South Shore Basin and Ninth Ward Basin Sewer Rehabilitation Design

As part of a large sewer system program being performed by the Sewerage and Water Board of New Orleans, Trigon was a sub-consultant for design and construction phase services of multiple projects for the rehabilitation of sewer facilities in two sewerage basins of New Orleans – the South Shore Basin and the Ninth Ward Basin.

The rehabilitation measures designed were intended to restore structural integrity and eliminate significant sources of infiltration/inflow and included manhole rehabilitation (e.g., frame and cover replacements, horizontal and vertical adjustments, internal lining of manhole walls) and gravity sewer line rehabilitation (e.g., excavated point repairs, full line replacements, cured-in-place pipe lining, pipe bursting, service lateral replacements).

The general services provided as part of these projects include:
• Preliminary Design—development of remedial measures, construction contract packaging, development of a Preliminary Design Report, and presentation to a Technical Review Committee
• Final Design—preparation of plans and specifications, cost estimates, and obtaining permits for multiple construction contracts
• Bid Phase Services—advertisement of contracts, pre-bid conferences, addenda preparation, bid tabulations and award recommendations
• Engineering Services During Construction—reviewing submittals and shop drawings and responding to contractor requests for information and clarifications

Approximately $15M of rehabilitation construction will result in South Shore, while $25M of construction occurred in Ninth Ward. Construction in the Ninth Ward has been ongoing while repackaging of the South Shore design work is underway due to Consent Decree requirements.

A GIS was used to develop the rehabilitation plans for each construction project. Coupled with standard specifications, these plans formed the basis for the construction contract documents.

Trigon Associates, LLC provided engineering services through all project phases.