Henry’s Fork, September 26th, 2023

It has not been cold enough to kill all the hoppers, honey ants and beetles. They are active along the entire river from St. Anthony upstream to the Flat Ranch. Wait until the mid-day sun warms things enough for them to become active. This activity could diminish this weekend as unsettled weather is expected. However such weather could enhance mahogany dun and BWO activity and make pitching streamers more effective . A few trico spinners are around in mornings.

Here are headlines from Dr. Rob Van Kirk’s Henry’s Fork Drainage water status report filed yesterday, September 25th.

• Last week was cool and very wet, boosting water-year precipitation to 111% of average with just 6 days left in the water year.
• Cool, wet weather is expected to kick off the new water.
• Diversion and natural flow both dropped over the weekend after heavy precipitation on Thursday and Friday.
• At an average outflow of 466 cfs, Island Park Reservoir gained 151 ac-ft/day over the past three days and is 64.9% full, compared with 45.9% on average.
• Water-quality data indicate decreased aquatic productivity watershed-wide as the growing season wanes.

Chester Dam