paden cash, post: 386623, member: 20 wrote: Anybody that has ever done any flood analysis knows that the nemesis to computer modeling is uneven rainfall amounts in localized areas. Trying to figure out wtf happened this last week in LA ( other than the fact a butt load of rain fell) will surely be one for the books. Before FEMA and flood mitigation we use to attempt to record or document local high water elevations after inundating floods, then the engineers would add a 'couple of feet' if some sort of base elevation was attempted to be determined.
Second guessing Mother Nature and her rivers is an exercise in futility.
ÛÏThe best laid schemes o' mice an' men
Gang aft a-gley.Û - Robert Burns
Why do you think the indigenous tribes of the SE and MS River flood way area were called the Moundbuilders?
From Cahokia,IL, Poverty Point, La, Moundville,Al, Emerald Mound,MS and etc etc. They always picked up
and moved to higher ground. Human Civilization was developed to combat flooding since the dawn of man. It's in the human DNA.
One of the oldest houses (later post office) here in a rural settlement was built atop a mound. It's still there about a few hundred yards off a small river.
That small river had the largest flood ever on record this past March.
Don't want to sound like an old timer but the weather sure has been odd this year. Intense. Storms and flora budding out of sync plus a heat wave.
The new normal?
Lee D, post: 386643, member: 7971 wrote: It also happened in about 1995; I was living in an apartment in Kenner, west of New Orleans. We had an overnight storm that dropped 14" in a couple of hours; I awoke to discover that I lived on a rather small island. The sun came out, the pump stations came on, and the water went back down, but the damage was done.
A few years before that I was living in Folsom and experienced TWO five-hundred years floods in a span of two weeks in the Bogue Falaya Watershed
But all those storms even going back to the big May flood in New Orleans in the late 70s when 20" of rain fell, occured in April or May when storm bands train in from the Gulf.
Robert Hill, post: 386652, member: 378 wrote: A few years before that I was living in Folsom and experienced TWO five-hundred years floods in a span of two weeks in the Bogue Falaya Watershed
I remember some pretty bad flooding in 1991, which was my first spring / summer in Louisiana as a resident. A guy I worked with had built a house in Ormond and got flooded; the other guys were giving him jazz about building a house in a cypress swamp.
They've extensively improved the levees and draining out there since then.
Lee D, post: 386653, member: 7971 wrote: I remember some pretty bad flooding in 1991, which was my first spring / summer in Louisiana as a resident. A guy I worked with had built a house in Ormond and got flooded; the other guys were giving him jazz about building a house in a cypress swamp.
They've extensively improved the levees and draining out there since then.
I think in 91, the annual
Rainfall in SE La was over 100"
I remember one lane on hwy 90 to Houma. Truckers losing control at night to avoid gators on the Hwy and ending up in the roadside ditches. It was pretty wild. I remember doing an emergency survey at the pump station at Ormond.
It started to list. I was working for GSE
Robert Hill, post: 386182, member: 378 wrote:
Still spinning around over Acafiana.
I hope [USER=553]@Lamon Miller[/USER] is doing ok. I know that he posted that he lives along a bayou.
I keep bringing up because I have never seen a weather system like this in all my years here. Rain totals in some areas are way over 20"s. You can see from my screenshots of yesterday and this morning that nothing has weakened.
Usually, we get rains like this in April/May when a system trains in from tha Gulf with a band of storms. Worst ever, I have been in lasted two days.
But this is a low pressure system that keeps spinning and remains stationary while being fed moisture from the Gulf.
Like a small tropical storm trying to form over land. Very odd.
All events are cancelled here this weekend or have been moved indoors.
I hope the folks west of us get a break from the rain.
I am also wondering about Dan McCabe....I though he was in a pretty low lying area.
Hope all is OK.
Angelo
sicilian cowboy, post: 386674, member: 705 wrote: I am also wondering about Dan McCabe....I though he was in a pretty low lying area.
Hope all is OK.
Angelo
I don't know about Dan.
There was some flooding in his area along the Tangipahoa River. There was some road flooding in his town too.
His Parish was one of the four placed on the Fed. Emergency Aid List but then again our governor is from
that parish. There were 2 deaths in his parish that occured much farther north of his town. Someone caught in car by overbank flooding and another who drove into a flooded ditch and was found when some of the water receded.
There used to be surveyor from Livingston Parish area but I don't think that he has posted in years.
I don't see how you can prepare for 15"+ of rain...Nothing around here is designed for that...I'd just send up a white flag.
Most city's design for maybe a 100-year storm..usually it's a 25 or 50- year.
I wish it was only ~15" of rain. I live in Watson, LA. As you can see by this Weather Channel graphic, we got over 31" in less than 3 days. More than the other LA has gotten in 4 years!
The thing that really caused huge issues is that none of the gage readings made sense compared to previous floods. For example, my employee had 6" in his house in 1983 (previous record of 41.5'). This time he got 6-8" with a crest of 46.2'). So he got 6 more feet of water with a crest only 4.7' higher. Where did the other 1.3' go? Same thing at my office. Water was 14" below the slab in 83 and we got 4.3' inside the building this time. Seems like there is over a foot missing somewhere. And down here 1 foot could mean thousands of homes. I suppose new construction built higher reduced the surface area and caused higher flooding.
I spoke with the owner of the building next door. Newer construction less than 10 yrs old. He said he built higher than the BFE (I don't know by how much). He still got over 2 feet in his office.
This event threw out all the record books and past history. If you look at all the previous records for the Amite River in Denham Springs, you'll see the previous top five events were all separated by less than 3'. Then this event shattered the record by 4.7'. How do you even plan for such an event???
On the plus side, since my entire subdivision was high and dry, I bet my property value just went up! Not many people around here can claim their house survived the great flood of 2016.
Historic crests for the Amite River at Denham Springs. This crest is just off the chart.
Robert Hill, post: 386648, member: 378 wrote: Why do you think the indigenous tribes of the SE and MS River flood way area were called the Moundbuilders? From Cahokia,IL, Poverty Point, La, Moundville,Al, Emerald Mound,MS and etc etc. They always picked up and moved to higher ground. Human Civilization was developed to combat flooding since the dawn of man.
That's a new theory to me. If you look at the Cahokia mounds you will see that a large number of mounds of various sizes were not designed to be the most efficient means of having local high ground. If you put two small mounds into one you get more height or area on top. And a great many mounds were on bluffs above a river, already high ground.
Bill93, post: 386733, member: 87 wrote: That's a new theory to me. If you look at the Cahokia mounds you will see that a large number of mounds of various sizes were not designed to be the most efficient means of having local high ground. If you put two small mounds into one you get more height or area on top. And a great many mounds were on bluffs above a river, already high ground.
major mounds were ceremonial in nature. Many were part of trade networks. But here in the South, Bill, many were along tributaries of rivers and bayous. Some were on lake shores where trade also occured. I have visited as many in LA,MS,AL and Fl. Most are near some body of water and trade route.
Which ones were on bluffs above a river? Let's recall that these earthworks were first built by primitive groups.
In my locale, I have noticed that quite a few mounds were used by early colonial
settlers as cemeteries.
I just sent a text to Dan McCabe, saying the surveying forum was asking about him. His response "We are good, waterlogged, but no flooding."
Lee D, post: 386643, member: 7971 wrote: It also happened in about 1995; I was living in an apartment in Kenner, west of New Orleans. We had an overnight storm that dropped 14" in a couple of hours; I awoke to discover that I lived on a rather small island. The sun came out, the pump stations came on, and the water went back down, but the damage was done.
I remember that flood, I was in Kenner back then also.
sicilian cowboy, post: 386674, member: 705 wrote: I am also wondering about Dan McCabe....I though he was in a pretty low lying area.
Hope all is OK.
Angelo
Thanks, we are good, our little town got hammered, flood waters got higher than the BFE in many areas, and non flood zones were also flooded.
We were told that the March flood was one of the worst in history, this flood was about a foot higher, lots of people were just getting back into their houses and now are flooded again. It is all very sad.
andrewm, post: 386720, member: 10888 wrote: I wish it was only ~15" of rain. I live in Watson, LA. As you can see by this Weather Channel graphic, we got over 31" in less than 3 days. More than the other LA has gotten in 4 years!
I thought the other LA was Lower Alabama! 🙂
The thing that really caused huge issues is that none of the gage readings made sense compared to previous floods.
I know absolutely nothing about the 83 flood but from the outside looking in, (arm chair quarterbacking) I would think that maybe the 83 flood was river water spilling the banks and flooding the low lying areas. This flood is from local rainfall that can't get into the river. It didn't come down the river and spread outward.
One would slope downhill from the riverbank out and the other would slope from the outermost areas toward the river.
James
