The Federal Highway Administration (FHWA) is investigating whether Minnesota's Department of Natural Resources properly reviewed environmental issues associated with a taxpayer-funded motorized trails project that the agency desires for outdoor recreation.

The proposed off-highway vehicle complex has divided the Driftless Region town of Houston while giving new life to criticism that DNR is ducking its environmental responsibilities as it shepherds unprecedented growth in trails for four-wheelers, side-by-sides, and off-roading trucks and jeeps.

"DNR leadership is violating the public's trust to protect our rare natural resources,'' said Karla Bloem, a former DNR naturalist who heads the International Owl Center in Houston.

Bloem contends that DNR Parks and Trails avoided formal environmental review and didn't heed local input from DNR field staff. She and other opponents of the so-called Houston Trail project say an influx of all-terrain vehicles and dirt bikes will create noise pollution, erode soils and disturb prime habitat for timber rattlesnakes, a threatened species in Minnesota.

But Houston Mayor David Olson and at least half of the four-person City Council have embraced the trail as a way to attract visitors and pump money into the local economy. The complex would provide a park-like experience for off-roaders to drive in, drive around and drive out. Plans call for 7.5 miles of hilly trails and a "rock crawl'' area, all on 120 acres to 200 acres of land inside city limits.

"It's my job to keep going forward with it,'' Olson said this week. "Yes, there's opposition … They're going to find every negative aspect that they can.''

The project, in the works since 2009, hit a roadblock this month when the City Council held off on hiring an archaeology study required before construction can begin. The pause was a reaction to the Federal Highway Administration's probe of DNR.

City Council Member Cody Mathers confirmed the investigation in a talk last week with David Scott, deputy division administrator for Federal Highway Administration in Minnesota. Mathers summed up his conversation in an e-mail he wrote to Houston City Administrator Michelle Quinn.

"He (Scott) did confirm for me that he thought it might behoove the city to pause spending until this investigation concludes,'' the e-mail said. "FHWA staff have been working with MNDNR to obtain documentation showing compliance with FHWA grant processes, and so far, he indicated they had not received anything satisfying those needs.''

Previously, Scott wrote in an email to Bloem that the DNR may have wrongly exempted the Houston project from the correct standard of federal environmental review, according a copy of the email provided by Bloem.

Scott referred the Star Tribune to the Washington, D.C., office of FHWA. On Thursday, the agency responded to a list of specific questions with a statement that said: "FHWA currently is reviewing the documentation related to this project.''

Mayor Olson said he's confident the project will proceed. "I think a lot of these government entities jockey back and forth,'' he said. "I'm pretty sure it's not a whole heck of a lot to worry about.''

DNR employee Joe Unger, the agency's off-highway vehicle consultant, said half a million dollars already has gone into the Houston Trail project, primarily for land acquisition. Construction — which has not begun — is budgeted to include about $300,000 from FHWA's Federal Recreational Grant Program.

Unger said he's not concerned about FHWA's request for information. "I still believe we followed all the acquisition protocols,'' he said. More environmental work will be required before construction can begin, Unger said, and the DNR will be compliant.

An interdisciplinary team of DNR field staff provided the agency a "coarse filter'' review of the project, reporting among other things that steep slopes and highly erodible soils weren't suitable for off-roading. But from there, higher-ups in the DNR said the concerns could be managed with professional trail building techniques and other precautions — including potential signage to educate riders about rattlesnakes.

Bloem, who also worked previously as a naturalist for the city of Houston, said DNR field staff members have been silenced by the agency "because their expert opinions don't fit with the official DNR narrative for this project.''

Once built, Unger said Houston Trail will be managed by the city and a trio of trail riding clubs. He said the DNR has been a partner in the project because southern Minnesota has a lack of motorized trails when compared to the northern tier of the state.

Earlier this year, the Legislature approved spending $13 million for motorized trail expansions to meet burgeoning demand for a larger, more-connected system Up North. Over the past 15 years, Minnesota ATV registrations have grown 36% and public trails have expanded by more than 100%. Critics say the motorized corridors are detrimental to cold-water streams, disruptive to wildlife, erode soils, and encroach on hunters, birders and other outdoors enthusiasts.

Unger said the DNR's approach for environmental review on the Houston project followed the same steps as always.

Mathers, the city council member, said in an interview this week that he wasn't against the off-roading project until opposition in town started to intensify over the past couple of years. Organizers started a "Save our Bluffs'' lawn sign campaign and circulated a petition signed by 400 people requesting that the City Council cancel Houston Trail. The petition constituted 59% of the city's voting population, Bloem said.

Mathers said the more he looked into the history of the project, he became convinced that the DNR "is more in the business of making trails than conserving resources.'' Now, if the City Council were to dump the project, local taxpayers could be on the hook to repay development costs.

City Council Member Tony Schultz, a champion of the project, said misconceptions are spreading that off-roaders will tear up the site and violate noise thresholds. The machines themselves are regulated and trail riding isn't a destructive pastime, he said.

"The hobby has grown exponentially in the past couple of years,'' said Schultz, himself an ATV enthusiast. "This would be another reason for someone to stop in town and help our local economy.''

He said none of the project's critics have presented information that would stop the city from moving forward. Some opponents have suggested a potential conflict of interest for Schultz because the city purchased 10 acres of land for the project from Schultz's mother, Marlene. The city also bought from her a property easement needed for the project, according to records obtained by Bloem.

Schultz said he didn't vote on either transaction and wasn't on the City Council when at least one of the transactions occurred. He said opponents of the project aren't sticking to the facts and have scared some residents into not wanting it.

"Houston needs something new,'' he said. "We are a town that's slowly dying.''