Talk Of Auxiliary Gates Is Bogus!

[Phil Lilley]

Wish I could post this on both Table Rock and Taneycomo forum but... this will have to do.

KY3 even got this wrong.

Table Rock Dam's flood gates can open up to 30 feet. I believe but may be wrong but they have them open 5 or 7 feet right now. I'll find out tomorrow. So the 10 gates can move that much more water WITHOUT opening the auxiliary gates.

Would they open the auxiliary gates BEFORE opening all 10 gate wide open? NO! Why would they destroy the hatchery and highway needlessly when they still have room to move water through the 10 gates?

KY3 reported that IF Table Rock had risen to 938, they would have opened the auxiliary gates. Maybe so... but to rise 2.58 more feet (over 935.42 feet where it crested), it would mean they had NOT opened the 10 gates enough and allowed the lake to rise to that level.

The ONLY way that would happen is if someone highjacked the control room, force the lake to rise to 938 and then opened the auxiliary gates, just to see if they worked.

The auxiliary gates were ONLY built to protect the earthen dam at Table Rock IF Beaver Dam failed - in my opinion. And I think that's a good reason.

[Iliketoflyfish]

Nobody wants to see that happen. Ever! The system is impressive without the "500 year gates", but if those were to be opened it would be catastrophic for those downstream.

[Brian K. Shaffer]

My knowledge on this subject.. from my 1995 records.. they wouldn't open the auxiliary gates unless the lake reached 949.

Which means.. the dam itself would already be ready to be compromised.

This is a link to the 1995 proposal (updated 2010?).. where at that time the price was negotiated from 55mil to 75mil when it was all said and done : http://www.swl.usace.army.mil/projmgt/trspillway.html

( be sure to back click or might click out of OzarkAnglers, but read it and get a kick out of the outdated logic and info )

If I remember right, the 10 TR gates are capable of dishing out 650,000cfs after being fully opened.

I do wonder sometimes why they call it " flood control " in situations like this.

Those 100yr, 500yr, 1,000yr flood instances are just propaganda. The aux spill is there if Beaver ever lost its grip.. totally and completely, and we (TR Lake and TR Dam) would have to hold an alarming amount of water in a very short time. That's the explanation I got 7 years ago.

Some think this is false info.. you be the judge.

Brian

[Born to Fish]

The Corps has a lake operation manual that documents how they are to operate Table Rock Dam. However, I'm not sure they ever anticipated lake levels this high since up till 2008, the previous lake record was 932.5 in 1961. The Corps web site, referenced above, just says the auxillary gates would only be used when the lake level exceeds 937. These gates are only intended to be used to save the dam from catostrophic failure, such as what a breach of the dam at Beaver could cause or some other near overtopping of the Table Rock Dam or failure of one of the flood gates. This record level also puts the dam under "record" pressure that it has not experienced before. Once the flood pool fills up at a Corps lake, the Corps is then out of the "flood control" business and it is up to Mother Nature (and God).

[Phil Lilley]

Good posts. I agree with you BtF.

[Wayne SW/MO]

I don't see Beaver influencing TR dam. Are there examples in other areas where downstream dams are modified to hold back upstream failures? I would think the more important aim would be to prevent topping of TR and washing out the downstream side. There's a lot of real estate and lives that could be at risk if TR failed.

[Born to Fish]

The Corps has never had a dam failure (nock on wood!!). However, if an upstream dam does fail it would potentially cause the downstream dam to fail too because of likely overtopping of the dam and embankment. There just wouldn't be enough storage left in the downstream lake to "catch" the upstream lake. Kind of the domino affect. It's better to use the emergency spillway and control the emergency release then to have the dam "break" and send a sudden wall of water gushing downstream. There would be relatively less property damage and you would have a little time to evacuate all the people downstream. The Corps does operate all the dams in a drainage, as a system.