When driving down a gravel road, dust can be annoying. When trying to land a helicopter in a desert war zone, dust can be deadly.
Rotor downwash kicks up huge dust clouds, blinding the pilot during the final moments of a landing.
Soil stabilization research that started in the sand country around the College’s Hancock Agricultural Research Station has found a life-saving application in the deserts of Iraq and Kuwait. The soil-bonding method uses polymers to clump soil particles together into larger granules. Developed to prevent soil erosion from hillsides and construction sites, the method also locks down dusty soils at helicopter landing sites.
Working with the U.S. Marine Corps, Dane County urban conservationist Aicardo Roa-Espinosa, a graduate of the College and adjunct professor at the Department of Biological Systems Engineering, adapted the technique to desert soils during four days of trials in the Mojave Desert. Soon afterwards the technique hit the ground in the Iraq war.
The technique increases visibility during landings from near zero to nearly 100 percent and also reduces the risk that static electricity in the dust cloud will fry on-board electronics.
Early this year Roa-Espinosa received a call from U.S. Marine Corps chief warrant officer Andrew Mikel, who was seeking ways to stabilize desert soils. Mikel had tried commercial soil stabilizers, but none stood up to helicopter propwash. Since he was based in South Carolina, Mikel talked with South Carolina extension agents. They sometimes used acetone, which creates explosive vapors – not a good idea around helicopters. Eventually he heard about Roa-Espinosa’s work.
Roa-Espinosa frequently recommends polyacrylamide applications to prevent erosion on Dane County construction sites. He has worked with polymers to stabilize soils for more than 15 years but never in a desert environment.
Roa-Espinosa and the Marines tried various techniques before hitting the winner. “We had been mixing the polymer with water first and then applied it to the sand, but we couldn’t spread it,” he said. “Then we figured out we could spread the polymer granules over the sand, rake it in and spray water on it. When we finally got it right, we all collapsed into each others’ arms hugging. It really was a joy.”
“Thanks to this technique, we were able to eliminate an enemy the Marine Corps was not trained to fight – dust clouds,” Mikel said. “I think this might have helped bring some pilots home to see their kids again.”
Crews need less than two hours to prepare a 150′ x 150′ landing area at an estimated cost of $150, versus thousands of dollars and several days for a concrete pad of equal size. The treated landing pads last up to three weeks in Iraq and Kuwait. Ground crews are also using the technique to treat dust around existing concrete landing zones. “We’ve educated a lot of Marines in polymers, copolymers and aluminum chlorhydrate,” Mikel says.
Roa-Espinosa says helicopters might eventually be equipped with on-board systems that spray polymers and water, allowing pilots to create landing pads on the fly. He has discussed the idea with military leaders.
Emeritus professor Gary Bubenzer first experimented with erosion-stopping polymers in the 1970s at the College’s Hancock research station. He was seeking ways to anchor the sandy soils of central Wisconsin. But the early polymers he tested clogged spray nozzles, were hard to apply and broke down under tractor traffic, so Bubenzer dropped the idea.
Roa-Espinosa arrived as a Ph.D. student in the mid-1980s with an interest in controlling water runoff on urban construction sites. He and Bubenzer revisited the polymer idea, screening for those with potential to prevent runoff. In a project in Middleton, they studied polyacrylamide.
“When we looked at different ways of applying the polymers, we found that the best was polyacrylamide with a straw mulch, and second-best was spraying wet polymers on the soil. Applying dry polymers was least effective,” Bubenzer said. But Roa-Espinosa made the dry-application technique work for desert landing sites.