Hydroelectric dams are required by law to have a warning device that
alerts anglers that water release is imminent. Fishing can turn from
great to poor in a matter of minutes because of the rapid rise of fall
of the water emanating from the dam.
In addition to hydroelectric dams, diversion, top draw, (top and bottom
draw), whereby the layers of water behind the dam are mixed by
alternately releasing from the top and bottom and lastly, bottom draw
dams, (dams that release water at the bottom of the dam, whereby the
coldest water from the bottom layers of the lake flows out), In the
south bottom draw dams enable trout to exist where it was once
impossible. Water flowing from a bottom draw dam will be around
forty-five to fifty degrees in temperature. Examples of rivers with
bottom draw dams and trout tail waters are the White River in Arkansas,
Guadalupe in Texas, San Juan in New Mexico, Lees Ferry in Arizona,
Chattahoochee near Atlanta, and the South Platte in Colorado.
Canyon Lake Dam, on the Guadalupe River near New Braunfels, Texas is a
bottom draw and as long as the water flow doesnt fall below 200 cubic
feet per second, the water will remain below 70 degrees, even in the
long hot Texas summers. The result is a self sustaining twelve mile long
trout fishery. I know its hard to believe you can catch trout in South
Central Texas, but you can also catch trout in any tailrace water in the
south that has stocked trout and receives cold water from a bottom draw
dam flowing at a rate that will keep the water temperature at or below 70.
Some of these rivers will over a period of years develop a reproducing
trout population. I know this for a fact because my TU chapter annually
stocks the Guadalupe with around 30,000 rainbow trout averaging a pound
to a pound and a half. Later, when we see trout fingerlings in the
river, we know they are not hatchery fish. The record Guadalupe rainbow
is 8 1/2 pounds. While rainbows on the Guadalupe have thrived, we
recently stopped stocking browns because they have never reproduced and
do not do well.
Fisheries biologists across the country are experimenting with rainbows
raised in lake or stream pens. These pens hold tiny rainbow trout during
the fall and winter months in hopes of teaching them how to feed and
better survive the cold winter months. They are fed several times daily
and by living in pens actually placed in a lake or stream, they are
protected from larger fish and other predators. In this manner, the fry
will thrive and grow and gain knowledge of lake or stream foods that
they can eat.
Pen raised trout are released into a stream when they reach about a
pound in weight. They are more akin to wild trout in their stamina and
are far more discerning of what they eat than the run of the mill
hatchery trout. They also have a better flavor than hatchery fish. Pen
raising definitely works, but the problem is having enough large pens to
produce enough surviving rainbow fry that grow to release size to make
the project worthwhile. Our TU chapter tried this several years ago with
a few small pens in the Guadalupe River with little success.
Ive rambled entirely too long and have probably lost some of you in the
process. If Ive bored you, I apologize. If youd like to know more
about fishing Tail Waters, get Ed Engles book Fly Fishing the Tail
Waters Stackpole Books 1991. Ed dedicates this book to the South
Platte River. He is a personal friend of mine and in addition to his
books hes also a columnist for several US fly fishing magazines.
