The Town of Sahuarita is considering placing a bridge over the Santa Cruz River on the road that will connect the Quail Creek area to Nogales Highway.
Adding the 200-foot low-flow bridge and a multi-use path for pedestrians and cyclists would add $1.1 million to the project, for a total of about $5.1 million.
The bridge plan was presented to the council Tuesday by design contractor Psomas; there was no vote on whether to proceed.
Quail Crossing Boulevard currently runs from Nogales Highway to the Santa Cruz River, and opened in 2018.
The original plan did not include a bridge, instead calling for the road to dip as it crossed the river. Alejandro Angel, vice president of traffic engineering for Psomas, said that would mean the road would be closed an average of 20 days a year because of water running in the river. The original budget with the dip crossing came with a $4 million price tag. Bridge construction would bring the total to $4.8 million. With a multi-use path lumped in at $300,000, that figure rises to $5.1 million.
The goal of the new road is to open up vacant land for development and offer a more direct connection for Madera Highlands and Quail Creek residents to the rest of the town and a major shopping district. The town has looked at several options to pay for the project, including bonds or other debt servicing, possibly combined with grants or town funds. It has made no decisions on funding.
Psomas unveiled a “straighter and shorter” two-lane route Tuesday that involves fewer land exchanges and that bypasses a wastewater treatment facility along the next phase of construction, which is about 1.2 miles. When completed, the entire road would be about 1.6 miles.
Angel said going with the dip crossing would mean significant grading within the river and would require a system with streamflow gauges. In addition, Pima County would not allow access to its Flood Control Alert system. Angel estimates that the cost to the town for barricades and debris removal after each closure would total $5,000 about 20 times a year.
Angel said the low-flow bridge option isn't a permanent solution though it has the integrity of a regular bridge. The cost is higher but it's more convenient and safer for motorists to use in all-weather conditions than the dip. Given the rainfall amounts of the last five years, no closures would have occurred with a low-flow bridge, he said. Other benefits include reduced maintenance, but major flood events might require repairs on bridge approaches, he said. Low-flow bridges are generally less expensive to construct. More often than not, designs are less complicated, construction is quicker and fewer materials are involved.
The concrete bridge proposed would have two abutments. A pier supporting the spans of the bridge would be sunk 100-feet into the riverbed, The upshot: a structure that could withstand the ravages of 100-year flows, he said.
“Public safety risks go way down and the county will let us connect to their alert system” with a bridge in place, he said.
The bridge could be expanded to handle increased traffic as the population grows, but that could cost “tens of millions of dollars,” Angel said.
Councilman Gil Lusk said adding a multi-access pathway totaling $300,000 “will resolve issues with the biking population” who want to use the road.
By giving residents quicker and easier access to retailers at The Crossing at Sahuarita shopping center, he said the investment in a bridge would likely be backfilled in time with increases retail sales revenues to the Town of Sahuarita.
The town’s contract with Psomas would require working with the U.S. Army Corps of Engineers and Union Pacific Railroad to work through the river crossing and a new intersection at Quail Crossing and Old Nogales Highway. The design phase is expected to be completed by August.