Contour Map Reading
wouldn't think about driving through several states without a
highway map. Neither should you go fishing without a lake map,
especially if it is your first time on the lake. For safety reasons, it will show you where there are shallow parts in the middle of
the lake. For fishing reasons, it will show you where the structure
is on the lake that is away from the shoreline. With an accurate
contour map of the lake you will be able to determine productive
fishing areas before you reach the lake to put your boat in the
Contour lines draw the
shape of the bottom by revealing a specific depth throughout the
lake. Try to purchase maps that have contour lines no
more than ten feet apart. A first hand inspection with a depthfinder and fishing
lures is necessary before you can visualize the bottom accurately.
Reservoir maps tend to be more detailed, because they are usually
made before impoundment while the eventual lake bottom is visible to
the naked eye. Maps of natural lakes are less detailed and often
overlook major structural elements, such as humps. Nevertheless,
contour maps provide a good feel for the lake and get you started in
the right direction.
Contour maps are usually available at bait and tackle shops near
popular lakes and impoundments. Many lake maps point out navigation markers, roads,
and trails around the lake, as well as the locations of marinas,
resorts, restaurants, and campgrounds. Some reservoir maps may also show
submerged buildings, roads, railroad tracks, bridges, stumps, trees,
ponds, and other structures. If you plan to visit a lake for a
vacation, call or write the local chamber of commerce or a local
bait and tackle shop and see if they can provide you with maps
before you go. The state’s department of natural resources may be
another source for maps.
In many cases, the best maps are those published by the U. S. Army
Corps of Engineers or the Department of the Interior, Geological
Survey. These topographic maps, as they are called, may not show the
depth contours of some natural lakes, so check before buying them.
If the lake you’re interested in is within the jurisdiction of the
U. S. Army Corps of Engineers, they may have a map. I buy my maps at
Ridgeways on 41st St. in Tulsa.
When dealing with reservoirs, dated maps that were printed before
the lake was impounded are often the best. If you get a map that was
made before impoundment, outline the shoreline with a felt pen. You
must first determine the normal pool elevation of the lake, which is
usually listed in the margin of the map in “feet above sea level”.
You may also get this information from the U. S. Army Corps of
Engineers. Simply find the contour that coincides with the lake’s
normal pool elevation, and follow the contour with a marking pen.
This is what that I had to do with my McGee Creek map.
Along with contour lines, the may have other marks and symbols
showing foundations, roads, and many other bottom features that may
hold bass. A publication entitled Standard Symbols, available from
the Geological Survey, will make it easier to identify such features
on the map.
Your ability to read contour lines, more than anything else, will
determine how well you interpret the shape of the bottom and locate
underwater hot spots. A submerged point, one of the most prominent
structures, appears as a series of contour lines pointing away from
the shoreline like a finger. The photo to the right shows a point. A drop-off exists where the contour
lines come close together. A reef, hump, or submerged island appears
a s a contour line in an irregular circle surrounded by deeper
circles. The more you learn about map reading, the better you will
become at finding these and other structures.
When looking for structural elements, keep in mind the season
of the year. Pick out
several spots on your map that appear to have potential, then find
them on the water. Say that you want to check out a submerged point
that reaches far out from the bank before dropping into deeper
water. Your map will get you to the general vicinity of the point.
Then you must use your depthfinder to determine the exact location
and shape of the point.
Begin by crisscrossing the point a few times to get
a general feel for it. Then follow the outline of the point at a
specific depth, such as ten feet deep. Drop marker buoys at
intervals as you follow the point's ten-foot contour. When you’re
finished, the markers will outline the point, making it much easier
to visualize the point's shape. Remember, bass are edge oriented,
whether they are using shallow cover or a deep structure. Should
your depthfinder reveal an especially promising feature, such as a
stump or rock pile, mark it with a buoy.
After marking any promising structure with buoys, fish it with a bottom-bumping
lure, such as a Texas-rigged plastic worm. Doing this, you can feel
the bottom through your rod tip. This is an important part it will help you determine whether the bottom
consists of mud, gravel, rock, or some other substance, and will let
you know if the structure has weeds, boulders, stumps, or other
features that attract bass. Very often a single stump or small patch
of weeds may hold an entire school of fish. Note the spot’s location
even if it fails to produce, because it may hold bass at another
Before retrieving your markers, locate landmarks so you can quickly
find the place at a later time. First find an obvious object on the
shoreline, such as a dock. Then line up another object directly
behind the dock, perhaps a house. Find another shoreline object at
right angles to the dock and line it up with another that is
directly behind it. Record these landmarks on the topo map or in a notebook. When
you return, position your boat so that the landmarks line up and you
will be directly over the structure.
By using a lake map
and a depthfinder, you can learn more about the bottom of a lake in
a few days than you could in years of fishing the lake without these