Section 220-660-390 - Boat ramps and launches in saltwater areas(1)Description: A boat ramp or launch is a sloping stabilized roadway or entry point constructed on the shoreline for launching boats from vehicular trailers or by hand. Ramps and launches extend into the water at a slope of typically twelve to fifteen percent and are typically oriented perpendicular to the shoreline. Ramp and launch widths vary with intended use, and the length often depends on the slope of the shoreline and tidal amplitudes. Ramps and launches are usually constructed in protected areas with access to deep water close to shore. Construction materials commonly consist of gravel, concrete, or asphalt; they are often associated with marinas and parking lots. A railway-type boat launch consists of a pair of railroad tracks supported by pilings, and extends from the upland down to the beach.(2)Fish life concerns: A boat ramp or launch covers seabed habitat that supports fish life. A large number of ramps or launches in a given area increases the amount of loss and fragments this habitat. Ramps and launches placed above beach grade can block sediment movement (littoral drift). Ramp and launch construction, maintenance and the associated vessel activity can damage or destroy aquatic vegetation and forage fish spawning beds.(3)Boat ramp and launch design:(a) The design and location of ramps and launches must avoid adverse impacts to saltwater habitats of special concern. (i) The department will require a seagrass/macroalgae habitat survey for new ramp or launch construction unless the department can determine the project will not impact sea-grass and kelp beds and in herring spawning beds other macroalgae used as spawning substrate.(ii) A survey is not required to replace an existing structure within its original footprint.(b) Design and locate boat ramps and launches to avoid or minimize excavation waterward of the OHWL.(c) Design boat ramps and launches to minimize impacts to tidal currents and littoral drift. Common alternatives are ordered from least to most impacting: (i) Elevated railway-type launches;(ii) Hoist or lift launches;(iii) Elevated ramps; and(iv) Ramps constructed at beach grade.(d) The department will authorize boat ramps and launches on marine accretion shoreforms (such as barrier beaches, points, spits, and hooks) only if there will be no impact to geomorphic processes that create and maintain nearshore habitat.(e) Design and construct boat ramps and launches to prevent erosive undercutting or breaking of ramp edges.(f) Ramps elevated above the beach grade must have side slopes no steeper than one and one-half feet horizontal to one foot vertical.(g) Design and locate new boat ramps and launches to prevent the need for dredging. The department will allow dredging to maintain access to an existing boat ramp or launch if the access was dredged as part of the original project.(h) Design boarding floats to minimize grounding on and shading of the bed and impacts to tidal currents and littoral drift.(i) Use the smallest number of pilings required to construct a safe railway-type launch.(j) The rails of a rail launching system must lie on and follow the grade of the existing bed and bank.(4)Ramp and launch construction:(a) Construct the ramp or launch when the work area is not covered by tidal water.(b) Construct footings or the base of the ramp and launch below the preexisting beach grade of the beach to minimize undermining of the structure.(c) To construct a concrete boat ramp waterward of the OHWL, use precast concrete slabs or isolate the wet concrete from waters of the state until it is fully hardened.(d) Securely anchor launching rails to the bed or support railway launch piling.(5)Ramp and hand launch maintenance: Whenever feasible, place sediment and woody material removed from ramps and launches at or waterward of the OHWL downdrift of the structure.Wash. Admin. Code § 220-660-390
Adopted by WSR 15-02-029, Filed 12/30/2014, effective 7/1/2015