Lompoc officials are exploring how to shore up a vulnerable section of the Riverbend Park Bikeway that is in danger of collapsing into the Santa Ynez River during the next big rainwater flow down the river.

However, funding the project is a considerable obstacle.

"We're going to try to fix this, if we can afford to," Public Works Director Larry Bean said.

Nov. 10 is the deadline for firms to submit their Request for Qualifications (RFQ) on solutions to protecting the riverbank, Bean said. The city will score each entry and pick the top firm to work on a long-term solution and design to remedy the erosion, he said.

Measures could include concrete piles with cabling or large, rock boulders with grout in between to make an armored levee, according to Bean.

Funding will always be a hurdle, he said. A "ballpark figure" for the cost of the development is $1 million, he said.

Completed in April 2008, at a cost of $885,000, the Riverbend Park Bikeway multipurpose trail covers 2.25 miles along the southwest bank of the Santa Ynez River, from Riverbend Park at the north end to the east terminus of College Avenue.

Residential neighborhoods border most of the west side of the 8-foot wide, two-lane asphalt path. The now-parched Santa Ynez River borders the east side of the path, which includes

2-foot wide native earth shoulders on each side.

In a September 2008 letter to the City Council, Lompoc resident Carl Walton said the riverbank has shifted more than 340 feet to the west in more than a dozen years. The problem is more prevalent when there is water flow in the river, creating a potential flood hazard to nearby property owners if more of the path gives way, he said.

"If no action is taken, the next significant flow in the Santa Ynez River may destroy portions of the bikeway," Walton said.

Walton echoed those comments in a phone interview Tuesday.

"Something needs to be done or it is going to keep continuing," he said.

His letter included aerial images from Google Maps comparing the same section of the river in 1994 to 2006.

For the Nov. 4, 2008, council meeting, a staff report from city Civil Engineer Craig Dierling, in response to Walton's letter, said staff is aware of the potential damage to the bikeway from erosion. He also noted that addressing the issues through river flow alignment or bank protection is costly.

As part of a two-year Measure D spending plan, the council approved $100,000 in funding for the feasibility study in April 2008.

Bean said the Environmental Impact Report (EIR) for the bikeway took into consideration likely flooding on what was a vacant city-owned flood plain.

"The EIR clearly points out it could flood or erode," Bean said.

It was determined to be more economical to repair a short section of the bikeway than to reroute the river, he said.

Digging pilot channels - meant to keep water flow down the middle by changing the river's behavior - is affordable, Bean said. The channels take away hard turns that would direct heavy flows toward the river banks. However, it is believed it would not hold in a El Niño year and is off the table as an option. Instead, the estimated $100,000 for the cost of the pilot channels will go toward a long-term solution.

El Niño conditions, which usually bring wetter years to California, occur when ocean temperatures in the tropical Pacific Ocean heat up, causing weather patterns to shift.