Showing posts with label floodwalls. Show all posts
Showing posts with label floodwalls. Show all posts

Tuesday, August 11, 2015

Hurricane Katrina 10-Year Anniversary - the Lower Ninth Ward

(Note: click any image to enlarge it.)
Hurricane Katrina made landfall on the Mississippi Gulf coast on August 29, 2005. It proved to be the costliest natural disaster in United States history as well as one of the 5 most deadly hurricanes in our history. People around the world were transfixed by dramatic television pictures of flooded residents on rooftops and the refugees in the Superdome. They were also amazed at the stupid and inept mayor, who bungled everything. My daughter and I were out of the country when the storm struck and watched the unfolding events on Greek television. As I recall, Greek TV crews were filming and interviewing in New Orleans even before FEMA representatives arrived. Many Greeks have a personal connection with and interest in New Orleans because Greek merchant marine sailors have visited or been stationed there.

I did not have a chance to see New Orleans immediately after the storm but spent some time exploring in 2006, when initial cleanup had begun but little restoration was underway. These photographs will show some of the destruction. We will start with a visit to the Lower Ninth Ward, but first let's discuss the geography of New Orleans and the Mississippi delta.

Many people are still confused about what part of the city flooded and why this happened. Possibly a short explanation will help. Nouvelle-Orléans was founded by the French in 1718. They founded it at a bend of the Mississippi River on natural high ground. I assume they must have learned from experience or from the native Americans which areas were high and, therefore, relatively safe from flooding.
This is a 1720 map from the British Admiralty (click to enlarge). It shows the core of the city with cypress forest and marsh surrounding it.
The figure above shows how the city in 1862 had grown but was still concentrated along the bend in the Mississippi River. The view looking north shows Lake Pontchartrain in the distance (from  Illustration from Campfires and Battlefields by Rossiter, Johnson, et al. (New York, 1894), from Wikipedia commons). New Orleans prospered and early in the 20th century, businessmen wondered how they could provide more living space near the downtown. Idea: build levees along Lake Pontchartrain, cut drainage canals, install pumps, and pump out the water. Once the land was drained, the developers cleared out trees and debris, platted the land, and instant suburbia was formed (Gentilly, New Orleans East, and other neighborhoods). The pumps had to be used whenever there was rainfall, and even during non-hurricane storms, they ran continuously to clear out the runoff.

Decades later, scientists learned that land subsidence had been grossly underestimated. Much of the former swamp terrain has continued to slowly sink as the soil dewaters. This is a natural process in all river deltas. As a result, many of the neighborhoods developed after 1900 have settled below sea level. A coworker told me that a common practice every spring was for homeowners to have sand spread over the their house lots to try to combat the settlement. I will leave it to you readers to decide if building suburbia below sea level in an area that needs pumps and depends on the integrity of the levees and on the electric supply is a wise idea.
In the colonial area, the area now occupied by the Lower Ninth Ward consisted of sugarcane plantations. In the late-1800s, house lots were developed along the Mississippi River waterfront (the higher ground). The interior then was cypress swamp, later to be drained and converted to residential. The Lower Ninth Ward has suffered from devastating flooding several times in the 20th century. When Hurricane Betsy roared through New Orleans on  September 9, 1965, with 110 mph winds, a levee breached and the Ward flooded. Recovery was slow, and many of the homes that flooded during Katrina in 2005 were post-Betsy vintage. The photograph above shows the flooded Ward on September 1965, (from a brochure prepared by the U.S. Army Corps of Engineers).
Forty years later, it happened again. Look at the figure above. The red "+" marks show where the levees or walls breached in various parts of town. Four of the breaks were in the canals that carry pumped-out rain runoff to Lake Pontchartrain. The blue areas show the extent of flooding on September 15, 2005 (map from Dartmouth Flood Observatory, Dartmouth College, Hanover, NH). The French Quarter and the historic Garden District did not flood because they were on natural high ground.
As of late-2006, very little recovery was underway, utilities were still not available, and the area looked like a ghost town. The streets had been cleared, and you could drive around. Grass was growing in the lots. Houses were unoccupied. Some had been cleared out, while others had their furniture and junk strewn about untouched since the water receded.
I did not record the exact location of the photographs. The group of three above are near the industrial Canal. The bridge in the distance spans the canal.
Some houses were untouched in over a year, with rotted furniture and abandoned possessions left unvandalized. Most of these mid-century houses were on ground-level slab foundations, utterly unsuitable for a wet area prone to flooding.
The former resident of this house had a sizable collection of LPs. They were probably playable if removed from their moldering jackets and cleaned. Hmmm, will the data on flooded hard drives be retrievable in the future?
There was a lot of graffiti expressing anger towards various agencies or cities. The reference towards Houston may refer to the fact that the Houston police cracked down hard on criminals who had fled New Orleans. They tried to set up practice in Houston and discovered that the Texas public prosecutors and police were much more strict than they had experienced in New Orleans. Don't mess with Texas was true; they really couldn't get away with murder. It underscores how dysfunctional the criminal justice system was in New Orleans in the years before Katrina.
I was surprised how many crushed cars were left abandoned.

This is just a sampling of the destruction wrought by Katrina. We will explore more parts of the city in later articles.

Much has been written about Katrina and its consequences. The article in Wikipedia provides a good summary. Another Wikipedia article describes the Lower Ninth Ward. The article on Hurricane Betsy is interesting reading. A summary on restoration efforts in the Mississippi River Delta is in this New York Times article. John McPhee's classic article "Atchafalaya" in The New Yorker is an excellent and readable introduction to why we control the flow of water and sediment down the Mississippi and the interplay with the Atchafalaya waterway.

Photographs were taken with a Sony DSC-R1 digital camera. This was a 10 mpixel camera with a superb lens.

Monday, May 30, 2011

High Water along the Atchafalaya and Mississippi Rivers, May 2011

As I described in the previous article, the Atchafalaya River carries 30 percent of the combined flow of the Mississippi and Red Rivers. In times of flood, more than 30 percent may have to be diverted to prevent levees being overtopped in Baton Rouge and New Orleans.


One of the towns subject to high water is Melville, Louisiana. The first photograph shows the landing for the former Melville-Pointe Coupee ferry service, which permanently closed in December 2010. Dump trucks were rumbling past to a site just south of the landing, where the levee was being elevated. The second photograph shows how high the water was under the railroad bridge, 14 May 2011.


Morgan City is a historic town near the Gulf of Mexico mouth of the Atchafalaya. Having suffered from many floods in the past, the Corps of Engineers built a levee and floodwall system around the town in 1926. The concrete floodwall is a popular tourist attraction because you can look down on the Atchafalaya on one side and down on the historic city on the other. Normally there are a boardwalk and docks on the river side, but this time, the river was well above the base of the floodwall (15 May). The bridge in the background is US 90


Finally, New Orleans. The levees have been reinforced since Hurricane Katrina and raised in some areas. Along the French Quarter, the levees were well above the water level, even under conditions of the 2011 flood. For tourists, it was a great opportunity to be photographed next to Ol' Man River (or The Big Muddy).

(Photographs taken with an Olympus E-330 camera and Olympus 14-54mm f/2.8 lens)

Wednesday, May 18, 2011

Close to the Crest, the Waterfront at Vicksburg, Mississippi


By Monday, May 16, the water had risen about 1.5 ft above the Friday level. It was 56.66 ft at 15:00, above the 1927 record. At the historic 1907 depot, water reached the ground floor windows. A week ago, someone bolted plywood panels in front of the doors and windows, but they had not been sealed with any caulk or gaskets, so it was an effort too late and too rushed.

Further north, water covered the entire dirt field north of the M/V Mississippi (compare with the photograph in the previous entry). I saw a snowy egret walking around looking for yummy worms and bugs, so at least some wildlife has been able to adapt. Tourists have adapted, too: I have never seen so many visitors downtown.

Here is some information on the Vicksburg Gage from the Corps of Engineers RiverGages.com:

Mississippi River at Vicksburg, MS
Stream Name: Mississippi River
Gage Zero: 46.23 Ft. NGVD29
Flood Elevation: 43.0 Ft.
Record High Elevation: 56.0 Ft.
Longitude: -90.90233200 Latitude: 32.31183200
River Mile: 435.7
Record High Elevation Date: 05/04/1927

Location of Gage: 1.6 miles downstream of the mouth of the Yazoo Diversion canal. Vicksburg Quandrangle.

Note that the level of 56 ft was as measured. If the levees had not failed at various locations along the basin, particularly at Greenville, the 1927 level would have been several feet higher. I believe the Vicksburg concrete floodwall was built to this higher stage. In effect, there is a considerable factor of safety built in to the Vicksburg walls.



This is the view of the waterfront south of the Depot on May 3, 1927, showing the old, lower floodwalls. The photograph is from the collection of the Mississippi Department of Archives and History, and is labeled:

1927 Flood Photograph Collection
"Vicksburg, Miss. 5-3-27." Flooded street and railroad tracks. Pedestrians and steamship in background.

Sunday, May 8, 2011

Mississippi River Floods - Background, 1927, and 1997

With the approach of record-breaking floods on the Mississippi in May of 2011, this blog is a reprint an issue of the Vicksburg Photopage newsletter from 1998, which gave some background to floods along the great waterway.

Introduction. “That Ol’ Man River, he just keeps rolling along...” (From Jerome Kern’s and Oscar Hammerstein’s 1927 Show Boat. The great American bass, Paul Robeson, recorded “Ol’ Man River” in 1928 and many times thereafter.) Ol’ Man River, is, of course, the mighty Mississippi, the father of waters. This grand waterway has always inspired awe and respect, and never more so than when it is in flood. When snow melt or unusual rainfall causes greater than normal inflow in a short time span, the waters rise, overtop the natural levees or banks, and spread out across the river valley. The greatest flood of record was in 1927, when 500 people were killed and half a million driven from their homes in the lower Mississippi Valley. The Mississippi Delta was particularly hard hit. In response to the tremendous economic damage and loss of life, Congress passed the Flood Control Act of 1928, directing the U.S. Army Corps of Engineers to embark on the ambitious project of taming the great river by building levees that would maintain it in its banks, even during floods. For the most part, the Corps has been remarkably successful. However, part of the project remains incomplete, and occasionally, the rivers rise so high that the existing levees are unable to contain the immense flow of water.

Geologic note. “The Delta” refers to the flat, fertile river plain north of Vicksburg and south of Memphis, a fertile agricultural area. Historically, the Mississippi periodically flooded the flat river plain and deposited rich soil. The geologic delta of the Mississippi River is an immense accumulation of un-consolidated sediment that protrudes south into the Gulf of Mexico. Normally, when folks say “the Delta,” they are referring to the farming area in northern Mississippi.

Definitions. Originally, the term flood meant an overflowing of water over land that was usually dry. Now that the river is channelized, flood is defined as a water level above a set elevation. Because a river flows downhill, the flood elevation varies at different points along its course. For example, flood elevation at Memphis is different than flood in Vicksburg, and gage zero (the elevation where the measuring staff is defined as zero) is different as well. The US Army Corps of Engineers and the US Geological Survey record water levels at hundreds of stations throughout the nation.

Vicksburg gage 15145. This gage is located about 0.3 miles south of the I-20 bridge. Zero on the gage is 46.23 feet above the National Geodetic Vertical Datum (which is approximately sea level). Bank full, or flood stage, is 43.0 feet above gage zero. During some droughts, the water elevation drops below gage zero, but this does not mean that there is no water flow.


The graph above shows river elevations for 1973 (major flood), 1988 (drought) and 1997 (flood). During the 1988 drought, the water level was so low, long-lost sunken barges and steamboats emerged.

-->
Table 1.
Mississippi River Elevations at Vicksburg
Event
Date
Elev.
Bank full
43.0
Record flood crest (estimated because levees failed)
1927
56.0
Record measured crest
Feb 21, 1937
53.24
Record low stage
Feb 3, 1940
-7.0
1973 flood crest
May 13, 1973
53.1
1993 high
May 18, 1993
43.6
1994 high
May 3, 1994
46.0
1995 high
June 12-13, 1995
47.0
1996 high
June 1-3, 1996
43.6
1997 flood crest
Mar 22-26, 1997
49.1
1998 high
May 14, 1998
43.5
Source: U.S. Army Corps of Engineers, Vicksburg District. Elevations in feet above gage zero.

In Table 1, you can see that the record low water was 7 feet below zero, while the crest of the 1927 flood was estimated to be 56.0 feet. This means the water level can vary as much as 63 feet, making it difficult to design wharfs and landings. In Vicksburg, the spring crest is typically at or above flood stage, but only when it is predicted to rise above 45 feet do the city workers prepare to close the flood gates.

The Flood of 1927. This was greatest natural disaster of the 20th century in this part of the world, destroying homes, inundating hundreds of square miles, displacing thousands, killing cattle and livestock, and bringing about vast social changes. Disaster relief was slow and haphazard. Blacks and rural poor whites were treated shabbily by the wealthy establishment. Barry (1997) speculates that populists like Huey Long in Louisiana gained political power as a direct result of the discontent that millions felt and their conviction that something in the social order needed to change.

Reference: Barry, John M. 1997. Rising Tide: the Great Mississippi Flood of 1927 and How it Changed America, Simon & Schuster, New York.

The following 1927 photographs were kindly loaned to me by a former coworker and life-long Vicksburg resident. They were taken by her father, Mr. Emil Menger. Mr. Menger and his brothers regularly walked about four miles from Clay Street to Long Lake to fish.
Mr. Emil Menger at Long Lake (northwest of Vicksburg in the flood plain of the Yazoo River).

Mr. Menger’s boat at Long Lake, Mississippi, during the 1927 flood. The gun is still in the family’s collection.

Flooded road in Vicksburg, probably Hwy 61 North (North Washington Street).

From New Orleans District Corps of Engineers: "The Mississippi River has the third largest drainage basin in the world, exceeded in size only by the watersheds of the Amazon and Congo Rivers. It drains 41 percent of the 48 contiguous states of the United States. The basin covers more than 1,245,000 square miles, includes all or parts of 31 states and two Canadian provinces, and roughly resembles a funnel which has its spout at the Gulf of Mexico. Waters from as far east as New York and as far west as Montana contribute to flows in the lower river."

Mississippi River drainage area with Mississippi River & Tributaries Project area (in pink). From New Orleans District

This map shows the areas flooded in 1927. The map was prepared by the Commission headed by Herbert Hoover. Image courtesy NOAA Central Library and Mr. John Cloud.

The Mississippi Department of Archives and History has a fascinating collection of 1927 photographs on their web page. Highly recommended!

http://mdah.state.ms.us/arrec/digital_archives/1927flood/

For more information on the 2011 flood, please see some of my later blog articles.