New Orleans District U.S. Army Corps of Engineers (USACE) team members working on the Morganza to the Gulf project hosted their first Industry Day for the Gulf Intracoastal Waterway (GIWW) East and West Floodgates at USACE New Orleans District headquarter Oct. 13, 2023.
Project Management, Engineering and Contracting representatives presented overviews of the Morganza to the Gulf Flood Risk Reduction system, GIWW East and West Floodgates and associated challenges, and the Integrated Design and Construction (IDaC) contracting method.
Feedback on the subjects was received from industry representatives during one-on-one meetings following the presentation.
The authorized Morganza to the Gulf (MTG) project is a hurricane and storm damage risk reduction (HSDRR) project involving a 98-mile alignment of earthen levees, floodgates, environmental water control structures, road/railroad gates, and fronting protection for existing pump stations. This system is being designed to reduce the risk of damage related to flooding for the 1% Annual Exceedance Probability (AEP) in Terrebonne and Lafourche Parishes, where a deterioration of coastal marsh has led to an increased risk of inundation.
More information about the GIWW East and West floodgates and IDaC can be found at the following websites: https://www.mvn.usace.army.mil/About/Projects/Morganza-to-the-Gulf/ and https://sam.gov/content/home.
As residents of Louisiana prepare for possible disruptions in their drinking water caused by saltwater intrusion, researchers from the U.S. Army Engineer Research and Development Center (ERDC) are assisting the U.S. Army Corps of Engineers (USACE) New Orleans District with assessment and mitigation efforts.
With much of the lower Mississippi River Valley experiencing extreme drought conditions, the lack of rainfall has led to lower levels of fresh water in the Mississippi River, allowing for a denser layer of salt water from the Gulf of Mexico to make its way upstream, threatening the drinking water supplies in several Louisiana communities, including the city of New Orleans.
River conditions are low and have been for some time. The bed of the Mississippi River is much lower than the sea level in the Gulf of Mexico, and if there's not enough fresh water to apply pressure to keep the salt water in the Gulf of Mexico, then it slowly migrates upstream in the shape of a wedge.
“When fluids of different densities encounter each other — which in this case, salt water is denser than fresh water — they tend to stratify,” said Gary Brown, a research hydraulic engineer with the ERDC’s Coastal and Hydraulics Laboratory. “So, the fresh water flows over the salt water, and the salt water flows under the fresh water.”
Salt water has been steadily migrating upstream against the current, and as long as those low river conditions persist, without intervention, that upstream migration will persist.
“Salt is not something that you can conventionally deal with in drinking water filtration,” said Brown. “You can't filter it out of the water, and it corrodes the pipes. It's a significant issue, not only for drinking, but also for agriculture and livestock.”
Though it’s a relatively new term to many, experts at ERDC have been studying these saltwater wedges and intrusion for decades.
“We owe a lot of our knowledge of the salt wedge and salt dynamics to the work that has been done here at ERDC over the years by many different people,” said Brown. “We have much understanding of the basic physics of saltwater wedges, and a lot of that pioneering research was done right here. There was a lot of the early physical and numerical modeling of salt wedges that was developed here, as well.”
To help assess the current conditions, the team is using a basic model they developed with a freshwater layer on a saltwater layer that interact.
“We have a fairly simplified model of the Mississippi River, but it's pretty effective,” said Brown. “It's been successful at predicting where the salt's going to be, and it runs quickly allowing for a lot of ‘what if’ analysis.”
“This is an emergency operation, and we need really quick turnaround of our assessments,” he continued. “We want to be able to do a lot of assessments, not only of what may happen in the future, but also what effects some of our interventions may have. With this tool, we can run very rapid, quick assessments.”
Though ERDC is known for its expertise in research and development, the organization often assists in actionable, emergency operations support — events that are happening right away and impacting a lot of people’s lives immediately.
“Gary and his team have been unwavering in their support to the New Orleans District’s Lower Mississippi River Engineering Branch during this event,” said David Ramirez, chief of the Lower Mississippi River and Tributaries Branch at the New Orleans District. “Their technical assistance by refining an existing hydrodynamic model of the Lower Mississippi River enabled us to respond quickly to this crisis and provide technical information — such as salinity intrusion progress and influence of the natural crevasses along the east bank of the Lower Mississippi River — to USACE leadership and the local governments.”
“The role we play is to try to provide the best information in real-time to support the decision makers,” said Brown. “It's our job to provide the best objective analysis we can — even if that objective analysis is bad news — so that the decision makers can have the opportunity to make the most informed, rational decisions.”
That work is still being used to provide critical data to the Water Management Section and the District Commander, who make real-time operational decisions.
“One of the main products from ERDC is the forecasted salinity locations,” said Ramirez. “The official timeline of when municipal freshwater intakes may be impacted is developed directly from these results. The data is also being used by many local and state government leaders to plan and design saltwater intrusion mitigation strategies.”
“We are working very hard with the district to try to mitigate this issue as much as possible,” said Brown. “We recognize that this is a serious situation for a lot of people in the New Orleans area and the downstream communities. It's a privilege to be able to do something like this and possibly impact people's lives.”
“Gary and his team continue to offer transformative novel, but technically sound, applied solutions to the district at the operational timescale immediately useable for decision making,” said Ramirez. “Cutting-edge technology for decision making today is a rare commodity at the best research intuitions, and we had that luxury through the current emergency saltwater intrusion operations thanks to Gary and the team at ERDC.”
The U.S. Army Corps of Engineers, New Orleans District, held a press conference Sept. 15, 2023, at their headquarters in New Orleans, La., to discuss planned efforts to address continued low-water conditions on the Mississippi River.
Col. Cullen Jones, USACE New Orleans District commander, briefed media on current steps the Corps plans to take to augment the existing underwater sill while working with the U.S. Coast Guard and navigation industry to maintain navigation along the Mississippi River. In addition, Plaquemines Parish President Keith Hinkley and Governor’s Office of Homeland Security and Emergency Preparedness director, Casey Tingle, spoke to media at the conference about steps to ensure safe and sufficient water supplies for parish residents.“
The current National Weather Service Mississippi River forecasts the river’s volume to fall to historic lows over the next several weeks,” said Jones. “If these conditions occur, the USACE-constructed saltwater barrier sill is expected to be overtopped by saltwater intruding upriver from the Gulf of Mexico, leading to unsafe salinity conditions at municipal water intakes located north of the sill location.
”Efforts under consideration include barging water downriver to municipal treatment facilities and placement of Reverse Osmosis Water Purification Units to allow for treatment of river water with high chloride levels. USACE has already issued a contract to place a reverse osmosis water purification unit at the East Pointe a la Hache Water Treatment Plant.
To mitigate for the Deep Draft Shipping Channel’s influence on the rate of upriver saltwater progression, USACE constructed an underwater barrier sill in July 2023 to create an artificial basin that delays the ingress of saltwater beyond river mile 64 above Head of Passes. An underwater sill was constructed on four previous occasions in 1988, 1999, 2012 and last year in 2022. During previous low-water events, such as 1988 and 2012, barging was used to transport fresh water to treatment facilities downriver of the saltwater wedge.
USACE continues to closely monitor, survey and model the impacts these conditions may have on the river with regards to both navigation and saltwater intrusion from the Gulf of Mexico. Saltwater intrusion is a naturally occurring phenomenon when the river flows fall below 300,000 cubic feet per second because the mass of fresh water is no longer capable of preventing saltwater from moving into the below-sea-level river channel. The current National Weather Service forecast projects river levels falling to approximately 130,000 cubic feet per second in the New Orleans area. These levels represent the lowest river volume in this area since the recorded low of 120,000 cubic feet per second in 1988.
“This low-water event marks the first time underwater sills were required in back-to-back years as a result of saltwater intrusion from the Gulf of Mexico,” Jones added. “However, the New Orleans District is ready to meet this challenge with the best science, engineering data, and technology available.”
The U.S. Army Corps of Engineers, New Orleans District has selected Horsepower Geospatial LLC for a five-year, $6 million architecture and engineering contract to deliver geospatial surveying and mapping services. The indefinite delivery, indefinite quantity contract will serve the needs of the New Orleans District and may be utilized within the Corps’ Mississippi Valley Division, South Atlantic Division, and Southwest Division. Horsepower Geospatial is a U.S. Small Business Administration mentor-protégé joint venture of Woolpert and Resolution LLC.
Under this contract, Horsepower Geospatial will provide services that include GIS and geospatial production, digital aerial photography, airborne lidar, photogrammetric mapping, remote sensing, large- and small-scale topographic mapping, river navigational charting, and land use/land cover analysis.
Woolpert Geospatial Program Director Tim Summey said Horsepower Geospatial unites the strengths of Woolpert and Resolution staffs, capabilities, and experience specific to the needs of the Corps. This was the first contract award and first contract submitted by Horsepower Geospatial.
“Staff members from our two companies have worked together for decades, and by formalizing our relationship, we can collaboratively build on past performance and responsiveness with the Corps, while gaining the inherent versatility of a true joint venture,” Summey said. “We’re very excited to get this first contract win because it confirms that the Corps sees the same value in this union that we do, and providing what the Corps needs will always be our top priority.”
Resolution COO Jeff Lower added that this extends the combined team’s work throughout the South, as well as the Mississippi Valley Region.
“Members of Horsepower have been involved in this contract in one way or another since 1994,” Lower said. “We know the area and the needs of the Corps, and our teams have a collaborative, client-focused approach to accurate and efficient geospatial data solutions. We founded our company based on integrity, service, and excellence, and this is what we will continue to deliver to the Corps.”
About Resolution LLC
Resolution LLC is a Service-Disabled Veteran Owned Small Business and SBA Certified 8(a) firm founded in 2016, with expertise in geospatial, surveying, environmental health and safety, and project management services. Resolution has experience in supporting geospatial data collection and production for agencies including USACE, Air Force, NAVFAC, and NASA. For more, visit resolutionhsv.com
Woolpert is the premier architecture, engineering, geospatial (AEG), and strategic consulting firm, with a vision to become one of the best companies in the world. We innovate within and across markets to effectively serve public, private, and government clients worldwide. Woolpert is a Global Top 100 Geospatial Company, a Top 100 ENR Global Design firm, earned six straight Great Place to Work certifications, and actively nurtures a culture of growth, inclusion, diversity, and respect. Founded in 1911 in Dayton, Ohio, Woolpert has been America’s fastest-growing AEG firm since 2015. Woolpert has over 2,000 employees and more than 60 offices on five continents. For more, visit woolpert.com.
With all 17 permanent pumps inspected and restored, the U.S. Army Corps of Engineers will remove the contingency pumps installed on the Pratt Drive side of the London Avenue Outfall Canal in New Orleans, La. The process to carefully remove the pumps and all associated piping will begin Monday, July 10, and take approximately one month to complete.
USACE, in partnership with the U.S. Navy Supervisor of Salvage and Diving, installed 34 temporary pumps to provide emergency pumping capacity while work was underway to inspect and restore the permanent pumps at the London Avenue Permanent Canal Closures and Pumps structure. These pumps provided a combined 1,000 cubic feet per second (cfs) in pumping capacity to ensure the pump station could perform as needed while the 1,800 cfs Pump #1 was under repair. These contingency pumps are no longer necessary as the London Ave. PCCP has been restored to its full design capacity of 9,000 cfs.
Once all temporary components have been removed, USACE will begin restoration of the impacted greenspace. This work will include seeding and fertilizing the site, mulching and aerating the existing trees, pruning the crape myrtle trees, and planting two additional oak trees. A licensed horticulturalist and arborist will be hired to ensure the effort is done appropriately.
In February 2023, USACE identified corrosion as the primary cause of failure at Pump #1 at the London Avenue PCCP. In response, USACE began efforts to restore Pump #1 and worked with the PCCP Joint Venture contractor to inspect and repair, if necessary, the remaining 16 pumps at the three PCCP locations to ensure the pump stations would perform as designed during the 2023 Atlantic Hurricane season. These inspections and repairs were completed on June 1, 2023, with all pumps deemed available and reliable for hurricane season.
Following hurricane season, USACE will begin a long-term effort to deliver pumps that are sustainable, reliable and meet the 35-year design life. This work will take place outside of hurricane season and is anticipated to take multiple years.
Col. Cullen Jones, commander, U.S. Army Corps of Engineers, New Orleans District, inspected progress on repairs to the London Avenue Permanent Canal Closures & Pumps (PCCP) in New Orleans, La., and installation of temporary pumps May 30, 2023, to ensure pump capacity will be met before the start of this year’s Hurricane Season.
In February 2023, USACE and its partners identified corrosion as the primary cause of failure for Pump #1 at the London Avenue PCCP.
Pump #1 is under repair and scheduled to be returned to service before the start of the 2023 Hurricane Season.
Jones interacted with Corps personnel and contractors working onsite to install temporary pumps and complete repairs to the PCCP. He also spoke with residents living close to the job site who had questions about the work being performed at London Avenue.
The U.S. Army Corps of Engineers, New Orleans District, recently awarded a contract for constructing the second levee reach on the West Shore Lake Pontchartrain (WSLP) Hurricane and Storm Damage Risk Reduction project. This contract will construct approximately one mile of the 17.5-mile-long levee system that will provide 100-year level risk reduction to the area extending from the Bonnet Carre’ spillway to Garyville.
The contract was awarded on March 15, 2022, to B&K Construction of Mandeville, Louisiana for the construction of levee reach 107, which is approximately 1.7 miles long. The contract at award is $25,467,475.00. Work will be performed in St. John the Baptist Parish, Louisiana. The levee elevation will be 9.6 feet.
“Delivering the West Shore Lake Pontchartrain Hurricane and Storm Damage Risk Reduction project is a top priority for the Corps of Engineers and its partners the Coastal Protection and Restoration Authority and Pontchartrain Levee District,” said USACE Senior Project Manager Bradley Drouant. “This contract for construction of the system’s second large-scale levee reach is another important step towards achieving the federal, state and local commitment to residents of St. Charles, St. John and St. James Parishes.”
The West Shore Lake Pontchartrain project will achieve 100-year storm surge risk reduction by a variety of structural and non-structural features to include: levees, floodwalls, and pumps. While these features will reduce risk from storm surge associated with tropical events, they do not specifically reduce risk of flooding from significant rainfall. The project design team continues to work with the Non-Federal sponsor to acquire Rights of Entry (ROE) and coordinate with utilities and pipelines within the project footprint. Contracts completed include test sections, clay stockpiles, sand stockpiles, sand placement, and access road construction.
For more information on the West Shore Lake Pontchartrain project: