Sinkhole bids coming in, construction in April
June 12, 2008 · Updated 9:01 AM
The City of Port Orchards Public Works Department is closing in on repair work on the large sinkhole that has marred Bethel Avenue since the Dec. 3 storms.
On Friday, Public Works Director Maher Abed and WestSound Engineering Project Engineer Alan Biggs took several contractors around the High Point Shopping Center parking lot to examine the sinkhole and discuss replacing a makeshift pipe blamed for the damage.
The work would run from the South end of the parking lot and cross over to the open-air creek across the roundabout at the Knights of Pythias Cemetery.
Biggs and Abed took the interested contractors to the sinkhole, then showed them where catch-basin structures will be built, and examined the creek by the cemetery, where the water comes out.
Biggs explained that the Washington State Department of Ecology and the Environmental Protection Agency have not yet set any requirements for that area, and that some plans could change in the future.
The work involves replacing a trapezoidal pipe and installing five catch-basins, accessible by manholes in the shopping center parking lot.
The catch-basins will serve to redirect the larger pipe and will have manholes and ladders for accessibility.
The new pipe will run 36 to 55 inches, and sit at a shallower depth than the original pipe.
Biggs estimated the whole project will cost $250,000. Some of the expense will be covered by the Federal Emergency Management Agency (FEMA). The designer work alone ran $80,000, but the city only covered $10,000 after FEMA covered 87.5 percent of the cost.
The overall $250,000 estimate is down from early estimates of $400,000.
The city is accepting sealed bids for the project now and will open them oat noon on March 28.
Abed said he wants construction to start mid-April.
The sinkhole appeared during the December storm that brought property damage across the whole state, including flood damage at many area homes and businesses.
The sinkhole appeared around 11 a.m. that day and resulted in no injuries. A break in the pipe leaked water underground and began washing the dirt out from under the parking lot.
Piles of stone and blacktop can still be seen in the creek by the cemetery.
The hole was due to non-standard piping, which was once open-air. The pipe is a non-standard trapezoid shape, meant to drain water at a surface level, but was later fashioned into an underground pipe by laying a concrete ceiling over the top.
According to a report by WestSound Engineering, the non-standard piping deteriorated in the vicinity of the sinkhole.
After sending a camera robot into the pipe, Public Works found a number of cracks and leaks in the pipe, including portions with bare metal exposed out of the corroding concrete.
The camera also found poorly installed feeder pipes in several locations.