Deepest spot on the Ohio? Bottom terrain?

[KentuckyBristle]

Here’s a question that I’m having a hard time getting an answer to. What is the single deepest spot on the Ohio River? When I Google it, I get answers of 55 feet, 85 feet, and 130 feet…though they all place it in the Louisville area.

What I am wondering is, if I were in a boat over the deepest single spot while the water was at typical summertime pool –no flooding, no droughts – how many feet down would I find the mud, gravel, or rocks? I figure if anyone has some good answers (or could make up good BS… ) it would be the people here

On a related note, can anyone say what the terrain of the river bottom would look like if the water suddenly disappeared? Would it be long stretches of bare mud and silt, with the occasional rocky spot? Would it be an undulating junkyard of rocks, wrecked cars, trees, and garbage.

Whenever I look at the river, I try to picture what it would look like underneath, but I just don’t know.

[King31]

up the river from the Cannelton dam to Mcalpine a lot of the river is 35-40 feet deep all the way across. That being said I'm sure there are a few deep holes. 130 feet seems ridiculous though but who knows. As far as what it looks like, I would have to say it would be all mud. Everything silts over is my reasoning.

["The Man"]

I'm going to say the deepest part of the Ohio river is in the Fossil beds about 40-50ft in parts.

[jrunger]

Wow, that is really a good and interesting question that got me thinking. I've never really thought about the bottom of the Ohio river until you asked.

As I thought about it, many creeks I have fished came to mind -- locally one's like Elkhorn, Floyd's Fork, Brashear's, and little Kentucky River. Your question made me think of those creeks and their bottoms. On the whole, those creeks have a lot of "shelves", some "pebbly" bottoms, and even some "silty" areas. It seems the bottoms change in all of them, some having to do with the surrounding areas (fields, bluffs, etc) and some with respect to flow (bends, straight areas, etc).

So, no, I have no idea if the river is just a "big creek" --- but your question sure had me wondering --- maybe there are different "bottoms", just like there are in the different creeks.

I'll be watching this post to listen and learn.

Great question,

Jeff

[KentuckyBristle]

Wow, that is really a good and interesting question that got me thinking. I've never really thought about the bottom of the Ohio river until you asked.

As I thought about it, many creeks I have fished came to mind -- locally one's like Elkhorn, Floyd's Fork, Brashear's, and little Kentucky River. Your question made me think of those creeks and their bottoms. On the whole, those creeks have a lot of "shelves", some "pebbly" bottoms, and even some "silty" areas. It seems the bottoms change in all of them, some having to do with the surrounding areas (fields, bluffs, etc) and some with respect to flow (bends, straight areas, etc).

So, no, I have no idea if the river is just a "big creek" --- but your question sure had me wondering --- maybe there are different "bottoms", just like there are in the different creeks.

I'll be watching this post to listen and learn.

Great question,

Jeff

Your comment about creek bottoms is similar to my way of thinking on it. The natural processes are the same, so the same principles must apply, right? The biggest difference is scale.

I bet there are areas that change and shift pretty frequently, depending on conditions; a blanket of silt might deposit, and then a field of debris on top of it (logs, whiskey bottles...) and then the next "flood stage" might scrub it back to bare limestone for a while. I dunno. At any rate, I agree with you and MarkW that it must differ depending on the terrain around the river--I bet that around the knobs, there must be more rocks along the bottom.

I would also guess that the current must sometimes carve out a deeper hole that will shift and disappear again.

Here's another question for people who are commenting about the depth from their own experiences: is you measurement based on depth/fish finders? And are those sonar-based? If so, do varying water temperatures give odd readings regarding depth? (for instance, can it exagerate the depth, or hide how deep something truly is?)

I want to sit down and talk with a geologist/hydrologist...but I don't know any...

[MagikSmallie]

Your comment about creek bottoms is similar to my way of thinking on it. The natural processes are the same, so the same principles must apply, right? The biggest difference is scale.

I bet there are areas that change and shift pretty frequently, depending on conditions; a blanket of silt might deposit, and then a field of debris on top of it (logs, whiskey bottles...) and then the next "flood stage" might scrub it back to bare limestone for a while. I dunno. At any rate, I agree with you and MarkW that it must differ depending on the terrain around the river--I bet that around the knobs, there must be more rocks along the bottom.

I would also guess that the current must sometimes carve out a deeper hole that will shift and disappear again.

Here's another question for people who are commenting about the depth from their own experiences: is you measurement based on depth/fish finders? And are those sonar-based? If so, do varying water temperatures give odd readings regarding depth? (for instance, can it exagerate the depth, or hide how deep something truly is?)

I want to sit down and talk with a geologist/hydrologist...but I don't know any...

I am a geologist, not exactly a Hydrologist. I think most of you are on point. in higher velocity flows you will obviously lose alot of the silt and will experience a more bare rock, boulder (anything bigger than a fist is considered a boulder), pebbles and gravel surfaces. In your lower velocity flow areas (the closer you get to the Mississippi the slower the flow gets) and the more silt and mud you will encounter on the bottom. Every area of the river will be different. A major factor to consider is tributary mouths and what type of sediment is being fed from these tributaries. Some will carry more silt and clay others will be "cleaner" (less turbid) and carry more sand. Always remember your grain sizes from largest to smallest in both terms of weight and size are sand, silt, and clay. In my opinion you will see every sort of bottom depending on the immediate environment. Of course the addition of dams along the Ohio has increased the depth and slowed the flow down considerably and you are most likely looking at a major increase in siltation and mud accumulation above these dams (just something to consider). I do believe from everything I've read that the max normal pool depth of the Ohio is around 132' (Louisville) and it shallows gradually until it reaches the Mississippi.

[smashdn]

I am a geologist, not exactly a Hydrologist. I think most of you are on point. in higher velocity flows you will obviously lose alot of the silt and will experience a more bare rock, boulder (anything bigger than a fist is considered a boulder), pebbles and gravel surfaces. In your lower velocity flow areas (the closer you get to the Mississippi the slower the flow gets) and the more silt and mud you will encounter on the bottom. Every area of the river will be different. A major factor to consider is tributary mouths and what type of sediment is being fed from these tributaries. Some will carry more silt and clay others will be "cleaner" (less turbid) and carry more sand. Always remember your grain sizes from largest to smallest in both terms of weight and size are sand, silt, and clay. In my opinion you will see every sort of bottom depending on the immediate environment. Of course the addition of dams along the Ohio has increased the depth and slowed the flow down considerably and you are most likely looking at a major increase in siltation and mud accumulation above these dams (just something to consider). I do believe from everything I've read that the max normal pool depth of the Ohio is around 132' (Louisville) and it shallows gradually until it reaches the Mississippi.

At the confluence with the Miss the Ohio is wider across. I agree that it just gets shallower and wider as it nears the confluence with the Miss.

[KentuckyBristle]

I am a geologist, not exactly a Hydrologist. I think most of you are on point. in higher velocity flows you will obviously lose alot of the silt and will experience a more bare rock, boulder (anything bigger than a fist is considered a boulder), pebbles and gravel surfaces. In your lower velocity flow areas (the closer you get to the Mississippi the slower the flow gets) and the more silt and mud you will encounter on the bottom. Every area of the river will be different. A major factor to consider is tributary mouths and what type of sediment is being fed from these tributaries. Some will carry more silt and clay others will be "cleaner" (less turbid) and carry more sand. Always remember your grain sizes from largest to smallest in both terms of weight and size are sand, silt, and clay. In my opinion you will see every sort of bottom depending on the immediate environment. Of course the addition of dams along the Ohio has increased the depth and slowed the flow down considerably and you are most likely looking at a major increase in siltation and mud accumulation above these dams (just something to consider). I do believe from everything I've read that the max normal pool depth of the Ohio is around 132' (Louisville) and it shallows gradually until it reaches the Mississippi.

Thanks, MagikSmallie, and everyone else who has commented.

[restornator]

I am a geologist, not exactly a Hydrologist. I think most of you are on point. in higher velocity flows you will obviously lose alot of the silt and will experience a more bare rock, boulder (anything bigger than a fist is considered a boulder), pebbles and gravel surfaces. In your lower velocity flow areas (the closer you get to the Mississippi the slower the flow gets) and the more silt and mud you will encounter on the bottom. Every area of the river will be different. A major factor to consider is tributary mouths and what type of sediment is being fed from these tributaries. Some will carry more silt and clay others will be "cleaner" (less turbid) and carry more sand. Always remember your grain sizes from largest to smallest in both terms of weight and size are sand, silt, and clay. In my opinion you will see every sort of bottom depending on the immediate environment. Of course the addition of dams along the Ohio has increased the depth and slowed the flow down considerably and you are most likely looking at a major increase in siltation and mud accumulation above these dams (just something to consider). I do believe from everything I've read that the max normal pool depth of the Ohio is around 132' (Louisville) and it shallows gradually until it reaches the Mississippi.

Silt and clay will not settle unless the water is stagnant. When there is current, any deposits are swept off the bottom. Sand bars and silt are constantly shifting after every flood event. Most of these suspended solids never settle to the bottom; the only predictable bottom structures are shoals and rapids where the river can't carve out the earth at the same rate as soft-bottom areas.

[MagikSmallie]

Silt and clay will not settle unless the water is stagnant. When there is current, any deposits are swept off the bottom. Sand bars and silt are constantly shifting after every flood event. Most of these suspended solids never settle to the bottom; the only predictable bottom structures are shoals and rapids where the river can't carve out the earth at the same rate as soft-bottom areas.

The water behind the River's 20+ lock and dams create the stagnant water and you do have sedimentation and settling of the Silt and Clay particles.

[test]

Right below Cannelton Dam it is real deep. I'm thinking 50 to 70. Maybe more.

There is a pretty big place on the upper side of Mcalpine in Louisville where it is 60'. I believe that is where they dredged to make I-71.

Way down river from Louisville I ran across a place that was 100' or so. It was not all that big. I have the place and depth marked on a river chart.

Peter - (logged in as test)

[onemorecast56]

I`ve run up and down that river with my depth finder and what i found is thats for the most part the river is shollow {25-30ft} from louisville to salt river,,but from salt on down it its deeper and deeper,,down around Otter Creek i`ve seen places 60-80 ft and aloy of more rock,,,