Flood Control Lakes

[DoublePslayer]

With the gates closed down in Steel Bayou, I am wondering why the spillway is going in Grenada. I pass over the Yalobusha River everyday on I-55, and it has been bank to bank for several weeks now. I also cross the Tallahatchie on Hwy 8 near Minter City every day, and it is high too. That lead me to think that Enid, Sardis, and Arkabutla are going too. Correct me if I am wrong, but this water doesn't have anywhere to go once it hits those gate right. I tried to call the gate house at Grenada the other day to see what the lake level was at, but all i got was a busy signal.

[DanP]

Tallahatchie and Yalobusha are headwaters of Yazoo and do not go through the SB gates.

[DoublePslayer]

But it does go somewhere right. Doesn't that water end up causing floods between the Yazoo and the hills below Yazoo City?

[DanP]

My understanding is that water is a drop in the bucket compared to what is coming down the MS and does not influence flood height much in situations such as that are in now. I'm sure Novocaine or others can provide a better explanation

[DoublePslayer]

Maybe so. I remember years ago when the Tallahatchie and Yalabusha would flood they always seemed to have to spillways running because the lakes were full. Just trying to wrap my head around it. Thanks.

[RNAIL]

The corp lakes are usually drawn down this time every year to prepare for spring rains. Grab you spinning rods and head to the spillways for some awesome fishing.

[RNAIL]

The corp lakes are usually drawn down this time every year to prepare for spring rains. Grab you spinning rods and head to the spillways for some awesome fishing.

[novacaine]

Since i think the flood of 1991 when the Corp got caught with their pants down, a rule curve was set up for crop season and non crop season for the 4 flood control lakes. Since that time, if stage is above the rule curve, they are required by law to draw down levels. When you hear that it takes an act of congress to change the stages on the 4 flood control lakes, that is actually true. Fishermen always complain about summer lake levels on the lakes
but it is flood control first, recreation second.
The rule curve is on the web. I will check it and post if i can find it.
I cant reduce the file and load it so here is how to get to it.

go to rivergages.com
vicksburg district
vicksburg flood control lakes
yalobusha river at grenada lake
bottom left corner...........guide curve

The stage is above the curve therefore water is being discharged until it gets down to the curve value

[DoublePslayer]

But do they not take into account what is happening downstream from the levees? I grew up between the Tallahatchie and Yalabusha rivers, and we almost lost the house during the '91 flood, so i understand the need to get the lake levels down during the winter to catch spring rain. I also agree %100 with that practice, but my father in law has a camp in Delta National Forest that is going to have a foot or two of water in it, if not already. There are also some people around Satartia that are going to lose sleep over this as well. It just seems like with the Mississippi River as high as it is, that all the water coming out of Grenada, Enid, etc are just adding to the water that is piling up down there now. Does it not make sense to at least limit the water in the spillways until the big river starts down?

[novacaine]

But do they not take into account what is happening downstream from the levees? I grew up between the Tallahatchie and Yalabusha rivers, and we almost lost the house during the '91 flood, so i understand the need to get the lake levels down during the winter to catch spring rain. I also agree %100 with that practice, but my father in law has a camp in Delta National Forest that is going to have a foot or two of water in it, if not already. There are also some people around Satartia that are going to lose sleep over this as well. It just seems like with the Mississippi River as high as it is, that all the water coming out of Grenada, Enid, etc are just adding to the water that is piling up down there now. Does it not make sense to at least limit the water in the spillways until the big river starts down?

91 was when the line was drawn in the sand..........since then its a new day.
The lower end of the delta is backwater controlled. The area between the levees on the Yazoo River up thru Satartia and ultimately up to Belzoni is backwater. For that matter, the lower end of the Satartia Levee (from Hwy up to bend at Dixie Farms and the other side from main Ms River levee to control structure are designed as overtopping levees. This ALMOST came into play during the GREAT FLOOD OF 2011.
Im sure the hydaulics branch (River controls people)at Vicksburg District does take into account what the rivers can handle from headwater during big events like we are going thru now but i doubt that they would ever shut down the discharge from the 4 flood control projects while the stage is above the guide curve.......Not sure they can actually.That would be a question for them but i bet you would get an "Off the record" verbal form some anonymous person.

[southdeltan]

I also agree %100 with that practice, but my father in law has a camp in Delta National Forest that is going to have a foot or two of water in it, if not already.

Our current camp on the Big Sunflower has been there for 40 years. We're across the river from "the Island" portion of the DNF. It's had water in it twice in the past 40 years - and that was our fault for not taking into account 2 things (and doing necessary maintenance): 1. (minor) increases in soil due to sedimentation and leaf litter decay and 2. (mainly) sinking of the building due to long periods of high water (posts not deep enough, softer soil due to water, wave action causing the camp to rock and sink into the softer soil). About 10 years ago we raised it a few feet (after replacing 75% of the joists and all of the floor boards). We had no water in the spring of 2014 and that was an extremely high year.

If he's got water in his camp now, he had water in it during March of last year. Based on your 1 or 2 feet possibility this year he had 3 to 5 feet of water in May of 2014. Over the past 25 years (if the camp has been there that long) he's had water in it 10 out of 25 years. It should be raised. If it's on a slab... I can't imagine why.

We raised ours ourselves using simple tools. If we had some money it'd have been even easier.

That being said, I'd like to raise ours another 2 or 3 feet. If it ever gets that high there'd likely be water to Anguilla.

[1010]

comparing the discharge of the four lakes and the MS river would be like a straw and a 4inch fire hose
They have very little effect at all on the river.
What gets the MS going is when large amounts of rain fall over the entire MS river basin. It's amazing how much land drains down the MS river.

Grenada is 2in of rain and Sardis is one inch of rain, in 24 hour period, the gates have to be closed or there will be local flooding.
It's broken down even more for heavy rain..

[Wingman]

It's amazing how much land drains down the MS river.

Four summers ago I stood looking at Yellowstone Falls, thinking about how that water from way up there goes right down the pipe to New Orleans.

[mlj300]

Tallahatchie and Yalobusha are headwaters of Yazoo and do not go through the SB gates.

^This^

Plus it is my understanding that when the MS river is cresting around Memphis and the north delta that the flood control reservoirs can release water ahead of the crest. Since the Yazoo makes confluence at Vicksburg. Then when the river is cresting down south the reservoirs hold water back. I dont make these decisions, they tell me to open the gates i say yes sir.

[DoublePslayer]

I also agree %100 with that practice, but my father in law has a camp in Delta National Forest that is going to have a foot or two of water in it, if not already.

Our current camp on the Big Sunflower has been there for 40 years. We're across the river from "the Island" portion of the DNF. It's had water in it twice in the past 40 years - and that was our fault for not taking into account 2 things (and doing necessary maintenance): 1. (minor) increases in soil due to sedimentation and leaf litter decay and 2. (mainly) sinking of the building due to long periods of high water (posts not deep enough, softer soil due to water, wave action causing the camp to rock and sink into the softer soil). About 10 years ago we raised it a few feet (after replacing 75% of the joists and all of the floor boards). We had no water in the spring of 2014 and that was an extremely high year.

If he's got water in his camp now, he had water in it during March of last year. Based on your 1 or 2 feet possibility this year he had 3 to 5 feet of water in May of 2014. Over the past 25 years (if the camp has been there that long) he's had water in it 10 out of 25 years. It should be raised. If it's on a slab... I can't imagine why.

We raised ours ourselves using simple tools. If we had some money it'd have been even easier.

That being said, I'd like to raise ours another 2 or 3 feet. If it ever gets that high there'd likely be water to Anguilla.

I gets water in it every time it gets remotely high down there. That being said, it has been there who know how long, and is not in the best shape anymore. If you tried to raise it now, it would probably fall apart. They have been talking about doing something different someday, but you know how that goes. I didn't know about the amount of rain that the reservoirs equal, but if that is the case, then is see what you mean about it not being enough to amount to anything.