17th Street Canal
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The 17th Street Canal is a drainage canal in New Orleans, Louisiana that flows into Lake Pontchartrain. The Canal forms a significant portion of the boundary between New Orleans and Metairie, Louisiana. The Canal has also been known as the Metairie Outlet Canal and the Upperline Canal.
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[edit] History
The canal that was to become later known as the 17th Street Canal seems to have had its origin at the start of the 1850s as a canal dug through swampy ground to raise a parallel right of way where the Jefferson and Lake Pontchartrain Railway was built. The Railway, in business from 1853 through 1864, connected the town of Carrollton, Louisiana (along the Mississippi River front) with a shipping port on Lake Pontchartrain at what became Bucktown, Louisiana, a distance of about 5 miles. At the time, most of the land between the two terminals was undeveloped swamp.
Meanwhile, in 1858, a secondary canal was built to aid in drainage in the low swampy area in "back of town" from Carrollton, with its head at what is now the intersection of Dublin and Palmetto streets, connecting to the Railway canal a short distance on the river side of the Metairie Ridge.
The railway was discontinued on 31 December 1864 as competing rail lines between the river and lake were more successful. The city of New Orleans annexed Carrollton, and the canal became the boundary line between Orleans Parish and Jefferson Parish. As the canal marked the up-river limit of Orleans Parish, it became known as the Upperline Canal.
The spur canal in the back of Carrollton was beside a projected street numbered "17th Street" (although at the time there was little actual development in back of Claiborne Avenue), and that canal was thus the first to be known as the "17th Street Canal", a name which would later come to commonly refer to the large canal which this connected to.
[edit] Improved drainage with pumping stations
By the 1870s, a steam engine powered pump known as the "Dublin Street Machine" at the back of the Carrollton neighborhood was used to drain that neighborhood, pumping the water out the Upperline Canal. Use of the canal to pump water from the streets of the city into Lake Pontchartrain grew with the city. The Claiborne Canal connected with the 17th and Upperline Canal system via a canal along Dublin Avenue; thus the canal served to carry rain water to the lake from the majority of Uptown New Orleans above the New Basin Canal. Another canal, Hoey's Canal, was added connecting to the Upperline from up river to help drain the back of the Jefferson Parish communities along the riverfront, now known as "Old Jefferson".
In 1894, "17th Street" was renamed "Palmetto Street" (later redesignated Palmetto Avenue), but the canal continued to be popularly known by the old street name.
In 1899 a new pumping station was opened atop the Canal a couple blocks back from Metairie Road. In the early 20th century new high-efficiency pumps designed by A. Baldwin Wood were installed, and remain in operation.
At the start of the 21st century Pumping Station 6, or the Metairie Pumping Station, astride the Canal had 15 pumps capable of moving over six billion gallons of water a day through the station. Run off from substantial areas of Uptown New Orleans, Metairie, and surrounding neighborhoods drains into the canals and basins on the River side of the pumping station, which pulls the water up into the portion of the 17th Street Canal flowing in to Lake Pontchartrain.
[edit] 20th Century: Residential development of the "Back of Town"
When the Station 6 was constructed, it was at the "back" end of the developed part of town. As the area along side the canal closer to the lake was largely undeveloped swamp, it was originally of little concern if waters pumped out of the city topped the canal and flowed into the swamp during heavy rains.
In the late 1920s and the 1930s, a project dredged fill along the lakefront, creating new land in what had been Lake Pontchartrain and creating a sizable levee along the lake side. However no efforts were made to raise the swampland between Metairie Ridge and the new lakefront fill. The areas along the Canal from Metairie Ridge to the Lake were substantially developed for residential use after World War II, and levees along the "back" sections of the Canal were raised. The water level of the canal is often significantly higher than the surrounding streets.
Additional smaller pumping stations were built to add drainage water to the canal from areas along its length.
After Hurricane Betsy, improved flood protection for the city and its canals to cope with storm surge from hurricanes was mandated, resulting in increasing the size and height of the canal levees further.
In 1998 Hurricane Georges elevated the level of Lake Pontchartrain, pushing lake waters into the canal. A report noted that there was at least one place where the water came within inches of topping the floodwall.
An upgrade of the Canal levees, floodwalls, and bridges began in 1999. The Canal was considered in good shape at the start of the 2005 Atlantic Hurricane Season.
[edit] Hurricane Katrina
After Hurricane Katrina struck New Orleans, the 17th Street Canal Levee was breached over a two city-block wide length on the New Orleans side, contributing to extensive flooding in New Orleans.
For two days after the storm, the Fox News television network repeatedly showed helicopter footage which they identified by narration and caption as the 17th Street Canal breach, but was actually a breach in the Industrial Canal, near the other side of the city. On 31 August Senator David Vitter corrected the network on air, but captions mislabeling the footage continued to be aired for hours more.
[edit] Investigations into the breach
On 10 November 2005, an article in the Times-Picayune revealed that sonar soundings discovered that the steel sheet pilings of the levee floodwall were 7 feet less deep than engineering specifications. Sample pilings pulled up were found to be of the length specified in the design, but it was then revealed that this length was less than the actual depth of the canal, in retrospect an obvious engineering mistake. Current analysis strongly suggests that the catastrophic breach was due to faulty design, rather than storm and water conditions more severe than the levee and storm wall system of the canal was intended to survive.
It also became public knowledge that homes in the area near what would become the breach were expericing problems with flooding in their yards from seepage from the canal, which they repeatedly reported. The Orleans Levee Board and the U.S. Army Corps of Engineers, who share responsibility for the levees, stated afterwards that they had been unaware of this.
Further investigations have confirmed that the canal floodwall failed catastrophically at significantly lower water level than the top of the floodwall due to faulty engineering. The Metairie side of the Canal was no better built the Orleans side, and portions of the floodwalls showed signs of displacement; the Metairie side could have experienced similar failure if pressure on the canal had not been relieved by the failure on the Orleans side.
[edit] After Katrina
In January of 2006 the U.S. Army Corps of Engineers announced it had finished the temporary repairs of the breached section of the levee, and construction of more permanent repairs would commence.
The future of the 17th Street Canal is likely to see changes in design. While plans are not finalized, it is likely that a new pumping station will be constructed at the lake edge of the canal, which will serve not only to improve pumping capacity but also to act as a barrier to storm surge and lake flooding; the building would be constructed to act as an additional levee. As a temporary measure until such a new station can be built, storm surge barrier gates at the lake end of the canal are under construction. These were to became operational shortly after the start of the 2006 Hurricane Season, but delays and problems have left them incomplete as of the end of August 2006. While the floodgate includes some pumps, it is significantly less than the capacity of the canal before Katrina, raising concerns that while the floodgates could protect from Lake storm surge, heavy rains could flood portions of the city while the gates are closed because it could not be pumped out. Since repairs began, there was discussion possible about expropriation of homes on either side of the canal in order to construct wider and more stable levees along its length. On August 8th, 2006, the Corps of Engineers began tearing down 14 homes on the Orleans side of the Canal. [1]
[edit] See also
- Drainage in New Orleans
- London Avenue Canal
- Industrial Canal
- Effect of Hurricane Katrina on New Orleans
[edit] External links
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