A proposed reservation system for Arches National Park visitors could drain up to $22 million from the economy of tourism-dependent Moab in the program’s first year, according to a study commissioned by the National Park Service.

The report predicted such a system would depress visitation by 5 percent to 10 percent, mostly by discouraging tour buses serving foreign tourists.

“Relying on NPS estimates of Arches visitor spending, this could result in a reduction in spending of $11 million to $22 million relative to what otherwise would be predicted in that first year, which in turn could reduce overall output, employment, wages, and tax receipts through associated multipliers,” states Cambridge, Mass.-based economist Robert Paterson.

Paterson loaded his report with caveats, however, adding he suspects visitation would rebound once the public and tour operators adapt to advanced reservations.

Last year, Arches’ visitation hit an all-time high of nearly 1.7 million, continuing an unbroken trend of increased crowding dating to 2004, when visitation was less than half what it is now.

The visitor experience has suffered accordingly, with long lines at the park entry booth outside Moab and chronically full parking lots at Devils Garden, Delicate Arch and other popular trailheads.

Arches Superintendent Kate Cannon unveiled a proposed “traffic congestion management plan” in 2017 with a draft environmental assessment. Her plan’s centerpiece is a reservation system that would be the first for a large national park and has been a lightning rod of controversy ever since.

The Moab City Council has registered support for Cannon’s recommendations, but that backing may be re-evaluated in light of the new economic report, said Mayor Emily Niehaus.

“The study shows a big hit for the first year. However, if it means organized and sustained long-term growth, maybe it’s worth the trade-off,” she said. “Stay tuned. The council is certainly going to go through the report. We are responsive to business. What happens to business happens to us.”

Paterson completed the report in August, and park officials recently posted it in front of anticipated open-house meetings on the proposed reservation system. A final decision is already a year overdue.

Critics seized on the report to further their case that reservations would exact an unacceptable and unnecessary toll on Moab’s economy and castigated park planners for refusing to explore other options for reducing congestions.

“Arches National Park generates 72 percent of the Moab tourism economy,” Moab businessman Michael Liss wrote in an email Sunday to the park service’s acting regional director, Kate Hammond. “Therefore, it is incumbent upon our community to do all we can to create the best possible Arches visitor experience, especially given the current situation where the National Park Service has abrogated this responsibility in favor of simply giving up and limiting visitation.”

Cannon, who could not be reached Monday, has argued the plan is not intended to reduce overall numbers but rather spread visitation to less-busy times of the day, week and year. The aim also is to improve visitors’ experience by guaranteeing them a place to park, reducing congestion and eliminating waits at the entrance. She believes her plan could enable even greater visitation.

“There’s room for growth," she said in an interview last July, “provided we get people to move to under-capacity times of day and season.”

The proposal would limit the number of cars entering the park to 2,006 between 7 a.m. and 6 p.m. each day during the high season from March through October. Visitors would buy a reservation that allows them to enter at a certain time, although they may stay as long as they like. Several entry passes would be set aside each day to accommodate some who show up without a reservation.

The park service initiated a similar system last year at Muir Woods National Monument that has been credited with reducing crowding at the small park that preserves ancient coastal redwood groves outside San Francisco. Visitation took a 10 percent dip in the program’s first year, from just over 1 million to just less than 1 million.

Liss and others believe reservations would exclude tourists who travel without a set itinerary and plan as they go. These critics would like to see congestion addressed with shuttles and more access roads, which could spread people into under-visited areas.

The Grand County Council has impaneled a committee, led by Liss, to explore a shuttle system for Arches similar to those at Zion, Bryce Canyon and Yosemite national parks.

Arches officials do not believe shuttles would be an affordable or viable option for their park because 18 miles of pavement separate the entrance and the end of the road at Devils Garden, not including the spurs to popular sites.

Utah Gov. Gary Herbert has urged the park to look into paving access roads from the west, but Cannon fears that could worsen traffic by enabling drivers to pass through Arches on their way to Moab from points north.

Meanwhile, Paterson’s report said much uncertainty surrounds his findings.

“They are based solely on existing data and information regarding imperfect analogies," he wrote. "In addition, they do not account for the potential to mitigate [negative economic] impacts through additional education and outreach regarding the proposed system.”

If the reservation system succeeds in reducing congestion, he wrote, then it may wind up enhancing the economic impact of a visit to Arches by making it more enjoyable.