When viewed from above, a great deal can be learned
about potential brook trout watersheds. In fact, when hunting
for potential watersheds, one of the best places to start is with
a topographical map of the entire area involved, such as the map
of Northeast Ohio below:
With this map you can easily pick out the areas of
higher elevation which are more likely to have Sharon sandstone
as bedrock and thus yield more springs. When looking for potential
streams on a contour map it is important to look for areas that
have the ideal stream gradient. Trout streams should not be so
steep that there are numerous waterfalls that prevent movement
of the fish, yet they should have enough gradient to avoid swampy
areas that accumulate silt and muck.
When looking for streams that will yield springs, it
is important that it does not run entirely through high ground.
There must be hill caps near by to the stream in order to keep
the ground water level high enough to constantly replenish the
springs. A clear example of this is the two hill caps to the north
and southwest of Spring Brook that maintain the groundwater levels
for the springs that feed the brook:
aerial photography can also be very useful in finding
streams. Once streams with the correct elevation and gradient
are found their aerial photographs should be looked at in order
to determine whether the watershed contains open fields, parking
lots, or roads that would cause potential flooding problems. Looking
at the aerial photo of Spring Brook bellow shows us that it has
a well forested riparian area, a key ingredient for potential
trout streams. Looking closely at the stream channel, you can
also see this streams very high sinuosity, another good sign in
a trout stream.
Though the use of aerial photography and contours can
be useful in creating a rough list of potential streams, it is
only a first step that must be backed up with ground-truthing;
before a stream can be considered a potential candidate for brook
trout reintroduction it has to be seen that the stream isn't polluted,
to warm, and has proper flow.
If you would like to download the Arcview files (10
foot contours and updated river files for all of Northeast Ohio)
that were used for making these maps you can do so here (BE WARNED!
the file is 130 MB due to very large contour files; it will take
a VERY long time to download!): troutspotting
Arcview files
