To local historians and preservationists, it's a valuable piece of Tempe's past making a last stand. To city officials, it's a hulking mass of decaying concrete, the cork blocking the city's plans to pour $440 million worth of sparkling development into the dry Salt River bed.

At issue is the 77-year-old Ash Avenue Bridge spanning the Salt River west of Mill Avenue, and the dispute threatens to cost the city $20 million in lost development funding and either delay or scuttle the Rio Salado urban park project.

The state historic preservation office complains that the park project would require demolition of the bridge, which is listed on the National Register of Historic Places as one of the first and longest vehicular bridges built in Arizona.

Some members of the Tempe City Council say they're willing to save the bridge if financially feasible, but city staffers insist it is a dangerous eyesore that would cost at least $8 million to repair--although some studies say the figure could be as low as $1.5 million.

When the council, on the recommendation of city staff and consultants, decided in May to demolish the bridge, it neglected to first notify state historic preservation officers, who have responded to the slight by denying the city's request for a federal permit necessary to begin work on the park project.

"The first time we heard about the bridge coming down was when we read about it in the newspaper," says Bob Gasser, a state historic preservation officer. "Needless to say, we were interested."

Just a bunch of miffed bureaucrats throwing their regulatory weight around? There's more to it than that.

According to the Tempe Museum, the city has the worst record in the state when it comes to preserving sites listed on the National Register of Historic Places--sixteen out of sixty Tempe structures have been destroyed in the past nine years. For the historic preservationists, the bridge is simply the last straw.

"Despite a few real efforts made to incorporate historic buildings and structures into the city, [Tempe] doesn't have a particularly good record when it comes to preservation," Gasser says. "We want the city to consider alternatives to knocking the bridge down."

Tempe plans to convert the river bottom from near Sky Harbor Airport to Hayden Road into lakes, parks and bike paths. The project, resembling Scottsdale's Indian Bend Wash, would restore constant water flow in the river for the first time in decades. But once completed, the Rio Salado rechannelization would also alter the water-flow pattern, producing new stresses on the bridge that city consultants say could cause it to crumble. In addition, city officials say the decrepit bridge would detract from the modern Rio Salado project.

Donohue and Associates, an engineering consulting firm, told the city council in May that the bridge "simply wouldn't work" with Rio Salado, and councilmembers ordered destruction of the structure, which was the only permanent crossing of the Salt River in the Phoenix area when it was built by prison laborers in 1913.

Before the state okays rechannelization, Gasser says Tempe will have to conduct another study of the bridge to determine what could be done to make it a safe part of the park project. The state also questions the validity of the Donohue study and wants to resolve a discrepancy between repair estimates, which range from a $1.5 million price tag according to a 1985 survey and Donohue's $8 million appraisal. Repairs could make the bridge suitable as a pedestrian crossing, Gasser suggests, or the river could be rechanneled so that the water wouldn't put extra stress on weak areas of the span.

In addition, Tempe must hold a public hearing to gauge local support for the bridge and document the structure with photos before any repairs or demolition can begin.

"No final decision on the Ash Avenue Bridge will be made before Tempe follows these steps," Gasser says. "When dealing with a project of the magnitude and expense of Rio Salado, doesn't it make sense to think about spending some money to save a historic old bridge that would add to, rather than detract from, the appeal of the final project?"

Tempe, however, maintains that the decision is water under the bridge. Public works director Jim Jones says the city is fully documenting the bridge through photos and diagrams, but will proceed promptly with demolition when that's complete.

"There is almost no chance that the bridge, in its current form, will be saved," Jones says, but he adds that the city may try to preserve a small segment, jutting out from one riverbank, as a memorial to it.

Why the rush? Because, says Rio Salado director Steve Nelson, the city will lose up to $20 million earmarked for the project by the Maricopa County Flood Control District if the rechannelization doesn't proceed on a strict construction schedule starting August 24--an unrealistic date if the city is forced to follow all the historic-preservation guidelines.

The county is interested in protecting the East Papago Freeway from Salt River flooding--which the Rio Salado rechannelization would accomplish--but can find cheaper, faster ways to shore up the riverbanks in time for spring waterflows.

The weathered old bridge has been ill-fated since its earliest days, when engineers noted that the chain gangs from Florence territorial prison used in construction hadn't exactly taken great pride in their work. Back in 1925, when Arizona Highways monitored the conditions of the state's roadways, the magazine featured a story headlined "Days of Tempe Bridge Are Numbered," detailing the sagging and cracking that began to afflict the structure in 1919--only six years after its completion.

Several of the bridge's spans are visibly sagging today, and cracks are present on the narrow, buckled road surface. Bent rebar protrudes from weathered spots in the concrete and railings lining the length of the structure are crumbling.

Still, the bridge is described by the National Park Service as "one of the most technologically and historically significant bridges in Arizona . . . an important remnant of early road construction."

Tempe activist Susan Harter, a Valley native and outspoken advocate for historic structures, says the city shouldn't forget the bridge's historic value in its rush to develop Rio Salado.

Pointing to a 1985 study that indicated the bridge was in much better shape than the Donohue study claims, she questions why the city attempted to by-pass state preservation officials and seems bent on destroying the structure. She advocates restoring and repairing the bridge to meet current safety concerns and envisions the structure as an integral part of Rio Salado, a "romantic" walkway over the Salt, which will once again flow as it did 100 years ago when one of her distant relatives helped design the arch.

"The bridge hasn't deteriorated that much since 1985," Harter says. "What has happened is that Rio Salado has accelerated and increased in importance.

"What's happening to the bridge is a metaphor for Rio Salado. It is sweeping away everything in its path. But it shouldn't sweep away an important link to the past.