THE WEEDY ACRES of Rio Nuevo South are among this community’s most valuable treasures.

They sure don’t look it right now. In the last hundred years, a series of destructive enterprises from a brickyard to a gym to a supermarket to a landfill and a bus barn have sorely distressed fields that for three millennia were this region’s Fertile Crescent. The land curving around the foot of A Mountain nourished archaic period peoples as early as 2000 B.C. Hohokams lived here from about 700 to 1200 A.D., Spanish missionaries and Pima Indians arrived in the late 18th century, followed in the 19th century by Mexicans, Apaches, Anglos and Chinese, all of them attracted by the once-flowing waters of the Santa Cruz.

Voters now have a chance to make up for years of abuse of this world-class archaeological site.

Proposition 400, on the ballot November 2, would divert sales tax money to seed a long list of projects on both sides of the river. Plans include a museum complex and housing at the northern end of the Rio Nuevo tract and an outdoor multicultural and family park and restoration of native cottonwoods at the southern end. Over on the east side of the river, a Sonoran Sea Aquarium and a visitors’ center would go in, and a series of public improvements meant to attract a privately financed hotel and an IMAX theatre. Some money would go toward existing downtown museums too, the Tucson Museum of Art, the Children’s Museum and El Centro Cultural, and to the Fox Theatre rehabilitation. New bridges and a shuttle would connect the two riverbanks.

At the top of the list — and the best reason to vote for Proposition 400 — is the restoration of Rio Nuevo’s historic riches.

Prop 400 would divert about $9.5 million to Mission San Agustín del Tucson Cultural Park, and another $2.1 million for archaeological work on the whole tract. The long-planned outdoor park would re-create the Spanish-era San Agustín visita, or mission outpost, including its famed Convento, mission gardens and chapel, along with the 19th century Warner’s Mill and Carrillo house. The much-older Indian sites, including a honeycomb of 2,500-year-old pit houses, would be interpreted in some yet-to-be-determined way. Across the river, at Church and Washington streets, the Presidio, the Spanish fort that was the military corollary to the religious mission, would be re-created.

The Presidioand the river land both are key to what Tucson is now and how it came to be, and Tucsonans for years have talked about bringing them back to life. Yet never before has there been any money to pay for restoration. Now there is.

Prop 400 allows the city a one-time-only chance to hang onto some state tax money, during a 10-year-period, to help pay for the Rio Nuevo projects. Called Tax Increment Financing (TIF), the plan would allow the city to keep about $60 million in state sales tax dollars, money that ordinarily would go back up the road to Phoenix. As written by the state legislators, this gift to the city requires a match-up of Tucson dollars, to be gleaned from city sales taxes and about $1 million a year from the general fund over the 10 years. Thus the public funds freed up by the measure amount to about $120 million. The city could take out bonds against this future expected income to get started on construction; the estimates are that $80 million would go directly to the Rio Nuevo projects, about $40 million to debt service.

But the Prop 400 money alone is not enough to pay for it all. It’s seed money that would help generate grants and private donations. The non-profit museums, including the aquarium, a new Arizona Historical Society Museum, a Flandrau Planetarium metamorphosed into the broader Universe of Discovery, and a National Museum of the American West, would have to raise their own cash in a 2-to-1 or 3-to-1 match before they’d be eligible for the TIF construction money. Thus, though a positive vote would unleash $120 million in public money, the whole public-private project likely would release some $320 million into the downtown.

That’s a lot of cash, and a lot of projects. The sheer size of the thing has some critics worrying about a repeat of urban renewal, the disastrous 1960s juggernaut that leveled the city’s historic heart. This is different. Urban renewal deliberately erased the city’s oldest neighborhood, a Mexican-American barrio, and replaced it with a bland, all-American cluster of half-baked modernist buildings. The point of Rio Nuevo is to honor Tucson’s birthplace, its history and cultures. And there simply aren’t any residents to evict or houses to level on the empty tract; the only thing being pitched out is the bus barn, whose bouncing buses are by any measure a bad use of hallowed ground.

Plus, neighborhoods in Tucson have more power than they did in those long-ago days, as Menlo Park’s fierce — and effective — opposition to the earlier Daystar proposal for Rio Nuevo demonstrated. We can expect extreme vigilance of the unfolding projects not only from the neighbors, but from the smart professionals, including archaeologists, historians and hydrologists, on the Tucson Origins Task Force. The main mayoral hopefuls, Democrat Molly McKasson and Republican Bob Walkup, have likewise pledged to keep a watchful eye on Rio Nuevo. The development authority that will permit the projects one by one is headed up by architect CorkyPoster, who’s shown fidelity to Tucson’s history in such projects as the Stone Avenue Temple and the Dunbar/Springs School restoration, and Ruben Suarez, who has the virtue of being both a Menlo Park resident and a former city budget director. These two, and others on the board, will serve at the whim of City Council, allowing another level of checks and balances.

The current plan calls for a reasonable number of gift shops and eateries in the museum complex, and a Native American market in the multicultural park. Those are fine. But let it be known now and forever that Daystar, with its 768,000 square feet of stores and multi-screen cinemas, was a wildly inappropriate scheme, an insulting monument to consumerism that would have been the worst possible neighbor to the historic sites. Not to mention that it would have about killed the Congress Street retail district. A few politicians and business types are still grousing about the loss of Daystar, but it was so far off the mark that it’s inconceivable anybody who cares about Tucson could have supported it. Some things in life are not about getting and spending, and Tucson’s outstanding archaeological site is one of them. The mayor, City Council and city manager were absolutely right to reject Daystar, as well as a proposed Colonial Tucson theme park. Why build a fake one when you’ve got real historic Tucson right next door?

If City Manager Luis Gutierrez had to draw a crazy-quilt funding map to avoid putting the Daystar mega-mall at Rio Nuevo, then so be it. It’s fine by us if some portion of the future sales taxes from El Con and Park Place malls trickles back downtown. Far better to preserve the Old Pueblo’s heritage than to invest it on sprawl on the city’s edges.

And besides, maybe, just maybe, real things, like an archaeological park and quality museums, will finally bring the tourists and their dollars downtown. It’s easy to dismiss heritage tourism as just the latest buzz term in the travel trade but Tucson’s experience shows that it makes economic sense. A new study commissioned by the Tucson Pima Arts Council says that the city’s museums and cultural groups generated $245 million in economic activity in Tucson last year; it estimated that the new Rio Nuevo museums could contribute an additional $76.8 million annually.. Two of the most popular Tucson attractions right now, the Arizona-Sonora Desert Museum and Mission San Xavier del Bac, are authentic places that speak to the region’s ecology and history. Mission San Agustín delTucson Cultural Park, with its 3,000-year timeline of human habitation on a single, fertile spot and its splendid archaeological resources, could easily rival those two. It could be one of the best things that happened to Tucson in a long, long time. Maybe not as great as those first ears of corn planted along the river in 1200 B.C., but darn close.