Rehabilitation of Highway 62 West, Crater Lake National Park, Klamath County, Oregon
MITIGATION MEASURES COMMON TO ACTION ALTERNATIVES
For much of the corridor, revegetation work would not be necessary because construction would be completed in previously disturbed areas of the roadway. Revegetation work would use topsoil conserved along the corridor and seeds or propagules from native species (genetic stocks originating in Crater Lake National Park). No imported topsoil, forest duff, or hay bales would be used during revegetation in an effort to avoid introduction of non-native plant species.
Undesirable species would be monitored and control strategies initiated if these species occur. To prevent the introduction of and to minimize the spread of non-native vegetation and noxious weeds, the following measures would be implemented wherever possible:
- Minimize soil disturbance;
- Pressure-wash all construction equipment before it is brought into Crater Lake National Park;
- Limit vehicle parking to existing roads, parking lots, or the access route;
- Obtain aggregate from solid rock or deep layers of the Wizard III Quarry site to avoid material potentially contaminated with weed seeds and reduce the potential introduction of non-native plants;
- Obtain additional topsoil and forest duff from the project area;
- Revegetate all disturbed sites immediately following construction activities by spreading soil and duff; and
- Monitor all disturbed areas for two to three years following construction to identify noxious weeds or non-native vegetation. The treatment of non-native vegetation would be completed in accordance with Director’s Order – 13: Integrated Pest Management Guidelines.
Salvaged soil and duff would be stored at temporary staging areas on existing turnouts within the corridor. Replacement of the soil would include spreading, scarification, mulching, and seeding and/or planting species native to the immediate area. Further treatments may include covering the soil with duff and woody litter. The overall goal of revegetation is to replicate the natural diversity and abundance of native species and avoid interfering with natural processes as much as possible.
Disturbed sites that remain following maintenance and rehabilitation projects are routinely reclaimed using techniques described in revegetation plans. Sites identified for the Highway 62 West rehabilitation project that may be available for revegetation would include abandoned turnouts and portions of the highway alignment. These plans address techniques for salvage and transplantation of existing vegetation and salvage and replacement of duff and coarse woody debris to reduce erosion potential following ground-disturbing activities. In some cases, sites would also be evaluated for direct seeding, if they are eligible. Field surveys for assessing revegetation needs would be performed within the Highway 62 West corridor to create an applicable revegetation plan.