In 2009, WSDOT completed an environmental assessment regarding effects of the proposed project. One finding of the report was that the project may adversely affect alkali bee populations within one mile of the new roadway.

"WSDOT understands the impacts the new roadway may have on this important resource, and we are working with WSU and alfalfa seed farmers to identify and consider design ideas that can minimize the effect of the new alignment on alkali bees,” said Jason Smith, environmental manager for WSDOT’s south central region.

"There’s a reason why they grow alfalfa seed here. Growers are only permitted to draw water from the Touchet River in winter and spring, but not summer because of salmon,” Walsh said. "Fortunately, water stress causes alfalfa to bloom, so this area is the ideal place to grow alfalfa seed.”

WSDOT approached Walsh to determine alkali bee populations, where and how far they travel and how high above the roadbed they can fly. Every fall, Walsh will survey bee beds by taking a core soil sample to see how many pupae are in each.

To learn how high the bees can fly, Walsh and graduate student Amber Vinchesi attached a bee sweeper rack to a car. The rack has 13 nets at varying heights, 1-13 feet above the ground, to capture bees in flight. Thirteen feet matches the height of a typical semitrailer on the highway.

Walsh and his team constructed a 14-foot-high bee mesh barrier along a quarter mile highway stretch in the Touchet-Lowden corridor. They observed foraging alkali bees climbing over the mesh and flying another 75 feet at the same height – clearing the roadway - before dropping back down to ground level.

"It’s been working pretty well,” Walsh said of the barrier. "The Department of Transportation really liked it because it looks like an inexpensive way to protect the bees.”

Preservation a priority

WSDOT and other state governmental agencies are required to consider native bee populations in their projects since the U.S. Congress made native bee preservation a priority in the 2008 Farm Bill, Walsh said. With the U.S. Highway 12 project still in preliminary design, and WSDOT preparing right-of-way plans, the department and Walsh will work to determine a solution that meets everyone’s needs.

"This project will decrease the impacts of WSDOT highway construction on both farmers and their important bee resource,” Walsh said.