FRIANT WATER UPDATE May 16, 2018 NOTE: Three ALERT items, on pages 4 and 6. Data current as of May 14, 2018, unless otherwise noted. Meteorology, Climate, and Hydrology Water Year 2018 Precipitation (Oct 2017 – Sep 2018) • Sacramento Valley: 81% of normal for this week (Link: HERE) • San Joaquin Valley: 78% of normal for this week (Link: HERE) • Tulare Lake Region: 65% of normal for this week (Link: HERE) WY2018 Snow Accumulation (Link: HERE) • North Sierra: 8% of Apr 1 average; 16% of normal for this week • Central Sierra: 12% of Apr 1 average; 20% of normal for this week • South Sierra: 10% of Apr 1 average; 16% of normal for this week Looking forward: • High elevation thunderstorms are forecast in the Sierra Nevada throughout the week, with up to 1.5 inches of precipitation expected. Highest amounts are forecast for the northern Sierra Nevada. See maps of the 6-day precipitation forecast (Link: HERE for Sacramento Basin and Eastside streams; HERE for San Joaquin Valley). • Medium-term precipitation forecasts are near normal, for the 6-10 day and 8-14 day outlooks (Link for 6- to 10-day: HERE; Link for 8- to 14-day: HERE). • May 1 Water Supply Index Forecasts were released on May 8 (Link: HERE) o Sacramento River Unimpaired Runoff Forecast: 50% exceedance is 12.8 (72% of average) o Sacramento Valley Water Year Type Index (40-30-30): 50% exceedance is 7.2 (Below Normal) o San Joaquin Valley Water Year Type Index (60-20-20): 75% exceedance is 3.0 (Below Normal) o The 50% exceedance for the Sacramento and 75% exceedance for the San Joaquin are the values used to make the final water year determination under D-1641. • The May 1 Bulletin 120 Report is available as of May 8 (Link: HERE) and a forecast update was posted on May 11 (Link: HERE). Detailed forecast breakdowns are available for major rivers (Link for Sacramento Basin: HERE, link for San Joaquin Basin: HERE), as is a forecast discussion (Link: HERE). This is the last Bulletin 120 Report for the 2018 water year. Other resources: • An authoritative California climate and meteorology blog (Link: HERE). • Interactive, real-time meteorology updates available at Ventusky (Link: HERE). • Weather updates from the National Weather Service Sacramento office are available (Link: HERE). NASA Airborne Snow Observatory • Five Airborne Snow Observatory (ASO) survey flights for the San Joaquin basin were flown on April 22- 24. The ASO measures snow water equivalent from an airborne platform using a coupled imaging spectrometer and lidar system. Results for estimated snow-water equivalent (SWE) are 688 TAF for the entire watershed, with 302 TAF in the Main Fork San Joaquin, 306 TAF in the South Fork San Joaquin, and 79.5 TAF in lower elevation watersheds (Jose and Willow Creek watersheds). These sub-basin SWEs are 29%, 31%, and 25% of observed SWE at this time last year. This compares to March’s estimated snow-water equivalent for the basin of 554 TAF. Looking forward: • One remaining survey is scheduled at the begin-of-month May 2018, with two optional flights. North of Delta Reservoirs • CVP reservoirs: all are fuller than normal with a total storage of 6,954 TAF. Trinity, Shasta, and Folsom are at 103%, 108%, and 119% of their 15-year average storages for this week, respectively. Shasta has been increasing releases since the end of April to meet demands in the Sacramento Valley, and flows below Keswick are now 8,600 cfs. • Reclamation’s current report on Sacramento River temperatures and cold-water pool in Shasta, Trinity, and Whiskeytown is available (Link: HERE). As of May 8, Shasta had about 2,900 TAF of coldwater pool (<52° F). The current temperature control point on the Sacramento River is at Balls Ferry. NMFS RPA II.2.1 requires temperatures at the selected control point to not exceed 56° F from May 15-October 31. Currently the Shasta TCD is releasing primarily from the upper levels of the reservoir, from 5 upper gates and two middle gates (Link: HERE). • Reclamation’s daily CVP water supply report is available (Link: HERE). • Oroville: storage is well below normal, at 2,459 TAF, in response to dry conditions and limitations on operations resulting from the condition of the spillway. • Storage levels were stable compared to last week, with CVP North of Delta reservoir storage decreasing by 37 TAF and Oroville storage decreasing by 10 TAF. Looking forward: • Reclamation updated the 2018 water supply allocation for the CVP north-of-Delta contractors on April 20 (Link: HERE), to 100% for Agricultural service contractors and M&I water service contractors (including in- Delta and the American River). • The American River Group met on April 19 and discussed forecasted Folsom operations and temperature management. Reclamation’s forecasted end-of September storage in Folsom is 402 TAF under a 90% exceedance forecast and 538 TAF under a 50% exceedance forecast. Temperature management scenarios presented showed the ability to meet a target of 65° F at Watt Ave through September under both exceedance forecasts, and identical or lower targets after that. Meeting handouts are available (Link: HERE). • The Sacramento River Temperature Task Group met on May 9 and discussed forecasted temperature operations. Meeting handouts are available (Link: HERE). Delta/South of Delta Operations Flow values in this section are rounded to the nearest 100 cfs. • Controlling Factor(s) in the Delta: Vernalis 3:1 (per DWR Delta Ops report) o NMFS RPA Action IV.2.1, the San Joaquin River Inflow to Export Ratio, is controlling. This RPA reduces the vulnerability of emigrating steelhead to entrainment in the export pumps. It restricts exports in April and May to a proportion of flows on the San Joaquin River at Vernalis, based on Page 2 the forecasted San Joaquin River 60-20-20 Water Year Type. Under the current forecast of a Below Normal Water Year type, the export cap is 33% of flow at Vernalis, met as a 14-day average. Vernalis 14-day average flows are currently 5,950 cfs. Under this RPA exports can never be constrained to be less than 1,500 cfs for health and safety reasons. o Four other restrictions are currently active, but are not controlling at this time: . NMFS RPA Action IV.2.3 for protection of salmonids, which restricts 14-day average OMR flows to no more negative than -5,000 cfs, and 5-day average flows to -3,500 cfs or -2,500 cfs under high salvage conditions. FWS OMR Action 3 to protect juvenile Delta Smelt, which restricts 14-day average OMR flows to no more negative than -5,000 cfs. The D-1641 E/I ratio export cap of 35%. The ratio is currently at 18%. D-1641 X2 requirements in May, which are 18 days at Port Chicago (64 km) and 31 days at Chipps Island (74 km). The Port Chicago requirement is currently being met with 30 carryover days from April. The Chipps Island requirement is being met by the 14-day average EC. o Current X2 location: 75 km. o The Delta is currently in Excess conditions, so COA accounting is suspended. Reclamation’s COA accounting report currently shows the SWP in debt to the CVP by 12,200 cfs of exports (Link: HERE). COA debt is typically settled up later in the year, but it can also be zeroed out if storage in the major reservoir (Shasta or Oroville) of the project that is owed water hits its flood pool. Currently both Shasta and Oroville are well below their flood pools. • Daily Delta outflow is 11,700 cfs, down from 13,800 cfs last week. • Delta inflow is 17,000 cfs, down from 19,200 cfs last week. Inflow is 9,200 cfs on the Sacramento River at Freeport, 5,300 cfs on the San Joaquin River at Vernalis, and 1,600 cfs from Eastside streams. • Jones pumping is at a 2-unit operation of 1,860 cfs, decreasing from a 3-unit operation of 2,600 cfs that occurred on Saturday and Sunday. Reduced pumping is necessary to comply with NMFS RPA Action IV.2.1, the San Joaquin River Inflow to Export Ratio. • Banks pumping is currently at 1,000 cfs, and is at reduced levels because of lining repairs on the California Aqueduct (CA). These repairs will continue through late June. Additional SWP water may be pumped through Jones or moved through the DMC/CA Intertie during this outage. 0 cfs pumping at Banks for the Cross Valley Canal. • CVP San Luis storage is at 777 TAF, down from last week’s storage of 808 TAF. This is below its capacity of 966 TAF, and is 116% of its 15-year average. • CVP San Luis storage includes 2018 Recapture water that has been accumulating in San Luis since March 1. Recapture has been occurring at Mendota Pool and at Patterson and Banta-Carbona irrigation districts. • SWP San Luis storage is 869 TAF, down from last week’s storage of 886 TAF. • Salinities at compliance locations in the Delta are all well below applicable standards (Link: HERE). • Delta Cross Channel gates have been closed since November 24 under NMFS RPA IV.1.2, to facilitate salmon migration in the Sacramento River. • Reclamation South of Delta daily operations report is available (Link: HERE). Looking forward: • Reclamation updated the 2018 water supply allocation for the CVP south-of-Delta contractors on April 20 (Link: HERE), which is: o Agricultural service contractors: 40% o M&I water service contractors: 75% • DWR increased the allocation for the vast majority of SWP contractors to 30% on April 24, from the January allocation of 20% (Link: HERE).