More On The Mississippi Flooding
Dr. Jeff Masters posted on the Mississippi – Ohio flood situation. He showed the results of the actions by the Corps of Engineers last night, which is a major decrease in the height of the crests on the rivers.
In passing almost, he explained that what the Corps did, wasn’t really blowing up the levee, but removing the plug across the Birds Point-New Madrid Spillway. The segment of the system that was removed, was built with removal in mind, the holes for the explosives were part of the construction. The Corps simply removed the caps over the holes and packed the explosives in for a pre-designed removal of the segment. The other side was a concrete spillway to forestall erosion if the “plug” was removed.
When the segment was built, it was obvious what could happen, and the people on the other side had to be aware of it. They were safe from flooding most of the time, but they were in a designated flood plain that was part of the overall plan for the river. This shouldn’t have come as a surprise to Missouri, as it was done in 1937 for the same reason.
There is more rain today.
6 comments
“and the people on the other side had to be aware of it.”
Indeed; I can sympathize. The people of Harris County, TX (that’s Houston, mostly) are aware that parts of the county are awfully close to flood plain level, and that the county will… not may, but will… flood catastrophically from time to time. T.S. Allison was the last bad example, though Hurricane Ike wasn’t great, either. Various mitigations have been tried, with varying degrees of success, but unsurprisingly no one seems interested in moving the city. I do wonder what will happen in 20 or 30 years…
I don’t know that I would want a farm with the open end of spillway pointed right at it, but the land will be rich, as it is along the Mohawk River in New York. The difference is that the farmers don’t build anything on the “mucklands”, they just use them for vegetables.
I have a feeling that the Houston Ship Channel is functioning a lot like the MRGO [Mississippi River – Gulf Outlet] did in New Orleans, making the flood control worse by funneling water, especially storm surge, into the bayous.
I am somewhat happier about my situation knowing it’s the morons with the McMansions and condos right on the water who will sink first.
The Houston Ship Channel is roughly just Buffalo Bayou, straightened and deepened. It’s not a brand new dagger through the heart of a marsh like MRGO was. MRGO not only serves as a funnel to push water into New Orleans, but by bringing salt water into the heart of the marsh, served to help destroy the Louisiana coastline, including doing more to destroy historic Fort Proctor than anything else ever done to the area.
Houston does have some storm tanks that are supposed to be allowed to fill with water during flooding along local rivers and streams. If you head out the Katy Freeway, for example, you’ll notice a big open area on either side, one of which is a park, the other which mysteriously has nothing in it. Those are supposed to be overflow areas for stormwater, though how stormwater is supposed to get way out there eludes me…
Based on local experience with people building seawalls and dredging for canals to increase the number of “waterfront lots” or to permit the use of larger vessels, the results are almost universally bad. Cinco Bayou no longer flushes out properly because of the change of shape, and the surge is higher because of the channel dredged under the main bridge. The water moves faster in the center of the bayou and no longer curves around to clean out the side inlets.
Messing around with water channels involves a lot more that people assume, and minor changes to water flow can have major impacts over time. Deepening a channel, even a natural channel changes the seafloor, and you need a really complex model to understand what will probably happen.
Yes, it is amazing how the water retention ponds don’t seem to actually be connected to the stormwater system, and in some local cases would require water to flow uphill.
Regarding the Birds Point Spillway, what happens is that people buy property in the floodway, they see the deed restriction that says it can be used only for agricultural use because it’s in a floodway (the original landowners were compensate for loss of all other use back when it was created in the late 20’s), and they ignore it because the floodway hasn’t been operated within their lifetime. Then when the floodway IS activated and floods their (illegal) homes (note that it’s *illegal* to build a home in a floodway, only agricultural use is allowed as a “secondary use” with the floodway as the primary use), they whine and whine and whine. Oh woe is me. Uhm, it’s a floodway, and you knew it when you *bought* the land (or if you happened to inherit the land, your parents or grandparents got paid for the loss of non-agricultural and primary agricultural use). Duh. Expecting the floodway to never be used in the future because it hasn’t been used since you bought or inherited the land is just silliness.
But just another checkmark in the annals of American self-entitlement. They feel *entitled* to flood out their neighbors via blocking use of the floodway because, well, just because. So it goes…
Same crap down here when the Feds take a property because they have paid for it three times from the Flood Insurance. It shouldn’t be a surprise because it is noted in the Flood Insurance policy and on the deed in most counties.
Frankly, just looking towards the levee and seeing the concrete spillway would tell me that there’s a problem, and as soon as I noticed the internal levees that create the rest of the spillway system. I would know it was not a place to be.
No one plants in the mucklands until after the Spring in New York, because your tractor will just sink in the mud, but the fertility of the soil makes up for the wait.