Water: Coastal Zone Act Reauthorization Amendments
H. Boat Operation Management Measure
(applies to boating only)
Restrict boating activities where necessary to decrease turbidity and physical destruction of shallow-water habitat.
This management measure is intended to be applied by States in non-marina surface waters where evidence indicates that boating activities are impacting shallow-water habitats. Under the Coastal Zone Act Reauthorization Amendments of 1990, States are subject to a number of requirements as they develop coastal nonpoint source programs in conformity with this measure and will have some flexibility in doing so. The application of management measures by States is described more fully in Coastal Nonpoint Pollution Control Program: Program Development and Approval Guidance, published jointly by the U.S. Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA) of the U.S. Department of Commerce.
Boat operation can resuspend bottom sediment, resulting in the reintroduction of toxic substances into the water column. It can increase turbidity, which affects the photosynthetic activity of algae and submerged aquatic vegetation (SAV). SAV provides habitat for fish, shellfish, and waterfowl and plays an important role in maintaining water quality through assimilating nutrients. It also reduces wave energy, protecting shorelines and bottom habitats from erosion. Replacing SAV once it has been uprooted or eliminated from an area is difficult, and the science of replacing it artificially is not well-developed. It is therefore important to protect existing SAV. Boat operation may also cut off or uproot SAV, damage corals and oyster reefs, and cause other habitat destruction. The definition of shallow-water habitat should be determined by State policy and should be dependent upon the ecological importance and sensitivity to direct and indirect disruption of the habitats found in the State.
This measure was selected because some areas are not suitable for boat traffic due to their shallow water depth and the ecological importance and sensitivity to disruption of the types of habitats in the area. Excluding boats from such areas will minimize direct habitat destruction. Establishing no-wake zones will minimize the indirect impacts of increased turbidity (e.g., decreased light availability).
As discussed more fully at the beginning of this chapter and in Chapter 1, the following practices are described for illustrative purposes only. State programs need not require implementation of these practices. However, as a practical matter, EPA anticipates that the management measure set forth above generally will be implemented by applying one or more management practices appropriate to the source, location, and climate. The practices set forth below have been found by EPA to be representative of the types of practices that can be applied successfully to achieve the management measure described above.
- a. Exclude motorized vessels from areas that contain important shallow-water habitat.
Many areas of shallow SAV exhibit troughs (areas of no vegetation) due to the action of boat propellers. This can result in increased erosion of the SAV due to the loss of bottom cover cohesion. SAV should be protected from boat or propeller damage because of its high habitat value.
- b. Establish and enforce no-wake zones to decrease turbidity.
No-wake zones should be used in place of speed zones in shallow surface waters for reducing the turbidity caused by boat traffic. Motorboats traveling at relatively slow speeds of 6 to 8 knots in shallow waters can be expected to produce waves at or near the maximum size that can be produced by the boats. The height of a wave is directly proportional to the depth of water in which the wave will disturb the bottom (e.g., a taller wave will disturb the bottom of water deeper than a shorter wave). Bottom sediments composed of fine material will be resuspended and result in turbidity. In areas of high boat traffic, boat-induced turbidity can reduce the photosynthetic activity of SAV. Chapter 6 contains additional information on how to implement this practice.