Client: U.S. Army Corps of Engineers - Jacksonville District
Completion Date: 9/30/2001
GEC was tasked by the Jacksonville District to provide a complete feasibility study and General Reevaluation Report (GRR) for the L-8 Basin in West Palm Beach, Florida. The L-8 Basin is a rapidly urbanizing area in western Palm Beach County with both natural and institutional constraints to flood water drainage. In this Phase 2 effort, GEC provided a quantitative and qualitative screening of the nine project alternatives developed by the Jacksonville District in its plan formulation activities. The primary purpose of this project was to develop costs and benefits for each of the nine alternatives in sufficient detail to recommend the three best alternatives for more detailed evaluation. While primarily a flood control effort, the protracted drought in South Florida in combination with the rapid population growth in Palm Beach County, heightened the importance of the water supply benefits and ecosystem restoration opportunities of the recommended alternatives. Another unique aspect of this project was the importance of collateral flood damages to detached buildings, landscaping, roads, and transportation delays in an area where homes are typically above the 100 year flood height. Additionally, the Comprehensive Everglades Restoration Program posed both development constraints and the opportunity for environmental enhancement in the formulation of the best alternatives.
The GRR required a feasibility level study to evaluate the originally authorized project and reformulation based on changed conditions. The study was conducted in accordance with ER 1105-2-100 dated 22 April 2000. The Feasibility Study Report began with the purpose and need for the study effort including problem and opportunity statements. Existing conditions were documented and the problem was clearly identified. Plan formulation was revisited to reaffirm the Federal objective, the National Economic Development Plan, planning goals and objectives, planning constraints, possible alternative measures and nine alternatives were evaluated and ranked based on their overall effectiveness, acceptability, completeness and efficiency in addressing the problems identified in the Basin. The Hydraulic Engineering Center-Flood Damage Assessment computer program was used to identify flood damages under existing conditions; and for each of the nine, project alternatives. Preliminary design was completed and costs were developed for each of the nine alternatives.
