State and federal reservoir levels have been dropping at dramatically different rates for the last couple of months, for reasons that figure into last week’s discussions about the twin tunnels under the Sacramento-San Joaquin Delta.

Lake Oroville has released more than 968,000 acre-feet of water into the Feather River since June 1, while just over 616,000 acre-feet have flowed from Shasta Lake into the Sacramento River. Oroville has gone from 83 percent full to 66 percent full in that time, while Shasta dipped from 86 percent full to 78 percent full. Oroville’s water level has dropped 62 feet, Shasta, just 15 feet.