Cars line up at Grand Canyon National Park's South Rim entrance on Tuesday, Sept. National parks would shut down Tuesday if an agreement on the federal budget isn't reached. AP Photo/Felicia Fonseca Karen and Tom Jacobs, of Carrollton, Texas, look out over the South Rim of the Grand Canyon on Tuesday, Sept. National parks would close Tuesday if an agreement is not reached on the federal budget. Leana Platt, of Pretoria, South Africa, looks over the South Rim of the Grand Canyon on Monday, Sept. National parks would shut down Tuesday Oct. 1, 2013 if an agreement is not reached on the federal budget. (AP) - Looking over the edge of the Grand Canyon. Check. Seeing the iconic park by foot? That might have to wait. Alan and Leana Platt spent six months planning their three-day trip to the Grand Canyon. But they will have to settle for seeing it from a helicopter - instead of on foot or in a Jeep - if lawmakers fail to reach an agreement on the federal budget by Tuesday and park workers are temporarily furloughed. "If people have gone to great lengths to come to the gate, there's a lot of cost in planning," said Alan Platt, of Pretoria, South Africa. Not only with that, the emotional damage. Employees of Grand Canyon National Park have been told to show up to work as scheduled on Tuesday. If the federal government shuts down, they'll have four hours to secure files and property, and leave a voicemail saying they'll be out of the office indefinitely. Law enforcement, security and health officials will stay on the job to carry out the shutdown over four days. Trails, campgrounds and hotels will be cleared, but park officials won't be scouring the entire 1.2 million-acre park looking for people. Visitors already hiking or camping in the backcountry or taking rafting trips on the Colorado River will be able to complete their trips. About 18,000 people visit the Grand Canyon daily in October, when temperatures are in the 70s and visitors can see the leaves changing colors on the drive. Nationally, about 715,000 people a day visited the 401 areas within the national park system last October, contributing about $76 million a day to local economies, said National Park Service spokesman Mike Litterst. In the event of a shutdown, the agency expects to lose about $450,000 a day through entrance fees, backcountry permits, boat rentals and other sales, he said. "We remain hopeful that a shutdown is averted," he said, noting, however, that plans are in place if one occurs. At the Grand Canyon park, authorities will be posted at entrance gates and turn back visitors, while others will cordon off overlooks along a state highway that will remain open to through traffic. Signs will be placed at trailheads telling people they have to leave. "We know there's going to be some inconveniences with the traveling public and our employees," Grand Canyon spokeswoman Maureen Oltrogge said. The last time the park shut down was 1995. Former Gov. Fife Symington offered National Guard troops and state park rangers to keep one of Arizona's prime tourist attractions open. But former Grand Canyon Superintendent Rob Arnberger rejected the offer. Nearly 5 million people visit the iconic park each year, and 1,500 people call it home. A new shutdown won't result in closure to residents, and water treatment and sewer facilities would be maintained. A shutdown would impact tour companies in Utah and Nevada that stake their business on access to the Grand Canyon. Nearby communities such as Flagstaff, Tusayan and Williams also depend heavily on tourists headed to the canyon to stay in hotels, buy souvenirs and eat at restaurants. Standing at the South Rim on Monday, Tom and Karen Jacobs said Congress shouldn't deny people the opportunity to learn about history at the national parks or take in the beauty. "Until you're standing on the edge of Grand Canyon or you're feeling the water spray from Old Faithful, it's not the same," said Tom Jacobs of Carrollton, Texas. It will still be there when the shutdown is over, but why keep people out? It's a shame. The couple is fortunate. They're staying at a lodge on the South Rim and were scheduled to check out Tuesday. Still, Karen Jacobs was angry at Congress and President Barack Obama for bickering on the budget and potentially ruining the trips of others. "Why make it about the parks and things like that?" she said. Why not make it about their pay?