Weekday visitors to Mount Rainier National Park might have to contend with traffic delays as the park does work to protect the Nisqually Road.
Park Superintendent Dave Uberuaga said a contractor will install a log-crib flood protection structure and reconstruct the eroding roadway embankment six miles east of the park’s Nisqually entrance.
The work is to begin next week.
During a December 2009 flood, a 110-foot long by 30-foot high section of the river bank was undermined and slumped into the Nisqually River. The slide came within seven feet of the roadway edge at milepost 6.0, approximately ½ mile west of Longmire.
Entrix Inc., of Seattle, has designed an engineered log-crib structure consisting of cabling together more than 200 horizontally layered logs to 22 vertical anchor logs that will be buried 15 feet into the river bed and held down by large river boulders.
The log-crib structure will form the base on which to rebuild the roadway embankment and provides a roughened face to reduce flow velocities and rate of river bank scour, said a park news release.
This relatively new technology, in addition to its primary purpose to protect the roadway embankment, mimics natural river banks throughout the park where large standing and downed trees provide protection. The park intends to plant the rebuilt road embankment with native trees, shrubs and grasses in order to eventually re-establish the forest edge lost to the river, the release said.
Saybr Construction Inc., of Tacoma, was awarded a nearly $450,000 contract to construct the log-crib structure.
Saybr will begin bringing equipment and materials to the site early next week to begin site preparation. According to the preliminary project schedule, delivery and placement of the logs will begin in mid September and work completed by the end of September.
Visitors should anticipate maximum of 20 minute delays at the project site during times of equipment and log delivery. Most of the work will take place in the river bed and should not impact visitors traveling on the Nisqually Road. Work schedule is primarily Monday through Thursday, with some work on Fridays if necessary. No work is scheduled on weekends.