Project Spotlight | Andre Street Drainage and Utility Improvements

On March 12, 2012, the City of Carencro, Louisiana was inundated with over 14” of water in one morning, amounting to nearly a 500-year storm event. Large areas of the city were completely flooded resulting in emergency rescues and widespread property damage. Many of the City’s wastewater, stormwater, and roadway infrastructure were severely damaged or destroyed. Fenstermaker was hired by the City to survey and map high water marks throughout the City, and quantify the amount of inundation and damage to the City’s infrastructure. Fenstermaker led a nearly 4-year collaboration with FEMA and GOHSEP to identify improvement projects that would repair and protect the City’s infrastructure from the 500-year storm event. Fenstermaker secured federal funding from FEMA’s Hazard Mitigation Grant Program (HMGP) for multiple projects including the Andre Street Drainage and Utility Project.

This project consisted of two coinciding elements:

• The installation of over 1,200 feet of articulated block mat in the Beau Bassin Coulee to stop erosion and protect homeowners.
• The conversion of the Church St. Lift Station to a “mega” lift station capable of 2.0MGD, elevating it above the 500-year Base Flood Elevation, and upgrading the sewer force main from a 12‐inch pipe to a 20‐inch pipe.

Beau Bassin Coulee

The Beau Bassin Coulee is a main drainage channel flowing through Lafayette Parish and the City of Carencro, Louisiana, and emptying into the Vermilion River immediately north of the City of Lafayette. Before this project, the coulee was showing severe erosion, causing property loss and damage to buildings and fences. By realigning and armoring its channel with articulating block mat, the surrounding area will benefit from the prevention of further erosion, all while showing no adverse impacts to water levels.

Church Street Lift Station

The Church Street Lift Station is a critical facility to the City of Carencro, being an integral component of the city’s sewer collection system. The March 12, 2012, flood event completely inundated the pre-existing lift station. Improvements included relocating the lift station out of the flood zone and increasing the capacity to account for future flows. Repairs included new submersible pumps, wet well, valve pit, piping, a new force main, and a control panel raised above flood elevations. The force main was increased in size from an 8” clay pipe to a 24” PVC pipe. The gravity sewer main transporting the flow to the new lift station has increased from an 8” pipe to a 24”. The reason is that, in the future, a force main will transport all of the flow from the Manola Wastewater Treatment Plant to the manhole that is connected to the 24” gravity sewer main.

From a client perspective, this project is the largest lift station within the Carencro City limits. It’s capacity is designed for handling increases in future flows and is protected from the 500-year storm event. Additionally, the Andre St. Drainage and Utility project provides permanent erosion control measures along Beau Bassin Coulee by articulated block matting. The March 2012 storm event caused significant erosion damage along the coulee throughout the city. Specifically, in downtown Carencro, channel erosion was threatening to undermine the structural foundations of multiple businesses, residential homes, the Jack Street bridge, and the Church Street bridge. The top bank of the channel was less than 5’ away from structures in many locations.

The project established a strong barrier with articulated block matting between the channel and structures, corrected various erosion issues throughout the project limits, provided continuous stabilization of the channel to minimize future erosion, and reduced the risk of failing of the coulee’s high bank. The project provides future sewer capacity, protects the sewer system from a 500-year storm event, and also protects infrastructure from continual erosion for many years to come.