Construction is underway to combat groundwater to improve drainage at the heavily traveled Highway 101 underpass at Castillo St. in Santa Barbara.

“The strength of the water pressure on the road here is phenomenal, so we’re constantly fighting that pressure and it wants to mushroom wherever the path of least resistance is,” Caltrans Senior Civil Engineer Jason Klein explained.

Klein, Castillo St. He says the underpass was built in the 1960s and the busy intersection constantly has standing water on the road.

It needs to be cleaned frequently to avoid slippery areas.

“The goal of this project is to provide a pressure relief valve for groundwater and encourage that water to exit through other means rather than over the highway,” Klein said.

The estimated $500,000 project began Monday and is expected to take eight weeks.

How will this affect traffic?

“We’re just closing the bike lane. They can share the road across the intersection, and that way we’re not blocking the lanes to get the job done,” Klein said.

Caltrans spokesman Jim Shivers says such projects are environmentally driven because of Santa Barbara’s high water levels.

“Our response to this is actually a response to what Mother Nature has to offer us, and we’re doing everything we can to control that,” he said.

According to Klein, this is the first place in Santa Barbara to implement this type of water diversion.

“And if this is successful, we will take that into consideration and consider opening additional locations if possible,” he said.