Warming and Dam/Reservoir Impact on Fishing Rivers

I got an email from the Henry's Fork Foundation yesterday with sobering information. Just after I left the Henry's Fork of the Snake River in early July, I heard from friends who were still there that the fishing deteriorated as the water levels increased quite significantly.

The Henry's Fork in Island Park, Idaho is impacted by a reservoir formed by a dam on the river at that point. The dam has a hydro electric component controlled by a local rural electric company.

In addition, all the farms anywhere near the river as it meanders downstream take water from the river via pumping stations and use it for massive irrigation systems. Their taking of water varies by time of year, amount of local rainfall, period of crop growth, etc. Their use of water is monitored and causes adjustments at the dam to maintain flows. Problems with the dam structure and the power company's facility at the dam sometimes cause dramatic increases or decreases in water flow. The dam controls are also adjusted to maintain levels in the reservoir.

Here is an excerpt from the Henry's Fork Foundation newsletter email:


​The Board and staff of HFF have heard loud and clear from anglers ? particularly those fishing the Railroad Ranch ? that fishing is poor, releases from Island Park Dam have been well above average, and the water is turbid. Many of us have personally experienced these same conditions and have stood in parking lots in Last Chance hearing directly from anglers, guides, outfitters, and business owners.