For game warden James Michael, his 15th year patrolling the waters of Lake Travis over Memorial Day weekend offers just one guarantee: It will be different — different from 2016, which was different from the year before and the year before that.

It’s not the job that changes. Every year, revelers hit the lake as the sun rises in the east and remain out long after it sets in the west. And every year, the longtime Texas Parks and Wildlife Department employee spot-checks boats to ensure they have the requirements — the life jackets, fire extinguisher, running lights and registration papers — to legally operate, while keeping an eye out for drunks and boaters blasting through no-wake areas.

What’s different? It’s everything else.

“Any given Memorial Day is not like the others,” Michael said. “It just really depends on the volume of traffic, the lake levels and the folks — the clientele — that is actually coming out to the lake and what their goal is.”

Are they families looking for a day of picnicking and tubing? Or are they out there to drink and party? Not that there’s anything wrong with that, Michael quickly added, provided they are being safe and have a designated driver.

“That’s the big focus of why we’re out here is to make sure that folks do this and do it in a safe manner and follow the rules,” he said.

It’s a line that law enforcement agencies around Lake Travis have teamed up to tout and enforce in the runup to the holiday weekend.

Officials warn that lake newbies might be unfamiliar with treacherous underwater threats, such as steep cliff drops and gnarled trees, left behind when the builders of Mansfield Dam drowned a canyon to create Lake Travis.

Last year, authorities responded to 95 calls for help on the 65-mile-long, serpentine lake, up from 75 in 2015 and 68 in 2014, figures from the Travis County sheriff’s office show. The number of accidents was up in 2016, too, jumping from 14 in 2015 to 21 in 2016.

The Travis County sheriff’s office said they will have all three of their boats on the lake this weekend. The deputies will be working alongside Michael and his partner, Ben Echelson, who joined the Parks and Wildlife Department just two years ago, as well as a phalanx of other agencies on and near the water — or on the roads leading to the lake.

“We always work at full capacity on holiday weekends,” sheriff’s office spokeswoman Kristen Dark said. “As the number of residents in our county continues to grow, we will continue to seek to upgrade and/or increase our watercraft to accommodate the needs out on Lake Travis.”

Authorities pinned the rising activity on the lake to rising lake levels.

Six years ago, a prolonged drought shriveled Lake Travis to its lowest level in more than half a century. But the Memorial Day weekend storms of 2015, which brought deadly and devastating floods to Central Texas, snapped that dry spell.

Heading into this year’s Memorial Day weekend, Lake Travis is 97 percent full, according to the agency that manages the reservoir, the Lower Colorado River Authority. As of Wednesday afternoon, the lake elevation at Mansfield Dam was 679 feet above mean sea level. That’s about 10 feet higher than the historical average elevation for this time of year, according to LCRA data.