Resource: Engineering & Technology for a Sustainable World, Oct 1997 v4 n10 p9(2) Nature-friendly dams. (rubber tires make an attractive, sturdy alternative) Stuart A. Hoenig; Joshua Minyard. Abstract: Whole tires are becoming popular as alternative materials for constructing dams in steep streams of Western states. In a research conducted by Goodyear Tire and Rubber Co and Phelps Dodge Co, in coordination with the Arizona Dept of Environmental Quality, it was found that dams made from tires help build up eroded areas with loose sand. This type of dam is inexpensive and require even unskilled workers to build. Full Text: COPYRIGHT 1997 American Society of Agricultural Engineers Rubber tires make an attractive, sturdy alternative By 1995, California had stockpiled about 30 million used, discarded tires. Other states -- and countries throughout the world -- are facing a similar challenge: to find environmentally-safe ways to reuse scrapped tires. Some have built roads or fabricated rubber hoses made of chipped or shredded tires. But tearing apart a highly-engineered, steel-belted tire is complicated and expensive. "It is like tearing down a house so that you can bum the wood in a fireplace," one observer commented. There is also a pollution problem associated with chopped tires. They tend to bleed dangerous hydrocarbons and other substances into local water supplies. However, the situation is different when using whole tires. There is a certain amount of street dirt on them, but no hydrocarbons are released when they become wet. Rock Canyon Marina in Elephant Butte, New Mexico, has used whole tires under water around its facility for about 20 years with no problems. California Tire Farms in Santa Rosa, California, has been using whole tires as underpinning for new golf courses. The tires are cut in half, like a bagel, and placed under golf course greens. This cuts water used for landscaping by The method could offer a major savings in a state such as Arizona where 25% of the water used is on golf courses. Whole tires are also being used for stream bank reinforcement, constructing buildings, drinking troughs, fences and corrals. Although these uses are commendable, a large-scale solution for recycling tires has yet to be found. Part of the problem is hiding the tires from public view, because most people consider them an unsightly landscaping material. A possible new application for discarded tires has recently been developed -- tire dams for the steep streams of the Western United States. These streams, called arroyos, are dry most of the year. But when it rains, it rains hard and the fast water moving in the arroyo carries sand, tree trunks and sometimes boulders with it. Adding to the problem in the West is the rate of slope, which is some 50 ft. per mile. In comparison, the Mississippi drops about 0.22 ft. per mile. Sand is washed with the streams to block roads and ruin land that might otherwise be used for animals, camping or agriculture. For example, 7 acres of Arizona land are lost each time one arroyo, the 45-mile Brawley Wash, floods. The Brawley began as a wagon road in 1886 and is now about 200 ft. wide and 20 ft. deep, due to the arroyo's heavy flow. In Northern Arizona, where land inclines steeper, there are arroyos 900 ft. wide and 60 ft. deep. Conventional sand dams made of concrete work well to contain flowing water with sediment from damaging surrounding land. One was built in the 1950s on the San Simon River in Southern Arizona. Upstream of the San Simon dam, sand collected to form a plain of flat land where trees and grass now grow. Downstream is an arroyo 25 ft. deep. However, these concrete dams are costly and require skilled personnel to build. This problem prompted the Goodyear Tire and Rubber Co. of Akron, Ohio, and the Phelps Dodge Co. in Morenci, Arizona, to fund a project to seek a low-cost alternative using available material. The Arizona Department of Environmental Quality gave its permission to conduct the research. The project involved designing tire dams, which uses old tires that are uncut and filled with 1-in. quarry rock. These tires are held together with plastic ties similar to those used to strap down loads on flatbed trucks. Footings and edges of the dam resemble those typically used in concrete dams. The water is slowed so it can seep into soil and loose sand is caught behind the dam to build up the eroded area. The tires soon become covered with sand, providing an attractive solution because they cannot be seen and last indefinitely. In Pima County, in Southern Arizona, tires are delivered to the dam site at no cost. Thousand, of clams are needed to stop erosion along the arroyos. An advantage of using tire dams is that unskilled laborers can be part of the entire construction process. University of Wisconsin tests show that whole tires are environmentally safe. The Pima County Department of Solid Waste Management also funded studies of a small-scale tire dam at the University of Arizona Civil Engineering Department. The first tire dam was approved by the U.S. Army Corps of Engineers and the Arizona Department of Environmental Quality. It was built in an arroyo leading to the Brawley Wash in in area that is part of the Pima County Natural Resource Conservation District on King's Anvil Ranch near Tucson. Arizona Construction labor came free from the Pima County Adult Probation Service. Three significant rains fell on the dam during construction. The first one caused water to rise 4 ft upon the tires, but none of them moved. This came as a surprise because only some of these tires had the 1-in. rocks in them. Some erosion occurred around the tires because they had not been fastened to the earth sides of the arroyo. Larger tire dams, made from 12-ft.-diameter tires of mining vehicles, are planned for the future. A proposal has been submitted to Arizona's state government to construct tire dams and tire groins and to use tires to prevent head cutting along all of Brawley Wash. Tire dams are low cost, can be installed by unskilled labor and do not pollute the region. After a short time, the tires are covered by earth and hidden from view. Sand is stopped behind the dam, to restore an eroded area. In the future tire bales 2.5 ft. x 4.5 ft. x 5.5 ft., weighing about 2,000 lbs. will be used. Once in place, they will hold sand, which will increase their weight to about 6.000 lbs. State-sponsored tests in Nebraska have found that tire bales are nearly impossible to set on fire. This makes them more indestructible than individual and chopped tires. Stuart Hoenig is professor emeritus and adjunct professor, Department of Agricultural and Computer Engineering, Biosystems Engineering, Box 210104, University of Arizona, Tucson, AZ 85721-0104, USA; 520-887-3815, fax 520-887-9727, hoenig@ece.arizona.edu. Joshua Minyard works with Hensel Phelps Co. in Houston, Texas. You can write to him at 735 International Blvd., Apt. M79, Houston, TX 77024, USA; or call 713-688-7558. Article A20235433