Mapping/Interpretation Exercise

[DRH2O]

So I'm looking at a full weekend of camping/fishing at a small reservoir coming up over Memorial Day Weekend and I'm going to get my first opportunity to apply my budding spoonplugging knowledge to this particular body of water.

In addition to the on-the-water practice applying the techniques I've been spending my off-water time trying to absorb the guidelines in general and improve my ability to "read" a lake's potential structure situations from the lay of the land.

I thought it might be a good exercise to bounce my interpretations and assumptions about this reservoir off of the forum here. So here goes.

My understanding is that the deepest area down by the dam bottoms out around 30 feet or so.
Water color here is typically pretty heavy yellow/green.

There are no contour maps available of the lake per se but with the link that Dennis provided in another thread I found an old image of the area before it was flooded.

Before I discovered the old map I had taken the 2 part Fishing Facts article about assessing potential structure situations by the surrounding topography and gone over it paragraph by paragraph, applying it to the satellite image.

My first assumption is that since the old channel existed as a creek for a substantial amount of time before the lower lake was flooded that there is likely to be a Delta type situation, a ridge formed on the edge of the channel on at least some parts of it.

Outlined below are what I have determined to be areas of interest:

A
The first thing that jumped out at me that I couldn't have known about without the old map is the start position of the old channel. Currently the water flows from the upper to the lower side under a bridge on the causeway at point A2 - so I had assumed the channel made a large slow turn around that big sweeping point. It turns out the original channel flowed in at point A1, making it much straighter than I had assumed.

Since the inlet has moved it seems possible that a smaller cut, like that from a feeder creek, may have formed and might intersect the larger original channel at some unknown spot. How much of a cut might have been formed is anyone's guess but it seems reasonable to me to at least assume that any existing ridge along the original channel might have been washed out at the intersection.

I would think this feature to be worth taking the time to look for, especially since there is a road that runs all the way around the lake and there are no actual discernible feeder creeks that might intersect with the main channel (more on this below).

B
It also appears that somewhere in the vicinity of point B would be the most likely place to find a structure that extends all the way, or most of the way, to the channel, at a point where it's very close to the deepest part of the basin.
Q. If the above holds true this might be the best looking structure situation to target in the summer post-spawn but what about during the spawning period itself?

C
As I said, there is a road that surrounds the lower lake and the drainage from the watershed in general is at the inlets of the upper lake. The tree lines and growth leading to the coves C1,C2 & C3 however, suggest that there were either once small creeks or that there may be some water flow here when runoff collects from heavy rains.

I'm on the fence about whether or not I think these little coves would carry any significant cut or channel that went all the way out to the main channel. The water temps right now should have the fish in pre-spawn, and if the weather trend holds I would expect to be close to spawning proper when we hit the water in a couple of weeks. Mr Perry's writings are pretty clear that the bars at the entrance of a cove with a feeder stream would be prime areas to check during the spawning season but that if the cove has no inlet stream stay away from it. I'm unclear how to apply the guidelines in a situation such as this though, where such a feeder stream may have only existed in the past or may only exist during periods of run-off from heavy rains.

D
Finally the lower dam has rip rap all along it (old bricks and rock) and has the sharpest drop to the deep water. The only breakline here that I would expect would be a weedline but my understanding is that these areas should ALWAYS be checked.

Thoughts, opinions, observations, critiques of my map-based assessment all welcome.
I understand many areas need to be checked but if I have to give a few spots more time than others I'd like to have some degree of confidence that I've picked the highest percentage ones to work over.

Thanks fellas!
~Denny

[Steve Craig]

Denny,
It is really good to see you posting these types of pics and asking these questions. This is what this board should be all about.
I will give your example a shot for you and I hope that we both learn something.

A1 and A2......
Your lower contour map shows you where you need to spend your time. The original channel hits the Causeway at your A1 spot. This spot on the Causeway will be a "hotspot". Why? It will have the deepest water in the area due to the main channel.(shown on the map coming out below that area.
What makes this spot an even better spot is there is also a feeder creek channel coming in at the same location. This is "Fishing Water". All the rest of the causeway on the upper side is "Trolling Water"
Because they put the bridge on the other side of the Causeway, it needs to be "checked out". aka "Trolling Water" until we prove it otherwise.( by finding deep water and a manmade channel over to that side).
Remember the guidelines for "Reservoirs". The Main channel and the feeder creek channels, are your Key.
Deep water is the Home of the fish. In reservoirs, this means the channels.
You also have another "hotspot" on that causeway to look at. It is on the downstream side where that Main channel used to flow. Across the causeway from your A1 Spot.

B........
From your map, this looks like a very nice looking bar. As long as it goes "all the way" to the channel.
From your map it appears to do just that.

C3 will be the area to look for Spawning bass. Rest assured that C1, 2, 3, are feeder creeks and rest assured they were there long before this lake was built.
Remember the Guidelines......The intersections of the feeder creeks with the main channels are your Key in any reservoir, large and small.
C1 could be another "hotspot" right next to your Causeway, it that feeder comes in close to it.
C2 could produce a nice bar at where it intersects the main channel.
All of these spots will need to be checked out to see what is really there.

D.......
You will probably not have weeds at the Dam. Most Dams with good rip-rap, are clean and easy to run with all the lure sizes.
The Key to the "hotspots" on a Dam, are to actually look at the back side(downstream side) and find where the old creek channel used to run. Then go back across to the upstream side, and pile you up a small rock pile at that area. Because that area will have the old channel right there. Deepest water in the area, Deepest water in the lake, and probably deepest water available.
Another Key area on a Dam is where the Rip-Rap ends under the water. That is a breakline. How good it is depends on what depth it is at.
Many times there will be small "fingers" of Rip-Rap that stick out just a little farther than the rest of that rip-rap breakline. Your lures will find them trolling.
But the main place to concentrate is where all that rip-rap meets that main channel.

Trolling each lure size down as deep as you can go is very easy to do on Dams and Causeways.
Buck did an entire video on them alone.
Trolling is our Teacher.

I hope this has helped in one way or another.
FWIW
Steve

[DRH2O]

Thanks for the feedback Steve I appreciate it!

Some great insights I hadn't considered there. Especially regarding the causeway and the dam.

Love that idea about checking the backside of the damn for the location of the old creek channel and marking it in front. You also got me to thinking some more about that causeway and the downstream side of A1 there is where they put in a boat ramp. Which means they probably scooped out a deep area that the old channel still intersects with.

I still have a couple more weekends practicing on my home waters before this trip. With any degree of luck I'll be able to apply what I've learned and come back with a positive report of some sort. I'm not expecting miracles overnight or anything but it would be pretty cool to go out with the sense that I have a definite plan to follow and to see it come together even if only in some small way to begin with.

~Denny