CAMP HUMPHREYS, South Korea — Dump trucks are rolling, and more than 10,000 workers are hammering and pouring concrete for 630 new buildings at this sprawling Army post in the South Korean port city of Pyeongtaek.

This is the peak construction year for the $10.7 billion project, which will see Camp Humphreys triple in size to accommodate tens of thousands of soldiers and civilians moving south as the U.S. vacates much of Yongsan Garrison in Seoul and two dozen other facilities used since the Korean War.

“It is, essentially, building a compound the size of (downtown) Washington, D.C.,” Maj. Gen. James T. Walton, U.S. Forces Korea’s director for Transformation and Restationing, said recently.

Construction will continue at a reduced rate next year, when the bulk of U.S. forces are due to move south. By the end of 2017, most of the moves will be complete, he said.

Construction began in November 2006 on the largest U.S. military project since the Panama Canal. The base will house 36,000, including servicemembers, dependents, civilian employees, contractors and Korean augmentees to the U.S. Army (KATUSAs), Walton said.

Organizations involved in the project — including Department of Defense Education Activity, the Army and Air Force Exchange Service, Defense Commissary Agency and medical officials — conducted a detailed rehearsal for the moves in April.

More than 100 senior U.S. officials, ranging from generals to civilian heads of support agencies and State Department personnel, were involved in the three days of meetings aimed at synchronizing their efforts and focusing on challenges posed by the move, according to officials.

“It is to ensure we are carefully planning the transition capability from Yongsan to Humphreys to support the growing population down there,” Walton said.

Moves will be based on conditions, he said, adding they will be balanced against the operational requirements of defending the Korean Peninsula.

“As evidence of our progress, currently over 10,000 workers are constructing headquarters, barracks, family housing and an assortment of other key facilities for our mission and life support,” USFK commander Gen. Curtis M. Scaparrotti said on USFK’s website.

The visible progress at Camp Humphreys may reassure skeptics that the project is finally on track. The relocation was scheduled to take place in 2008 but was delayed until 2012, then to 2016, before the latest announcement.

USFK public affairs officer Capt. Fred Agee said in an email that delays are common with any major construction project. Officials are still working on detailed timelines for moves in 2016-17 and don’t have dates to release yet, Agee said.

“In the future, you will see a number of units announcing timelines for moves when facilities become available at USAG Humphreys,” he said.

‘It’s everywhere’ Much of the Humphreys expansion is happening just outside the fence line of the existing post. Humphreys public affairs officer Clint Stone said 630 buildings are under construction. Two new fire stations, schools and family housing towers have opened since he got there two years ago.

“Most of the expansion has happened to the west near the Anseong River,” he said, driving along a rutted dirt road into the construction zone.

The build-up is obvious to residents. Everywhere you look, there’s another building sprouting up — an A-frame chapel, an NCO academy with its own barracks and parade grounds, a new American Forces Network studio.

Laurie Allemand, a kindergarten teacher, said more construction is going on than she imagined before she arrived six months ago.

“It’s everywhere,” she said at lunch at the Exchange food court.

Several schools have been built, each with gleaming classrooms and plenty of outdoor recreational space, including sports fields with artificial turf. Staffing will increase as students move south, Walton said.

“The plan is to close the elementary school on Camp Casey at the end of the 2015-2016 school year,” he said. “The school population will dwindle to a point where it no longer makes sense to keep that school open.”

Closure dates for the Yongsan schools are being analyzed, he said.

Seoul American High School will be open through the 2015-16 school year “and in all likelihood the 2016-17 school year as well,” Walton said.

Movement of personnel and units will drive the schedule, he said.

In the center of Humphreys last month, the flight line was buzzing with helicopters, adding to the construction din. Nearby, the shell of the massive Brian Allgood Army Community Hospital was taking shape near a large pond.

“The hospital is pretty complex because they have to go through an accreditation process,” Walton said.

To make sure there’s enough medical support for people who move before it is finished, military medical officials are developing relationships with off-post medical facilities, something that happens in Seoul, he said.

Planners have sited small-arms and vehicle-maneuver ranges beside the river. Just east of the ranges are unit headquarter buildings, workshops and motor pools. Base housing and schools are on the far eastern side of the construction zone, away from the work areas. A new bridge will link the camp to Highway 17 — a shortcut for the main route to Seoul.

Soldiers will live in massive, eight-story barracks within walking distance of gyms and dining facilities. Planners tried to make the base friendly for people on foot because most enlisted soldiers here are not authorized to have vehicles, Stone said.

Field-grade officers will have their own neighborhood, where tasteful, terra cotta-roofed duplexes are rising from former rice paddies.

Another neighborhood will be home to the top brass. Only one general officer is on post now — the 2nd Infantry Division’s deputy commander for support — but there will be 14, Stone said.

Expected to grow The Army isn’t the only organization moving to Pyeongtaek. The port has attracted interest from some of South Korea’s top technology firms and is expected to more than double its population of 400,000 in years to come, Stone said.

Near the schools, massive, family-housing towers loom over the horizon. Only 1,100 of the command-sponsored personnel — 40 percent — will have housing on post, while 1,600 will live in Pyeongtaek, Walton said.

Officials have focused on making sure suitable housing exists for command-sponsored personnel, expecting investors to provide homes for contractors working in the area, he said.

“We are confident the local residential real estate market within the 30-minute commute from USAG Humphreys can accommodate those personnel who will be living off post,” Agee said.

Meanwhile, construction on facilities for the 2nd Infantry Division — which will move south from camps Red Cloud, Casey, Hovey, Stanley and several smaller posts — is on schedule, Walton said.

“As facilities become available, units will move,” he said.

Planners are taking into account the division’s training schedule and the movement of rotational forces onto the peninsula to make sure they get the timing right, he said.

Two 2nd Infantry Division units moved in 2013: The 304th Signal Battalion relocated from Red Cloud, and the 94th MP battalion moved from Yongsan.

“Those moves were scheduled early to learn about how long it would take to move other units and costs,” Walton said.

One unit that won’t move south immediately is the 2nd Infantry Division’s 210th Field Artillery Brigade, which includes 2,000 soldiers and 4,000 dependents, civilians, contractors and KATUSAs at Camp Casey. The unit, tasked with destroying North Korean long-range artillery if war were to break out, will stay put until South Korea develops its own capability, he said.

Maj. Gen. Thomas Vandal, who spent the past two years planning for the move to Humphreys as 2nd Infantry Division commander — a position he vacated in April — said tanks and armored vehicles would move from Hovey and Casey to Humphreys next summer, after the 2nd “Black Jack” Brigade, 1st Cavalry Division out of Fort Hood, Texas, wraps up a nine-month rotational deployment.

“In January 2017, the new division headquarters will be completed (at Humphreys), and we will move there,” he said.

Different environment South Korean government officials and developers are eager for the return of land where U.S. bases sit. Some, especially properties in downtown Seoul, are among the most valuable in Asia.

The move to Pyeongtaek might be a culture shock for people used to living north of Seoul, where some troops still work in ancient Quonset huts surrounded by stunning mountain scenery. Humphreys is surrounded by flat rice paddies.

Vandal said camps such as Red Cloud, Stanley, Jackson and Hovey would be returned to South Korea in 2017.

The move from Yongsan will begin this summer with U.S. Naval Forces Korea scheduled to leave for a new home at Busan, Walton said.

In the long term, only a small U.S. military element with the Combined Forces Command will stay in Seoul, although there will still be a U.S. base encompassing the Dragon Hill Lodge and a headquarters to provide synchronization between U.S. and South Korean forces, Walton said.

The ranges at Camp Humphreys will support basic training, with the bulk of field exercises and gunnery still going on to the north, where the U.S. will retain areas such as the Rodriguez Range live-fire complex.

Walton described a new railhead at Camp Humphreys as a “key capability” that negates the prospect of driving heavy equipment north through the Seoul area’s heavy traffic.

“Rail access is a capability that has to be in place,” he said. “It is one of the first facilities that has been completed.”

After transformation, U.S. facilities near the border will mostly be training areas, he said.

robson.seth@stripes.com Twitter: @SethRobson1

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