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Post by the illustrious potentate on Dec 19, 2019 9:48:39 GMT -6
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Post by greybeard on Dec 20, 2019 1:01:04 GMT -6
Will legally open 'the litigation floodgates' on several fronts regarding Harvey. 1. Opening the floodgates on Lake Conroe dam. 2. Opening the gates on Lake Houston dam...(small that they are) 3. opening the floodgates on Lake Livingston.
Both 1 & 2 resulted in extreme flooding during Harvey downstream and in areas that were residential and business before either lakes were built. Lake Conroe is on the West Fork San Jacinto River. East and West fork converge just above Lake Houston. When Lake Houston is at capacity, & Conroe's gates are opened, West Fork back flows into East Fork and that causes extreme flooding for me.
Before anyone wonders why people build in areas like mine and in what is now the flood zone below Addicks Dam in Houston, here's what the US Govt's NOAA and Weather.gov final report on Hurricane Harvey said. It's sombering to read in totality but here's the condensed part:
Dr. Sanja Perica, chief of the National Weather Service’s Hydrometeorological Design Studies Center, has noted that preliminary estimates for the area suggest that some locations likely received rainfall amounts that have a 0.1 (one in a thousand) percent chance of occurring in any year.
Analysis from other groups also came to similar conclusion. As noted by the Washington Post, in an analysis of the highest one-day rainfall amounts done by Shane Hubbard of the University of Wisconsin, such a large amount of rain falling over a one-day period has a 0.1% chance of occurring in any given year. Analysis of the five-day rainfall amounts by the company MetSat found that five-day rainfall totals on par with Harvey’s had a 0.004% to 0.0002% chance of occurring in any given year.
That puts Harvey in somewhere between a "once in one thousand to once in 20,000 year" flood range.
As the storm wore on and just hung around, NWS was simply overwhelmed and said this:
This event is unprecedented & all impacts are unknown & beyond anything ever experienced.
In some circles, scientists believe it was even worse.
Hurricane Harvey may have dumped an unprecedented level of water, one expected to be seen just once every 500,000 years, in some areas of Southeast Texas, according to a new report.
The 24-hour measures of rain falling during Hurricane Harvey were unprecedented and exceeded the rate predicted to occur once every 1,000 years, researchers found. And the flood levels seen in some isolated areas of Houston over a five-day period exceeded those predicted to occur twice in a million years, a new analysis found. In some parts of texas, more than 51 inches (130 centimeters) fell over the five-day period, the report found.
To get to those eye-popping statistics, scientists combined rainfall modeling data with a century of precipitation statistics compiled in a 1998 U.S. Geological Survey (USGS) report. The odds of certain flooding are based in part on those statistics and in part on flood plain maps that account for things like elevation.
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Post by ebenezer on Dec 20, 2019 8:33:31 GMT -6
Someone with COE was sloppy and did not do top of dam flood easements for upstream issues. I used to work with this type of thing and it was a common deal to get the easement and also to enforce the restrictions. Downstream is a lot different as breach analysis did not become such a big deal until after the Toccoa College and the big dam breach in the west occurred close to the same time. I also spent a lot of time on dam breach analysis after tat. Many would not want to know what it shows. The COE used to design with the PMP or a % PMP model (probably maximum precipitation). It was mostly around 39" here in SC and increased towards the coast. Something does not sound fully correct or complete in the info coming from the news sources.
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Post by greybeard on Dec 20, 2019 10:24:19 GMT -6
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