Sheriff Marlin Gusman announced plans Monday to send dozens of Orleans Parish inmates who require “acute mental health treatment” to a state prison in St. Gabriel, where they would remain for as long as three years, during which time Gusman hopes to build a new jail building that can meet their needs and satisfy the demands of a court order for sweeping reforms at the jail.

Gusman pitched the proposal in a letter to U.S. District Judge Lance Africk, the jurist overseeing implementation of a federal consent decree intended to usher in wholesale changes at the long-troubled Orleans Parish Prison.

Gusman and his spokesman, Philip Stelly, did not respond to a request for a copy of the letter but announced its contents in a news release.

Under the sheriff’s plan, the Sheriff’s Office would relocate the severely mentally ill inmates to a “special needs unit” at the Elayn Hunt Correctional Center, about an hour’s drive from New Orleans, while Gusman builds a new facility that would be designed to house “acute and sub-acute mental health inmates.” The proposal comes amid continuing discussions between the Sheriff’s Office and city officials — who, under state law, are required to pay for the care of local prisoners — over where to house “special populations” of inmates, such as those who are mentally ill.

Africk has determined that acutely mentally ill inmates should no longer be held at Templeman V — where they are now housed — because the structure is woefully ill-suited to meet their supervision needs.

A new $145 million jail building, built with hurricane recovery funds from the Federal Emergency Management Agency, is slated to open at the end of the year with 1,438 beds, but that facility was not designed to house acutely mentally ill inmates. Gusman has not made clear how he would finance the construction of another jail building.

“While it is clearly the responsibility of the city to build a good and sufficient jail, we’re suggesting this (relocation) to meet the needs of acute mental health inmates and to speed our compliance with the consent agreement,” the sheriff said in the news release.

City Attorney Sharonda Williams, in a statement late Monday, said city officials “are reviewing and evaluating (Gusman’s plan), as well as other proposed plans, so that constitutional and cost-effective housing can be in place both on a temporary and long-term basis.”

Mayor Mitch Landrieu’s administration recently proposed retrofitting the fourth floor of the jail building that is nearing completion so it could provide acute mental health treatment, but the sheriff has rejected that idea.

Gusman’s news release said the special-needs facility at Elayn Hunt was originally designed for “inmates with mental health challenges (and) is expected to accommodate about 44 acute mental health inmates.”

“The Hunt facility can be retrofitted for approximately $500,000,” the news release stated. “A cooperative endeavor agreement with the state Department of Public Safety and Corrections would include the responsibilities of the two agencies.”

Pam Laborde, a Corrections Department spokeswoman, did not return messages seeking comment late Monday. She said last week the Sheriff’s Office would be responsible for “all costs” involved in housing Orleans Parish inmates in St. Gabriel.

Inmates requiring “sub-acute mental health” treatment, meanwhile, would be housed at the Temporary Detention Center, another facility in the OPP complex that had been slated to close after the opening of the new 433,409-square-foot jail.

The Templeman V building, according to the news release, “could be modified to house acute and sub-acute female inmates on the first floor,” with the second floor being reserved for inmates designated for “administrative segregation.”

“If all parties approve and funding is available, construction of a permanent building to house acute and sub-acute mental health inmates could start later this year with a completion date of late 2017,” the news release said. After it is completed, “the Sheriff’s Office would end the temporary arrangement with the Hunt facility and relocate the acute and sub-acute mental health inmates to the building.”

Mental health treatment plays a key role in the consent decree, which was approved a year ago and went into effect in October. The sheriff is expected to reveal more details later this month about how he plans to satisfy the decree’s mental health provisions.

Follow Jim Mustian on Twitter, @JimMustian.