DDG was engaged as a project partner in the planning, design, engineering, and permitting of a $9.4 billion industrial complex. Project involvement has included site evaluation, land acquisition assistance, local and state permitting support, land use approval assistance, project stakeholder coordination, community outreach involvement, drainage modeling, preparation of permitting plans, and associated marine terminal facilities, architectural design, and project due dilligence coordination.
Specific H&H tasks included conducting a floodplain evaluation to support the site development and engineering activities associated with the proposed industrial complex. The project area, located approximately 3 miles southeast of the Sunshine Bridge in St. James Parish, Louisiana, is located within a FEMA Special Flood Hazard Area (SFHA) Zone AE. Development activities are thus subject to the National Flood Insurance Program (NFIP) Regulations44 CFR 59 through 44 CFR 80) and associated local floodplain management ordinances. DDG was responsible for demonstrating that the existing floodplain and associated flood elevations would not be affected by the development of the site. To accomplish this, DDG updated an existing HEC-HMS and HEC-RAS model previously developed for the Donaldsonville to the Gulf Feasibility Study to reflect changes in hydrology as well as site grading activities.
In addition to floodplain evaluation, DDG conducted a comprehensive study of the existing hydrologic conditions, designed facilities to mitigate the potential for increased runoff, and sized all critical drainage infrastructure including storm drains, culverts, and channels. DDG documented the results of the drainage analysis for review by DOTD to demonstrate no impacts to existing highway culverts and for Louisiana DNR Office of Coastal Management to demonstrate no hydrologic impacts to downstream waterways. A myriad of hydrologic and hydraulic models was used in the design and analysis (PCWMM, Storm and Sanitary Analysis).
The total evaluated area was 2,567.25 acres which included 1,873.71 acres within the actual project boundary and 693.54 acres of offsite area.