Oroville >> An independent forensic team has “essentially completed” its investigation into what caused the Oroville Dam spillway to collapse in February and its findings are expected to be made public sometime in the next few weeks.

The forensic team’s final report was expected by the end of November, but as that deadline passed, the United States Society of Dams issued a short press release Tuesday explaining the vast amount of information to sift through and interviews to be conducted took longer than anticipated.

The team issued an initial report in May that listed 24 factors that could have caused a gaping hole to appear in the spillway in February, and triggered a string of events that ended up with 180,000 people being ordered to flee their homes on Feb. 12.

The Department of Water Resources has said all the factors cited in the initial report were addressed in the design for the spillway repairs that followed.

This year’s work on the main spillway was completed Nov. 1, though some minor finishing touches are still underway. Another full season of construction will be necessary to finish that part of the project, although DWR maintains the chute could handle flows of 100,000 cubic feet per second if necessary.

Repairs are continuing on the emergency spillway this month, with construction of a wall down to bedrock to prevent erosion back toward the weir, the situation that prompted the evacuation orders.

A buttress is also being built to support the weir, and the area between the weir and the wall is being paved. There has been some blasting to facilitate that work, and residents have reported hearing it.

The forensic team released an interim report in September stating that the flaws in design, construction and repairs led to water seeping below the spillway and then lifting of a concrete slab.

The board also said in that report there were warning signs of the spillway’s pending collapse that should have been seen, and called for periodic independent reviews of dam’s design and construction looking forward.

That report was issued to provide guidance for review of dozens of other spillways in the state that were ordered after the Oroville emregency.

One of the isses riding on the release of this report is a request from local advocates and politicians asking for a delay in the relicensing of the dam to DWR until all affected parties have time to review and process the findings.

That license, which could be good for up to 50 years, has not yet been granted, and DWR continues to operate under the terms of the previous license.

The independent Board of Consultants, a different group analyzing the redesign process of the dam, had its 14th meeting with DWR last week. Its next memorandum is also expected soon.