Portfolio Projects: Drainage & Flood Control

Service Type: Drainage/Flood Control
Project Name:   Dipple Canal Drainage Improvements
Project Location St. Francisville, LA
Client:   Town of St. Francisville
Estimated Const. Cost: $1,100,000
Funding Sources: Facility Planning, Treasury’s Office of the State of Louisiana and Local Funding

The Town of St Francisville retained PEC to solve the 30 year old erosion of the Dipple Canal drainage segment that had evolved to a critical phase endangering 12-15 residential houses located along the East Bank of this stream.  The project encompassed very complex construction and coordination elements due to environmental concerns, compliance with Corps of Engineers requirements and obtaining the overall project funding to get the design and construction underway.

The Dipple Canal is actually a natural stream segment that meanders through the community and is considered a significant ecosystem of the area.  However, the continuous deterioration of the East bank along this stream had actually destroyed or eroded much of the yards of the homes along the East bank of the stream.  If action was not taken soon, the unstable condition of the banks would have lead to severe consequences.

Funding of the project was a project unto itself.  PEC worked with the Town of St Francisville to eventually be awarded over $1,000,000 of grant funding sufficient for the whole project through the State Capital Outlay program and the Governor’s Local Government Assistance Program.  These project dollars were one of the largest State per capital grant awards made through 2008.

To initiate the program, PEC did an extensive hydraulic analysis of the existing stream segment and its ability to adequately handle various flow conditions related to storm events. The analysis showed an estimated 2100 feet of stream bed had to be both raised and contoured to enhance flow and prevent accelerated erosion.  In coordination with the COE’s environmental and hydraulics group monitoring and permitting the project, it was determined the proposed stream alignment must follow the existing natural meanderings of the stream to protect the extensive wildlife, in-stream vegetation and forest stand along the West bank.  The COE also would not allow the installation of a temporary bypass pipeline in the stream bed to allow continuous work on the project.  Construction activities had to be critically scheduled in dry periods to allow the work to proceed.  All erosion control work was done on the East bank of the stream while the West Bank flora and fauna was not to be disturbed.  However, two temporary road accesses on the West Bank were identified. Each was highly scrutinized for impact on existing wetlands and subsequently approved to allow adequate fill to be brought into the site.  PEC assisted in the acquisition and donation of the fill from a private landowner which saved the Town substantial dollars and the land owner was able to use the excavation for a pond site.  Extensive geotechnical work was done at the site to determine quality of the fill to be placed, stability of the existing slopes and bank stabilization recommendations.  Approximately 2100 feet of bank was stabilized using combinations of rip rap, hydro mulching and geotextile matting.  An additional 400 feet of an upstream segment was required to be desnagged and cleared of debris to also improve stream hydraulics.  The project was completed in 4 months at the proposed $1.1 million dollars of funding.

Service Type: Drainage/Flood Control
Project Name:   Plaquemines Parish Stormwater Pump Stations Replacement
Project Location Empire & Homeplace (Plaquemines Parish, LA)
Client:   Plaquemines Parish Government
Estimated Const. Cost: $17,200,000
Funding Sources: FEMA

PEC as a sub consultant to Stuart Consulting is responsible for the complete design and construction administration of two major stormwater pumping stations that are part of the FEMA funded replacement work for damaged infrastructure due to Hurricane Katrina. The stations have rated capacities of 190 and 408 CFS and require major reconstruction efforts. The firm is responsible for designing the new station hydraulics to conform to new ABFE elevations and approval and coordination of all aspects of design with local parish authorities, their Program Manager, the COE, and FEMA officials. PEC is working extremely close with Parish officials to ensure the station conforms to their needs and any future levee improvements that will effect the pump stations discharge hydraulics and relocation of the discharge outfall line. The firm is coordinating a multi disciplined team of surveying, geotechnical, structural, electrical, and civil personnel to meet a mandated fast track schedule demanded by the Parish officials. The firm must provide plans that provide constructability with Parish ROW and meet the new flood elevations for structures in this Parish.

Service Type: Drainage/Flood Control
Project Name:   Pointe Coupee Parish Drainage Improvements
Project Location Pointe Coupee Parish, LA
Client:   Pointe Coupee Parish Police Jury
Estimated Const. Cost: $662,000 (construction)
Funding Sources: State of Louisiana – Capital Outlay Program

Project consisted of the design and construction management for bridge repairs, new bulkheads, sediment basin dredging, and concrete lining of False Bayou. Project also included the clearing and desnagging of Lighthouse Canal which is the outfall for False River. PEC had to work closely with the Parish and landowners along the various drainage routes to ensure work was done within ROW and construction servitudes.   Disposal of dredged material and canal debris had to be  permitted and disposed of in DEQ and COE approved procedures.   This project demonstrates  PEC’s capability to coordinate  a variety of disciplines and activities including stakeholder input topographic survey, drainage design, CADD drawing preparation and construction management.