BEsT MANAGEMENT PRACTICEs HANDbooK - Tahoe BMP

Table 8-20: Advantages and Disadvantages of Boat Ramp Construction andVehicle Source ControlADVANTAGES• Reduces overall turbidity and minimizesdischarges of turbid waters into the lake.• Minimizes maintenance dredging which maycause additional discharge of turbid waters.• Prevents vehicle intrusion into the lake,which may result in the discharge ofcontaminant to surface waters.• May prevent Polycyclic aromatichydrocarbon (PAH) accumulations in thelake.• Can prevent the introduction of invasiveflora and fauna from other navigable watersor other parts of the lake.• Can improve water quality conditions,particularly at boat launching facilities withpoor water circulation.DISADVANTAGES• Restricts the number of locations availablefor new boat ramps due to slope limitations.• May restrict the ability to expand existingboat ramps depending upon existingtopography.• Limits the ability to modify existingbackshore topography to accommodatedesired boat ramp length and slope• Inspections may be costly• Close proximity to groundwater may limittreatment ability of a vehicle wash stationwithout an associated lift station.• If not enforced, voluntary compliance withvehicle washing may not occur.• Treatment facilities require periodicmaintenance.• Parking space may be reduced by a washstation and associated staging areas.• Certain elements of a vehicle wash stationmay require scenic quality mitigation.• The cost to implement alternative launchingmethods, such as the use of tractors, maynot be feasible at all boat launching facilities.If properly constructed, the negative impacts of boat ramp construction couldbe minimized or avoided entirely. Launching of boats with vehicles that areladen with sediment, oils, and grease often create direct discharges ofcontaminants to the surface waters of the lake. Discharge standards may beexceeded, particularly early in the boating season, as vehicles, trailers, and boatsare most likely to be covered with road grime. Providing a vehicle wash stationwill direct common vehicle contaminants to treatment facilities where they canbe removed and not discharged to the surface waters of the lake. These vehiclewash stations shall be located at selected larger marinas. This programmatic setof strategies also provides complimentary support to the AIS control effortswithin the Lake Tahoe Region and the AIS inspections currently beingconducted prior to all motorized boat launches at designated stations aroundthe lake.8.12.3 DESIGN CONSIDERATIONS AND PLANNINGThe construction of boat ramps often requires grading below the water line(dredging) to establish optimal length and slope for the completed boat rampfacility. To minimize the extent of dredging required, restrict the siting of newboat ramps to existing backshore slopes of 15 percent or less, and to existingforeshores that are at least a continuous 12 to 15 percent from high water toelevation 6,219 feet. Steeper backshore and foreshore slopes may requireTRPA BMP HandbookCHAPTER 8: Shorezone Protective Structures and BMPs2012 8.12 Boat Ramp Construction and Vehicle Source Control Methods and DesignPage 8-79