Baptiste Collette Channel Deepening Section 202 Feasibility Study

Baptiste Colette Spanish PassAs a sub consultant to HNTB Corporation, Coastal Engineering Solutions, LLC was responsible for the evaluation of the beneficial use of the dredged material associated with the proposed channel deepening maintenance dredging. This analyses included the quantification of dredged material, identification of potential restoration projects for the dredged material, and the assessment of feasibility and cost associated with each restoration project.  The various costs were developed and compared to the cost of disposal within the federal standard.  The identification of potential projects for beneficial use included the CPRA Master Plan, Plaquemines Ridge Restoration Program, Fringe Marsh Program, and projects submitted to CPRA for 2017Master Plan update.  Alternative dredge material delivery methods were also evaluated, including barge transport of dredge material and offloading.  From the analysis, a transport option and associated costs could be developed based on the quantity of material being dredged in the cycle.   

An evaluation was also performed to determine the average quantity of material beneficially used to create a unit acre of wetlands, as well as a historic evaluation of wetlands created through the maintenance dredging of Baptiste Collette.  An economic evaluation of wetland benefits was also performed to monetize the benefits of wetlands created, through beneficial use, for the life of the project.  This monetization involved the assessment of cost incurred for wetlands impacts mitigation associated with flood protection projects, the cost associated with CPRA restoration projects, and the Natural Resources Damage Assessment (NRDA) monetary valuation of wetland impacts associated with the BP Spill.  From this analysis, wetlands restored from the beneficial use of the maintenance dredging could be evaluated in the benefit cost (B/C) analysis.  At the request of the Secretary of the Army, pursuant to Presidential Memorandum M-16-01 of October 7, 2015, this evaluation of environmental benefits was included as an appendix to the Section 202 Feasibility Study and will be used in the evaluation for authorization.  

FEMA Levee Analysis and Mapping Procedures (LAMP) Pilot Program Modeling Review

LAMP 1LAMP 2As a sub consultant to HNTB Corporation, Coastal Engineering Solutions, LLC was responsible for the technical review of model applications used to develop the preliminary base flood maps for Plaquemines Parish Government (PPG). This review was held in connection with the FEMA Levee Analysis and Mapping Procedures (LAMP) Pilot Program. Specific responsibilities included the review of applied hydrodynamic and wave models, specifically ADCIRC and WHAFIS. This review included analysis of model inputs, including WHAFIS transects, tidal and wave boundaries, bathymetric data, polders and associated pumping rates, levee alignments and associated heights, vegetation and manning’s roughness coefficients. An inventory of updated modeling efforts of a similar nature was performed to provide insight to improvements in model bathymetry or other model inputs and inclusion of subsequent completed restoration works. Research was also performed to identify existing successful appeals submitted to FEMA as examples for Plaquemines Parish Government to pursue on the FEMA preliminary DFIRMs.

Iberia Parish Flood Protection Master Plan

Iberia Master PlanAs a sub consultant to Royal Engineers and Consultants, LLC, Coastal Engineering Solutions, LLC was responsible for the research and review of existing hydrodynamic modeling data, economic analysis, and the development of planning level design and cost estimates for a new flood protection system across Iberia Parish.  The planning level preliminary design consisted evaluating potential alignments, identifying potential constraints, reviewing and incorporating other studies in the project area, sizing features based on the hydrodynamic modeling for the design storm event, developing quantities and developing costs.  Features included various gate structures, levee systems, highway crossings, and railroad crossings.  Cost estimates were developed by comparing recently bid items of similar size and type and making adjustments based on scale and project conditions.  For the levee sections, construction layout had to be developed and construction methods had to be predicted in order to determine fill cost.  CPRA socioeconomic data and damage assessment data was also researched, reviewed, and incorporated into the plan.  During the master planning effort, alignments were modified and refined to maximize cost benefit ratios.  The end product of the Master Plan included preferred reach alignments, project costs by reach, project phasing and project schedule, as well as an evaluation of potential funding sources.

Plaquemines Parish East Bank New Orleans to Venice Non Federal Levees (NOV-NFL) Mitigation Engineering and Design
Mitigation Area B

This project involved the engineering, design, final plans and specifications for the offset mitigation wetland restoration associated with the NOV-NFL levee lifts.  A bathymetric survey was performed on the mitigation areas and borrow areas.  The engineering and design involved site selection, borrow source evaluation, site layout, settlement analysis, containment design, and the development of final plans and specifications for two (2) mitigation areas totaling over 20 acres.  Borrow source analysis involved identification of potential “least impact” borrow areas within the vicinity of the project, as well as collection and review of available geotechnical data for the locations.  Slope stability analysis on the containment dikes was performed using the Slope-W program and settlement of the dredge material was performed using the Primary Consolidation, Secondary Consolidation, and Desiccation of Dredged Material (PSDDF) software.