Coventry Court Drainage Evaluation Feasibility Report and Subsurface Design
River Ridge, Louisiana
Overview
In early 2017, and following repetitive street flooding in the Coventry Court area of River Ridge, MSMM Engineering worked with the Jefferson Parish District 2 office to propose a solution to the flooding issues in the area. The MSMM engineering team identified several potential options that could be evaluated, and in 2018 the Jefferson Parish Council tasked our staff with developing a multi-phase feasibility report to evaluate several drainage solutions in the area.
As part of the Coventry Court evaluation, the Jefferson Parish drainage department requested that MSMM investigate and determine the feasibility of providing improved drainage. The investigation consisted of the following:
– Evaluation Phase/Data Review – collection and analysis of existing information
– Field Reconnaissance and Preliminary Survey – collection of relevant field information
– Model Runs and Calibration – updated the HEC-RAS model with the area’s data for 10-year, 50-year and 100-year storm events.
– Cost Estimating of Multiple Alternatives – provided detailed cost breakouts consisting of vendor furnished pricing data for materials
– Development of a Prioritized List of Recommendations
The final report was completed in less than 6 months, and the final recommendation is to design a new drainage pump station on a vacant parcel owned by the parish between Coventry Court and Lee Court, westerly of Jefferson Highway. This 90 cfs (120 cfs ultimate) pump station with a 48’ open cut discharge forcemain placed down Colonial Heights Road and over the Mississippi River levee. Other project features consist of a discharge dolphin in the Mississippi River and upsizing of the Jefferson Highway drainage crossings and downstream conveyance. This recommended alternative provides the greatest pumping capacity while requiring the least amount of permanent drainage servitudes.
MSMM was also selected to provide subsurface drainage design phase of the Coventry Court project. For this component of the project, our civil and structural engineers are currently designing 500 linear feet of 48” RCP drain pipe from Rex to Hazel Street, 1,100 linear feet of 54” RCP drain pipe from Hazel to Colonial Heights, and 200 linear feet of 72’ RCP drain pipe from Jefferson Highway to the proposed site of the drainage pump station. This drainage design was the first step in the Coventry Court drainage pump station process, and allowed the project to move forward as utility conflicts and permitting for this phase.