The National Park Service began barricading the monuments and memorials on the Mall and turning off its 45 fountains after the federal government shut down at midnight.

Park Service spokeswoman Carol Bradley Johnson said the Lincoln Memorial, Franklin Delano Roosevelt Memorial, Jefferson Memorial and Martin Luther King Jr. Memorial, among others, would be barricaded so that visitors cannot enter them.

In addition, maintenance workers would shut off the fountains at the World War II Memorial, the Roosevelt Memorial and other monuments with water features on the Mall and within the park system.

She said the new pumping and filtration system at the Lincoln Memorial Reflecting Pool would also be shut down.

More than 300 Park Service workers on the Mall would be furloughed during a shutdown, Johnson said. Workers have been told to report for duty Tuesday morning and then plan to stay for four hours to help shutter operations.

“We are pre-staging barricades,” she said, meaning that workers were delivering barricades to the various sites to be set up now that the government has shut down. Indeed, barricades were seen stacked at the World War II Memorial on Monday afternoon.

“We’re also contacting anybody who has a permit to let them know that in the event of a shutdown, all permits will be canceled,” she said.

One organization that will feel the impact of a shutdown is the Honor Flight program, which flies World War II veterans from around the country to Washington for a one-day visit to the memorial.

“We have been getting quite a few calls from honor flights and have had to let them know that the memorial will be closed and the fountain will be off, that the Mall is legally closed,” Johnson said. “So, unfortunately, they won’t be able to access the memorial.”

“Jefferson will be closed,” as well as “MLK, FDR, Ford’s Theatre, Korea, Vietnam,” she said, referring to various Park Service sites. “There’s going to be signs saying that they’re closed, and they will be probably blocked off. We’re limited in how much fencing we can get.”

Arlington National Cemetery, which is operated by the Army, will be open, but the cemetery’s Arlington House, run by the Park Service, will be closed if there’s a shutdown.

Renda Overbo, D.C. volunteer coordinator and board member for Honor Flight Chicago, said her organization has a group of 90 World War II veterans and 45 volunteer guardians and medics scheduled to fly to Washington on Wednesday.

Their plan was to visit the World War II Memorial, where a ceremony with a color guard, the sounding of taps and the singing of the national anthem would honor the veterans.

Her group is checking whether the airline will let it reschedule. “As you know, these World War II veterans are 85-plus years old,” Overbo said. “So, if we schedule it again for next year, they may not be around to come and visit.”

Of the 90 Chicago area veterans, “probably 70 are in a wheelchair or may need a wheelchair before the end of the day,” she said. “So, you can imagine the logistics of all this.”

The veterans “will be greatly disappointed” if the visit doesn’t happen, she said. Many veterans count such a visit among the best events of their lives. “It’s a major event,” she said.

Mary Pettinato, founder of Honor Flight Chicago, said: “They are so excited about the trip and about their chance to see the memorial that was built in their honor.”

“We have doctors,” she said. “We have nurses. We have paramedics. All of the logistics, the food, everything has been ordered and planned for for six months now. This is a huge undertaking.”

She said she had not yet told the veterans that the trip might be off: “But they’re calling every 30 seconds.”

“It’s a logistical nightmare,” she said.

“It’s embarrassing,” she said of the government stalemate. “It really is. It’s embarrassing for both sides. When it comes to the memorials and the men and women who fought for our country, they should be sacred, and [veterans] should be allowed to see the memorial when they can.”