The proposed Wawona Road maintenance project includes repairing the most severely damaged areas of the 27 mile roadway. The proposed project will stay within the existing road prism and there are no plans to modify the existing retaining walls and guardwalls that are contributing to the historic character of the road. The project limits are from Yosemite Valley at Southside Drive to the southern park boundary near Wawona. The specific work includes patching of potholes, crack sealing, shoulder and curb repair, placement of an overlay, microseal, or chip seal, depending upon the best design for the specific location. The specific overlay work includes applying a thin layer of oil, fabric and a 2" application of compacted bituminous asphalt. Where necessary the overlay areas may also require adding a 2' wide maximum compacted base rock shoulder to protect the 2" drop- off associated with the overlay. The specific microseal and/or chip seal work includes the placement of an emulsion (mixture of water, asphalt cement and emulsifying agent, such as soap) over the road, immediately followed by typically placing 3/8" - 1/2" uniformly graded rock chips over the top of the emulsion. The road would then be re-striped upon completion of the overlays and seals. Asphalt patching and crack sealing will be kept to a maximum depth of 12". The failed asphalt and subgrade will be removed and replaced with new base material and new asphalt pavement. Curb installation is limited to repairing the existing damaged or destroyed curbing and finally the shoulder repair would include stabilizing the existing embankment with rock and then capping with compacted base material. The replacement in-kind curbs shall match the existing type and color, whether it is asphalt or concrete. If specific embankment stabilization designs and/or repairs are necessary they will be developed on a case by case basis in consultation with the History, Architecture & Landscapes Branch Historical Landscape Architect Daniel Schaible to ensure compatibility with the historic character of the road. These designs will meet the Secretary of the Interiors Standards and when possible rocks salvaged from the proposed project site or other park project sites will be incorporated into the project construction.
The purpose of the proposed project is to make the existing historic Wawona Road safe for visitors and employees as it is currently aligned and where necessary repairs shall be limited to replacement in kind for all features within the existing road prism.
The plan is to award the contract this spring and commence work by August and have the work completed by the end of October 2008. However, if contracting, weather, or traffic concerns are a problem then it may get delayed until 2009. The patching, crack filling and curb work, as well as the chip and microseal would occur during the week days (Monday thru Friday) in May through August between the hours of 9:00 PM and 6:00 am days. Whereas, the overlay work would occur after Labor Day (September-October) Monday thru Friday between the hours of 7:00 AM and 5:00 PM. It is anticipated there will be 1 month of night work, patching and 2 months of day time work patching and sealing. All work will be coordinated with the park wildlife office to minimize disturbance and/or impacts to park wildlife.
The project scope shall include an approved storm water plan and a spill prevention plan prior to commencing any ground disturbing work, as well as an approved traffic control plan. Also, this project will require that all construction equipment coming into the park be inspected by either park revegetation staff or an approved Federal Highways Administration staff member. The contract specifications will also require submission and approval of any material sources proposed to be used on this project.