In Rehoboth, outfall work nears deadline
A significant portion of Rehoboth Beach’s ocean outfall pipe is now buried in the ocean floor, and the diffuser that will disperse treated effluent into the ocean has been installed, but the city’s contractor is now fighting a tight deadline and bad weather.
Joe Patterson, construction manager of the ocean work for city engineers GHD, said the weather and technical problems have delayed the work, which by permit must be finished by Thursday, March 15. Officials have submitted a request for an extension of the permit to work in the water until Saturday, March 31.
Patterson said the contractor Manson Construction has drilled case piping into the ocean; the already-assembled outfall pipe is expected to be pulled through the case piping back toward land. However, problems arose with the casing which has not yet entirely been installed; GHD Project Manager Kelvin George said for unknown reasons, sections of the casing became detached. George said the casing must be firmly attached to prevent drill fluid, which will help the pipe get through the casing, from leaking into the ocean. Because of problems with nonwelded case piping, George said Manson decided to weld sections together so the casing will not come apart if it meets resistance as it is drilled through the ocean floor.
Once the casing is installed, Patterson said, the project is weather dependent. He said recent 3-foot swells with 7-foot waves have slowed work. While those waves may not be bad for surfers, Patterson said, with a crane on a barge, those conditions can be dangerous because the barge could capsize.
“We can’t put the contractor at risk. We can’t put the environment at risk. So we have to wait for weather windows where we can perform this work. We only have 10 days of actual in-water work remaining, but we only get half-a-day at a time over two weeks,” Patterson said.
He said Manson crews are on call at all hours and will go out and work whenever the weather allows.
Besides the ocean work, Patterson said Manson has begun work to connect the pipe to the force main on Henlopen Avenue. He said 90 percent of the project should be completed by Sunday, April 1, with only onshore work left to be done.
Change orders
At the Feb. 16 Rehoboth commissioners’ meeting, George presented a list of change orders. One change regarded a mechanical fix to the diffuser at a cost of $16,000. George said the contract called for a PVC blind flange at the end of the diffuser to maintain pressure, but the manufacturer said that flange could not withstand the pressure of the system. So, he said, GHD recommended a stainless steel blind flange. George said one manufacturer could not guarantee production of a stainless steel flange in time; Manson first planned to install the PVC blind flange and replace it with steel later, at a cost of $106,000. In the end, George said, GHD was able to find a manufacturer in Pennsylvania that could deliver the required stainless steel part while Manson is still on-site, reducing the cost of the change order to $16,000.
Another change order related to testing the diffuser is still under review and negotiation, George said. He said the issue there is that testing was required by permit, but the item was not included in the city’s bid package.
George said the city will also receive two credits related to the force main project. The first is for narrowing the trench depth for the pipe, which George said could save the city $169,000. The second is a $33,000 credit for a redesign of the pipe/joint restraints as a result of changes to the path of the force main as workers continue to install it.
These two credits are on top of nearly $2 million in credits the city received from Manson for changes to the ocean portion of the project.
Mayor Paul Kuhns said while the city does now have some change orders to pay for, the credits have helped the city not only save money, but not yet have to touch any contingencies for the project.
“From a financial perspective, we’re in pretty good shape,” he said.
