It could soon be a bit more expensive to explore the cliff dwellings at Walnut Canyon National Monument in Arizona/NPS photo

Public concern over higher entrance fees at three national monuments in Arizona have led National Park Service officials to revisit the issue and come up with another pricing option.

Initially, officials had proposed to increase the per-person fee for entering Wupatki, Sunset Crater Volcano and Walnut Canyon national monuments, all located in the general area of Flagstaff. The proposal was to increase the entrance fee for Walnut Canyon from $5 to $8 per person, good for seven days. At Sunset Crater Volcano and Wupatki the proposal was to double the fee, from $5 to $10.

"Originally, we had only one option being proposed," said Superintendent Kayci Cook Collins in a release. "Based on some initial public responses, a second fee rate option is now being considered and we would like to get public feedback on both options before we move ahead," she said.

The added option is to charge by the vehicle: $20/vehicle/week for each of the Walnut Canyon and a $20/vehicle/week that would get you into both Sunset Crater Volcano and Wupatki national monuments. This would be a "flat rate" entrance fee, regardless of the number of passengers, Park Service officials said. For motorcycles, the fee would be $15.

Proposed Fee changes common to both options:

* The proposed monuments' annual pass would increase from $25 to $40. Note that this pass allows unlimited visits to all three monuments for one year from purchase.

* The proposed fee for Crack-in-Rock Overnight Hikes at Wupatki would increase from $50 per person to $75 per person.

The proposed timeline for increasing the fees is January 1, 2016, for the entrance fees and October 2015 for the Wupatki Crack-in-Rock Hikes.

Entrance fees are not charged to holders of the America the Beautiful National Parks and federal recreational Senior, Access, or Military passes. These passes may be obtained at the monuments. Interagency Passes, which are honored at all federally managed land units, are not affected by the proposed fee increase and will remain at $80 for the Interagency Annual Pass, $10 for the Senior Pass and free for the Access or Military passes. For per person entry, children under 16 are not charged.

By law, revenue from entrance fees is used to support projects that directly benefit visitors. At the Flagstaff Area National Monuments, the National Park Service retains 100 percent of the fees collected and uses them to enhance visitor services, restore and rehabilitate monument facilities, provide additional interpretive programs, and increase resource protection. Projects that have been completed with fee revenue include: renovation of the historic ranger cabin at Walnut Canyon, stabilization of archaeological sites at Wupatki and a new ADA accessible trail at Sunset Crater Volcano.

Revenue generated from the proposed fee increase will be used to upgrade visitor center exhibits and redesign the Lenox Crater Trailhead. Additional revenue for Crack-in-Rock Hikes will be used to cover costs to conduct the overnight hikes.

Details on the proposed increases can be found at this site, which also allows you to make comments.

Public comment forms are also available at all three monument visitor centers and can be turned in, dropped off at or mailed to the Headquarters Building. The public engagement period will be open through Sunday, February 8, 2015. Following the public engagement, feedback will determine how, or if, a fee increase would be implemented.