at adjacent properties and to not change the flow of littoral material along the shore. If the proposed structure will result in significant changes to wave energy or the littoral system, the engineer must fully consider the expected magnitude of the potential effects, justification for the extent of potential harm and a plan to mitigate such effects.
The two most important questions related to effects on adjacent or nearby properties that must be addressed in the design of a shore structure are:
- Will the structure sufficiently change the direction or magnitude of wave energy at an adjacent or nearby property to adversely affect the shore or bluff?
- Will the project change the flow patterns, interrupt or entrap sufficient littoral material to create a deficit of beach material and increased erosion along the shore on nearby properties?
Impact of Design on Habitat
Structures that occupy existing beaches or the shallow nearshore areas have impacts on these unique and limited habitats. In simplest terms, structures use space that would otherwise be available to the organisms that would normally be there.
Beaches are ephemeral over seasons and years but they can be sustained and augmented with appropriate care and design. Unfortunately, shore structures, such as revetments and seawalls, can result in the complete loss of the beach that cannot be replaced. The cumulative impact of the addition of thousands of small shore structures along the shore over many decades has significantly changed both the quality and the quantity of beach and near shore habitats.
The most straight-forward design approach to minimize the impact on beach and nearshore habitats is not to construct on the beach but instead locate structures up the bluff or bank face. This is not always possible, so the next level of habitat-impact design is to minimize the distance the structure extends from the toe of the bluff or bank.
Structures that extend waterward beyond a minimum distance from the toe of the bluff or bank must be balanced between one person's use and the good of all the people.
