rholmes – mammoth // building nothing out of something

Author Archives: rholmes

August 17, 2011 – 6:00 am

the atchafalaya basin project and the wax lake delta

[A map of the administrative units of the Atchafalaya Basin Project in 1982, produced by the Army Corps of Engineers.  The Atchafalaya Basin system is made up of three floodways: the Morganza Floodway (fed by the Morganza Spillway), the West Atchafalaya Floodway, and the Lower Atchafalaya Floodway; the latter is composed of the confluence of […]

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August 16, 2011 – 6:00 pm

bayou chene closure project

[During the May 2011 operation of the Morganza Spillway, the Army Corps of Engineers closed one channel within the southern Atchafalaya Basin, Bayou Chene, by dredging the edges of a narrow strait in the Bayou, lining it with rip-rap and sinking a 20,000-ton, 500-foot long barge in the resulting chokepoint.  By stemming the flow down […]

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August 14, 2011 – 10:12 pm

atchafalaya iii: the morgan city floodwall

[The twin Atchafalaya river ports of Morgan City (on the east bank) and Berwick (on the west bank), captured in false-color by the “Advanced Spaceborne Thermal Emission and Reflection Radiometer” on NASA’s Terra earth-imaging satellite, May 27, 2011 — after the second opening of the Morganza Spillway.] Old River Control sits at the northern end […]

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August 10, 2011 – 6:00 am

atchafalaya ii-c: old river hydraulic sediment response model study

[Video from the Army Corps of Engineers’ “Old River Hydraulic Sediment Response Model Study”, in which a physical model of Old River Control was used to test the distribution of sediment deposition under various flow conditions in the Low Sill and Auxiliary Structures. The testing was prompted by the observation of problematic deposition in the […]

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August 3, 2011 – 6:00 am

atchafalaya ii-b: the geomorphology of old river

[Image compiled from Army Corps of Engineers diagrams via Wikimedia.] Quoting further from McPhee’s “Atchafalaya”: “…In the Red River, [Shreve] undertook to disassemble a “raft”—uprooted trees by the tens of thousands that were stopping navigation for a hundred and sixty miles. Shreve cleared eighty miles in one year. Meanwhile, at 31 degrees north latitude (about […]

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August 1, 2011 – 9:21 pm

atchafalaya ii: old river control

[The Auxiliary Structure at Old River Control; photographed by the Army Corps of Engineers, Team New Orleans. Various circumstances have conspired to keep me from finishing the Floods series last week like I had hoped; there are still a few posts yet to come, and several of them will be part of this mini-series within […]

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July 23, 2011 – 6:00 am

willow fascine mattress

[Before the use of articulated concrete mats was standardized, the Army Corps often relied on a variety of other methods of revetment construction.  The weaving and placement of willow fascine mattresses, as seen above, was one such earlier practice; the installation process is remarkably similar to and prefigures the process for concrete mats.  Images via […]

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July 21, 2011 – 8:46 pm

casting fields

[Map of revetments under the purview of the Army Corps of Engineers’ Team New Orleans, on the Mississippi and Atchafalaya Rivers; image produced by mammoth using data from the Army Corps.] I’ve already talked a fair about the idea that the Mississippi River is, at this point in its history, an artificially-constructed system that should […]

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July 19, 2011 – 6:00 pm

hamburg, iowa (2)

[Flooding on the Missouri River, up and downstream from Hamburg, Iowa.  The distinct spray pattern produced by burst levees is visible in at least three locations, while the raised outline of the emergency Ditch 6 levee can be seen on the western edge of Hamburg, protecting the city from the insistent floodwaters.  Imagery captured by […]

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July 18, 2011 – 8:00 pm

a quick and unnecessary defense of density against some chart

Grist recently cross-posted an article by Per Square Mile’s Tim De Chant which mines an old (2009) study from the Journal of Urban Economics to argue that “only the steepest increases in density could reduce car usage”.  Unfortunately, I think that’s entirely the wrong conclusion to draw from the study. Here’s the key graph that […]

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July 15, 2011 – 6:00 am

dike field

[A dike field in the Mississippi River near Greenfield, Mississippi; via bing maps.] In the Mississippi River, dike fields are constructed in order to direct the river’s flow to a central channel, scouring it and reducing the need for dredging.  Though their primary purpose is to thus maintain navigability for shipping, dike fields tend, as […]

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July 14, 2011 – 8:00 pm

flooding, previously

As I’m gathering projects, proposals, practices, and places to be covered before I wrap up our summer flood-blogging extravaganza (which I expect to do by the end of the month), I thought it worth looking back at a handful of notable posts from mammoth‘s past that concerned flooding.  Hopefully some of these, since they are […]

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July 13, 2011 – 8:00 pm

the waterways experiment station

[The Waterways Experiment Station, in Vicksburg, Mississippi, is currently the home of the Army Corp’s Coastal and Hydraulics Laboratory.  (It also is the entity which operated the Mississippi Basin Model, and the research into flood control and river hydrology which was once conducted physically on that model and its sister models is now conducted, primarily […]

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July 7, 2011 – 6:00 am

san francisco bay model

The San Francisco Bay Model was, like the Mississippi Basin Model, built by the Army Corps of Engineers to study the flow of water — in this case, simulating “the rise and fall of tide, flow, and currents of water, mixing of salt and fresh water, and… trends in sediment movement”, permitting the study of […]

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July 6, 2011 – 6:00 am

the mississippi basin model

[The Mississippi River Basin Model today, via Bing Maps.] At Places, Kristi Dykema Cheramie writes about the one of Mississippi flood control’s most fantastical landscapes, the Basin Model — “a 200-acre working hydraulic model [replicating] the Mississippi River and its major tributaries — the Tennessee, Arkansas and Missouri Rivers”, on a small tract of land […]

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July 1, 2011 – 6:00 am

magnitude

[Cahokia mounds, photographed by Ira Block for National Geographic; the mound immediately above is “Monk’s Mound”, the largest (ten stories tall) of the Cahokia mounds.] Around a month ago, FASLANYC ran an excellent post that described the Mississippian mound culture as a potential source of inspiration for a reconsidered Louisiana delta urbanism.  In the post, […]

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June 30, 2011 – 6:00 am

blowing the fuse

[Detonation at the Birds Point inflow crevasse, during the night of 2 May 2011.] As sand boils appeared in Cairo, the swollen rivers continued to rise.  The city was under mandatory evacuation orders, and the flood gauge was expected to reach 63 feet — not high enough to over-top the city’s levees, but high enough […]

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June 29, 2011 – 6:00 pm

sand boil

[The breach in Missouri River Levee 575, on June 14.] The breach at Hamburg — mentioned a few posts back — began with a “sand boil”, a geotechnical phenomenon shared by earthquakes and floods, in which subterranean water pressure becomes so strong that ground water erupts, typically bubbling like a gentle geyser, and bringing soil […]

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June 28, 2011 – 6:00 pm

patterns

[Flooding on the Indus river around Hyderbad, Pakistan, 19 August 2010; image via NASA Earth Observatory.] At Weather Underground, Jeff Masters reflects on the extreme weather of 2010 — which included monsoon flooding in China, the Pakistani floods (the most expensive disaster in Pakistan’s history), the Queensland flood (Australia’s most expensive natural disaster), Colombia’s record […]

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June 28, 2011 – 6:00 am

the mouse

[Just north of the Missouri River, another, smaller river has been smashing flood records, propelled by the same combination of snow pack and heavy rains.  In the oil boomtown of Minot, North Dakota, the Souris River (French for “mouse”, which has produced the local nickname “the Mouse”) has reached thirteen feet over flood stage — […]

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