andrewm, post: 386561, member: 10888 wrote: By the way, I see a huge business opportunity for me now doing elevation certificates in this area. Remember I'm not a surveyor, but I am a registered civil engineer, so I can prepare them. Other than RTK GPS, which I already have, what other equipment would I need for this? I'm assuming a level, but anything else? What kind of level do I need?
Thanks
Just to add to what Lamon and others have posted:
You will need an automatic level/tripod.
Level rod and a Keson pocket rod.
Digital camera (one that time stamps is preferable).
Keson reel tape (or other brand) for getting square footage of structures and enclosed garage areas.
Your RTK should be connected to LSUÛªs GulfNet. Personally, static session tied to Gulfnet CORS stations is preferable. Processed though a software and QCed by OPUS, IMO.
Pocket tape for measuring vents.
From experience, there will be more requests for ÛÏBuilder PackageÛ surveys that will include a Elevation Certificate and setting a TBM for construction.People are going to rebuild and raise the FFE
Jim Frame, post: 386585, member: 10 wrote: A solid understanding of the elevation references you're going to use. Land subsidence is a huge problem in some areas, and published bench mark elevations aren't necessarily reliable.
My understanding is that some of the flooded areas weren't in designated flood zones. Without a flood zone designation and associated BFE, I don't know what good an Elevation Certificate will do.
Most of the concerns, that you mentioned were addressed after Katrina, 10 years ago.
Lamon Miller, post: 386580, member: 553 wrote: Communities can add to FEMA's requirement known as free board. Another item you may be dealing with is ABFE's which can go from advisory to mandatory.
Yes, FEMA may pause existing requirements. Immediately, there will HWM studies by FEMA, COE and USGS contractors to find out WTF happened. (besides a lot of rain)
There may form a joint task force and they may not.
The ABFE is a long process. In the end, the community must approve the ABFE to make it mandatory though public meetings. As they say, "It's not a sprint, It's a marathon.
Robert Hill, post: 386596, member: 378 wrote: Most of the concerns, that you mentioned were addressed after Katrina, 10 years ago.
You're right, this is stuff that doesn't happen in my area, so I'm not familiar with it. (We have land subsidence, but it's very slow compared to LA.)
So how long does it take FEMA or the local community to develop ABFEs for areas that previously weren't designated flood hazard areas?
In my area all ABFE's are in a special flood hazard area to begin width and are about 1' above the current BFE. The only exception I have seen is in an AO zone where a depth is given on the firm and now it has an elevation associated with it.
I seem to remember it took about a year for the ABFE maps to come out. For the first year they, the communities advised the home owner about the elevations because they weren't mandatory. After about another year, fema required the communities to make the new BFE's mandatory but the old maps, old BFE's, are to be used for insurance purposes.
It basically is treated like a 1' free board.
Lamon Miller, post: 386606, member: 553 wrote: It basically is treated like a 1' free board.
How does that help when the water in the videos we were seeing comes up to the eave line?
I realize it is far too early to draw any conclusions behind the causes behind this flooding other than a freak weather anomaly stalling out a weather system that has so completely inundated this area of LA, but in the aftermath of Katrina it's difficult to understand how these areas could be outside previously designated flood areas and yet be so inundated. Sitting as far away as I do it's not clear to me that the dynamics behind these flood prone areas are clearly understood and defined. Chalk it up to an act of God?, or to a less than stellar understanding of the hydrodynamics of this region?
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
We all need to keep in mind that the one percent flood plain IS NOT representative of what Mother Nature may deliver someday. In 2007 we had places a half mile apart where one experienced two feet higher than the one percent flood plain and the other experienced six feet lower than that similar magic number. In the next county to the west, the high water level was up to eight feet higher than the highest recorded level and about 10 feet higher than the official one percent figure.
paden cash, post: 386623, member: 20 wrote: Second guessing Mother Nature and her rivers is an exercise in futility.
I completely agree. However given the untold thousands of miles of levees and canals and billions upon billions of dollars spent in an attempt to control mother nature and her plumbing, it just doesn't leave me with that warm and fuzzy feeling that the powers that be have a real handle on the net effects of those efforts. But you're right in the sense that trying to model every possible scenario mother nature can throw our way is ultimately an exercise in futility, just as developing flood planes is rolling the dice. Not trying to armchair quarterback, just better understand what happened.
Williwaw, post: 386630, member: 7066 wrote: I completely agree. However given the untold thousands of miles of levees and canals and billions upon billions of dollars spent in an attempt to control mother nature and her plumbing, it just doesn't leave me with that warm and fuzzy feeling that the powers that be have a real handle on the net effects of those efforts. But you're right in the sense that trying to model every possible scenario mother nature can throw our way is ultimately an exercise in futility, just as developing flood planes is rolling the dice. Not trying to armchair quarterback, just better understand what happened.
I'm sure the canals, levees and flood controls down there are similar to everywhere else in the country...they run out of money. We design highway boxes and channels here in Oklahoma for a 15 or 20 year frequency, with FHWA blessings. Nobody has the money to build for "the big one". The vastness of the drainage basins in So. Louisiana are staggering to me. We measure Q's up here in cubic feet. I'm sure down there it's probably in acre feet..or something.
I remember standing on a truss bridge somewhere in So. Louisiana and there was a painted line 14 or 15 feet above the deck that had a date like "May 5, 1957" or something. It was a high water mark. The staggering thing was you had to drive six or seven miles in either direction to even get four or five feet higher than the bridge deck. The amount of water they deal with down there boggled this little Okie's mind.
Jim Frame, post: 386603, member: 10 wrote: You're right, this is stuff that doesn't happen in my area, so I'm not familiar with it. (We have land subsidence, but it's very slow compared to LA.)
So how long does it take FEMA or the local community to develop ABFEs for areas that previously weren't designated flood hazard areas?
Unfortunately, it is a political process so it depends. After Katrinas, ABFEs were completed after the studies were finalized. Some had a clue of what the new BFEs would be and some didn't. FEMA used recovery monies as an arm-bender to adopt the new maps.
I know of one incorporated area that signed off very quickly so the politicos could access funds(for their pockets) and also to generate work for their favored engineering firms. Remember this is Louisiana. South of the lake, Orleans parish was doa so they signed off quickly.
Locally, most incorporated areas went thorough the process (public meetings etc) and adopted But the Parish challenged for some of the unincorporated areas, IMO basically being lobbied by the developers and homebuilder association which has an arm lock on Parish government. Also because of a very conservative political POV about government restrictions and regulations. But there were a few valid appeals in some areas.
One small city/town challenged. A historic settlement along a river and near the lake. New BFEs would cause major rebuilding.
google Madisonville LA and check out the new swankiendo structures along the river and the new library and Maritime museum.
The Parish and Madisonville took years to adopt.
At google earth, you can get street views from the river also.
'
Jim Frame, post: 386617, member: 10 wrote: How does that help when the water in the videos we were seeing comes up to the eave line?
Basically it doesn't help but by adopting the freeboard by the community, premiums are offered at lower costs.
Williwaw, post: 386620, member: 7066 wrote: in the aftermath of Katrina it's difficult to understand how these areas could be outside previously designated flood areas and yet be so inundated
These areas that are flooding now are well to the west of what was affected by Katrina, for the most part. And they're getting bad flooding in areas that are not in flood zones and have never flooded before, to anyone's knowledge. This is an example of what happens when a freak storm stalls and drops over 2' of rain in a localized area. Louisiana residents may recall the footage coming out of Lower Livingston Parish after the 2012 hurricane; we had a similar event but in a smaller, less populated area.
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.
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
