Community Update, Short Term Emergency Mitigation Measures Southern Erosion December 2023

Community Update, Short Term Emergency Mitigation Measures Southern Erosion December 2023

Ocean Shores Permit Drawings 11.30.2023

After receiving the final report of the Southern Shoreline Erosion Assessment in August 2023. The city, with the help of Shoreline Consultant Mott MacDonald, did an evaluation of the shoreline along Marine View Drive to identify the area's most at risk of damage to public infrastructure.

The area identified that poses the greatest risk, is that area known as Neptune Way. This is the area directly across from the Water Departments South Reservoir and Booster Pumpstation, as well as the South end of Lake Minard. Should a storm event and resulting high surf conditions, cut a path through the existing foot trail into Marine View Drive, damage to several critical public infrastructure assets could be compromised.

A plan has been designed to provide for temporary, short-term protection of this area that would potentially breach in a significant storm event. The plan involves the placement of a sacrificial sand berm parallel to the beach at the ordinary high-water mark. This berm would be approximately 350 feet in length and range from 5-10 feet in height. The bulk of the berm will be constructed of native beach sand. The top and ocean side of the berm is designed to use coarser screened sand sourced from a local quarry.

It is anticipated that if storm conditions reach the berm, the berm will absorb the wave energy and erode. It is forecast that this berm will have to be nourished throughout the storm season to continue to provide protection to the public infrastructure landward of the berm.

The City is in communication with the Army Corps of Engineers to facilitate a backup plan for this soft structure approach. The Corps has offered to provide supersacks, which are 1 cu/yd sandbags that can be placed and serve as a temporary stopgap to an imminent breach. The city will request additional supersacks to be used in other areas, if damage to other areas of this region appears imminent. The Corps has indicated that they could be available to assist the city if an imminent event were to be forecast. The Corps by law, is not allowed to pre-emptively place erosion control measures on private property without an emergency event taking place. They have indicated that because the city is taking a proactive approach to mitigating some risk, they will be able to provide support much faster if they are needed.

These short-term measures are intended to get the city through the winter while medium- and longer-term solutions are sought. There are several challenges to the longer-term solutions including funding sources, the fact that this shoreline is largely privately owned, permitting timelines and having an effective design strategy.

During the construction of the short-term measure in front of the water tower, there will be a short period where public access to the beach at the east side of Oyhut Bay will be closed. Alternate access to this area is through the trail at the south end of Tonquin Ave. There is a trail that goes past the FAA Vortac Station which is visible from the parking area at the end of Tonquin Ave. Work may start as early as December 6, pending approval of permits.

Questions regarding this project can be directed to:

Project Manager:

Beck Leach

bleach@osgov.com

Phone: 360-940-7542 office, cell 564-544-0903

Planner/Shoreline Administrator

Marshall Read

mread@osgov.com

Phone: 360-580-4465

Street Dept. Crew Chief

Shawn Pease

spease@osgov.com

Phone: 360-581-0887

City Administrator

Scott Andersen

sandersen@osgov.com

Phone: 360-940-7643