Mapping/Interpretation Exercise
Posted: Wed May 07, 2014 11:07 am
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
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