Rehabilitation of the Remaining Wawona Road-Mariposa Grove Road and South Entrance Intersection

Yosemite National Park » Rehabilitation of the Remaining Wawona Road-Mariposa Grove Road and South Entrance Intersection » Document List

This project will pulverize and repave approximately 0.86 miles of the Wawona Road (Route 0014; FMSS# 10814) from 1/4 mile north of South Entrance Station to the southern park boundary and the western 2.06 miles of the Mariposa Grove Road. [The roundabout at the South Entrance Intersection and the curve adjustment at the Grove entrance were addressed under the Mariposa Grove Restoration EIS/ROD (2013).]

• The existing 24 foot wide paved Wawona Road and 22 foot wide paved Mariposa Grove Road will be recycled (pulverized to a maximum depth of 12") and overlaid with spot reconstruction of subgrade and shoulders as required (spot reconstruction to a maximum depth of 2-ft.).

• The work includes minimal drainage work with two culverts being replaced due to failure and 6 new culverts due to a lack of drainage which is causing water ponding and creating icy conditions, as well as saturated pavement and road failures. The new culverts will allow the water to flow across the road into the natural drainage instead of being dammed up as it currently is. For any culverts that are relatively deep, slip-lining will be considered as a preferred repair. The proposed drainage work also includes installing an underdrain system at approximately 50 road locations where there is currently a road failure concern (maximum trench width of 3-ft. and depth of 5-ft.). The existing paved ditches will be repaved. The drainage design repairs will be coordinated with park hydrologists and revegetation specialists. Natural water flows will not be changed.

• The proposal includes minimal work at pullouts and intersections, which will be within the existing paved footprint. Work includes pulverizing and re-grading the existing paved and unpaved pullouts/intersections and then repaving the existing paved pullouts and re-grading the unpaved pullouts. Also, at some pullout locations the proposal includes adding boulders and/or berms to contain the pullout area and prevent any further expansion/disturbance of the surrounding pullout areas. There are also shoulder areas that have been widened due to informal stopping/parking; this project includes re-grading these areas to minimize the traffic safety concerns and resource disturbance.

• The proposed design will be submitted to the appropriate Park resource specialists (Park Historical Landscape Architect, Hydrologist, Botanist, Revegetation Specialist, Protection-Traffic Staff, etc.) for review and guidance to help minimize or eliminate impacts to park resources.

• A wildlife crossing will be added at Big Creek (A 36" diameter culvert will be added adjacent to the existing Big Creek box culvert so animals can cross the road without getting hit when there are high flows in the existing Big Creek box culvert).

• This project will not alter the historic character of the road. The road width will remain the same and all drainage improvements will be done in accordance with the Secretary of the Interiors' Standards for the Treatment of Historic Properties, in consultation with the Cultural Resources Program of the Division of Resources Management and Science.