Llano River flooding. (Austin, Mansfield, Barton Creek: to move, estimate, land)

[cBach]

Lake Travis is at 690 feet. Still rising with 4 flood gates open.

Lake Buchanan is now full at 1018 feet. It's been a long time since I've seen that.

LCRA just opened the first flood gate on Buchanan Dam.

[cBach]

I was driving around today, the Sometimes Islands are gone and Windy Point is almost gone now, covered by water.

[Trainwreck20]

Originally Posted by cBach

Lake Travis is at 690 feet. Still rising with 4 flood gates open.

Lake Buchanan is now full at 1018 feet. It's been a long time since I've seen that.

Buchanan has two 'full' targets - 1018 and 1020. They change back and forth at some point during the year, I am not sure when. It rarely gets to 1020 (even when that is the target), but it was at 1018 for at least part of last year and quite a bit of 2016, iirc.

Just looked at Hydromet, and Travis is 691 now....it is probably getting a net 90,000 cfs right now if you look at the difference between inflows and outflow through the gates.

The Llano and Pedernales are falling (cfs) relatively rapidly with no new rain. The Llano is decreasing at around 16,000 cfs per hour; interestingly, though, the San Saba got another 1/3" of rain over the last hour and it may fall more slowly (and through Buchanan). That is 'only' 30,000 cfs but it may continue at a larger-than-normal rate for a little longer if the rain keeps falling. Back-of-the-envelope calculations have the inflow/outflow still being greater than one for at least 10 hours. At a foot/hour, that would put the lake over 700; however, the basin surface area starts increasing notably as the lake rises and the inflows are decreasing, so I suppose they have they figured into their 695' level they are estimating. And they have a way better computer model to make that estimation, of course

Edit: The rain on the San Saba looks to be over for the moment. Minimal rain for Llano forecast tomorrow, but maybe another couple of inches from Thursday through Saturday.

[Ole Texan]

LCRA dropped the ball. Waited to long to open up gates on LBJ and Marble Falls. Lost the 2900 bridge and lots of flooding on LBJ that could have been avoided. Now lots of water in the system and just now opening Travis. As often happens LCRA a day late and $millions short.

[Trainwreck20]

Originally Posted by Ole Texan

LCRA dropped the ball. Waited to long to open up gates on LBJ and Marble Falls. Lost the 2900 bridge and lots of flooding on LBJ that could have been avoided. Now lots of water in the system and just now opening Travis. As often happens LCRA a day late and $millions short.

Ding ding ding! You win the prize as the first to say LCRA screwed up! No matter what they do, we all know what they really SHOULD have done .

[Ole Texan]

Ding, dong, based on the rain starting over a week ago, not much needed to take proactive action. The concentrated rain in the total run off basin was an easy early clue for action.
My hindsight is based on over 60 years of observing poor decision making by LCRA. Thanks for the prize. Always enjoy your nice post.

[Trainwreck20]

The 'rise starting a week ago' refers to what? The Llano river was <1,000 cfs two days ago and LBJ was below full at the start of the event and the gates were opened before the flood waters reached the lake (or the bridge). There is a maximum amount that they can lower the lake. And even if they broke protocol and dropped the lake another foot on a premonition, that would likely not have any effect on the bridge. Although I am sure the property damage on the lake would have people screaming at the LCRA and how they always do it wrong.

[Ole Texan]

Did you work for LCRA. Ok you got me. Llano at flood stage 10/09. 10/15-10/09 is not really a week.

[Trainwreck20]

696' and the rise looks to be slowed down to a couple of inches per hour. The Llano is almost back in its banks, but still getting some rain out there - 0.25" to 0.50" inch since midnight. The San Saba got some significant rain overnight (0.5" to 1.0") and the flow into Buchanan is picking up. It is over 50,000 cfs right now and increasing. If they are dumping 30,000 out of Travis now, it is going to keep creeping up for a while......

The latest from LCRA:

Lake Travis is expected to rise to 695 to 700 feet msl by mid-day Wednesday, October 17th and may continue to rise with additional rain.

[ashbeeigh]

Austin High let students leave 30 minutes early yesterday because they thought the lake might flood in their direction. I'm not sure if I should be laughing or applauding their somewhat over reactive response to the rain. AISD has a way of overreacting at times to weather. But I won't complain about it.