I think the gauge at little York and hwy 6 on Langham Creek has quit recording rainfall. I live about a mile away, and it has shown no rainfall for the last 3 hours since the water level peaked. It hasn't been raining hard, but it has been raining steady for those 3 hours. Wonder what the actual total is? Probably 16-17"..

WHY ARE YOU YELLING??!!!

https://imgur.com/a/2gzBj

Jones Rd between Louetta and Cypresswood Dr. Creek is over banks and road at all crossings.

Blows my mind that all those morons still buy homes around the bayous. Might as well just call it a flood plain. This happens ALL THE TIME. Why do these people never learn?

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Blows my mind that all those morons still buy homes around the bayous. Might as well just call it a flood plain. This happens ALL THE TIME. Why do these people never learn?

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Quick question. What do you consider "around" a bayou or creek / drainage?

What percentage of homes do you think that might be in a city built on a swamp?

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Thttps://imgur.com/a/2gzBj

Jones Rd between Louetta and Cypresswood Dr. Creek is over banks and road at all crossings.

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That is near my office, hope we didn't flood.

So my nearest official rain gauge is about 20 miles, and shows 17.6" in 24 hours.

My own hot tub was bone dry yesterday, and i just measured it now at 24"

Almost twice as much water as allison.

Cows are out.

San Felipe supposed to hit 124 ft. 3 ft higher than the historic levels.

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Cows are out.

San Felipe supposed to hit 124 ft. 3 ft higher than the historic levels.

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Brazos River at Hwy 21 (between Bryan and Caldwell) rose 10+ feet between 0800 and 1230!

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Quick question. What do you consider "around" a bayou or creek / drainage?

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Are you watching the news? Well, when you hear about the folks just getting back into their homes from the last flood and getting flooded out again, that's probably a sign.

In extreme rain events, the flood plain is not the only factor. You can get lamellar flow over high but level ground towards any lower ground simply due to the volume of water.

NOAA released 24 hour rain totals

http://forecast.weather.gov/product.php?site=NWS&issuedby=HGX&product=PNS&format=CI&version=1

Colorado River in La Grange and in Columbus rose 23 feet since 2 AM this morning.

Nobody said anything about eliminating certain areas. And I couldn't care less if people want to live in lower-lying areas that are next to creeks/bayous with really poor drainage. Just saying that you would think these folks were learn their lesson after multiple floods or close calls.

But this is pretty awesome

Guys unloading john boats into Allen's Creek to go fishing. Idiots. The thing was rising over 1ft/hr and back flowing.

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Why is everyone surprised with all the record flooding?

Development comes deforestation and more concrete which mean more runoff.

Same out here in Wimberly area. People keep moving out here and build build buuld.

There has been rain this hard and as much before and no record flooding.

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Why don't you tear down your home and leave wimberley? That will fix it. That new heb didn't put in a detention pond where there used to be none on the old Bowen campus? Building a home on a rocky hill and deforesting some cedar trees causes the flooding problem in wimberley from a huge rain event out towards blanco? Ok, I get it now.

As said before. Development raises the amount of water and force in a stream or river.

Wimberly is not a small town anymore. Development everywhere. More and more concrete.

Yes there have been record rains but development has a major part.

We are using drones at work to fly the drainage areas behind houses in Houston. There are 60 plus percent of the drainage area that are clogged and have not been cleaned in over 40 years. Causing flooding and insurance problems.

Mostly trash and limbs.

http://pubs.usgs.gov/fs/fs07603/

Go ahead and show me the time we got 15 inches of rain in 9 hours out in Katy in the past and it didn't cause massive flooding. You can't, because it hasn't happened. That much rain in that little time on a flat prairie is always going to cause massive flooding, regardless of how much development is occurring. I agree, development without good drainage engineering makes it worse, but 15" in 9 hours is going to cause massive flooding no matter what the developers have done.

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As said before. Development raises the amount of water and force in a stream or river.

Wimberly is not a small town anymore. Development everywhere. More and more concrete.

Yes there have been record rains but development has a major part.

We are using drones at work to fly the drainage areas behind houses in Houston. There are 60 plus percent of the drainage area that are clogged and have not been cleaned in over 40 years. Causing flooding and insurance problems.

Mostly trash and limbs.

http://pubs.usgs.gov/fs/fs07603/

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My last post was harsh. Don't tear your house down. Trust me, I know wimberley is growing, but that is not the cause of creek flooding. It floods cause it rains a lot. wimberley city limits MAY be approaching 5-8 percent impervious cover, but what is the impervious cover of lone man creek, cypress creek, or blanco river whatersheds? No way they are over 3-5. I will still maintain that there would be more runoff off the hills in photos I have from the 50's of a nearly undeveloped wimberley valley full of overgrazed rocky goat farms than there is now.
We are talking about enormous drainage areas that just aren't that influenced by small patches of development. That's not to say wood creek north finally being built out isn't going to cause some upticks on tiny tributaries, but people have always been flooded in Wimberley, it's not a new thing caused by development.

My family has farmed and ranched the same land on the Brazos for over 100 years. My Great Uncle turned 90 last week and his experiences with the recent floods are roughly the same as they were when he was a kid in terms of the stages of flood. It happens a little faster with Richmond being a choke point.

The biggest difference he will tell you is the gawkers are numerous, coming to get a Facebook update photo of the water, while you're holding back tears from losing cattle moments before.

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My family has farmed and ranched the same land on the Brazos for over 100 years. My Great Uncle turned 90 last week and his experiences with the recent floods are roughly the same as they were when he was a kid in terms of the stages of flood. It happens a little faster with Richmond being a choke point.

The biggest difference he will tell you is the gawkers are numerous, coming to get a Facebook update photo of the water, while you're holding back tears from losing cattle moments before.

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Man that is so true. We and our few neighbors are busting ass, big time, trying to save animals and property and help each other out and a bunch freaking yuppies from katy are parked blocking our road and driveways to take selfies on the river. Right over a bank thats going to cave in and possibly kill them.

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My family has farmed and ranched the same land on the Brazos for over 100 years. My Great Uncle turned 90 last week and his experiences with the recent floods are roughly the same as they were when he was a kid in terms of the stages of flood

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My count of dams on the Brazos is 11. I suspect none were built when he was a kid. On a related note, three of the reservoirs are currently releasing water:

Limestone 7,000 cfs
Possum Kingdom 18,800 cfs
Granbury 45,300 cfs

My rough math is that each 1000 cfs is a little less than a half million gallons of water a minute.

All three together, 71,100 cubic feet a second. A standard NCAA football field is 160 feet by 360 feet from sideline to sideline and including end zones. So enough water every second to cover a football field 15 inches deep. Seventy four feet deep in a minute.

Or spread it out only a foot deep, it covers 141,024 acres a day. 220 Square miles, or a square a little less than 15 miles on a side.

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Man that is so true. We and our few neighbors are busting ass, big time, trying to save animals and property and help each other out and a bunch freaking yuppies from katy are parked blocking our road and driveways to take selfies on the river. Right over a bank thats going to cave in and possibly kill them.

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I'm thinking this would be an appropriate occasion to call the Sheriff's Department to remove said gawkers for their safety.

If you know someone in simonton or wallis you need to get them out of bed. People are watching the hempstead noaa site showing 49 feet on friday. Thats wrong. Its already at 46 RIGHT NOW just west of simonton and rising fast. If it does hit 49 tonight there may be valley lodge homes flooding before they even activate the pumps or expect any problems. All this first peak is from rain south of the hempstead gauge they are watching. If the predictions are wrong and it goes over 50 then it will be a real bad night.

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16+ inches north of Katy in past 12 hours. The 100-year event in the Houston region is a little less than 13 inches in 24 hours.

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Not exactly sure what the "100 year event in the Houston region" was and maybe I'm comparing apples to grapes here, but Alvin had 43 inches in 24 hours in 1979.

Alvin, TX 1979 Rain event

We got as many cattle out as we could all day right there on FM 1458 on Monday. I pray for those folks every waking hour.

Mills Creek was running with the same volume as the Brazos river. San Felipe is rising fast too.

Another interesting stat from yesterday's event:

Averaged 24 hour precipitation across Harris County was 7.75 inches, or approximately 240 billion gallons of water, enough to run Niagara Falls for 88 hours.

Seems like this thread is as good a place as any to post this. Back when I was a CE major I interned for several summers for a firm that specialized in stormwater management. This was back when FEMA was beginning their updates on the Houston area flood maps and the first was Brays Bayou. That study was the first to integrate the use of LIDAR data for elevation mapping. The firm I was working for did the majority of the work and all of the flood mapping.

There are two principal pieces of software used; both created and supported the the USACoE. One determines the volume and timing of water that will pass a given location within the watershed following a given rainfall event. The second takes those volumes and determines the depth that volume will reach as it passes that reach along the stream.

For those that might be curious... It's a good deal of reading, but here are the NOAA papers for rainfall duration, intensity, and probably frequency that are used by the smart people to model 100yr floods.

Hydro-35 5 to 60 Min Precip Freq for Eastern & Central US

Tech Paper 40 -- Rainfall Freq Atlas for Duration of 30min-24hrs for 1-100yr events

Tech Paper 49 -- Rainfall Intensity 2-10Day for Return Periods of 2 to 100 Years

These contain the graphs for hypothetical returns that generate a given flood event. I believe most modeling is done from the 24 hr events. The thing is there are actually 5 min 100yr rains, 10 min 100 yr rains, 30 min, 60 min, 2 hr, 12 hr, all the way out to 10 days. Obviously the shorter duration are higher intensity. Each of these however (for a "100 Year flood') has a 1.0% chance of occurring in any given year. Same goes for the 500 year event, it's a 0.2% chance in any given year event. Furthermore, it's for that given area.

It just kinda grinds on me when I hear folks say, "this is the second 500 year flood in X years." Well that's not entirely true. Take TS Allison for example. Allison dumped most of its rain inside Beltway8 on the west side between there an downtown. The vast majority of that was inside Loop 610. Yesterday's rain was more focused outside Beltway 8 towards Katy, Hockley, Tomball, and around to the Woodlands. So I'd argue that, No, you have not had 2 500 year floods in X years. Two different areas have each seen 1 500 Year (0.2% chance) floods.

Can someone remind me where the Memorial Day floods in Houston were the worst?

I realize there has been widespread localized flooding and a lot of street flooding. Most streets are designed to handle a 2 year (50% chance) rainfall event. Neighborhood and individual business retention/detention ponds are designed to hold back 100 yr events to slow their release into the watershed at pre-development rates. Once the 100 Yr design capacity is reached the excess spills unchecked over a weir into the bayou or creek. Back-flow preventers should keep creeks from backing up into neighborhoods where they are installed and functioning properly.

Memorial Day rain hit heaviest around the Meyerland/Westbury/Missouri City area. That's why the homes along Braes Bayou flooded so badly then.

Braes Bayou got hit big time again this time at Meyerland, but that was more downstream flooding then localized rain flooding.