See a larger image here:
http://www.pbase.com/image/31238595/original.jpg
This is a plan prepared for local neighborhood groups along the Delaware River about a year ago showing a conceptual strategy for waterfront development between Penn Treaty Park and Pier 70, the Home Depot/Walmart shopping center.
The dark shapes are buildable sites, including some over I-95. The green areas are proposed parks and recreation facilities. Philadelphia has over 40 miles of waterfront, but does a lot of it.
The plan shows conceptual feasibility based only on the existing elevations of I-95 and the river (which are assumed as more or less immutable), not on financial or engineering feasibility, which requires much more investigation. Still, there are some exciting ideas. New development would justify mass transit.
Although the plan does not show a rail line on Delaware Avenue specifically, you will note that it has a wide median in place -- perfect for light rail or some versions of heavy rail as shown in the picture below.
Part of the plan deals with Penn's Landing. Don't discount this idea before seeing a good 3-D illustration. Based on inititial investigation, it may be possible to extend the street grid right down to the water over I-95. The highway is in a trench for a precious few blocks, and is at grade in other locations. In some locations, actual streets just won't work because they would be too steep-- in those locations streets of stairs are used as existin in Seattle, San Francisco, and numerous other cities.
By raising a small portion of Columbus boulevard up 20 feet, intersections with Chestnut and Walnut Sts. could be created, thus solving the main problem of Penn's Landing -- it's isolation. Instead of crossing fourteen lanes of highway on bridges, you would cross I-95 on bridges with buildings on the sides to hide the highway. At Penn's Landing, buildings, terraces, and streets would ramp down to the water level, 20 feet below, over the space of about one block. Parking and a rail transit station could occur below the raised street.
This approach would create a waterfront that is functionally the same as waterfronts in a dozen US cities and many international cities where the street grid connects to a waterfront boulevard street with facing buildings, and where a substantial grade change happens in a short space, creating the walls of an outdoor terrace looking over the water.
I have a lot of images to support to explain the design and to show examples, but in the interest of brevity, I'm not posting those.
The point is, Philadelphia's waterfront could be a real economic catalyst for the city, but only if it is an entire district, not just scattered development sites.
