Oroville >> There’s more debris in the water at the Oroville Dam Diversion Pool than initially thought, and state Department of Water Resources officials now don’t expect to complete dredging and hauling of debris until December. DWR is seeking bids for the remaining work.

Daily incident reports have shown the debris removal was almost complete for weeks. The total amount was previously reported to be 1.7 million cubic-yards of material by DWR and Wednesday’s incident report states 1.69 million cubic-yards of debris have been removed.

According to a new filing with the Federal Energy Regulatory Commission, the department’s goal is to get the pool’s capacity back to what it was before the spillway’s collapse, and plans for achieving this by December are 95 percent complete. Some Critical Energy Infrastructure Information which has been redacted. Those documents were not attached for public view, but the preliminary schedule was included:

• May 12: Final drawings and specifications to be submitted, begin soliciting for bids

• June 1: Notice to begin work

• Dec. 15: Completion of construction

With a U.S. Army Corps of Engineers permit, the material has been taken to four dump sites, including a pond near residences and an area between Cherokee Road and Thompson Flat Cemetery Road.

Removal of the vast amount of debris became essential as it was impeding the Hyatt Powerplant’s ability to operate. The material comes from the main spillway that began to crumble Feb. 7 and the emergency spillway which was used for the first time Feb. 11. The emergency spillway is not a structure at all, but a clearing on the hillside, so trees, rocks and dirt were swept up in the gushing water’s path, ending up in the Diversion Pool below.

It was the first time the emergency spillway was used, as the water level surpassed Lake Oroville’s holding capacity of 901 feet, sending water over the hillside by default.