CLEVELAND — Every so often, Lake Erie smells rotten. Sometimes, it’s the algae. On rare occasions, including in 2012, fish die by the thousands and wash up on the shoreline. Several weeks ago, it was a natural sediment churn that led Ohioans to hold their noses.

It didn’t smell that way Thursday after a line of thunderstorms roared through northeast Ohio. The water smelled fine, and at 64 degrees, was still warm enough for the hardiest of souls to take a swim.

So, what was that fetid stench on the lakeshore for much of the night?

It was Vic Fangio’s Broncos defense.

Against a Cleveland Browns offense without starting quarterback Baker Mayfield, first-team right tackle Jack Conklin and its top two running backs in Nick Chubb and Kareem Hunt, Cleveland shredded the Broncos.

They were dominated by a ground game paced by third-team running back D’Ernest Johnson.

Or perhaps one should say the Broncos were D’Ominated, leaving them D’Flated and D’Pressed as they slinked back to D’Enver with their fourth consecutive defeat, 17-14.

The most expensive defense in football struggled again.

Yes, injuries have dented the Broncos throughout the year. But among the nine defenders with the largest salary-cap charges for 2021, only Bradley Chubb was not on the field Thursday. Being shredded at inside linebacker doesn’t explain the constant push the Browns’ offensive linemen got, particularly on runs.

The Broncos weren’t built to succeed with even an average defense. In the last four games, they haven’t even hit that modest level.

And forget about the 17 points allowed on the scoreboard. Only Shelby Harris’ pass-rush and special-teams heroics late in the first half and Johnson smartly bypassing a sure touchdown to go down to the ground with just over 60 seconds remaining kept the Browns from a 27-point output and a tally of 3.4 points per possession that would have more accurately reflected their control of the game.

“You look at the final score — 17-14 — and you’re gonna think, ‘Well, 17 points is good enough defensively,’ but we didn’t play good defense tonight,” Fangio said.

“We let ‘em drive it too much. Way too many third-and-1s. We didn’t play well enough to win the game.”

But it’s not just this game. It’s giving up deep shots to the Ravens, Steelers and Raiders. It’s allowing Najee Harris to have the first 100-yard game of his career behind a sieve of an offensive line after he averaged just 3.36 yards per carry in the first four weeks.

It’s a defense that has gone from allowing 221.7 yards per game against the lesser competition of Weeks 1-3 to 399.8 yards per game in the last four weeks.

The Broncos plugged the holes deep in coverage Thursday, but then saw their run defense leak.

And now the Broncos have allowed more than 375 yards in four consecutive games for the first time since games 4-8 in 2007 — the ill-fated single season of Jim Bates as defensive coordinator.

As Cleveland kept sustaining drives — with just one three-and-out, coming right before halftime, when the Browns went hurry-up and D’Viated from their game plan — the Broncos went three-and-out four times.

“We’ve just go to play better,” Fangio said. “We’ve got to coach better. I don’t want to be remiss in saying that. We’ve got to coach better, and we’ve got to adjust to what we have right now.”

That means adjusting to life without inside linebackers Josey Jewell and Alexander Johnson. It could mean dealing with the absence of fill-in Micah Kiser, who departed in the first half with a groin injury, leaving Curtis Robinson to play alongside Justin Strnad.

Missed tackles were commonplace by the Broncos’ D’Pleted linebacker corps as Johnson, Demetric Felton, John Kelly and even Case Keenum ran through one potential tackler after another.

Then, you throw in the Browns’ dominant play at the line of scrimmage, which frequently resulted in no contact on Browns ballcarriers until they reached the second level.

The result was have a ground game that dominated in a way not reflected by Cleveland’s 33-carry, 182-yard tally.

Consider this: Cleveland’s running backs never lost yardage on any of their attempts. The only time the Browns went backward on the ground came on a reverse to wide receiver Anthony Schwartz and Keenum’s final-play kneeldown.

In the big picture, the offense is culpable, too. Early in the second quarter, Teddy Bridgewater threw his fifth interception since the final pass against Pittsburgh in Week 5 when he underthrew John Brown on a post route.

“It was just one of those throws when you watch it, it is like, ‘Man, that is a throw I know I can make,’ but just did not get it to where I wanted it to.”

Bridgewater now has as many interceptions — five — in his lat 84 throws as he had in his previous 618 dating back to last November with Carolina. The Broncos’ ground game was ineffective; Cleveland had more rushing yards on its first four carries — 46 yards — than the Broncos did for the entire game with just 41 yards.

The Broncos are a team breaking down bit by bit. And now they have a four-game losing streak. Every time the Broncos have had a skid of at least four games, they’ve missed the playoffs; heading into this season, they’re a perfect 20-for-20.

Four weeks of D’Cline.

It’s always meant that the Broncos are D’Oomed.

Barring a massive change in fortune, that will be true once again — and that likely means a new coach, a new staff, a reset — and the start of yet another potential rebuild.

And that notion would smell worse than Lake Erie ever has.