Environmentalists see a fight looming in City Council over a bit of business left over from last year's zoning code reform - a bill that would determine how close something can be built to the city's rivers and streams.

Legislation introduced in September would create a 50-foot buffer, or "setback," around those bodies of water - less than the 100 feet environmental advocates preferred, but a number they saw as a compromise with builders.

Now environmentalists fear Council will try to reduce the setback on the city's streams - basically, everything except the Schuylkill and Delaware Rivers - to 25 feet, a distance they say could harm already polluted waterways.

In an e-mail alert to supporters Tuesday, the advocacy group PennFuture said a 25-foot setback "flies in the face of science, good public policy," and the opinion of city Water Department experts.

"We want a comprehensive set of buffers that protect all our waterways," said Andrew Sharp, PennFuture's outreach coordinator. "We don't want one-third of the Wissahickon and one-fourth of the Schuylkill protected."

Councilman Bill Green, who sat on the commission that rewrote the zoning code, has been embroiled in the setback debate. He admitted that some unnamed District Council members had objected to a 50-foot buffer.

But Green rebutted Sharp's contention that he was preparing to amend the legislation and reduce the setback.

"I'm not prejudging anything," he said Tuesday. "I don't know if amendments will be introduced or not."

Green said there were a number of issues surrounding the setbacks that would have to be worked out in Council. (A committee hearing on the legislation has yet to be scheduled.)

Among the concerns, Green said, was whether setbacks would apply to streams already routed underground.

He also wondered if it wasn't advisable to keep the 50-foot buffer but allow exceptions beyond seeking a "full-blown variance," a more restrictive process.

And, he asked, what happens to buildings already within a 50-foot limit?

"Any change you'd want to make to that property would require a variance," Green said. "Is there something we can agree on . . . that would allow some expansion within the 50-foot setback? Those are all issues that we need the answers to."

The 50-foot buffers should have gone into effect with the rest of the zoning code reform, which was passed last year after a special commission spent four years redesigning the city's rule book for building.

But the buffers got hung up when the Nutter administration submitted a "clean-up" bill in the spring to make what was described as mostly minor corrections to the new code before it went into effect in August.

The development community - led by a coalition of lawyers, developers and architects called the Development Workshop - objected that some of the "clean-up" measures represented substantial policy changes, including an addition to the setback provision that defined its purpose in broad environmental terms.

Green and Councilman Bobby Henon then introduced amendments that reflected some of the Development Workshop's concerns. With Council embroiled in the budget season, the members "punted" on sorting out the setback issue in the spring, Green said.

A handful of amendments did pass, including one that requires Council to approve a hydrology map of rivers and streams before the buffer can go into effect.

In August, a working group of Council members and administration officials, builders, and environmentalists met to discuss the setbacks.

The group emerged with what the administration and environmentalists described as a consensus for 50-foot setbacks, but with concessions for certain types of development along the rivers.

Council staffers then drafted a bill to reflect the working group's discussions, including a hydrology map. Council leadership introduced the bill in the first meeting of the fall session.

Green, however, rejected the characterization that the working group had reached a consensus.

"If people who participated in that thought that the working group spoke for Council, that's ridiculous," he said. "Nobody in that working group committed to anything but to introduce a bill."

Green said "there was no point in arguing" with the working group but, in his case, "silence is not acquiescence."

Sharp said Green's just "not getting the answer he's looking for."

"We've all come up with the 50-foot buffer," he said. "I guess Councilman Green isn't convinced."

Sharp did say the Development Workshop, which participated in the working group, still had objections. Craig Schelter, the group's executive director, did not return a call seeking comment Tuesday.

Schelter has told the website PlanPhilly that the buffer would unduly hamper development, and that placing a setback on private property was an overreach. He also said he feared the buffers were a prelude to creating river trails without the city having to acquire the land.

Eva Gladstein, the deputy director of the city Planning Commission, said all the administration "absolutely" prefers the 50-foot barrier.

All of the city's streams are considered "impaired" by pollution and the federal Environmental Protection Agency requires the city to have a plan to mitigate the problem, Gladstein said.

Setbacks are part of the strategy, she said, and Water Department experts have said a 25-foot barrier would do little good.

"Fifty feet would be much more effective and 100 feet would be even more effective than that," Gladstein said.

Maya van Rossum, the Delaware Riverkeeper, also stressed the need for the buffer.

"If we are going to reopen this process then we should . . . get back to the science, which says 100-foot buffers are the appropriate requirement," she said.

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