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 the Managing Director's Office, which is overseeing the bidding.

The city proposed moving the tours, which include land and water travel, from the Delaware River to the Schuylkill. In a July 7 accident, a barge owned by the city hit a duck on the Delaware, killing two passengers.

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

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 bid.

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

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

He said Philadelphia might not award a contract if plans for the vehicles conflict with recreational needs. He and other city officials have not yet reviewed the bid, he said.

Bob Salmon, vice president of Ride the Ducks, said the company remained confident that it would resume business here in the spring. The company's website heralds a March 2011 return to Philadelphia, on the Schuylkill.

"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 against the plan at a recent meeting, Salmon said. "At this point, there is nothing to indicate otherwise."

He has said that the ducks are safe and that he thinks the barge was at fault. The barge was being pushed by a tug owned by a private contractor, and the first mate 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 might not be eligible to bid because it is a party to litigation over the accident, but the city disagreed, saying 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 will include representatives from the Managing Director's Office, the Planning Commission, the Office of the Deputy Mayor for Transportation, 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 contact the Managing Director's Office.

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