2018 has been an unusual year when it comes to the twofold restriction of winter water diversions. In the months November, December, and January, RD 108 is allowed to divert from the Sacramento River under Permit 21274. This permit allows for 36,000 Acre-feet (ac ft) of diversion at a maximum rate of 240 Cubic Feet per Second (cfs) from screened diversion points Wilkins Slough and Emery Poundstone. The two restrictions included in Permit 21274 that emerged in 2018 are Minimum Instream Flows Passing Wilkins Slough and Term 91. A brief explanation of the restrictions follows respectively:
- No water shall be diverted under this permit at times when the flow in the Sacramento River below Wilkins Slough is less than, or diversions under this permit would cause the flow to be less than 4,000 cfs during the month of November and 3,500 cfs during the months of December and January.
- When the State Water Resources Control Board’s Division of Water Rights gives notice that Term 91 is in effect, no water can be diverted under this permit. Term 91 is designed to interrupt diversions under junior water rights when conditions in the Delta watershed threaten certain water quality objectives.
After 24 days of combined restriction, Term 91 was lifted on 12/1/18 and diversions were immediately resumed. Staff demonstrated strict adherence to the maximum diversion rate which could not have been achieved without amicable cooperation with water users. As of Monday, 12/17/18, 95% of the 12,000 total scheduled acres have been partially or completely flooded. Maintenance flows will be delivered as soon as all fields have received a flood up, and in the same order that floods began. RD 108 thanks all water users for their patience during this process.
The chart below illustrates the period in which diversions were restricted in 2018.