In the fly fishing world, typically we classify fish holding rivers/streams in three different categories, tailwaters, freestones, and spring creeks. So how do they differ and why should we care? Well, in fact, each classification is very different and typically supports different biology based on the amount of oxygen, vegetation, entomology and a lot of scientific facts that is beyond my understanding. But, as anglers, it is important to understand the basics of the differences between these classifications as our tactics typically will be different. Some proper preparation will lead to a more successful day on the water.
A tailwater is classified as a dam controlled piece of water. The dam controls the flows and thus the temperatures. Man and computers typically regulate the flows and discharges from the dam. There are many famous tailwater trout streams throughout the states. To name a few, the Green River, Missouri River, Frying Pan River, Blue River, South Platte, North Platte, Madison River, San Juan River, Bighorn River, Yellowstone River, and even the Colorado River. They are famous for the quality trout fishing with large populations of trout and bigger on average fish. On the Green River, there are 22,000 trout per mile in each of the first 6 miles of the river below the Flaming Gorge Dam. That is a lot of trout!
Well since the flows are regulated, the temperatures do not fluctuate as much. Thus, there is more bio-productivity meaning larger concentrations of bugs, plants, and just biomass. With all of this biomass large populations of trout are able to thrive and the trout have enough food to eat a lot and grow larger.
While many tailwaters across the West typically mean productive trout fishing, this is due to the proper management of the river flows. Fortunately, many of the dams have regulations and standards in place that help sustain a healthy fishery. If flows in the summer aren’t high enough this can result in rising temps and fish kills as well as if too much water is released it can result in thermal shock to the fish. But, if managed properly they can provide anglers with some phenomenal trout fishing.
The wild freestone fisheries are systems that are fed by rainfall and snowmelt and entirely dependant on the natural water supply. The flows of a freestone river fluctuate constantly and are entirely at mercy of mother nature. The Eagle River and Gore Creek are prime examples of freestone rivers as they are completely dependant on the natural water supply. If we have a bad snowfall year in the area, we should expect lower flows and warmer water. If there are periods of not a lot of rainfall in the summer the Eagle River’s flows will drop and the temperatures will warm. This happened this past summer and fishing conditions were challenging due to the high water temps.
Since the flows and water temps are constantly changing, tactics for fly fishing can change with a flick of a switch. The bug life and hatches are all dependant on water temps. When the water hits that certain mark, a certain species of insects will begin hatching. Typically on a year to year basis you can expect similar hatches but you can never be never certain.
A thermometer is a freestone angler’s best friend. Checking the temp throughout the day can give you an idea of the bug hatches and what to expect. It can also be a great tool to know when to stop fishing due to warm temperatures.
Spring creeks are probably the most irrelevant in the Vail fishing region as spring creeks are solely fed by groundwater seepage of natural and nutrient rich spring water. While there are a variety of different groundwater fed streams in the Rockies most of them are also fed by snowmelt. Thus, making them not your classic “Spring Creek.” While you will find some especially on private property in the high country. If you do find yourself fly fishing a spring creek here are some points to keep in mind.
While many of these different river systems can be a mix of all three different systems (Like the Colorado River). From spring creeks to some sort of regulated flow/dam to a snowmelt tributary it is important to identify what type of fishery you will be fishing in order to better prepare for your trip. Each system can provide unique challenges for every angler, as fly fishers, I guess that is part of the fun.
For up to date conditions on the local rivers be sure to check out our fishing report. Feel free to call the shop for river conditions and reports on the local tailwaters like the Frying Pan River, Yampa River, and Blue River.
Patrick Perry Former Guide and Content Contributor @patperry