Posted on 10/18/2018 7:15:41 AM PDT by janetjanet998
Background: Over the past 3 days widespread rains of 6-10 have fallen on the Colorado river watershed above Austin. You may have seen amazing video of the Llano River wiping out homes and bridges. The llano river hit its highest level since 1935 with 300,000 cfs of water flowing into the CO River above Lake Travis at one point, This combined with other runoff caused Lake Travis to rise over 30 feet in 2 days!!
The current level at Lake Travis is over 701 feet with many homes flooded already...5th highest of all time
Llona river has receded with only 15,000 CFs now. Above the mouth of the LLona river is lake Manfield which was holding back water until after the rivers feeding in Lake Travis recede
They opened a record 8 floodgates on that Dam and 60,000 cfs is now flowing out,,this combined with other runoff means 90,000 cfs is still flowing into Lake Travis
Lake Travis now has 4 floodgates opened with outflow of 28,000 cfs. The record number is 6 gates in 1957. They are planning to open up to another 4 gates today which will cause flooding problems downstream for a record of 8 gates opened!!
with 90,000 inflow in and only 28,000 out Lake Travis is still rising about a foot every 6 hours 701.43 right now with a rise of about a foot every 6 hours
LCRA has been behind the curve.. first saying Lake travis will peak 690-695 then 695-700
now 705 to 710ft which will be around the record of just over 710 feet
The top of the spillway over on the Dam at lake Travis is about 714 feet,
Forecast is More heavy rains for the next week
NWS DISCUSSION
WITH THE SATURATED SOILS ACROSS PARTS OF SOUTH CENTRAL TEXAS AND THE CONTINUED WET FORECAST THIS REMAINS A DANGEROUS SITUATION AS RAINFALL FROM THE LAST FEW DAYS CONTINUES TO WORK ITS WAY THROUGH AREA RIVERS. THE LOWER COLORADO RIVER AUTHORITY ANNOUNCED THAT BY MID-DAY THURSDAY UP TO 8 FLOOD GATES AT MANSFIELD DAM COULD BE OPENED (4 ARE CURRENTLY RELEASING ABOUT 25,000 CFS DOWN THE COLORADO) TO MOVE SOME OF THE WATER FROM LAKE TRAVIS DOWN THE COLORADO. LAKE TRAVIS, AS OF 3AM IS AT JUST OVER 700 FEET MSL, THE 6TH HIGHEST THE LAKE HAS EVER BEEN (VISIT THE NWS AHPS PAGE AND SEARCH FOR MSDT2 TO VIEW THE OTHER PAST CRESTS). THE DEVILS RIVER IN VAL VERDE COUNTY, THE NUECES RIVER IN DIMMIT COUNTY, AND THE FRIO RIVER IN FRIO COUNTY ALL CONTINUE TO BE IN FLOOD THIS MORNING AS WELL.
WE URGE RESIDENTS AND VISITORS TO SOUTH CENTRAL TEXAS TO MONITOR CLOSELY THE WEATHER CONDITIONS FOR THE NEXT SEVERAL DAYS AS ANY RAINFALL AMOUNTS COULD LEAD TO ADDITIONAL FLASH FLOODING OR RIVER FLOODING. ALSO, THOSE ALONG THE COLORADO RIVER SHOULD MONITOR INFORMATION COMING FROM THE LOWER COLORADO RIVER AUTHORITY CONCERNING RELEASES FROM AREA LAKES AND TAKE NEEDED ACTIONS TO PROTECT LIVES AND PROPERTY ALONG THE COLORADO.
updated info https://floodstatus.lcra.org/#llevels
10pm lake now at 703 ft
although no PR’s about it,.... outflows from lake Buchanan are decreasing down to 49K from 54K. this combined with the lack of new heavy rainfall rainfall have allowed inflow from the dams to lake Travis to fall to 57K from 67K earlier in the day
This is slowing the rise of the lake the past few hours slightly ..with outlaw still study around 26K
but still a a pace of a foot every 9 hours. therefore the lake should be around 704 ft or so at 7am
light to moderate rain has dumped about a quarter inch of rain so far over the western portion of the basin this evening
although short term models are not showing it..the NWS still expects heavy rain to increase over night into Friday
a wildcard is also how much rain falls downstream in the skinny (width wise ) basin blow Austin.. heavy rain would cause more inflow on the lower Clorado river complicating any change in releases from Travis
update on buchanan. they closed two of the gates
Oct 18 2018 10:11PM At Buchanan Dam, inflows are being passed with six floodgates open.
COLORADO?
I guess it’s NOT the one thru the Grand Canyon
sounds like something native Moabite (UT) would say
update 6:45am.
lake level 703.77
they closed another gate on Buchanan ....so far the heavy rain hasn’t developed this has allowed flows to decrease ..flows into Buchanan about 30K outflows 33K
Travis inflows 42,000 or so outflows 25,000 for a net positive of about 17K
a slug of heavier rain moving in and may afferct the lower basin this morning
Lake level forecast: Lake Travis is expected to rise to 705 to 710 feet msl by Saturday, Oct. 20. Weather forecasts call for additional rain over the next several days that could cause a significant increase in storm runoff, which may result in the need to open up to four additional floodgates in the coming days.
And FEMA is no help:
https://m.facebook.com/story.php?story_fbid=10160901546795655&id=508930654
What a mess....
good news:
current radar and latest models indicate the heaviest rains will fall just East of the lake today. Indeed, up to an inch has fallen just SE of the lake the past few hours and another inch or two possible
Lake Buchanan closed another gate.. now 3 open outflows down to 28,000...this should help offset any increase in inflows form rain over and near the lake
even though the lake itself may get heavy rain today it is only a small part of the larger watershed..if trends contunie, much of the watershed will once again miss the heavy rain this round
That would be 2 days of underachieving rainfall
not sure if they need ot open more gates now with the lack of basin rainfall plus the extra runoff flowing tino areas downstream
Oct 19 2018 7:53AM At Buchanan Dam, inflows are being passed with three floodgates open.
The lack of heavy rainfall has lead to a lower lake forecast....
lake just hit 704 but in only rising at a rate of an inch every 2 hours or so
Lake level forecast: Lake Travis is expected to rise within a range of 704 to 706 feet msl today and Saturday, Oct. 19 - 20. This projection could change with additional rainfall.
moderate rain falling in parts of the basin looks like 1/4 to 1/2 inch over the lower basin since midnight...
now only two gates opened on Buchanan with outflows down to 16K inflows still 27K so Buchanan should slowly rise again
Lake Travis 704.15 still slowly rising
I Suspect the plan is to let Buchanan rise as inflows increase from rains today then open more gates again this weekend with drier weather as runoff inflows decrease
the net result may be steady inflow into travis 35-40cfs starting this afternoon with 26K outflow into Sunday
so a slowly rising lake over the next couple of days
then the next problem next Tuesday and weds with more heavy rain
after that looks like a huge pattern change with much drier weather
Come on down
The long term outlook forth winter over Texas is WET..so this may be a long battle bur for now things have stabilized it seems........
LCRA urges caution, readiness as rains predicted into next week
Though levels throughout the Highland Lakes chain are not rising rapidly like they were midweek, impending rains over the weekend coupled with another rain event predicted for Monday mean the levels are far from stabilized for the long run.
“We’re in a pretty good place, but we’re anxiously watching the rainfall that might come because the watershed is already very saturated, particularly upstream of Lake Travis,” Hoffman said. “If we get meaningful amounts of heavy rainfall up there, it could cause pretty instantaneous flooding.”
Today the lakes have seen about a half inch to an inch of rainfall, which is not meaningful in terms of flooding, Hoffman said, emphasizing that that could change depending on coming rains.
eally that’s kind of where I see us being for the immediate, foreseeable future until the weather comes in and changes that,” he said, adding that Lake Travis levels should remain at between 704 and 706 feet for now.
Hoffman also pointed out that once the rains let up for a longer period, it will still take weeks for Lake Travis to draw back down.
“But if nature brings more water into the picture then it changes the whole scenario,” he said.
RE:Buchanan Dam’s repairs. They’ve been “repairing” for longer than it took to built the thing. That’s the dirty secret. They can’t allow it to fill to capacity or it might break.
hi
well it looks look Lake travis may have peaked. its having a hard time getting over 804.3 feet the closing of the two gates at Buchanan today helped but Buchanan is rising again since 26K is till going in and only 16K out
now back up to 1018.4 feet (it was down below 1018 after maxing out at 1091.2
being local, could you explain more about buchanan lake issues..I found this article about FEMA not allowing it to over 2018 feet
https://www.kxan.com/news/lake-buchanan-staying-below-full-despite-flooding/1049735880
Thanks
PS this may go off and on all winter if long term forecast are correct
7am update
Lake Travis 704.36 only up 1/10 of a foot since last evening. with the closing of another gate at Buchanan I suepect it may start slowly falling later today
Lake Buchanan up to 1018.87, inflows slowing to around 23Kcfs..they just closed another gate
6:15AM At Buchanan Dam, inflows are being passed through hydroelectric generation and one floodgates that is fully open.
Outlook: a dry weekend and the trend is for the heavy rain to fall just south of the basin next week now...good news but that could change..then a drier pattern
but the system is full and has no more flood capacity. and even if they open 8 gates later after another heavy rain event, that’s only 55K outflow or so
example: Lets assume no rain the next 2 weeks...well the lake will have to fall an average of 1.3 feet a day(even including today) to get around 690 feet
bottom line: the system will be very susceptible to more problems for a long time
it appears lake Travis has crested at 704.39 feet and is now falling at a decent clip the past 30 minutes as the lower outflows form the buchanan gate closing move in..
...the new models continue the trend of the heavy rainfall falling just south of the basin next week
after that a much more dry overall pattern for Texas
the next 10 days or more
As Luck had it...the first two heavy rain events (post deluge) missed the basin and the same may be true next week too
alot can change the next few days though but it looks like Basin average rainfall may be only an inch or so (more south/ less northwest) next week and almost zero the week after that..those amounts will just slow the fall rather the incerease lake levels
Hopefully the lake can drop to around 680-685 feet by the end of the month before the projected wet pattern sets in later this year.. The lake was at 666 Ft before the deluge
LCRA about 8-12 hours behind live “real time” like usual about the lake level
models have increased rainfall amounts some now 1-2 inches across the basin
but then a long dry period..but sign of an active pattern again in early November...
Mansfield Dam / Lake Travis
LCRA:
Lake Travis reached a peak level of 704.39 on Saturday, October 20. Based on current conditions, LCRA now projects that Lake Travis will slowly fall in a range of 704 to 702 feet above mean sea level today and Monday. Those projections could change if additional rain falls in the lower Colorado River basin.
As someone very dear to me used to say before her untimely death, “It’s either too much or too NONE.”
models have increased precipitation amounts both upstream and downstream of travis with a tropical system moisture starting Tuesday into weds
they may have to close some gates on travis ..the lake is at 703.65 now and slowly falling...I think the lake will still be about 701.25 the the rain starts Tuesday afternoon and Buchanan 1018.35 or so
in the past 12 hours Buchanan has fallen .22 feet, Travis .34 feet
LCRA:
Mansfield Dam / Lake Travis
Lake Travis reached a peak level of 704.39 on Saturday, October 20. Based on current conditions, LCRA now projects that Lake Travis will slowly fall in a range of 704 to 702 feet above mean sea level today and Monday. Those projections could change if additional rain falls in the lower Colorado River basin.
There are currently four floodgates open at Mansfield Dam, which forms Lake Travis. LCRA is making controlled releases from the flood pool of Lake Travis to manage river levels downstream of Mansfield Dam. Weather forecasts call for additional rain over the next several days, which could cause a significant increase in storm runoff, which may result in the need to open or close floodgates in the coming days.
Additional rainfall could cause LCRA to need to open up to four additional floodgates at Mansfield Dam to move floodwaters downstream. If that happens, we will alert the public and local officials immediately. Anyone downstream of Mansfield Dam should remain prepared for the potential that additional floodgates may be needed. Please check this page frequently for updates.
Buchanan Dam / Lake Buchanan
One floodgate is open at Buchanan Dam. Flood releases from Lake Buchanan have been reduced as inflows to Lake Buchanan have declined. Based on current conditions, LCRA projects that floodgate operations at Buchanan Dam will continue today and tomorrow, Oct. 21 and 22, to gradually lower Lake Buchanan to near 1,018 feet msl. Forecasts for Lake Buchanan and gate operations at Buchanan Dam may change with additional rainfall.
new NAM model is very concerning dumps 2-3 inches in the basin and 3-5 just downstream with a faster arrival time too
its the first of the models in this evening
so we will have to wait a few hours for the others
lake travis still at 703.08 feet Buchanan still 1018.48. both falling at a are of 3/4 of a foot per day one gate open on Buchanan and 4 on Travis still
2-3 inches of rain expected ......
Mansfield Dam / Lake Travis
Lake Travis reached a peak level of 704.39 on Saturday, October 20. Based on current conditions, LCRA projects that Lake Travis will fall in a range of 703 to 701 feet above mean sea level today and Tuesday. Those projections could change if additional rain falls in the lower Colorado River basin.
There are currently four floodgates open at Mansfield Dam, which forms Lake Travis. LCRA is making controlled releases from the flood pool of Lake Travis to manage river levels downstream of Mansfield Dam. Weather forecasts call for additional rain over the next several days, which could cause a significant increase in storm runoff, which may result in the need to open or close floodgates in the coming days.
Additional rainfall could cause LCRA to need to open up to four additional floodgates at Mansfield Dam to move floodwaters downstream. If that happens, we will alert the public and local officials immediately. Anyone downstream of Mansfield Dam should remain prepared for the potential that additional floodgates may be needed. Please check this page frequently for updates.
Buchanan Dam / Lake Buchanan
One floodgate is open at Buchanan Dam. Flood releases from Lake Buchanan have been reduced as inflows to Lake Buchanan have declined. Based on current conditions, LCRA projects that floodgate operations at Buchanan Dam will continue today and tomorrow, Oct. 22 and 23, to gradually lower Lake Buchanan to near 1,018 feet msl. Forecasts for Lake Buchanan and gate operations at Buchanan Dam may change with additional rainfall.
HYDROLOGY
RIVER RISES ARE LIKELY ACROSS MUCH THE REGION, ESPECIALLY TUESDAY
THROUGH THURSDAY AS WIDESPREAD RAINFALL AND RESULTING RUNOFF CAN BE
EXPECTED. THROUGH WEDNESDAY, ALMOST ALL AREAS CAN EXPECT AT LEAST 1
INCH OF RAIN, WITH MOST AREAS IN STORE FOR 2 TO 3 INCHES OF RAIN. IN
ADDITION, SOME ISOLATED AMOUNTS NEAR 4 INCHES ARE POSSIBLE. RENEWED
RIVER FLOODING CONTINUES TO BE OUR MAIN CONCERN, ESPECIALLY ALONG
THE RIO GRANDE, NUECES, FRIO, LLANO, GUADALUPE, PEDERNALES AND
COLORADO RIVERS.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.