PORTLAND, Ore. (KOIN) — Reservoirs 1 and 5 at Mt. Tabor Park may soon be fully refilled for the enjoyment of park goers after sitting empty since the summer of 2022.

Portland Water Bureau spokesperson Felicia Heaton told KOIN 6 News that all of the park’s picturesque reservoirs were drained within the past two years after structural damages and leaks were discovered.

While the man-made lakes served as sources of drinking water for more than 100 years, the City of Portland disconnected the reservoirs from the public water system in 2015 to comply with federal and state mandates for public drinking water. No longer in use, the reservoirs are now regulated by the Oregon Water Resources Department as active dams, and are maintained for their historic and beautification purposes.

Portland Water Chief Engineer Jodie Inman said that the inspections and repairs are crucial to preserving the historic dams and maintaining the safety of Portland residents.

“We share our community’s love for Mt. Tabor Park and look forward to seeing water in these historic and scenic reservoirs,” Inman said. “We must also deliver on our commitment to keep park-goers and the surrounding neighborhoods safe from risks that can develop due to reservoir leaks or voids, like flooding. There’s no quick fix when it comes to aging infrastructure. We must be thoughtful, careful and use public dollars wisely. We’re grateful for Portlanders’ support as we put safety first.”

File photo of Reservoir 6, seen in July of 2020 when it remained filled. (KOIN 6)

Reservoir 5 was drained during the summer of 2022, after crews discovered that water was unexpectedly leaking from the 49-million-gallon tank’s drain. The Portland Water Bureau began refilling Reservoir 5 last week, when drier weather allowed for workers to repair the tank’s lining. While the repairs are still undergoing tests, Heaton said that Reservoir 5 could be fully refilled by the end of the week. Workers will continue to test for leaks by refilling the tank several feet at a time. If a leak is discovered, the City of Portland hopes that it will be able to make repairs at the affected level without re-draining the entire pool.

“No leaks so far,” Heaton said. “Good news.”

By refilling Reservoir 5, the city will also refill Reservoir 1, the smallest of the park’s historic reservoirs. While Reservoir 1 has maintained a shallow pool of water, the tank is fed by Reservoir 5, and it too will slowly refill as its water source is replenished.

Images of the voids underneath reservoir 6. (City of Portland)

Reservoir 6, the largest of the park’s three reservoirs, has also proven to be the most complicated fix. The dam was drained in the summer of 2021 after an inspection revealed voids underneath the structure. The Portland City Council approved funding for ground penetrating radar tests to determine the extent of the damage and provide estimates for the repair costs. Reservoir 6 will remain empty until a repair plan is devised. A report on the radar tests findings are expected to be presented to the city council in May.

While the extent of Reservoir 6’s repairs remain uncertain, Heaton said that the Portland Water Bureau intends to maintain its agreement with the community to preserve reservoirs as a scenic and historic feature of Mt. Tabor Park.

“We’re committed to keeping the reservoirs filled with water to preserve the historic nature of the park,” she said. “Once repairs are successful and safe, we will refill the reservoirs.”