The first month of the 2010 water year is done and there is one interesting development in the South Fork Boise River. During October the flows upstream of Anderson Ranch Reservoir were higher than last year (see alternating graph above). The blue line (it’s hard to see) was higher through the month owing to the big storm that blew across the northern Rockies in early October. Trinity Mountain supposedly has 25 inches of snow. So, as that snow melted the meter at Featherville recorded a higher flow than October 2008.
IDFG crews are on their marking run this week on the South Fork Boise River. They were to complete the first phase during Tuesday and Wednesday, and then come back next week for the recapture run.
See the little blue tick mark, just below the red line on the left axis? That’s where we are as far as water in Anderson Ranch Reservoir so far this water year (water years start October 1st, just like the Federal fiscal year).
We start this water year near the average and pretty well ahead of last year. And the Snotel site at Trinity Mtn. had 25 inches of snow this morning. Much of that should melt this month, and soak the ground pretty well. Good start to the fish and float opportunities in 2010.
Anderson Reservoir is draining at the same rate as last year.
Flows should step down at about the same time as last year in the coming weeks. Look for 600 cfs soon.
The Boise River reservoir system overall is carrying more water than at this time last year.
Flows at the Featherville gage fell below last year’s flows for the 2nd half of June. So much for the earlier post and predictions.
Snow is melted from the Trinity Mtn. station. 2009 was below the average of the 1971-2000 period, but total precipitation was slightly higher.
Flows at Featherville on the upper South Fork Boise have settled to about 2,300 cfs and are slightly lower than at this time last year. However, with Anderson Ranch Reservoir at 99 percent full you can expect water managers to pass all inflows and keep the lower SFB at higher flows for quite some time.