Groton — Torrential rain interrupted the Connecticut Senior Open’s first round on Monday, turning fairways into lakes, filling bunkers and soaking greens.

The bad weather led to a two-hour, 20-minute delay and also softened a normally firm and fast Shennecossett Golf Course, creating a golfer-friendly track and producing low scores.

“The shots hit and stayed where you hit them,” amateur Bill Hermanson said, “so it was like throwing darts. The course played pretty easy.”

East Lyme’s Hermanson took advantage of the favorable conditions, firing a 3-under 68, putting him in a four-way tie for second place. Frank Bensel of Jupiter, Fla., stands alone atop a crowded leaderboard at 4-under 67, thanks to a tap-in eagle on the par 5 18th hole.

In all, 16 golfers shot under par, including Dave Jones of Norwich. Jones is tied for sixth at 2-under 69.

Not everyone finished the first round, which will be completed Tuesday morning. The low 70 scores and ties will make the cut for the final round of the 36-hole, stroke play event.

Hermanson certainly doesn’t have to worry about making the cut.

A reliable putter helped Hermanson earn contender status. After an even-par front nine, he finished strong with birdies on Nos. 12, 14 and 17 to finish 3-under on the back.

He had five birdies overall, tied for the most in the first round.

“I actually made a few putts out there, which I usually don’t do here,” Hermanson said. “I played really solid and hit a lot of good shots.”

Hermanson and many others had yet to begin their round before bad weather halted action at around 9 a.m. Other golfers weren’t as fortunate, as they played through some miserable conditions before being forced off the course.

An inch and a half of rain fell and play resumed after the delay.

Superintendent Eric Morrison and his staff, who worked hard before the tournament to prepare the course, used squeegees to push water off the greens.

“We had everything prepped and everything was great and then that happened,” Morrison said of the rain. “Washed out all the bunkers. All our hard work for a couple weeks and this morning got wasted by Mother Nature.”

On the plus side, Morrison’s crew didn’t have to water the course after the first round.

The course was in remarkably good shape despite the heavy rains.

“They got the golf course in playable shape,” said Kevin Foster, a veteran of the Connecticut Senior Open and former two-time champion. “I was sad for the guys that played eight holes in the pouring rain. If they canceled that round and we all came back tomorrow, I’m sure they would have liked that a lot better.”

Foster, who made “a scary, hectic drive” from Simsbury in the downpour, finished the first round with a 2-over 73.

“It’s always fun to be here,” Foster said. “I’ve been here since 2004. People here are great. They don’t jack the prices up. They treat you so nicely in the bar and pro shop. I’ve been fortunate to win it twice as an amateur. Win or lose, I always love coming back here.”

Robert Rittberger of Garden City, N.Y., is making his debut in the Connecticut Senior Open. Playing Shennecossett for the first time, he posted a 2-under, putting him in contention for the title.

He said he’s lucky just to be in the field.

At one point, Rittberger was No. 48 on the waiting list for the popular tournament.

“I’m just happy to be here,” Rittberger said.

As far as his impressions of Shennecossett, he said: “I’m originally from Ohio. This reminds me of some courses we used to play the Ohio Open on. It’s kinda fun.”

g.keefe@theday.com