Fiction: "The Potter Valley Project diverts 350 cfs from the Eel River year round."
It is impossible to divert 350 cfs through the tunnel due to physical constraints. Potter Valley Project flows are regulated on a day by day basis so that minimum flows, determined by NMFS, are always maintained on the Eel River no matter what the diversion rate is through the Potter Valley Project. These rates are based on complex formulas that take into account natural flows and several habitat parameters. From spring until the fall, on a normal rainfall year, approximately 125 cfs is diverted through the Potter Valley Project. Summer flows through the Potter Valley Project are released from water stored in Lake Pillsbury during the winter and early spring. The releases from Lake Pillsbury are dependent on the type of water year which is based on cumulative inflow to Lake Pillsbury received by specific dates. To help put the diversion rate for the Potter Valley Project (which is at the most 285 cfs) into perspective it is interesting to note that the highest flow ever recorded on the Eel River at Cape Horn Dam, during the massive flood of 1964, was 752,000 cfs. This is equal to 1,520,000 acre feet every 24 hours, or 63,333 acre feet per hour, or 1,055 acre feet every minute! At that rate of flow, the entire amount of water diverted in the 2009 season would have passed by Van Arsdale Reservoir in less than an hour.
It is impossible to divert 350 cfs through the tunnel due to physical constraints. Potter Valley Project flows are regulated on a day by day basis so that minimum flows, determined by NMFS, are always maintained on the Eel River no matter what the diversion rate is through the Potter Valley Project. These rates are based on complex formulas that take into account natural flows and several habitat parameters. From spring until the fall, on a normal rainfall year, approximately 125 cfs is diverted through the Potter Valley Project. Summer flows through the Potter Valley Project are released from water stored in Lake Pillsbury during the winter and early spring. The releases from Lake Pillsbury are dependent on the type of water year which is based on cumulative inflow to Lake Pillsbury received by specific dates. To help put the diversion rate for the Potter Valley Project (which is at the most 285 cfs) into perspective it is interesting to note that the highest flow ever recorded on the Eel River at Cape Horn Dam, during the massive flood of 1964, was 752,000 cfs. This is equal to 1,520,000 acre feet every 24 hours, or 63,333 acre feet per hour, or 1,055 acre feet every minute! At that rate of flow, the entire amount of water diverted in the 2009 season would have passed by Van Arsdale Reservoir in less than an hour.