A popular resort that's been drawing visitors to an Olympic-size hot springs swimming pool in Central Oregon for decades will shut down at the end of the summer.

Kah-Nee-Ta Resort & Spa, which sits on the land of the Confederated Tribes of Warm Springs about two hours from Portland, filed a WARN notice with the state Friday, announcing that it plans to permanently lay off 146 employees starting Sept. 5, 2018.

Along with the layoffs will come the closure of the resort, which includes a lodge, spa, hotel and RV park.

A letter to employees included in the WARN notice thanked them for their service and efforts "in providing our guests a relaxing vacation for the remainder of the 2018 season."

The letter noted that AV Northwest, a management and investment team that partnered with the tribes to run the resort in February, is "continuing to search for a pathway to financing. However, with no lease in place, the resort cannot continue operating below a self-sustaining level."

"This is necessary to ensure we protect any further risk to the Confederated Tribes of Warm Springs," the letter continued. "The Tribal Council has asked that we continue to search for an option that can enable KNT to be self-sustaining."

According to a tribal newsletter from last fall, AV Northwest had planned to invest $17 million in the resort to bring it back up to par. The company was set to sign a 25-year lease with the tribes to run the resort. It's not clear if that lease was ever signed or if any investments were made.

The tribes originally bought the hot springs and the surrounding property in 1959 using funds from a settlement with the U.S. Army Corps of Engineers due to the loss of Celilo Falls on the Columbia River.

The first resort facilities were up and running on the property by the mid 1960s; several expansions and additions have been added in the decades since.

The Portland Business Journal is a KGW News partner.