When it comes to the rhythms of life on a Broncos Sunday, nobody has a handle on the ebb and flow quite like Dario Diaz.

On the second-floor of a building on the city’s west side, the load control system operator for Denver Water keeps an eye on nine video monitors. One of them is tuned to the game. The others track the water usage of 1.3 million people.

As halftime arrives, Diaz and two other workers brace for the inevitable: Sudden water-pressure drops across the metro area turn the monitors red with alarm notifications.

On any other day, these might signal a water main break or a jammed valve that would send repair crews rushing to the scene. But in this case, it’s just a bathroom break for Broncos Nation.

“You can’t react to them, because it’s going to be back in five minutes,” Diaz says of the pressure alerts. “The Red Screen of Death, that’s what we call it. If you see that any other day than a Broncos Sunday, you better get somebody on the phone.

“On Broncos Sunday, you chalk it up to the game.”

Although interest in the Denver Broncos — and their playoff game this weekend, no less — ranges from indifference to fanatical devotion, certain routines do rearrange themselves on game day.

Customer traffic patterns at the grocery store align with the run-up to the game — and sometimes allow for relatively crowd-free shopping after kickoff. Skiers cram their runs into the morning hours. Museums see early visitors, while this Sunday, game-time also offers an optimal last chance to view a popular art exhibit.

Drivers clog major arteries during the influx and exodus of ticket-holding fans around the stadium, impacting scheduled road repairs and vehicle traffic hours after the game.

Among longtime Denver residents, the manic consumer migration to area groceries on Bronco Sundays has long been an article of faith. Some seek to stock up on the week’s necessities before kickoff while others find themselves making an 11th-hour rush for food and drink to fuel watch parties.

Once the game is under way, opportunistic shoppers seize the moment.

“It’s even to the point we schedule our associates around that, to make sure we’re staffed before the game when we see our peak, then also when they’re done playing,” says Kelli McGannon, spokeswoman for King Soopers. “If you’re not a Broncos fan and want to go to the grocery store when they’re not busy, go during a Broncos game.”

Even the product mix reflects a football influence. King Soopers stores carry team merchandise — “hopefully AFC championship shirts,” McGannon says — and even added new items lauding the team’s defense as it asserted its dominance on the field over the course of the season.

But this time of year, even food purchases hint at a steady backbeat of game-day festivities.

“Playoffs elevate it to a different level,” McGannon notes. “Our party tray sales indicate more gatherings.”

The Loveland Ski Area, a close-in commuter option for powder hounds, doesn’t release visitor numbers. But, anecdotally speaking, events and promotions coordinator Duncan Maxwell sees avid skiers adjusting their schedules to feed dual passions.

“A lot of Denverites can come and get a full morning in and still make it home in time to make it to the game or parties,” he says. “Overall do we see a lull? Not much. But home games, people tend to come and get runs in and leave earlier.”

Those who stay tend to work their runs around frequent stops in the cafeteria and bar, where TVs remain tuned to the game. Maxwell can gauge the score by the cheers he hears from the main cafeteria above his office.

Broncos game days also can produce a melding of football and the arts. Jill Boyd, director of visitor services for the Denver Art Museum, sees a lot of crossover between those who appreciate the diverse artistry of both Andrew Wyeth and DeMarcus Ware.

And they game-plan to maximize their enjoyment — often arriving at the 10 a.m. Sunday opening in order to devote the afternoon to the home team.

“People tend to be savvy and strategic if they’re regular visitors,” says Boyd. “Some seek us out during Broncos games because they know they’ll have more space in galleries, more elbow room for hands-on activities.”

That could well be the case this weekend, as Sunday marks the last day of an exhibit of paintings by renowned artist Fritz Scholder.

“Predicting that the Broncos game may draw lot of our visitors away from the museum,” Boyd says, “it could be a great time to see the exhibition one last time.”

Sometimes the arts come to the game.

The Denver Center for the Performing Arts periodically lends visiting — and sometimes home-grown — talent to the game-day pageantry, usually in the form of national anthem singers.

Local products Andy Kelso and Beth Malone delivered the anthem at games last season. This year, Gabe Gibbs (“The Book of Mormon”) sang at a preseason game. LaChanze (“If/Then”) presided at the home opener. Kevin Massey, who attended the game against New England with co-star John Rapson (“A Gentleman’s Guide to Love & Murder”), performed at the start of what turned into a thrilling win for the Broncos.

It marked a sharp change in their routine.

“They jumped right into Broncomania — willingly,” recalls DCPA spokeswoman Heidi Bosk, who tagged along. “That game was so crazy down to the end with overtime, one of the guys got in the car afterward and said, ‘I don’t know if I’ll ever experience anything like that again.’ It was insane.”

Did someone mention insanity?

The major roads channeling traffic through the metro area on game day produce predictable logjams — beware Interstates 25 and 70, U.S. 6 and state roads like Colfax Avenue and Federal Boulevard — as fans stream toward the stadium not only from the suburbs but from all across the state.

But what some people, even the Colorado Department of Transportation, sometimes forget is that the anticipated flow can extend well beyond that pre- and post-game rush.

The Broncos’ second game of the 2014 regular season, against the Kansas City Chiefs, was a typical Sunday afternoon affair. And so CDOT scheduled a southbound lane closure for some guardrail work at Tomah Road, about seven miles south of Castle Rock, for 8 p.m.

“It was one of those situations where they didn’t think it all the way through, how heavy traffic remains later into evening,” says CDOT spokesman Bob Wilson. “A lot of people stay in Denver, have dinner, then head south. So it’s not like it’s just between 5:30 and 7. Heavy traffic can extend til 9 or 10 at night.”

Traffic backed up to Castle Rock. Complaints backed up the department’s voice mail. Now, even I-25 projects in Colorado Springs are put on notice to be mindful of the Broncos schedule.

“I guess it was good it was very early in the season so our teachable moment came early as well,” says Wilson. “We haven’t had a similar problem since.”

Back at Denver Water, the numbers on its consumption charts continually repeat the same basic truths about Bronco Sunday (or Monday night, or Thursday night, as the case may be).

The 2014 Super Bowl, a 43-8 loss to the Seattle Seahawks, provides perhaps the most compelling example for how fans’ water habits reflect Broncomania.

Around 2 p.m., more than two hours before game time, usage jumped to 178.4 million gallons — far above the rate for a non-game day. “That’s people cooking, getting ready,” says Diaz, who has watched these patterns through his eight years with the department. “You never see it that high, especially on a Sunday.”

It tailed off toward kickoff and then spiked, predictably, at halftime. But sometimes, Diaz discerns interesting wrinkles when he overlays the water usage timeline with certain junctures of a game.

Remember when Seattle’s Percy Harvin ran back the second-half kickoff for a touchdown? That marked the moment hope left the building — and, Diaz theorizes, water consumption jumped again as disappointed Denver fans saw a Super opportunity flushed away.

“Traditionally,” he adds, “there’s also a Sunday spike at night, when people are showering, getting ready for the morning rush.”

Because whatever the outcome, each Broncos Sunday gives way to another, less thrilling inevitability.

Monday.

Kevin Simpson: 303-954-1739, ksimpson@denverpost.com or @ksimpsondp