Pontchartrain Levee District West Shore Hurricane Protection Feasibility Study
BKI was selected by the Pontchartrain Levee District and U.S. Army Corps of Engineers, New Orleans District, to conduct a feasibility study.
The mission of the West Shore Lake Pontchartrain Hurricane Protection Project was to provide hurricane protection to existing developments in the Montz, LaPlace, Reserve, and Garyville areas.
Protection was provided from the Upper Guide Levee of the Bonnet Carré Floodway westward through the LaPlace area to the Maurepas Diversion Levee along the Hope Canal, and included protection for portions of I-10, I-55 and U.S. 51. These roadways were designated hurricane evacuation routes for this area and the New Orleans Metropolitan area.
The Pontchartrain Levee District, St. Charles Parish, St. John the Baptist Parish, and the U.S. Army Corps of Engineers analyzed a levee alignment acceptable to all parties. The feasibility study report and draft environmental impact statement was finalized and submitted to the U.S. Army Corps of Engineers Regional and Headquarter offices for approval.
The alternative alignment concept has been accepted by the Corps and has been incorporated into the feasibility study and the draft environmental impact statement with favorable benefit to cost ratios. Three alignments were fully analyzed as part of the feasibility study and the draft environmental impact statement.
BKI’s assignment on the project included a technical review of the draft feasibility study, development of a third levee alignment, and the completion of portions of the feasibility study and the draft environmental impact statement.
St. Charles Parish Westbank Hurricane Protection Levee
BKI was selected by St. Charles Parish to perform hydraulic and hydrologic modeling using HEC-RAS to assure adequate protection of the Parish, adjacent wetlands and the ecosystem.
The west bank of St. Charles Parish (west side of the Mississippi River) outside of the US Army Corps of Engineers' Hurricane Storm Damage Risk Reduction System (HSDRRS) is unprotected from storm surges associated with both hurricanes and high tide conditions. Levee projects currently adjacent to this area have the potential to act as a funnel, thereby increasing the storm surge elevations in the project area.
This portion of the Parish is subject to heavy rainfall, tidal surges from the Gulf of Mexico, and hurricane flooding, often resulting in damages to industrial, commercial, residential, agricultural, and environmental facilities. The area has been declared a federal disaster area numerous times, and as recent as 2008, the Federal Emergency Management Agency (FEMA) provided disaster assistance to St. Charles Parish.
As a result, St. Charles Parish is constructing a new earthen levee (The St. Charles Parish West Bank Hurricane Protection Levee, or “WBHPL”) to reduce the damages caused by storm surges. The nine-mile levee alignment extends from the Sunset Levee District on the western flank to the Davis Pond Guide Levee to the east. Three new drainage pumping stations and numerous tidal exchange structures are necessary to address both the interior drainage and the encapsulated wetlands ecosystem. The total construction cost of the project is in excess of $100 million.
The St. Charles Parish West Bank Hurricane Protection Levee is a phased project consisting of the following: The Magnolia Ridge Phase has a partially constructed earthen levee, including a first lift. A second lift, tidal interchange structures, and major pumping station are currently in the design stages. Permits have been secured to complete this work and the work in the two other major phases of the WBHPL.
The Willowridge Phase includes earthen levees, drainage canals, tidal exchange structures, concrete T-Walls, and a drainage pumping station. Construction of the first segment of this phase completed in 2015. The limits of this current construction phase will provide hurricane risk reduction via an earthen levee built to an elevation of +7.50 which will protect the Willowridge and Willowdale subdivisions.
The Parish is currently constructing additional components of the Willowridge Phase of the WBHPL: First, a 300 cfs pumping station near the southern center of the Willowridge levee alignment to drain the adjacent Willowridge/Willowdale basin and to serve as a complement to the nearby Cousins Pumping Station in emergency situations to assist in draining a larger portion of the West Bank. Concurrently, a 1,500 levee segment (Elevation +7.50) from the western end of the existing construction project to the Davis Diversion Levee, including T-Wall frontal protection at the existing Willowdale Pumping Station.
The Ellington Phase includes earthen levees, drainage canals, tidal exchange structures, concrete T-Walls at the existing Cousins and Kellogg Pumping Stations and across two gas pipeline locations, and a drainage pumping station. Design of various components of this phase of the WBHPL is underway, and construction of the earthen levee portion of this phase is under construction.
The attached maps illustrate the WBHPL system and the major phases therein.
USACE Chalmette Levee Loop: Verret to Caernarvon Levee Reach
BKI was selected by the U.S. Army Corps of Engineers, New Orleans District, to perform engineering services during design, advertisement and construction for the enlargement of approximately 44,165 linear feet of levee between Verret, LA and the Caernarvon floodwall.
The construction consisted of clearing and grubbing, placing silt fencing, placing compacted and un-compacted embankment, fertilizing, seeding, and mulching, placing crushed stone surfacing material, constructing ramps, earthen I-wall transitions with slope paving and scour protection, and other incidental work.
Minimal damage occurred to this levee after Hurricane Katrina. However, the height of the existing levee was below the authorized design grade.
BKI was called upon to initiate design through verification of levee stability to meet the latest Interagency Performance Evaluation Taskforce design guidelines that had recently been developed. Through levee stability analysis, BKI was able to establish design templates and identify grade deficiencies.
Plans and specifications were developed to reflect the enlargement of the levee, to address the height deficiencies, and to provide a level of protection coincident with the authorized design grade.
BKI’s services extended through the advertisement and construction phases. During construction, BKI provided oversight through regular site visits, review of contractor’s submittals, and responses to requests for information.