The Silverbell Road Design Concept Study concluded the second series of three scheduled public meetings last week, presenting preliminary corridor improvement concepts for Silverbell Road to interested parties.
The presentation, held at the Coyote Trail Elementary School and attended by about 30 citizens and a dozen staff and consultants, was sponsored by the Regional Transportation Authority, Pima County, the town of Marana and the city of Tucson, the four entities involved in the upcoming reconstruction of Silverbell Road.
Improvements to Silverbell Road are scheduled to take place in two phases — from El Camino del Cerro to Grant Road in 2010 to 2016, and from Ina Road to El Camino del Cerro, from 2002 to 2026.
The improvement project, approved by the voters in May 2006 as part of the RTA plan, calls for Silverbell Road to be improved to a four-lane divided desert parkway with pedestrian facilities, bike lanes, drainage improvements, new native landscaping and enhanced wildlife crossings.
Jim Schoen, design manager of project engineer Kittleston & Associates Inc. of Tucson, said the roadway improvement project will promote mobility and provide improved capacity and safety.
"Right now we're defining the new cross-section and profile or elevation of the roadway," Schoen said. "We're also identifying the pedestrian, bike and equestrian facilities that will be included, as well as the wildlife and environmental mitigation that will be needed, and the impact to archeological sites."
Schoen said the archeological footprint of the area is very large because of the many ancient and modern peoples who lived along the corridor due to its proximity to the Santa Cruz River. He noted that the Anza Trail also runs along the Santa Cruz.
"All the historical peoples have settled along the river," he noted, "including those of the homesteading era," Schoen said.
Schoen said the project would identify archeological sites and recover any artifacts that are in the path of the improved roadway.
Suzanne Griset, Ph.D, principal investigator at SWCA Environmental Consultants in Tucson, said her firm would remove and relocate any artifacts or human remains that are found.
"There are 4,000 years of human history at various sites along the roadway," Griset said. "That covers a panoply of people who lived along the Santa Cruz River. There are a huge number of ancient developments along this stretch of the river, more so than the number during the homesteading era."
Griset said any archeological areas identified by the project will be mitigated and any human remains relocated.
"If they are Native American remains, we would repatriate them to the tribe that inhabited the area, which in this case would be the Tohono O'odham nation," Griset pointed out. "If the remains are not Native American, we would contact the county coroner first and then handle the remains according to Arizona's burial laws."
The design concept study has a citizens task force and technical advisory committee that provides input on planning, land use and the overall character of the roadway. Hurvie Davis of Marana, a task force member and retired head of the city of Tucson's transportation department, said the 15-member task force has received good cooperation from all parties involved in the project.
"The staff and consultants have done a good job of explaining to us and citizens about the redesign of the roadway and are being very responsive to the issues we've raised," Davis said. "They have been very good about communicating what they are doing and what the timetable will be, as well as being extremely receptive to ideas from the public."
The project includes a number of wildlife-friendly crossings below the improved roadway, concentrating low vegetation at crossings and minimizing plantings between crossings to channel wildlife.
Accents at roadway intersections include the use of unique native tree species to emphasize the intersection and enhance safety, while still blending in with the existing landscape. The project will include rainwater harvesting in the roadway median and along its shoulders.
Slopes will be revegetated, soil nail retaining walls and poured in place concrete walls installed where needed, and drainage crossings placed with inlet and outlet options for greater flexibility.
Schoen said wildlife crossings are an important part of the improved roadway because such a diverse cross-section of wildlife moves through the area.
"We'll encourage wildlife to go under the roadway and will find the best ways to channel that movement," he said.
Schoen noted that because Silverbell Road transects so many drainages from the foothills of the Tucson Mountains, "in some places the roadway will be raised up to 10 feet because of drainage issues."
Accordingly, the project is conducting a noise study, he said, to identify properties where noise mitigation may be needed.