Aquatic weeds are breaking up everywhere giving better chances for landing larger fish especially on using finer tippets when presenting BWO, mahogany dun or midge life cycle patterns. Wherever you try the river, streamer patterns are a must. Brown trout are moving in the lower river, and locations in the upper river such as Box Canyon, Cardiac Canyon holes and runs, and The Tubs now host large foraging trout.
Below are excerpts from Dr. Rob Van Kirk’s summary of water conditions up to this morning in the Henry’s Fork drainage.
REPORT NOTE: I will be presenting a brief summary of water year 2021 at the Henry’s Fork Watershed Council meeting tomorrow, following a presentation on upper Snake River reservoir operations by the US Bureau of Reclamation. The meeting starts at 9:00 a.m., and you can join via Zoom at https://us02web.zoom.us/j/81474786741
Headlines:
- Last week was cool and wet, putting us in a good position to receive above-average precipitation for the first month of water year 2022.
- Natural flow has dropped a little from the effects of last week’s precipitation and is 75% of average.
- At a mean outflow of 110 cfs, Island Park Reservoir gained 592 ac-ft/day last week and is 51% full, compared with 50% on average.
Details:
Mean temperature last week was 7 degrees F below average, and precipitation totaled over 1 inch for the watershed. All stations received precipitation over the week, ranging from 0.02 inch at Ashton to 2.6 inches at Lewis Lake Divide. Total watershed precipitation for the water year to date is 2.10 inches, and with more on the way, the first month of water year 2022 will very likely receive above-average precipitation. That happened in only four months during water year 2021. Precipitation this evening is now forecast to be lighter than anticipated a few days ago, with most areas receiving 0.1-0.2 inch. However, very heavy precipitation is expected next weekend and into the beginning of next week. Totals over the next week are expected to range from 0.75 inch at the western edge of the watershed to as much as 2.5 inches along the Teton crest. Temperatures will generally remain near to slightly above average over that time period, but snow will continue to accumulate at elevations above 7,500 feet.
Natural flow has dropped a little from the effects of precipitation early last week and is 75% of average across the watershed and within a few percentage points of that in each of the three subwatersheds. Accumulated natural flow for the water year to date is 74% of average. Diversion is still on a generally downward trajectory with two weeks remaining in the administrative irrigation year.
At a mean outflow of 110 cfs, Island Park Reservoir gained an average of 592 ac-ft/day last week and is 51% full, compared with 50% full on average. The upper Snake River reservoir system is at 14% of average and filling slowly.
Rob Van Kirk, Ph.D.
Senior Scientist
Henry’s Fork Foundation
P.O. Box 550
Ashton, ID 83420
208-652-3567 OFFICE
208-881-3407 CELL
208-652-3568 FAX
