Finishing the South Lawrence Trafficway through the Baker Wetlands stands the best chance of meeting the city’s growing traffic, safety and development needs, a new federal study concludes.

But building the four-lane highway south of the Wakarusa River would best protect existing wetlands and preserve cultural and historic resources, the U.S. Army Corps of Engineers said in the study released last week.

Either way, the corps said, the unfinished trafficway already connecting the Kansas Turnpike and U.S. Highway 59 should be extended to Kansas Highway 10 east of town.

And one of the two routes should be chosen by the end of the year, said Robert Smith, the corps’ project manager for the trafficway.

“We just don’t want this project to drag on for too long,” said Smith, whose agency’s ruling will determine the road’s fate. “We think that sufficient time has passed. We need to move forward and bring this thing to completion.”

The document, called a draft environmental impact statement, makes a case for building along either of the two routes, taking into account the presence of natural and community resources. At more than 1,000 pages it fills three fat three-ring binders the two routes are weighed against each other in six “key screening criteria.” Those are safety, efficiency, environment (land use), environment (wetlands), environment (cultural/historic), and cost.

The corps prefers the 32nd Street alignment as it relates to safety, efficiency, environment (land use) and cost, while 42nd Street gets the nod for environment (wetlands) and environment (cultural and historic resources).

The 32nd Street route would be shorter, attract more traffic from clogged streets and roads around the county, and fit better with Lawrence’s growth patterns because it would be closer to existing development, according to the study. But the road also would cut through the wetlands and be closer to Haskell University, properties eligible for consideration as historic districts.

The 32nd Street route would cost about $105 million, which would include an $8.5 million plan to expand the existing wetlands, relocate 31st Street south of the Haskell campus, build a $1.2 million wetlands education center, relocate Haskell Avenue and Louisiana Street to reduce effects on the site and reroute a water line now in the wetlands that serves the city of Baldwin.

“It’s fair to say that we do not damage the wetlands in any way,” said Mike Rees, KDOT chief counsel, “and (that) we, in fact, enhance and improve them for future generations.”

The 42nd Street alignment, meanwhile, would avoid disturbing Haskell and most of the wetlands, the study said. But it would be longer, require several bridges including one nearly a mile long and possibly encourage development outside the city’s urban growth area.

The 42nd Street route would cost $128.5 million, and would not include the wetlands mitigation plan connected with the 32nd Street proposal.