Dike Road on North Whidbey likely won’t be reopened until the end of the month because of stability issues, the state Department of Transportation reported.

The project is part of the state’s Dugualla Bay environmental mitigation project, intended to restore saltwater marshes to 23 acres where settlers created farmland by building a dike nearly 100 years ago.

The road — the only alternative to State Highway 20 in the area — closed May 9. It was originally scheduled to reopen in early August. Crews removed the existing road, built a new dike and then built a new road on top of that dike.

The contractor ran into problems when the unexpected settling of materials occurred.

“To give perspective, a typical project like this settles about an inch or so. However, because of the conditions out there, we’ve seen over 30 inches of settlement,” Department of Transportation spokesman Marquise Allen wrote in an email.

The concern, he said, is that the ground underneath the new road could be washed out once it is exposed to tidal action. The final step in the project is to breach the original dike, which is located a few hundred yards east of Dike Road.

The project will let water from Dugualla Bay flow into the area at high tide, while still protecting from flooding the homes and farmland between Highway 20 and Dike Road, the agency said.

After allowing the settlement, the contractor crew started work at the site again last week and will be placing some construction fabric and rocks on the side of the new dike to better armor it, according to Allen.

The original project budget was $4.5 million, Allen said, but the additional work will add to the overall cost. The amount is being negotiated with the contractor.