There should be little doubt that the National Park Service's Find Your Park campaign for its centennial in 2016 was a resounding success, with overall visitation up nearly 8 percent to 331 million, setting a record for the third consecutive year. But those visitation levels are having adverse impacts on both park resources and the national park experience in some corners of the National Park System.

Whether you consider resource damage or the crush of visitation, the adage that the park system is being loved to death might be closer to the truth than ever before. From Acadia to Zion, park managers are looking at last year's crowds, this year's staffing and funding levels, and working on strategies that will enable them to welcome the world while keeping them from leaving too many improper signs of their visits. 

"Our current systems are already beginning to break down," said Ryan Atwell, a social scientist whom Yellowstone National Park Superintendent Dan Wenk hired in 2015 to monitor increasing visitation at the iconic park and to help develop methods for dealing with those crowds.

At Zion National Park, officials are working on a visitor use management plan that might place a cap on daily visitation. Acadia National Park officials are developing a transportation management plan to, among other things, stem the traffic jams en route to the summit of Cadillac Mountain and make it possible for visitors to reach Thunder Hole without walking on the Park Loop Road. At Yosemite National Park, you might have to ride a shuttle from the Badger Pass Ski Area down to the Yosemite Valley if you want to cool off in the spray of Yosemite Falls and marvel at Half Dome.

"It is no secret that visitation to national parks has increased substantially in the last 5-7 years. More and diverse socioeconomic groups are coming to the parks. This is a good thing," said Zion spokesman John Marciano. "As you know, our challenge is to preserve the resource(s) of the park into perpetuity, as well as create a safe and valuable experience for the visitor. What is not good is that this increased visitation has resulted in over-capacity issues on infrastructure, particularly in the narrow Zion Canyon corridor."

At Theodore Roosevelt National Park in North Dakota, 2016 visitation was up 29 percent over 2015, to 753,880, a total that challenged the staff at times.

"We were very short-staffed last year for seasonals," said Superintendent Wendy Ross. "We have several permanent staff vacancies, so we aren't anticipating being short budget-wise (this year). We may be short different types of seasonals, but we are planning on shifting people from other jobs to rotate through visitor service jobs if we have to to make up for any shortfall in interpreters, visitor use assistants, and facilities."

The ability to shift personnel on the fly is good to when faced with increasing visitation and stagnant staff growth. Still, in the past year or two, more and more park superintendents could be heard voicing the words "carrying capacity." Now, some also are considering parking space reservations (it's already happened at Yosemite), mass transit options such as those employed at Bryce Canyon National Park and Acadia, and even timed entry into the parks.

At the National Parks Conservation Association, while President and CEO Theresa Pierno welcomed the increasing popularity of the parks, she also worried about the strain it was bringing upon the National Park Service.

“...this popularity also means more stress on the staff charged with protecting our national parks. Greeting park visitors, giving tours, maintaining historic buildings, monitoring iconic wildlife and rescuing lost hikers require the dedicated efforts of tens of thousands of people. But for years, our national parks have been woefully understaffed," she said.

“Superintendents operate parks on shoestring budgets and can’t afford to fill open positions, leaving current staff to work long hours and perform the jobs of multiple people. The same park ranger greeting visitors may also need to lead a tour, fix a display and clean a bathroom because there is simply no one else to do it," Ms. Pierno continued. "This is an unsustainable situation that threatens local economies, and the president's recent federal worker hiring freeze only makes a bad situation worse."

At the Coalition to Protect America's National Parks, Executive Council member Phil Francis said now is not the time to be cutting the National Park Service's budget or its staff.

"When you look at parks and look at capacity, you have to consider your staffing capacity, for one, to be able to manage the number of people who are coming to your parks. You have to look at it from a maintenance point of view, picking up litter. You have to look at the damage visitor use is causing," said Mr. Francis, whose four-decade Park Service career wrapped up with his tenure as Blue Ridge Parkway superintendent.

"If you don’t have the capacity, I guess we could run it like the private sector would and say we’re full. That would require some management of visitation that we would only allow the number of people in that would protect our resources," he said. "With reduced budgets, it seems to me that we would have to do less. We’ve been doing more with less for way too long.”

It can, at times, be a tight squeeze maneuvering vehicles and shuttle buses at Zion National Park/NPS

Across the National Park System, park managers have been boasting about last year's record visitation.

“We noticed a lot of first-time park visitors this year,” said Mike Reynolds, superintendent of Death Valley National Park, which recorded 1.3 million visitors in 2016, many who turned out for the amazing "super bloom" of wildflowers that swept across the valley in February and March. “It’s rewarding to think that a new audience of people is experiencing and caring for our nation’s most special places.”

But not all are caring. In Yellowstone, visitors anxious to explore geyser basins and wade (against park regulations) into the Firehole River north of the Old Faithful complex illegally park their cars along the shoulder of the Grand Loop Road. At Zion, there are roughly three times as many miles of social trails as official trails in the scenic canyon, and at Acadia, the crowds have caused congestion on the Park Loop Road and exceeded the capacity of parking lots. These and other issues can have a negative impact not only on park resources, but on visitor experiences.

"We have approximately 12 designated developed front-country trails that are approximately 15 miles in total," Mr. Marciano said in assessing conditions in Zion Canyon. "Today, because of over-crowding and impatience, etc., we have approximately 650 social trails equaling 35 miles."

Across the nation at Acadia, visitor use specialist Charlie Jacobi noted during a conversation that, "Last year, we closed the Cadillac Summit Road 12 times because of traffic."

"That's probably one of the big issues that the transportation plan is trying to address," he replied when asked if Acadia is overcrowded. "Beyond those experiential issues on the roads, we don’t have any recent data. But for sure, some of our hiking trails and carriage roads are a little more crowded. Is that experience degraded? We don’t know because we don’t collect that data on a regular basis, but it makes you wonder.”

John Kelly, the management assistant at Acadia who has been the point person on developing the park’s transportation plan, said the goal is to develop a plan built around a daily “carrying capacity” of visitation.. 

"So we’re looking at that issue almost site by site, within the Park Loop Road system as a capacity for vehicles," he said. "We don’t want to be in the reactive position of having to close part of these roads because it’s a safety issue.”

Next month, Zion officials will meet to discuss how best to manage their crowds, which in January showed an increase of 7,000 over January 2016. Mr. Marciano said that at the April meeting, which will involve personnel from the park as well as the NPS regional office in Denver, the topic of defining a daily capacity for visitation will be discussed.

"What can the park deal with? How many people can the park deal with on its resources and infrastructure and so forth?" the spokesman explained. "Once we get done with that, sometime in the summer we will come up with solid options to propose to the public.”

Adding to the struggle to manage the crowds is the fact that park staff has not increased at the same time that visitation has skyrocketed, said Mr. Marciano. In 2010, when the park welcomed 2.6 million visitors, it had a staff of 245. Last year, when 4.3 million came to Zion, the park had 217 employees, he noted.

Much the same message is voiced by Mr. Atwell at Yellowstone, where annual visitation has grown by about 40 percent since the early 2000s while the staff level has remained constant.

So great was visitation at Yellowstone in 2015 that there were an uncomfortable number of times when traffic at the West Entrance backed up into West Yellowstone and caused gridlock at the intersection of North Canyon Street and Yellowstone Avenue.

"We backed up emergency services out of West Yellowstone," Mr. Atwell recalled. "The local town wasn’t happy, the visitors weren’t happy."

While some adjustments to staffing of the entrance station, which has four entry lanes, alleviated the problem, Yellowstone staff still struggles to deal with visitation levels. When the parking lot at Grand Prismatic Spring fills up, visitors park on the roads.

"People sometimes will park literally in the middle of the road. Or half on, half off the road, and that further slows down road performance and creates huge safety issues as people are trying to cross the major roads, back and forth," he said. "In an ideal world, we’d have 10 staff people in that area helping manage parking, helping interpret visitor experiences. But on a given day, we have very few staff in that area. Usually just a volunteer or two, and it’s an overwhelming job for a volunteer. We literally don’t have the staff to get to those areas."

Down the road, the solution might involve placing a visitation limit on the park or coming up with some form of alternative transportation system, Mr. Atwell said. In the meantime, staff will do its best to manage parking lots, point visitors to less-crowded areas of the park, and recommend that folks get out earlier in the day and stay out longer in the afternoons to avoid the worst of the crowding.

"It’s hard to define park capacity because it’s based on so many different factors and considerations," he said. "But I think we are nearing the capacity of our current systems. The current roadway system, the current parking system, the current staffing system, the current number of restrooms we have. And in a place like Yellowstone, when you think of expanding the infrastructure, it’s challenging. We’re already a number of years behind in updating our current roads, let alone trying to expand roads or parking lots. And then there’s the bigger question: Is that even a desirable thing in a place like Yellowstone?”

Yosemite utilizes crews of traffic control aides to deal with crowded parking lots/Barbara Moritsch

At Yosemite, park managers have taken a number of steps to better manage the crowds. Parking patterns have been altered, parking reservations have been implemented on a trial basis, and shuttles are available to take visitors from the Badger Pass Ski Area parking lot to Yosemite Valley, said park spokesman Scott Gediman.

“We could always use more rangers and traffic control aides," he said. "But we feel really good about the system we have. We’re finding with the traffic control aides, we’re putting them in more places each year. Like Yellowstone, we’re finding more traffic and more people.”

Additional steps Yosemite managers are taking involve reconfiguring parking lots and signs to better direct visitors around the valley floor.

“We have a lot of cars, and no one is denying that. At the same time, a lot of our parking areas and roads, and road alignments and signs, are very confusing and not very efficient," said Mr. Gediman.

There is a daily capacity limit for the Yosemite Valley -- 18,710 people at one time, and a peak visitation of approximately 20,100 visitors per day -- though it's largely controlled by parking spaces. Once those spaces are full, incoming traffic is directed back out of the park via the "El Cap crossover" road before they reach the east end of the valley.

"When there’s no more parking, we’ll have a ranger or a traffic control aide at El Cap and we’ll stop the cars and we’ll basically say there’s no more parking, come back later," Mr. Gediman said, adding that the visitors are pointed to less-crowded areas of the park, such as Tuolumne Meadows and Glacier Point.

Late-arriving Yosemite visitors could find themselves in a bind later this spring and early summer, though, if the high snowpack delays opening of the Tioga and Glacier Point roads while the fury of the Yosemite Valley's waterfalls draws millions of visitors, he said.

"I think that our challenge this spring and summer is not so much the staffing, it’s the outlets. It’s always a challenge of you get people in and we're beyond capacity,” said Mr. Gediman. "We’ve always had the opportunity to tell people to go to Glacier Pass or Tuolumne or Mariposa. With the projected late openings of Tuolumne Meadows and Glacier Point, it’s going to be less places to displace the impact on the valley.”

Back at the Coalition to Protect America's National Parks, Mr. Francis, who has a tendency to speak as if he wasn't retired, hopes the Park Service can somehow get out in front of the growing visitation.

“Our job first is to protect resources and make sure people have a quality visitor experience. When it’s over-congested, too many people, the quality of visitor experience declines and we’re not doing our job anymore," he said. "We need to have the capacity to manage those folks and perform our mission.”

And that capacity cannot be achieved with the Trump administration's intention to cut the federal workforce, said Ms. Pierno.

“While the Park Service eventually got an exemption to the hiring freeze so it could hire the more than 8,000 seasonal workers it brings on every year for busy summers at parks like Yosemite and Grand Canyon, parks simply cannot rely on seasonal workers alone to fill the void," she said. "Parks need more rangers, not less, to handle record-breaking crowds, care for our natural resources and tackle parks' $12 billion deferred maintenance backlog. Rather than freezing the hiring of new park staff or further reducing their ranks, the administration should exempt the Park Service entirely from the freeze and work with Congress to get the agency the resources it needs so that visitors can continue enjoying America’s favorite places.”