Henry’s Fork, September 5th, 2023
Now that cooling weather has arrived and fly fisher populations are dropping, some the best fishing days anywhere on the river are arriving. True, the autumn mayfly activity peak is not as great as that of late spring-early summer, but terrestrial insects will thrive along the river to feed trout until a killing frost. Streamer patterns will become most effective in interesting trout in the entire river, but as autumn marches on, brown trout in the lower river will become increasingly interested as they begin migrations to spawning areas.
Headlines from Dr. Rob Van Kirk’s Henry’s Fork Drainage Water Status Report of September 2nd
- The month of August was slightly cooler than average but 2nd wettest in the 1989-2023 record, with 215% of average precipitation for the month.
- Natural flow continued to decrease yesterday, while diversion increased again, dropping lower Henry’s Fork stream flow right to the irrigation-season target.
- At an average outflow of 507 cfs, Island Park Reservoir dropped by 109 ac-ft and is 62.6% full, compared with 49.4% full on average.
- Our Island Park Reservoir sampling yesterday confirmed well-mixed, turbid conditions on the West End, but so far that turbid water has not traveled to the dam. I still expect the possibility of increased turbidity this weekend, depending on whether all outflow is transferred to the power plant.
Details
Rob Van Kirk, Ph.D.
Senior Scientist
P.O. Box 550
Ashton, ID 83420
208-881-3407 CELL
208-652-3568 FAX