Two brand new tribal jails built by the Navajo Nation in Arizona and paid for by the federal government are sitting almost empty because they’re more than twice as large as planned — and now there’s not enough money to run them.

That’s what the Justice Department’s watchdog found in a report released Wednesday that shows how $70.3 million in economic stimulus grants turned a crucial need in Indian country to incarcerate and rehabilitate adult offenders into two white elephants.

The audit by Inspector General Michael E. Horowitz says about half of that money went out the door improperly, more than $32 million of it on the jails’ “excessive” and “larger than planned” size. The construction lacked proper oversight not just by the Navajo Nation but the Justice Department itself, the watchdog found.

The office that gave the grants to the Navajo tribe was aware of the projects’ creeping scope but didn’t take “sufficient action” to prevent them from moving forward.

“The excessive size of both facilities creates increased costs for operations and maintenance staff,” auditors wrote — costs that are mostly funded by the Interior Department’s Bureau of Indian Affairs.

Right now, that office can pay for just 40 percent of the tribal corrections officers needed to staff the new, larger-than-planned jails.

As a result, “there is an increased risk that the [facilities] will not become fully operational due to a lack of funding,” says the report, which also found sloppy accounting and financial controls over the construction and inadequate vetting of the builders.

The sprawling Navajo Nation, located in parts of Arizona, Utah and New Mexico, is the largest and most populous Indian reservation, with 250,000 people on more than 27,000 square miles.

The tribe, like many others, has long struggled with tiny, run-down jails that need replacing and a shortage of beds. Modernizing its correctional system has been a high priority.

The new prisons in Tuba City and Kayenta, Ariz., have court space and peacemaking rooms, but the space for prisoners grew to 132 beds from a planned 48 beds, and 80 beds from a planned 32 beds, respectively.

The increases seem at odds with crime rates on the reservation: The average monthly jail occupancy for Tuba City from 2008 through 2014 was between 14 and 22 inmates, with a high of 49, auditors found. And the average occupancy for Kayenta during the same period was between 7 and 11 inmates, with a high of 24.

The inspector general says the Justice Department should recoup the extra $32 million in construction costs from the Navajo Division of Public Safety, which received the grants. But Justice Department officials and the tribe said the changes to planned bed space were carefully vetted with planning studies and documentation.

But the watchdog said new designs for the Kayenta jail were done more than two years after the grants were awarded and way after construction had started.

The Justice Department “does not believe these facilities are excessive,” Ralph Martin, director of the Office of Audit, Assessment, and Management for the Office of Justice Programs wrote in response to a draft of the report.

Martin acknowledged that “in hindsight,” the office that made the grants “recognizes that there appears to be some discrepancy with the recommended size for the facilities in relation to the [plan completed in 2007].” But he said “no formal scope change” was required by the terms of the project, which was desperately needed by the tribe to alleviate years of poor jail conditions.

The Navajo Nation, in a similar response, wrote that the crime statistics cited by the inspector general are misleading: The tribe’s judges had to stop prosecuting certain crimes because there was no safe space for offenders to be incarcerated. And the master plan was intended only as a “vision” that could be modified.

The Justice Department and Indian tribes share jurisdiction in criminal justice matters, with the federal government prosecuting serious crimes and tribal governments handling smaller offenses. Construction of correctional centers is generally funded by federal grants, and the Indian Affairs bureau covers most staffing costs.

The Tuba City corrections center opened in 2013, but today it is 82 percent vacant because the tribe does not have the money to pay corrections officers. The Kayenta jail is completed but still not opened.

The Indian Affairs bureau told auditors that they can pay for just 25 of the 63 full-time correction officers needed to staff the Tuba City jail and 20 of the 51 officers needed at Kayenta.