Turning the Spigot On … And Off

Just as rivers like Montana’s Bighorn suffer from dramatic changes in water release levels, similar policies exist in other large and important tailwater fisheries in the U.S. east. Many are questioning the simplistic “off or on” policies of resources managers, who seem to ignore the health of rivers in favor of pure risk management. Perhaps the best example is the West Branch of the Delaware, which was visited recently by New York Times writer Peter Kaminsky. “[Al] Caucci was gratified, but disturbed, explaining that wild fluctuations in river flow, like the one we had experienced, disorient the trout. And when a high flow is followed immediately by a precipitous drop, precious insect life is stranded to die on exposed gravel beds, thus depleting the food supply of the river.”
Meanwhile, on Arkansas’s North Fork River, the massive releases of this spring have caused another problem: warm-water fish invading the tailwaters. Of course dam releases here have been a response to true potential disasters, but it does show how tricky managing large impoundments can be. The state is now electro-shocking the tailwaters and transporting bass and walleye back above the dam.
And finally, in this morning’s news The New York Times covers the March breaching of the Milltown dam, which few can doubt will have an enormously beneficial impact on the Clark Fork and Blackfoot Rivers. Not surprisingly, the loudest calls for the dam’s removal came after a sudden release of water in 1996 — in response to the threat of damage from a huge ice jam — caused a massive fish kill because of the heavy metals contained in the sediment behind the dam.