A 20-story residential tower planned at the entrance to the popular Schuylkill River Park won final approval Tuesday from the Civic Design Review board, despite concerns that the project could seriously affect pedestrian safety and an adjacent community garden.

The unanimous decision cleared the way for developer Carl Dranoff to start construction next fall.

Joan Wells, president of the Schuylkill River Park Community Garden, said she was disappointed that the review board gave the project a green light, especially after several board members pointed out problems with the design.

"He doesn't have to change anything now," she complained.

While Dranoff has all the approvals he needs to start construction, he acknowledged during the hearing that some of the criticism was legitimate, and offered to continue meeting with residents to discuss revisions to the design, by Cecil Baker + Partners.

"I want to be collaborative," he said.

Any changes are likely to be modest. For instance, Dranoff said he that he could not agree to a key demand from opponents to shift the tower farther away from the garden. Doing so, he argued, would require a major redesign and time-consuming city approvals.

The mixed-used project, which is being called One Riverside, is planned for a small triangular parking lot on 25th Street immediately south of the Locust Street entrance to the Schuylkill Banks trail. The slim glass tower would rise along the southern edge of the site, just eight feet from the community garden. It would stand alongside a one-story parking garage on 25th Street.

The Center City Residents Association has been concerned that the project's three driveways - one for the garage, two for loading docks - would create a dangerous situation for people approaching the entrance to the Schuylkill Banks trail from 25th Street. Some also complained that the tower would increase the competition for parking spaces in the neighborhood.

However valid those concerns, the opponents had little leverage because the half-acre site is zoned for a high-rise tower, meaning Dranoff's project could be built without a variance or a special permit. The hearing before the design board was the project's last hurdle.

The design review board is a relatively recent innovation, a creation of the new zoning code that was intended to elevate the architectural quality of large projects. But the board's recommendations are merely advisory.

Tuesday's hearing did spark a conversation about several city rules that contributed to problems with the design.

Dranoff's attorney, Peter Kelsen, said that the developer would have preferred to build just one loading dock but that the zoning code requires two for any building over 150,000 square feet. At 167,000 square feet, One Riverside is just past the cutoff.

"The second loading dock is functionally and operationally unnecessary," Kelsen argued.

Dranoff's building should have come in at 140,000 square feet. But city building officials awarded Dranoff the extra 27,000 square feet of space as a zoning bonus for including one level of underground parking.

Nancy Rogo Trainer, the head of the review board, said she was surprised that Dranoff received such a generous bonus - a 20 percent increase in the total - simply for putting a portion of the parking underground. Such bonuses, she said, are generally given out only when the entire parking garage is situated underground. She asked the city building department to reaffirm that the bonus is correct.

The additional square footage had a huge influence on the design. Because of the requirement to accommodate two loading docks, most of the tower's narrow frontage on 25th Street is eaten up by the driveways. What's more, the loading docks will be situated right at the entrance to the community garden.

Kelsen said that Dranoff would like to find a way to eliminate one of the loading docks. He suggested that the city could solve the problem by changing the requirement when it undertakes its annual review of the zoning code this fall.

Contact Inga Saffron at ingasaffron@gmail.com, 215-854-2213, or on Twitter @ingasaffron.