Ride the Ducks is the sole bidder to run a water cruise but city officials say they may not allow the popular attraction to operate if it disrupts a local park.

"We understand the concerns and are very cognizant of the impact that a poor proposal could have on Schuylkill Banks," said Brian Abernathy, chief of staff in Philadelphia's Managing Director's Office which is overseeing the competition.

The city has proposed moving the tours, which include both land and water travel, from the Delaware River to the Schuylkill River. The decision follows a July 7 accident in which a barge owned by the city hit a Duck boat on the Delaware, killing two passengers.

The proposed move has met strong opposition from neighbors along the route from Old City to the entrance site on the Schuylkill near the Art Museum. They fear it will disrupt the peacefulness of the park, Schuylkill Banks, near the entrance site and its popular running, biking and walking path.

Plans call for the vehicles to enter the river either from the west bank or by going under the recreational path on the east bank.

Jonathan Bari, who operates the Constitutional Walking Tour of Philadelphia and who has complained that the city has favored Ride the Ducks over other tour operators, said he was not surprised that only one company submitted a bid.

"It's a fait accompli," he said. "It's exactly what the city intended and it's exactly what the city got."

He argues that by putting out the request for bids between Thanksgiving and Christmas, the city left little time for interested companies to respond.

Abernathy said the bidding period of four weeks was standard.

Abernathy said the city "would have liked to see more bidders, but it is what it is."

He said Philadelphia may not award the bid to anyone at all, if plans for the vehicles conflict with recreational needs. He and other city officials have not yet reviewed the bid.

Bob Salmon, vice president for Ride the Ducks, said the company remains confident that it will resume business here in the spring. The company's web site heralds a March 2011 return to Philadelphia, on the Schuylkill River.

"I think we're confident that our proposal will be met with approval by the city and will be embraced by others," including park neighbors who spoke out against the plan at a recent meeting," Salmon said. "At this point, there is nothing to indicate otherwise."

He has said the Duck vehicles are safe and believes the barge was at fault in the accident. The barge was being pushed by a tug owned by a private contractor, and the first mate on the tug has refused to talk to authorities.

The National Transportation Safety Board is expected to complete its investigation of the accident next year.

Bari said Ride the Ducks may not be eligible to bid because it is a party to litigation over the accident, but the city disagreed since Ride the Ducks and Philadelphia are not opposing parties in the lawsuit.

The city will begin reviewing the bid after Jan. 3, though Abernathy could not provide an exact date. He hopes a decision will be made by mid to late-January, he said.

The committee reviewing the bid includes representatives from the Managing Director's Office, the City Planning Commission, the Office of the Deputy Mayor for Transportation and the Office of Economic Opportunity and the Commerce and Parks and Recreation departments.

Abernathy would not name the members of the committee and said people interested in commenting on the proposal should get in touch with the Managing Director's Office.

Contact staff writer Miriam Hill at 215-854-5520 or hillmb@phillynews.com.