Photo credit: Charlie Lansche and Devan Ence
The Henry’s Fork Foundation is honored to receive a $1 million federal grant from the US Bureau of Reclamation’s WaterSMART program to develop the revolutionary DIRTT Plan: Developing Infrastructure to Reduce Temperature and Turbidity.
Water temperatures and changing hatches are at the forefront of anglers’ minds, and for good reason. Average water temperatures are increasing and may be the culprit in changing hatches. Plus, nutrient levels in the river are looking like the next big issue on the horizon.
It’s time to look at massive-scale engineering solutions, as well as grounded, nature-based solutions. We want to reduce the amount of sediment sent into the river, and to reduce water temperatures flowing through Harriman Ranch.
DIRTT aims to improve water temperatures and turbidity to build resilience for the river and the fish and insects that call it home. This might include variable-elevation withdrawal gates at Island Park Dam, tributary restoration, sediment stabilization, and deep-water oxygenation (adding oxygen to the reservoir for trout).
HFF is uniquely positioned – with the expertise, experience, data, and community – to be a leader in answering the difficult questions being asked across the fly-fishing world.
Our Aquatic Ecology Program Manager, Dr. Jack McLaren, joined Idaho Falls city and FIPS-Mouche leadership at the opening ceremony parade along the Snake River Greenbelt to welcome competitors to the watershed and to make sure conservation was front and center.
Drone photo of Island Park Dam taken on September 9, 2026 Looking Back on September September brought lows and highs to Island Park. Island Park Reservoir started September at 29% full and quickly fell to a low of 12% full on September 19. The rapid drawdown of the reservoir was the result of managers needing to move water downstream to American Falls (to irrigate farms in the Magic Valley with senior water rights). Such low
This story was written by Audrey Hunter (2026 intern) and was originally published in the Fall 2026 Newsletter. It’s no secret that late summers on Island Park Reservoir haven’t been in perfect conditions in recent years. Warm, turbid, algae-filled water plague reservoir recreationists while diminishing water quality downstream. Cyclical algal blooms decrease water clarity and create less-than-ideal circumstances for the reservoir’s flora and fauna. What’s the solution? HFF’s DIRTT Plan. In-Reservoir Oxygenation Nutrients released from
Drone photo taken on September 9, 2026 The Henry’s Fork Drought Management Planning Committee met on Wednesday, September 16 2026 to develop an updated reservoir management strategy. Downstream of the Henry’s Fork watershed, lower-valley irrigation demand over the rest of the season is anticipated to be slightly lower than projected last week, so Island Park Reservoir and Grassy Lake (in the Fall River drainage) do not need to deliver any more water out of the
