South Fork Boise River flows downstream of Anderson Ranch Dam
The Bureau of Reclamation began turning down the dial on the boating flows after the end of the Labor Day weekend.
By the end of Tuesday September 4th flows dropped from 1,850 cfs to 900 cfs. On Wednesday the 5th the flows were at 600 cfs.
Summer boating flows lasted longer and were slightly higher than the typical 1,600 cfs. In fact, the 1,800 cfs flow seems to be a “new normal.”
So why did flows stay higher through Labor Day? Continue Reading…
If you are interested in helping study the effects of the South Fork Boise River flow changes on the wild trout fishery in September, read more below and contact us with your availability.
For several years the South Fork Boise River wild trout fishery has been getting significant attention from a number of sportsmen, state and Federal resource agencies. You reading this website story is just one example. River flow changes and effects on the aquatic system has gained attention with angler concerns about potential adverse effects on juvenile rainbow trout and macroinvertebrates (aquatic insects that provide a food base for trout), when Anderson Ranch Dam flows are routinely ramped down to 600 cfs and 300 cfs as irrigation storage releases are ended in September.
Whitefish Ed in his formal fishing dress on the banks of the Henry's Fork (photo from westfly message board)
Back in November 2009 interested anglers and agency staff met at the Boise Public Library to hear about a genetic study of the South Fork Boise River fishery. During a panel discussion several topics came up, including flow management.
Could the Bureau of Reclamation do something to change their flow management? There was no answer to that question, but the topic did stick with one local angler who goes by the handle “Whitefish Ed” on the westfly.com message board.
Ed initiated his own study and looked at the SFB on September 15, 2011, a few hours after the flow dropped from 600 to 300 cfs, and observed many stranded wild juvenile trout along the river’s shoreline in three locations. You can find Ed’s story at this westfly.com message thread which is worth the read. Ed’s writing style is as colorful as that shirt he is wearing in the photo
After some meeting this spring with state and Federal agency biologists a plan has Continue Reading…
On Friday April 27, 2012, releases from Anderson Ranch Dam hit 6,000 cfs. This is a flow quantity rarely seen on the South Fork Boise River. Based on records dating back to 1943 (seven years before the dam’s completion) here’s the top years where peak flows got nearly to, or exceeded, 6,000 cfs.
Since 1943 here are the years where peak flows were 6,000 cfs or better
Word on the street, or should we say stream, is that the flow releases out of Anderson Ranch will drop to the minimum 300 cfs flows on or around September 15. You can keep an eye on our handy Current Conditions page, or access the other websites with the flow graphs. Specific date aside, we know for certain there is a lot of water in Anderson Ranch, and we it appears La Nina is Back – which could mean another year of favorable winter snowpack in the Pacific Northwest.
A new measuring station has been established at Neal Bridge. The US Geological Survey and Bureau of Reclamation installed the gage and it has been reporting river flows since May 2011. Continue Reading…
This is the time of summer when thoughts and conversations among fly anglers turn to the question of when Anderson Ranch Dam flows will drop from the summer boating flows to the wading flows of late summer and fall.
You might hear hushed, brief conversations at the fly shops. The USGS and Bureau of Reclamation river flow web pages get more looks. People start to look at some days in September they can block on their calendar.
Unlike the precision of Friday night lights coming on the last weekend in August for high school football, the exact days for the flows dropping is different year to year. Our prediction is after the jump:
We are holding steady at 2,000 cfs from Anderson Ranch Dam. Anderson Reservoir is now 98 percent full and should top off in the next week.
The slow, steady melt this year has been rather amazing. Despite a dry 2010 water was saved and we entered 2011 with reservoir contents in pretty good shape. Lots of snow this year, but a slow melt, has meant the pools are filling slowly in May and June. Today the pool finally fills to the point to equal that of last year. But this year it is still filling and in 2010 by the first week of July the reservoir was starting to drop. Check out the chart -
Indications point to ending the year with more water than a year ago. And 2010 was slightly higher than average.
The Bureau of Reclamation and the US Geological Survey are teaming up on a study of the South Fork Boise River. Work began in the past few months with the goal of a better understanding of the spawning habitats.
Agency scientists are starting by gathering existing data, conducting sample location reconnaissance, and developing a sampling design for the project. The reason for this step is, “to provide statistical rigor to future sampling efforts, develop a consistent sampling plan, and determine the appropriate level of spatial and temporal sampling.”
Flows on Sunday were 1,600 cfs. Then on Monday the flows dropped to 1,000 cfs. After less than 24 hours flows dropped to 600 cfs.