As coalition forces withdraw from Afghanistan, US-funded reconstruction projects worth billions of dollars in far-flung regions of the country will soon be impossible for American officials to safely visit and directly inspect.

The planned removal of more than 40,000 troops and the closure of dozens of bases over the next year will shrink the protective umbrella for US officials to keep tabs on construction work, training programs and other initiatives in the corruption-plagued nation. Only about 20 percent of the country will be accessible to US civilian oversight personnel in 2014.

Instead of curtailing those projects, the Pentagon, the State Department and the US Agency for International Development plan to rely on teams of private contractors to monitor the work of other private contractors on the taxpayer-funded projects. In a document soliciting firms to help with inspections, USAID said it also intends to use satellite photos and “crowdsourcing” experiments that will solicit feedback on progress from Afghans who are supposed to benefit from US-financed work.

The inability of US government personnel to inspect development projects is prompting worry among lawmakers and government inspectors that millions more dollars could be squandered in what has become the costliest reconstruction of a single country in American history. “I would be shocked if this doesn’t have an unhappy ending,” said Sen. Claire McCaskill, D-Missouri, who has been critical of reconstruction programs in Afghanistan and Iraq. “They are kissing oversight goodbye.”

By plotting some of the largest civilian and military projects on a map generated by the inspector general’s office, The Washington Post found that at least 15 major reconstruction initiatives, projected to cost more than $1 billion, are expected to be beyond the reach of US government personnel next year. Among them are two of the US government’s signature development endeavors: the $75 million installation of a new turbine at a dam in the southwest and part of the area where a $230 million highway is being built in the east.

The US Army Corps of Engineers is building three garrisons for the Afghan army — each costing between $60 million and $80 million — in parts of the country that are outside the sectors identified by the inspector general as accessible. “Many of these projects will never be seen by an American government employee, and that’s a concern,” said John Sopko, the special inspector general. “We need to ensure that tax dollars dollars for these propro programs are properly spent.”

On-site monitoring by State, USAID and the Pentagon, as well as audits by inspectors general, led to dozens of projects being redesigned or scaled back over the past few years. The ability of civilian government officials and military personnel to visit projects depends on the proximity of troops to respond to an attack — and on the ability of medical personnel to transport the wounded to coalition hospitals within an hour. As US troops pull back to a handful of bases next year, travel will be circumscribed to areas within the radius of a 30-minute helicopter flight from those facilities.

• THE ASSOCIATED PRESS/THE WASHINGTON POST