With the help of a retired professor, a UA graduate is proving that old, worn-out auto tires can be useful.

Joshua Minyard, a geological engineering major who graduated in August, designed a 45-foot-long, 35-foot-wide and 6-foot-high tire dam to control erosion on the King Anvil Ranch near Three Points. Three Points is about 30 miles from the University of Arizona.

The idea for a soil-conserving tire dam began to evolve during a visit to the ranch in November, Minyard said. It was then that he began talking to John Bill King, the ranch's owner, who was having trouble with erosion and was looking for a solution.

After reading information about the uses of old tires, Minyard said he proposed a plan to King. He also used it as the subject for his senior project.

About 1,500 tires, donated by Pima County, were used to build the $5,000 dam, said Stuart Hoenig, a retired electrical and computer engineer professor. In an interview via electronic mail, he said a conventional concrete dam would cost about $35,000.

Hoenig was in charge of finding funding for this project, which he got from Goodyear Tire and Rubber Co. in Akron, Ohio, and Phelps Dodge Corp. in Morenci.

Construction for the dam is done on weekends by the Adult Probation Department of Superior Court in Pima County.

On the average, about 15 people on probation are working. He said working with them has been an educational experience.

"They are good people."

Minyard said construction is very simple. Tires are laid down and strapped together with rope used for shipping and fastened with steel buckles. After they are strapped together, rocks are used to fill the tires.

UA civil engineering department head Dinshaw Contractor helped Minyard design the dam. This dam is different because it allows water to go through it.

"It's a leaky kind of dam," Contractor said. This keeps the sediments from all stripping away.

Contractor said the basis for the design was public safety. He said the use of tires covered with rock is a safe and stable design.

Last year, Pima County collected 649,000 tires for recycling. That is about one for each person residing here, said Warren Whitehead, the recycling program coordinator for Pima County. Since 1991, it has been against Arizona state law to bury whole tires in landfills.

"Tires climb back out of the ground," Whitehead said.

Disposing of tires in landfills without burying them is not a solution either, because it increases the risk of toxic fire, Whitehead said. He also said that if tires get rained on, they will become a breeding ground for mosquitoes and rats.

"Tires are bad in landfills," Whitehead said.

Patricia King, John Bill's wife, said that over the years they just dumped rocks into the arroyo to control erosion. Now, however, there seems to be an alternative.

"Tires are becoming a big problem," she said. "If this is something that can be used, it's a good thing."

According to press releases, this is the first tire dam to be built in the Western United States.

If it proves to be successful, then requests to build them elsewhere will be fulfilled, Hoenig said via electronic mail. The state will be solicited to fund any future endeavors.

As of yesterday, approximately 40 percent of the dam was fully constructed, Minyard said. He estimates that by next week the tire structure will be completed. An additional weekend may be needed to fill the tires with rocks, he said.