PMC Property Group has taken a step forward with its plan for a pair of residential towers along the Schuylkill's eastern bank near Arch Street, with legislation to permit the proposal approved Tuesday by the Philadelphia Planning Commission.

The commission voted in favor of the bill that extends through 2020 a previously passed — and since lapsed — zoning change allowing the towers at the site. It also permits above-ground parking to be built there, which PMC says is necessary because the site's location on a flood plain makes an underground garage unfeasible.

City Council must also vote to approve the bill for its provisions to take effect. A date for that vote has not yet been set.

PMC's proposal calls for 32- and 28-story towers with 321 and 291 units, with space for retail tenants that are to include a large supermarket.