Archive: SFAR Water Year Forecast February 2018

Below Normal: February flows only guaranteed on Saturday & Sunday with 1,300 cfs 9am-12pm, otherwise minimum of 200 cfs

South Fork American River water year forecast as of February 8, 2018: Below Normal

The February Water Forecast Report for 2018 was released Thursday February 8th, with the Water-Year forecasted for Below Normal. Specifically it’s forecasting the American River below Folsom at 1,750 million acre-feet (MAF), with Below Normal being considered 1,700 MAF to less than 2,600 MAF.

Guaranteed Minimum Flows

The February forecast will be used to determine minimum guaranteed flows from February 10th through Mid-March[1. March forecast will take effect 3 days after it is issued around the 8th]

February

1. Saturday & Sunday: 1,300 cfs 9am-12pm

2. No guaranteed raftable flows Monday through Friday

3. Minimum Flow: 200 cfs

Forecasted

If the forecast of Below Normal holds, the flows will be as follows.

March-May

1. Monday, Tuesday, Thursday, Friday: 1,300 cfs 9am-12pm

2. Saturday & Sunday: 1,500 cfs 9am-12pm

3. No guaranteed raftable flows Wednesday

4. Minimum Flow: 200 cfs March , 250 cfs April & May

Summer Flows – May 28th through September 3rd

1. Monday, Tuesday, Thursday, Friday: 1,300 cfs 9am-12pm

2. Saturday & Sunday: 1,500 cfs 7am-1pm

3. No guaranteed raftable flows Wednesday

4. Minimum Flow: 250 cfs May through September

September 4-30, 2018

1. Thursday & Friday: 1,300 cfs 9am-12pm

2. Saturday & Sunday: 1,500 cfs 9am-12pm

3. No guaranteed raftable flows Monday, Tuesday, Wednesday

4. Minimum Flow: 250 cfs

October

1. Monday & Friday: 1,300 cfs 9am-12pm

2. Saturday & Sunday: 1,500 cfs 9am-12pm

3. No guaranteed raftable flows Tuesday, Wednesday, Thursday

4. Minimum Flow: 250 cfs October

November through early February

1. Saturday & Sunday: 1,300 cfs 9am-12pm

2. No guaranteed raftable flows Monday through Friday

3. Minimum Flow: 200 cfs November through February

The next water year forecast should be released around March 8th, with it taking effect 3 days after issuance. The final (actual) water year report should be released sometime in October.

Reservoir Storage Amounts of Interest

Here are some reservoirs in the Upper American River Project (UARP) that might be of interest.

As of February 12th – 10 AM

1. Loon Lake – 6,387.45 ft (spills at 6,418 ft) with 66,397 AF (spills at ~76,500 AF)

2. Ice House – 5,425.00 ft (spills at 5,436.5 ft Nov-April 1, then April 2-15: 5,445 ft max , April 16-Oct: 5,447 ft max[1. April-Oct these are the maxes, but they can choose to spill earlier.])

3. Union Valley – 4,832.34 ft (spills at 4,855 ft Nov-April 1, then April 2-15: 4,865 ft max , April 16-Oct: 4,867 max[1. April-Oct are the maxes, but they can choose to spill earlier by opening the Ogee gate.])

4. Slab Creek -1,835.78 ft (spills at 1,850 ft) with 13,651 AF (spills at ~13,350 AF)[1. Official data claims 1,870 ft for spill and 16,600 AF of storage, but historical data shows 1,850 ft and 13,350 AF to be more realistic – I’m looking into it.]

5. Chili Bar –  997.62 ft (spills at 997.5 ft) with a max capacity of only about 1,340 AF.

Related Links and References

1. SFAR River Flow Agreement

2. Quick B120 Report – Just the numbers

3. Detailed DWR Bulletin 120 Report – Note: this report is typically released a week or two after the quick report comes out.

4. Short Executive Summary

5. American River at Folsom – Full Natural Flow (FNF) record of what actually happened.

6. Snow Water Content – graph

7. Most Recent Snow Water Content Data – table – Limited to American River Basin

8. NOAA Sierra Nevada snow analysis

9. California Snow Water Equivalents – map

Note: This page is updated with current forecasts as they become available. Previous forecasts are archived for reference.

#SnowPack #WaterYearForecast