A consulting group tasked with analyzing potential routes for a long-discussed diversion on the Boardman River has identified a Hartman-Hammond crossing as the “best build” scenario, telling the Grand Traverse County Road Commission (GTCRC) on Thursday that alternate routes using Cass Road or the old Sabin Dam site faced significant problems and were less desirable than Hartman-Hammond. The consultants are expected to hold a public meeting in early March to discuss the group’s findings before delivering a final report to the Road Commission by the end of March.

GTCRC hired OHM advisors to guide the organization through an Environmental Planning and Linkage Study (ELP), a federally mandated process when making transportation decisions like building new highways and new bridges. The PEL aims to identify a possible new crossing of the Boardman River and analyze the impacts of the route, ranging from construction cost and land acquisition requirements to environmental, social and economic effects.

Last fall, OHM Advisors identified three possible routes to connect Keystone Road to US-31 over the Boardman River. The first, and most expensive option – estimated at $81.4 million – would require the construction of a new causeway over the Boardman River Valley to connect the Hammond and Hartman roads. A second option called the Sabin Dam Crossing, estimated at $59.2 million, would start at Birmley Road and cross Cass and Dracka Roads, winding up Silver Pines Road at US-31. This route would still require a bridge, although it would probably be a quarter the size of a Hartman-Hammond bridge. A third option, estimated at $53.8 million, would use the existing infrastructure of the recently rebuilt Cass Road Bridge crossing from Keystone over Cass, Broad and Dracka Roads to Silver Pines Road. In this scenario, GTCRC could potentially take the existing Cass Road bridge and widen it to accommodate more lanes, or build a parallel structure so the route could expand from two lanes to four or five lanes.

At Thursday’s GTCRC meeting, Bill Zipp of OHM Advisors said the company had “entered the final phase of study and is ready to move into what we call a locally preferred alternative.” This recommended route is the Hartman-Hammond crossing, which the consulting group believes would be the most effective in reducing crosstown traffic congestion, reducing traffic by 37% on South Airport Road by 2045 compared to a scenario of non-construction. A Hartman-Hammond crossing would also cause the least amount of residential travel, provide “the most logical east-west connections with existing roads on either side of the river”, and provide “the most suitable and direct route” for a bypass over the river. Boardman, according to the OHM.

With environmental opposition sinking a Hartman-Hammond bypass project in the past, Zipp noted Thursday that the estimated 2,200-foot bridge could be designed to “minimize the impact on the wetland” below by placing the structure 75 feet in the air and using minimal dock piles in the floodplain. “It won’t be cheap, but it minimizes (the impact) on the ground below,” he said.

Zipp also said the Hartman-Hammond route was the least environmentally impactful of the three routes. Crossing Sabin Dam would fragment the Boardman River Nature Center and Grand Traverse Nature Education Preserve and disrupt a planned pedestrian bridge completing a loop around the property. The Cass Road crossing would not only put “noise and other highway-related issues at the heart of the reservation”, but would impact the property of the Robbins Farm conservation easement and the historic property of Meyer, home of the Great Lakes Incubator Farm, according to OHM. This route would also require a tunnel under the existing railway to the west of Cass Road, “impacting wetlands and groundwater feeding adjacent wetlands and waterways”, the group determined. Although cheaper to build, the Sabin Dam and Cass Road crossings would require more residential travel and be less effective in relieving road traffic from the South Airport than Hartman-Hammond, according to the OHM. “There are a lot of real problems with these two alternatives,” Zipp told GTCRC board members.

According to Zipp, the Grand Traverse Conservation District issued a letter stating its opposition to the Sabin Dam and Cass Road routes. OHM plans to appear before the Grand Traverse County Parks and Recreation Commissioners in February, where Zipp said he expects council to also pass a resolution opposing those two crossings. This could mean that the only scenarios recommended for further study when the OHM delivers its report would be the Hartman-Hammond crossover and a no-build scenario. The company, however, indicated that a no-build scenario would be “less desirable” than Hartman-Hammond, saying the choice to do nothing “does not allow for the continued growth of the Grand Traverse area”, does not offer “no relief or accommodation”. for existing and future network congestion problems”, has “no benefit or improvement in non-motorized connectivity” and “does not improve the resilience or redundancy of the regional road network”.

Even if GTCRC were to eventually pursue a Hartman-Hammond crossover, Zipp acknowledged that in addition to its high price, there were still many outstanding issues with this option, including the exact route path. “The connection to US-31 is not yet defined,” he said, noting that due to the grading of the freeway, there are “engineering challenges” throughout. corridor. The crossing could connect to McRae Hill Road or end at some point with a relocation from Silver Pines Road as two options, Zipp said. “These can be reviewed as part of the NEPA process,” he added, referring to the National Environmental Policy Act. NEPA dictates the requirements for the next phase of transportation planning, in which an option like a Hartman-Hammond Bridge would be analyzed in much greater detail.

According to an OHM schedule, the consultants will hold a public meeting in early March (March 3 is listed as the target date) to discuss the group’s findings before submitting a final report to the GTCRC by March 25, closing the process. PEL – or that particular phase of the bypass planning study – by the end of this month.