March 2016 Water Year Forecast for the South Fork of the American River
tl;dr: No Change. Forecast drops slightly but stays in the upper range of Below Normal
SFAR Water Year Forecast as of March 1, 2016
The March Water Report was released yesterday March 8th, with the Water-Year forecast staying in the Below Normal range. Specifically it’s forecasting the American River below Folsom at 2,365 (thousand acre-feet), with 1,700-2,600 being Below Normal. It’s a slight drop from the February forecast of 2,570, but stays on the upper side of Below Normal. The 80% probability range is 1,770-3,560.
While the numbers are promising, be careful to not let percentages play tricks with your mind. Let’s assume the remaining 20% is evenly split above and below that range. With 1,770 being so close to 1,700 (the start of Water Year Type = Dry), let’s say it’s a 10% chance of a Dry water year. Which, based on prior years would actually mean we’d be under a Super Dry Water Year (ouch). Now, instead of thinking in percentages (which our human brains are notoriously bad at) let’s think in terms of years. Given ten separate years with the exact same forecast, one of those year’s would be a Super Dry year! Again, ouch.
So we’re not out of the woods yet, but it is looking good.
March & April Flows
No change for March flows, staying with raftable flow all but Wednesday guaranteed. Same for April with the April results taking effect ~ April 15th.
Summer flows (and actually all the way through October) will lock in based on the May report, which should be released around May 10th. If the forecast stays in the Below Normal range, the South Fork of the American River will have the following guaranteed minimum flows from Memorial Day through Labor Day:
- Monday, Tuesday, Thursday, Friday: 1,300 cfs 9AM-12PM
- Saturday & Sunday: 1,500 cfs7AM-1PM
- Minimum Flows: 250 cfs
Related Links and References
- SFAR River Flow Agreement
- Quick B120 Report – Just the numbers
- Short Executive Summary – not yet updated with March results
- Detailed DWR Bulletin 120 Report – also not yet updated with March results
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