Bayshore Bikeway Collapse Averted with Tons of Rock

A series of pipes that carry water from San Diego Bay to a former salt pond on the northern tip of Imperial Beach received emergency repairs Monday after it was found that erosion could cause the area to collapse.

The area at risk is located east of Highway 75 and west of 7th Street. The  runs along Imperial Beach's northern border, through Coronado and in total, 24 miles around San Diego Bay.

Heavy impact from erosion was first brought to the attention of engineers and U.S. Fish and Wildlife Service two weeks ago. On Monday an excavator placed 75 tons of gravel under the pipes and on its sides and damned up the area to stop tidal flow and temporarily fortify the area.

"It was really eating away at it," said Andy Yuen, Project Leader for the U.S. Fish and Wildlife Service in San Diego. "We were afraid that if we didn't do something right away that this thing would buckle, and more of it would fall in."

The Bayshore Bikeway runs atop a concrete structure called a culvert, that holds the pipes in place.

"At first we thought it's just the sides. And then we realized, oh it's actually going underneath, and so that was more of the worry as the foundation under this bank of culverts began to get undercut," Yuen said.

Tidal flow was reintroduced to pond 10A and others bordering Imperial Beach last fall following the to incorporate the area into the San Diego Bay National Wildlife Refuge.

Erosion was beginning to make the culvert lean forward, evident by loosened soil near the pipes. Some pipe connections were also beginning to loosen, Yuen said.

The structure and portion of the Bayshore Bikeway is thought to be structurally sound for the time being, according to engineers from Everest International, the firm that did the design work for the restoration.

More rock will be brought in possibly within the next week for more substantial repairs.