SEOUL — Turning Camp Humphreys into the U.S. military’s flagship installation in South Korea isn’t as tough as building the Panama Canal, but it’s taking nearly as long.

The targeted completion date for what has been described by the military as one of the largest building projects in its history — at a cost of $10.7 billion to $13 billion — has been pushed back twice due to construction and funding delays since a groundbreaking ceremony in 2007.

Now there are three years to go and the work is just over half-finished. Yet U.S. and South Korean officials maintain that construction will be largely done by 2016, when a sizable number of U.S. soldiers on the peninsula are scheduled to relocate there as part of a larger plan to turn over more of the security near the Demilitarized Zone to South Korea.

The relocation will move the bulk of U.S. forces stationed in and north of Seoul to two hubs in Pyeongtaek — where Humphreys is located — and Daegu. This will allow U.S. Forces Korea to consolidate its footprint on the peninsula from more than 100 installations to less than 50.

The vacated bases will be returned to South Korean control, including most of U.S. Army Garrison Yongsan. Located on valuable property in the heart of Seoul, it will become a green zone similar to New York City’s Central Park.

The Humphreys expansion is the key to the relocation project because so many troops — 17,000, according to military officials — will be stationed there.

Nearly 53 percent of the expansion work had been completed as of May, according to South Korea’s Ministry of National Defense Relocation Office, the agency overseeing Seoul’s portion of the relocation.

The expansion has been dogged by delays. The move initially was scheduled for 2008, then was pushed back to 2012 and later to 2016. When asked how the work at Humphreys could be finished in three years, a Relocation Office spokesman, speaking on customary condition of anonymity, refused to provide further information about the construction schedule. Instead, he pointed out that some military housing, recreational and other facilities have been completed, including two schools scheduled to open in the fall.

U.S. Forces Korea said in an email to Stars and Stripes that the expansion will be completed by 2016 “assuming the two governments continue with (their) close collaboration.”

Of the remaining 47 percent of construction, about 15 percent will be completed each year with the exception of minor projects such as landscaping, USFK said.

USFK has refused to release significant details about the pace of building and the scheduled movement of units to the base. However, USFK commander Gen. James Thurman told a community forum at U.S. Army Garrison Yongsan in Seoul earlier this year that some delays in the Humphreys move were possible, but “in 2016, we’re going to be pretty much down there.”

According to USFK’s 2013 Strategic Digest, the Humphreys expansion will triple the garrison’s size from 1,210 acres to 3,538 acres, eventually serving 36,000 troops, civilians and family members.

More than $1 billion in construction is under way, according to the 2013 report. The military has pegged the total cost of the Humphreys expansion at $13 billion, though the Strategic Digest said the transformation will cost $10.7 billion.

The expansion has been described as the largest U.S. military construction project in history. Former Eighth Army commander Lt. Gen. Joseph Fil told Stars and Stripes in 2010 that it was the biggest U.S. Army Corps of Engineers project since the construction of the Panama Canal.

“You’re building a modern city from scratch,” Fil said.

South Korea’s government also has been reluctant to discuss the relocation, possibly due to fallout over the costs it is bearing.

According to South Korean media reports, the Ministry of National Defense publicly stated in U.S. diplomatic cables that South Korea would pay for half of the relocation project, yet the U.S. estimated in 2007 that Seoul might be responsible for as much as 93 percent.

South Korea’s Relocation Office initially refused this spring to release the costs of Humphreys Central Elementary School and Humphreys High School, both scheduled to open this fall and both paid for by Seoul. Officials feared the announcement of the combined $81.3 million price tag would cause public anger since the schools were built to expensive U.S. standards.

USFK and DODEA would not release the cost of the schools, saying it was the responsibility of the South Korean government to do so. The Relocation Office eventually released the figures.

Additionally, an April report from the Senate Armed Services Committee was critical of the lack of oversight of military construction projects funded by South Korea. Most current or planned construction projects for USFK are funded by South Korea, the report said, with no congressional authorization required.

“The amount spent on such projects is not easily determined and there are significant gaps in requirements relating to reporting how South Korean contributions are spent,” the report said, noting that it was important that new construction and facility improvements be scrutinized “to ensure that we do not overinvest in non-enduring facilities at Yongsan.”

South Korean funds are meant to offset, not supplement, the use of U.S. taxpayer dollars and should be spent on mission-critical projects, the report said. However, some South Korean contributions had been put toward “projects of questionable value or that do not make economic sense,” such as a $10.4 million planned 2nd Infantry Division museum at Humphreys and the $1.4 million consolidation of two dining facilities at Yongsan. The report said the garrison treated the South Korean funds as “free money” rather than a way to offset the U.S. costs of the project, and actually increased operating costs for the dining facility by $53,000 a year rather than delivering the promised $295,000 in annual savings.

rowland.ashley@stripes.com chang.yookyong@stripes.com