- Company: Conti
- Industry: Water/Wastewater
- Location: Jefferson Parish, Louisiana
- Expected Completion Date: December 2016
In the aftermath of Hurricane Katrina in 2005 which devastated New Orleans and its surrounding parishes, the US Army Corps of Engineers (USACE) initiated a flood protection program to protect against a ten-year rainfall event and reduce damages from future flooding. This program would mitigate the immediate dangers posed to local citizens and businesses in this hurricane-prone area and lessen the impact the next major storm would have on the region.
Conti’s $24M Southeast Louisiana Urban Flood Control Project, Harahan Pump to the River, South Discharge Tubes (SELA 07b), was located in Jefferson Parish, Louisiana and performed for the USACE New Orleans District under the SELA Drainage Program. This program involved the construction of new pumping stations and better drainage canals and culverts throughout the area to alleviate flooding concerns.
Conti completed the construction of the SELA 07b contract in December 2016. The work consisted of 13,500 linear feet of three 84-inch cement lined steel pipes connecting the discharge pipes from a pump station to a levee crossing and outlet structure for discharge into the Mississippi River. Conti’s contract included the longest portion of piping installed amongst all of the SELA projects under the program, which included twelve completed projects and eight under construction.
In addition to the steel discharge piping, Conti’s work included installation of drainage and water connections, installation of concrete storm drainage pipes, construction and modification of existing utilities, construction of two pump stations including concrete foundations and fiberglass wet wells, pile driving, installation of waterlines, mass excavation and hauling, asphalt and concrete paving, concrete slope pavement, dewatering, construction of temporary retaining structures, construction of a pile support concrete discharge basin, stone and bedding construction, major excavation of 138,000 cubic yards of soil, structural excavation, backfill, demolition and other incidental work.
Conti laid as much as 600 linear feet of pipe per month and coordinated with USACE, the Louisiana Department of Transportation and Development, the local utility company and Jefferson Parish to redesign the traffic configuration, temporary retaining structure (TRS) and dewatering system to improve efficiency while crossing Jefferson Highway.
What impact does this project have on America?
This project is part of the USACE’s Hurricane & Storm Damage Risk Reduction System (HSDRRS) program aimed at improving the flood protection infrastructure in the New Orleans area. Conti’s SELA 07b project was intended to improve the livelihood and safety of New Orleans residents and businesses. New Orleans is a home to many Americans and a popular travel destination. The city and surrounding area have a rich history and without this program to protect against future natural disasters, the region would remain at a heightened risk for catastrophic damage.
Over time, New Orleans has experienced the devastating impacts of hurricanes in the Gulf Coast region, which cause flooding that devastates the area. These hurricanes have taken the lives of thousands and endangered the lives of more; have left Americans homeless; and destroyed local businesses, communities and structures.
The improvements provided under Conti’s project are so important to the residents and businesses of the region and have a huge impact on preserving American citizens’ lives, and the region’s economy and history. Specifically, this project provides pump stations, drainage canals and culverts to divert stormwater to mitigate the disastrous effects of future flooding events in Gulf Coast areas. The overall program will cut three miles of distance stormwater will need to travel, thereby reducing volume and easing flows into the Soniat Canal. This provides protection against flooding and drastically decreases the risk of flooding potential and the resultant damage the floodwaters cause.
During Conti’s construction progress, the team experienced immense levels of flash flooding, reminding them of the lasting impact this crucial project would provide to the community. A number of local citizens whose roads were often under water during flash floods could see the size of Conti’s piping being installed, and often commented to the team that the long term benefits greatly outweighed any short term delays during construction.
This, combined with Conti’s local hiring of subcontractors and vendors to boost the region’s economy, made Conti’s presence beneficial in this area. Construction projects often provide a number of jobs for American citizens and this project helped provide work for locals on a project of immeasurable regional value.
What interesting obstacles or unusual circumstances did you overcome to complete the project?
This complex project involved a number of obstacles. These included coordination with residents and other contractors who were part of the massive SELA program; a large diameter pipe installation initiative across a busy highway; extensive coordination of power outages to avoid disruption to local users; frequent flash flooding; and a high sense of urgency to complete the project in time to beat the next hurricane that could pass through.
Coordination with other contractors and residents. Conti’s work on this project occurred simultaneously with three other contractors who were installing sections of piping under this program, and a fourth contractor installing a pumping station. Communication and cooperation with these contractors was required while coordinating power outages for transmission lines that ran parallel with all four projects, and also while working across Jefferson Highway.
Conti’s work also passed very closely to several residences and business. Conti proactively and respectfully contacted residents and business owners prior to working alongside their properties to communicate upcoming activities for awareness and safety, and to mitigate any complaints or inconveniences.
Highway Pipeline Installation. Conti’s biggest obstacle by far was the pipeline installation on the Jefferson Highway portion of the project which occurred in two phases. The pipeline needed to be installed underneath an active 4-lane highway which was also located within 1,500 feet of the Mississippi River and underneath 200 KVA transmission power lines. The USACE originally proposed the construction of this area in three phases, but Conti proposed a new design which reduced this work to two phases. This re-design saved four to five months from the original project schedule.
Scheduling Power line Outages. Timing the sheet pile operations with energy outages was another crucial project obstacle. If the project had remained as three phases, two additional outages would have been required.
The power lines located along the project route posed a tremendous issue as outages were required in order to drive the sheet pile cofferdam. These outages needed to be formally requested six weeks in advance of the outage event. In summer months these outages were never guaranteed. If energy demand spiked due to high summer temperatures, then the utility would cancel the scheduled outages. This occurred during Conti’s project on two separate occasions, emphasizing that reducing the number of planned outages from seven to five was a crucial time saver.
Flooding. Flash flooding on this project was a major and constant issue due to rain events, and streets would often be four to six inches under water making it virtually impossible to drive. When these flooding events occurred, Conti would stop work due to safety concerns. To make up for the impacted schedule, the team worked when weather cooperated; cancelling rainy week days and making up time on Saturdays.
The Mississippi River also posed a major obstacle when planning the power outages. If the river elevation rose above 11.0, all work within 1,500 feet needed to cease. The ability to effectively time the energy outages with the river elevations proved to be difficult, and Conti ultimately had to cancel two outages due to elevations in the spring and early summer when the river frequently rises above safe levels. Conti overcame this issue throughout the project largely by working closely with the utility company and other contractors in the area.
All three contractors simultaneously working on the other pipeline contracts under this program were requesting power outages on the same lines. Only one contractor could have an outage at any given time to avoid disrupting or impacting the community. Conti ended up trading outages with nearby contractors since scheduling became unpredictable due to the varying river elevations.
What dangers and risks did you encounter, and describe any extraordinary methods used to keep workers safe?
The most dangerous construction activity on this project was the sheet pile operation, which often occurred in close proximity to the high powered transmission lines. Communication between the crane operator and pile foreman was key. Conti crews always made sure to mark a 20-foot offset from the transmission lines so we knew our clearance was within specification and always had the swing radius of the crane marked off.
Setting the large, 84-inch pipe was also very dangerous to crew members with the pipes weighing in at 30,000 pounds. The team installed and set these pipes using cranes. Setting the pipe often created a caught-in-between or pinch risk, so thorough safety and hazard training for the pipe setting crew was crucial. All members of Conti’s crews – including subcontractors – were well trained to stay away from pinch points and never stand between the pipe and a fixed object. Due to the extreme Louisiana summer heat, Conti also paid special attention to welders, using various methods to keep them cool. When the heat was too strong, the team discontinued the activity.
Another danger involved the swale that ran alongside the pipeline as it was being installed. During heavy rain events, if the cofferdam was not properly protected with a berm, there was a risk that the swale could flood the cofferdam. Additional dangers on this project involved working across an active highway and three active roadways where traffic mitigation plans were in place, and being mindful of snapping turtles in the area.
This project had several near misses, but thanks to Conti’s safety program, specific Activity Hazard Analyses and proactive risk mitigation efforts, the SELA 07b project was completed with zero lost time incidents.
How did you leverage new technologies to work faster and reduce waste?
As the end of the project neared, Conti looked to the growing local marketplaces for trading materials. Conti ended up re-selling over 1.72 million pounds of recycled steel through an online marketplace used by local contractors.
One innovation Conti employed was the use of two different pumping systems concurrently to lower the groundwater table due to high river elevations, needed to successfully install the drainage pump station.
Conti hired a subcontractor to lower the existing groundwater table from EL. 26 to EL. -5.0 for safety purposes by installing six deep wells pumping approximately 300 gallons per minute (gpm). This proved to not be sufficient enough to lower the groundwater to elevation -5.0, and the team therefore installed three additional wells. When the supplemental wells were still unsuccessful in lowering the groundwater table, the team installed a Point Well system in conjunction with the deep well system.
These two pumping systems together allowed Conti to pump over 500 gpm and successfully lower the groundwater in our 30-foot excavation located 850-feet off of the Mississippi River where the groundwater pressure was substantially higher than anticipated.