Streams getting shallower?

[Justin Spencer]

They try to use the hellbender as leverage which really pisses the hellbender biologists off because they realize these projects won't make a difference to their animal and only makes people less supportive of hellbender conservation. It is the old "we have money that we need to spend or we will lose it" game. With a million bucks they could purchase land (riverside canoe rental is for sale) and build a research facility, and that might actually benefit this endangered creature.

[Guest]

The Ozarks have a massive plug of gravel slugging its way downstream.

I floated the big sugar last week & all of my best holes were GONE.

Channel jumped to different sides, huge areas of shallow gravel, holes filled in, bedrock once exposed now covered in gravel.

I managed to catch 32 bass in brand new scour holes that never existed before.

Its not all bad, just different. Completely different.

I had to adjust to the "new" layout of the creek, but that's okay. the fish are still there.

[cwc87]

Just a thought. My opinion only. The headwaters of the Meramec Huzzah and Courtois are disappearing into the worlds largest lead mine and either being pumped out or sucked away by the Black river watershed. Hmmmnnn

Can or will they do the dye the water test and find out what is really going on in that particular watershed?? When the west fork of the black got diverted from the massive cave in last summer.

[TheRustyHook]

Rivers and alluvial formations are very much organic ever-changing systems. Big river systems like the Arkansas and Mississippi have drastically different riparian zones from year to year. Over the course of thousands of years, rivers ebb and flow in different areas naturally. I really feel our attempts to severely impede natural erosion (like that from continual reduced precipitation) is an act of futility. We want the river to flow in the direction we are used to seeing it. We want the same banks and the same holes to fish out of, but the truth is after every large flood, theres usually some new spot or formation, a random change providing additional habitat. Its give and take always, but we could save a lot of big money by letting the rivers navigate themselves.

Now that doesn't mean we don't need to reduce the unnatural erosion. Bank erosion from land clearing or human bank traffic, boat wakes, wading disturbances...of course, we can reduce and learn to responsibly limit our interference. We honestly don't know what the ozark looked like 500 years ago, and how the climate may have changed them from 500 years before that!

[Al Agnew]

Rivers and alluvial formations are very much organic ever-changing systems. Big river systems like the Arkansas and Mississippi have drastically different riparian zones from year to year. Over the course of thousands of years, rivers ebb and flow in different areas naturally. I really feel our attempts to severely impede natural erosion (like that from continual reduced precipitation) is an act of futility. We want the river to flow in the direction we are used to seeing it. We want the same banks and the same holes to fish out of, but the truth is after every large flood, theres usually some new spot or formation, a random change providing additional habitat. Its give and take always, but we could save a lot of big money by letting the rivers navigate themselves.

Now that doesn't mean we don't need to reduce the unnatural erosion. Bank erosion from land clearing or human bank traffic, boat wakes, wading disturbances...of course, we can reduce and learn to responsibly limit our interference. We honestly don't know what the ozark looked like 500 years ago, and how the climate may have changed them from 500 years before that!

You are right, of course. We've all seen changes after floods, and realize that a certain amount of change is natural and expected. The question is, how much change and how fast is natural?

I can close my eyes and mentally paddle down about 40 miles of Big River, I know it so well after having floated and fished it for more than 50 years. MOST of the larger, deeper pools are still there after all this time, and have changed very little. Those that HAVE changed have one thing in common; some human activity disturbed the bank either alongside the pool or just upstream. Let me describe some of them...

1. The pool used to be narrow and deep, 6 feet or more. There was an island at the riffle just upstream, with nearly all the water coming down the river left side of the island. The pool itself was up against a high mud bank with a single row of trees atop the bank on river left. River right was a lower bank completely covered in willows and young sycamores. There was a big old log situated in almost the exact center of the pool, with 6 feet of water surrounding it.

Two things happened, one man-caused, one natural. The landowner cut down a couple of those trees lining the left bank. And the river scoured out the right channel of the island above. That caused the main force of the current at higher water levels to hit that vulnerable left bank at an angle, instead of sweeping along parallel to it. The bank began to erode. The pool widened. The right side began to shallow in with gravel.

Now the pool is twice as wide as it was. The old log is still there, but is now much closer to the right side--it didn't move, the river widened to the left of it. Gravel has filled in around the log until it is only in two feet of water, much of it buried. The deepest part of the pool is still along that migrating left bank, but is less than 4 feet deep.

2. It's a bluff pool, rocky on river left. It used to be 4-6 feet deep along the outside edge of the bigger rocks. Along the upper portion of the pool, it was narrow and the right bank was low but covered in trees. The channel widened toward the downstream part of the pool, and there was a fairly narrow gravel bar along the river right side, mostly covered in willows and lined with water willow. The entire right side was 18 inches to three feet deep along the bank.

Somebody decided it would be a good idea to dig some gravel off that gravel bar. They scraped off the vegetation and dug out the bar, leaving a narrow band of gravel with the water willow weed bed along it. Behind that narrow band, no more than five feet wide, they dug the bar out to where it was a 6 foot deep hole instead.

The river wiped out that narrow band of gravel and water willow, dumped the gravel into the hole behind it, and essentially widened the pool. The current in high water now wants to swing over into what's left of the hole that was dug, and has begun to erode the bank behind it. With the force of the current swinging over toward that river right side, it has slowed on the deep, natural river left side and began to dump gravel on that side. The result is that the entire pool has shallowed and most of the rocks on the left side are now buried.

3. This was the only apparently natural change. It was a long, still pool, bluff on river right, lots of big rocks for cover, 6-8 feet deep. One early summer day, floating it for the first time that year, I noticed the pool was a good 18 inches shallower. There was even an obvious previous water level mark on the banks. The level of the pool had simply dropped 18 inches. When I got to the riffle at the bottom, I could see why. The riffle was gravel bottomed, and the gravel had simply been a dam that had kept the water level of the pool above at the higher level. Floods had, for whatever reason after many years of stability, simply dug a channel through the gravel, basically removing the "dam" and lowering the level of the pool above.

4. Along the outside of the bend that surrounds one of the old mine waste sites that is a Superfund site, there were four pools, three with bluff and rocks on river left, fairly deep for that section, though often changing with every flood as more mine waste was eroded into the channel and moved around. The fourth was not a deep pool, having a gravel bar on the left and a brushy bank with a mine waste dump just behind it on the right.

The Superfund cleanup stopped the mine waste from continuing to enter the river. Now the three bluff pools still change as the mine waste already in the channel moves in floods, but have mostly gotten somewhat deeper. That fourth pool had the waste dump behind the right bank was partially removed and then covered in stone, and big rock rip rap was put in place along that right bank to keep the river from eating away the bank and uncovering what remained of the mine waste. Now that pool is quite a bit deeper as the rip rap causes turbulence in high water that helps scour out the bottom of the pool; it's now far better habitat for bass than it was before.

5. It was one of the deepest pools on the whole upper river, up to 10 feet deep even with occasional fill-ins with mine waste and gravel. It stayed deep because the left bank was rocky and bluffy, the right bank was lined with big sycamores, and the channel was narrow. Current in high water was fast through that narrow pool, with rocks and sycamore roots causing enough turbulence to keep it scoured out. It was 4-6 feet deep even along the right bank.

The landowner on river right decided to clear ALL those big sycamores and re-shape the bank so that it was more sloping. I think he had visions of selling riverfront lots or something. Without the sycamores to hold the bank in place, it began eroding.

Now the pool is a good 1/3rd wider than it was before, and while the rocks on river left keep high water turbulent enough to scour out holes around them, most of the pool is now less than a foot deep. There is bare gravel showing above normal water levels where the deepest part of the pool used to be.

6. My absolute favorite pool as a kid was not a bluff pool, it was a long, narrow pool, deep water on both sides. Huge sycamores lined the river left bank all the way down it, and there was a sloping, low hillside on the right covered in forest. The riffle at the top angled into the left bank, and the water on that bank stayed 6-8 feet deep for the whole upper half of the pool. Then the current shifted to the swing along the right bank, the left bank shallowed to 3 feet or so, with the right bank becoming 5-7 feet deep all the way to the bottom of the pool, where a tributary came in on river right and piled up a gravel bar to form the riffle.

The landowner decided to use the bottom field behind those big sycamores to dig out topsoil to sell. He removed some of the big trees, and removed 2-4 feet of topsoil off the whole bottom. The river did the rest, removing the rest of the sycamores and lowering that whole bank, widening the pool in the process.

Now the left bank is more or less a gravel bar covered in young willow trees, with the water along it no more than 3 feet deep and mostly shallower than that. The only deeper water left in the pool is along the right bank at the lower end, where there is about 50 feet of bank with water 5-6 feet deep along it.

I could go on. Suffice it to say that the vast majority of the pools, and ALL of them that have intact vegetation along the banks and immediately upstream, are little changed from what they were 50 years ago. They shallow a bit some years, deepen a bit other years. Riffle areas change from year to year, especially if they have big gravel bars along them or immediately upstream, or if they have disturbed banks.

Point is, I don't think that wholesale changes in these rivers should happen on a yearly or even a 10 or 20 year scale. It's only when humans do something stupid to the banks or channel that the big changes become more common and happen more quickly.

[Guest]

After fishing the same stretch of creek for years, at least the floods bring a new look. It's like I'm fishing a different stretch of the same creek.

[Riverwhy]

I floated and camped Tuesday night on the North Fork. While cooking dinner we heard load splashes up stream and witnessed repeated portions of the dirt bank caving into the stream. One huge cave in actually made a very large wake that traveled across the river. The water below the cave in went from murky to chocolate brown for hours after the event. Smaller cave ins continued into the night. Not much left of the cattle fence by the time it was over.

[Brian Jones]

A friend of mine who has fished the middle and lower Meramec since the mid 80's theorizes that not only is the river filling in but that the water table has actually dropped. He has shown me places where concrete steps that use to be at water level are now 18 to 24 inches from the water; even in wet years. Could it be that we are pulling more water out of the river and it's watershed through more wells being drilled and people living and developing the watershed and that is having an effect on the river getting shallower??

[Greasy B]

https://en.wikipedia.org/wiki/Degradation_%28geology%29

[Al Agnew]

A friend of mine who has fished the middle and lower Meramec since the mid 80's theorizes that not only is the river filling in but that the water table has actually dropped. He has shown me places where concrete steps that use to be at water level are now 18 to 24 inches from the water; even in wet years. Could it be that we are pulling more water out of the river and it's watershed through more wells being drilled and people living and developing the watershed and that is having an effect on the river getting shallower??

Lots of things could cause a lowering of normal water level in a specific pool, which is what would make those steps higher above the water. I don't think a lowering of the water table would cause it, other than that it would make the springs flow less and some dry up, which would lower the base flow of the river. In this part of the Ozarks, there has been a rain deficit for a good 15 years...some years have been wet, but a lot of years have been drier than historic normals, and that may be causing such a lowering of the water table, along with more water being pumped out of the ground. But I think the steps thing is more of change in the physical shape of the channel. If a pool is wider from bank to bank than it has been in the past, and the riffle below it is also wider, this would result in a lowering of the pool level by a few inches. If the riffle gets scoured out deeper, it would lower the level of the pool above.

There's no doubt that the Meramec has changed quite a bit since I first started fishing it in the 1970s. There has been a lot of bank erosion and widening of the channel in many places.