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Fly Fishing For Trout – Changing Water Conditions

The stream’s volume of water and rate of flow strictly depends upon Mother
Nature. The amount of water in the stream can vary drastically with the seasons
of the year. Heavy rainfall that usually occurs in the spring months makes the
freestone streams large and turbulent and sometimes flood beyond their normal
banks. In the late summer and fall months of the year, most freestone streams
reach their lowest levels. Sometimes the flow can become so slow and the
dissolved oxygen levels so low that it become tough for trout to survive. This is
especially true in the lower sections of the streams in the foothills.

At the headwaters, most eastern freestone mountain streams support native
brook trout. These fish are usually small, averaging from four to eight inches
because they have less space to live and less food to eat but they are also
usually very aggressive and lighting fast. Most of the time, trout found in the
acidic, headwater streams feed opportunistically. It is rare that they have enough
of any one species of food to feed on. Selective feeding times are few and far
between.

The angler usually does not have to be concerned with specific patterns of flies.
Most of the time, attractor or non-specific type flies that imitate a variety of  
insects will work fine. There are a few times when the trout do concentrate on a
particular insect. There is usually a few species that can cause selective feeding
for short periods of time in the headwater streams.

As many of you may know, in the Eastern Appalachian Mountains, rainbow and
brown trout are a problem for the native brook trout. They will compete for the
same space and food. This has forced the smaller brook trout to exist only at
higher and more remote locations than they once did. In many cases, in the
middle and lower elevations of the streams in the Great Smoky Mountains
National Park, brook trout have been completely eliminated by the rainbow and
brown trout. The park service along with concerned anglers are working on
changing this in a few streams.

It doesn’t take much to upset the balance of nature in a freestone stream. Many,
many factors have done just that. The logging of timber has been a major  
problem for many streams. The construction of roads has also affected many of
the streams and in many different ways. The construction of lakes has
also affected many trout streams. This is a big issue with many western trout
streams. Acid rain is yet another adverse factor that has affected streams in the
Eastern United States. The list goes on and on.

For our purposes here, the main thing to be gained from these adverse affects
is that anglers should be aware of what makes a freestone stream produce good
trout fishing and what hurts them. Two important points to stop and register is
water temperature (which also affects the oxygen content) and water levels or
stream flows. Knowing these two things about a freestone stream is the first and
primarily the most important things to know.

By far the best source of information is the angler’s thermometer. It will provide
water temperatures that are accurate at the time you are fishing at the particular
point you are fishing.  

Stream flows can be obtained from this site under the Information Section for any
stream in the nation. Thunderstorms that occur in a different watershed can
change the flows very quickly.

The next most important thing would probably be the clarity of the stream’s water.
The stream levels and flow rates are good indicators of the water clarity but this
information alone is sometimes deceptive. Of course, once you are on the
stream, you can see the watercolor conditions for yourself.

The pH of the water is yet another factor that affects the trout and its food but it
is one you can do little about. You can change the way you fish to adjust to water
temperature and water levels but you can’t adjust for high pH levels. Of course,
just knowing the water temperature and level is not enough. The information is
worthless if you do not know how it affects the trout and how it affects your fishing

Copyright James Marsh 2013