water quality

Aerial photo of Island Park Reservoir. The dam is in the bottom left corner. The Centennial Mountain Range is in the top.

Water Quality

History of Water Quality in Island Park Reservoir

Warmer and drier conditions have slowly degraded water quality in Island Park Reservoir over the last 50 years. In the 1970s and 1980s, federal reports

Christina Morrisett May 22, 2026

A photo taken of Island Park Reservoir while standing on the dam and looking north. The sky is cloudy, Mt Sawtelle sits with little snow in the background, and the reservoir is open water (save for a few small sheets of ice in the distance).

Water Quality

Reservoir Ices Off, Growing Season Turns On

Photo of an ice-free Island Park Reservoir taken on March 31, 2026 On March 31, 2026, with no accompanying commentary, HFF scientist Christina Morrisett stood

Christina Morrisett May 7, 2026

Drift boat with anglers rowing downriver surrounded by tall trees

Water Quality

The River Rundown: Your FAQs from June 2025

“It feels like July!” was a common sentiment shared around the watershed last month. Anglers enjoyed Brown Drakes on the Ranch three weeks earlier than

Christina Morrisett July 8, 2025

History of Water Quality in Island Park Reservoir

Reservoir Ices Off, Growing Season Turns On

The River Rundown: Your FAQs from June 2025

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