Framed by two sweeping pavilions shaping a gateway to one of Philadelphia’s busiest transit hubs, a proposed $55 million Dilworth Plaza redesign seeks to replace an unwelcoming concrete space on the west side of City Hall with expanses of grass and pools forming a civic front yard for the city. In October, supported by the private-sector Center City District, the project received $15 million in funding from the federal Transportation Investment Generating Economic Recovery (TIGER) II grant program.

Now in its second round, TIGER grants totaling $600 million from the Department of Transportation are being awarded nationally to fund innovative transportation projects, spur economic development, and improve environmental benefits. As one of the program’s 75 recipients, Dilworth Plaza covers four layers of subterranean transit connecting the Philadelphia region and serving an estimated 300,000 riders daily. City Hall Station will undergo its own $200 million renovation set to run concurrently with construction of Dilworth Plaza. Funding for station improvements is being handled by the Philadelphia transportation authority, SEPTA.

The revamped plaza and station are expected to improve commuter convenience and increase the station’s efficiency, where ridership levels are projected to increase by 150,000 people annually. To that end, symmetrical 20-foot-tall glass station entrances will feature artful lighting displays and gently curve to the ground plane, allowing natural light into the concourse and creating the appearance of sliding under the sidewalk. A sunken plaza and its granite colonnade will be preserved but bridged over to form an expanded concourse level.

Designed by Urban Engineers with Kieran Timberlake and landscape architects Olin, the new plaza will displace an underutilized 1960s-era sunken space that does not easily accommodate events. The redesign calls for a programmable fountain and a cafe with outdoor seating to bring street life to the plaza. The new space can be reconfigured to accommodate ice-skating and concert seating for events of up to 8,000 people.

With new porous paving, Dilworth Plaza will additionally provide significant reductions in runoff and quadruple the landscaped area absorbing airborne pollutants. A 36,000-gallon underground cistern will collect rainwater for on-site irrigation.

Construction on the plaza is not expected to start until next summer, but construction documents are being prepared and the project is expected to open in late 2013. In addition to the TIGER II grant, the project is funded by a matching $15.5 million contribution from the commonwealth of Pennsylvania and contributions from the William Penn Foundation, the Knight Foundation, and adjacent property owners. Remaining funds are expected from the city of Philadelphia, SEPTA, and loan financing.