For years, fishermen and conservationists have viewed the grist mill dam on Souadabscook Stream in Hampden as a barrier to the return of anadromous fish, and have rallied to remove it.

In September, that dam was torn down, to the applause of many.

On Saturday, participants in the 23rd Souadabscook Stream Race will find out that what affects the fish may well affect the paddler.

Spring runoff once left a large, fairly placid lagoon where paddlers could cool down after the finish line, then move to the banks to get out of their boats.

Now the stream carves a more svelte route through the middle of the former lagoon, and two veteran racers said they expect the course to be shortened on Saturday to avoid a potential hazard.

The narrow chute and postrace congestion could force an inexperienced paddler over the falls where the dam used to be.

“There’s not a good place to take out at the [old] finish,” Jeff Sands of Kenduskeag said after running the stream Thursday.

“I don’t think they want anybody to go down over the Class 20 drop there at the dam,” he said with a chuckle.

Sands quickly pointed out that Class 5 rapids are considered extremely difficult and potentially deadly.

Sands said removing the dam has made the final half-mile of the traditional course very shallow.

“The water’s only a foot deep in places,” he said. “It’s like paddling in Jello.”

But friend and fellow kayaker Kenny Cushman said the fact that the stream has some current where it formerly lacked any is OK with him.

“There’s a little bit of ripples now, as opposed to all that flat water that you’re killing yourself in,” he said, adding that he also expects the race’s finish line to move upstream.

The race starts at Vafiades Landing on the Bog Road in Hampden. The registration fee is $15 per person, with registration beginning at 9 a.m. and continuing until 11:30 a.m. The race starts at noon.

The race is recognized as one of the spring’s top tests, with an 8 1/2-mile course on a technically demanding stream.

The race features five different sections that can reach Class 4 status, depending on the water level.

Fans often gather on Emerson Mill Road, where they can stand on a bridge and watch paddlers negotiate a set of rapids.

Cushman said that with no rain forecast, paddlers may find a pretty dry stream.

“There’s a lot of places where I wanted to go that I couldn’t,” he said after paddling the course Thursday evening. “There’s a lot of rocks sticking up that aren’t usually there.”

Paddlers will compete for awards in 18 categories based on age, gender and craft.

The awards ceremony is set for 4 p.m.