Canal entering the tunnel

Jeff Bloomfield of Roscoe, Ill., and Heidi Gordon of Lodi enter the Portage Canal tunnel that travels beneath several streets near downtown Portage in this June 2014 file photo. As road construction is planned for the area, Portage city officials are tasked with deciding what kind of tunnel or bridge they want for the canal.

Daily Register file photo

There aren’t many people rowing boats on the Portage Canal these days, and even fewer are brave enough to row through the pest-infested culvert under Highway 51.

If Portage city officials want an upgraded canal crossing installed when the state refurbishes Highway 51 in a few years, they’ll have to pay for it.

That’s what Public Works Director Aaron Jahncke told the city’s Municipal Services and Utilities Committee on Thursday — and some wondered whether other entities, such as the Canal Society, might be able or willing to help pay for an improved passage below the highway.

“I wonder if anything can be done to make it an attractive reason to come to Portage, and an attractive place to take your canoe or rowboat,” said Common Council member Bill Kutzke, who represents the city’s District 6.

The panel voted 3-2 to recommend the least expensive option for the structure that would run under Wisconsin and DeWitt streets — a pipe arch structural plate estimated to cost $295,000 — and the most expensive option for both ends of the pipe — decorative concrete cast-in-place end walls estimated to cost $42,000.

Opposing the measure were Kutzke and Doug Klapper, the committee’s chairman, who said he would also like the State Historic Preservation Office to weigh in on the appearance of the structure. Voting in favor were Council members Dennis Nachreiner, Jeffrey Monfort and Mike Charles.

Jahncke said Wisconsin Department of Transportation officials are under more stringent budget constraints in the wake of the recent passage of the 2017-19 state biennial budget. As a result, he said, the state only will pay for the least expensive options regarding the canal when it undertakes the $7.5 million Highway 51 project in 2021.

The existing metal arch culvert was installed in 1960, Jahncke said. It’s about 11 feet wide, a little less than 7 feet high and 250 feet long, with a water depth of 3 to 4 feet. The Highway 51 reconstruction would present an opportunity to improve the passage, he said, to make it more spacious and attractive.

People who row through the culvert report it’s full of spider webs. Kutzke noted the corrugated surface of a culvert gives spiders more nooks and crannies to inhabit.

KL Engineering of Madison presented five alternatives for the canal conduit under the road, ranging in price from $295,000 for the metal culvert to $1 million for a pipe arch of reinforced concrete.

All of the options, including the culvert, likely would have a longer life expectancy than the road surface. The galvanized steel plate culvert could be expected to last about 60 years, Jahncke said.

And, in response to a question from Charles, Jahncke said the culvert would provide sufficient space for boaters, possibly including two boats entering the culvert at the same time from opposite directions.

A memo Jahncke prepared for the meeting noted that the Wisconsin Department of Natural Resources requires a minimum of 5 feet of clearance from the water surface to the top of the structure, to accommodate small, hand-propelled boats like canoes and rowboats.

It’s the end walls that most affect the appearance, Jahncke said.

The options for end treatments range in cost from $3,000 for rip-rap to $42,000 for decorative concrete.

Nachreiner noted that, structurally speaking, there is little difference between the decorative concrete and an undecorated concrete end wall that is estimated to cost $36,000. But the decorative structure, which would be stained and cast with a pattern, is more attractive.

“That’s what we should be spending our money on — making it appealing,” Nachreiner said.

Jahncke pointed to a $250,000 difference between the cost of the metal culvert and the second-least costly option, a culvert pipe with reinforced concrete.

Klapper, who also leads the city’s Historic Preservation Commission, said he’d like input from group not only on the culvert proposal, but also on proposals for structures on other parts of the historic canal.

Follow Lyn Jerde on Twitter @LynJerde