At a certain point in any urban planning process, the talking has to stop - and the drawing has to begin. That's the watershed being reached this week in the wide-ranging project to craft a master plan for Philadelphia's seven-mile central Delaware River waterfront.

A design workshop over the next three days will bring together five recognized experts in landscape and urban design to create what's being called "the first broad strokes of the civic vision for the waterfront."

The five - from as far away as Germany and as nearby as Manayunk - will work with local designers, and government, business and civic leaders to sketch various scenarios for the waterfront's development.

The resulting plans, to be unveiled publicly at the Independence Seaport Museum at 3 p.m. on Saturday, are to be guided by a set of principles developed over the last few months in civic dialogues conducted with Philadelphians of every stripe.

Harris M. Steinberg, the University of Pennsylvania architect heading up the waterfront plan at the behest of Mayor Street, predicts "very different viewpoints from big thinkers."

As always, the challenge on the waterfront will be to balance diverse uses, such as port operations, casinos and other nightlife, and neighborhoods' recreational access to the river itself.

Making every stakeholder happy isn't an option. As one visiting expert, Toronto's former director of urban design and architecture Ken Greenberg, notes, the best solution could be "one where nothing is achieved to perfection, but the overall result is better than what any single objective on its own would be."

Over the next few days, Greenberg, joined by Philadelphia architect, planner and urban designer Denise Scott Brown; German landscape architect Peter Latz; former University of California, Berkeley, landscape architecture chairman Walter Hood, and Penn School of Design dean Gary A. Hack, will sketch out their best ideas for a vibrant waterfront. The central Delaware is bound to benefit from their insights.