Florida Avenue Canal Widening

The Florida Avenue Canal Widening Project in New Orleans is part of a $280 million construction effort to improve drainage in New Orleans and Jefferson Parish so that it can handle major rainstorms. As a subconsultant to Boh Brothers Construction, Thompson Engineering provided services on Phases II and III of the project. Responsibilities included:

Develop dewatering plans for the project, specifically for a series of temporary retaining structures (TRS) along the project alignment. Each TRS is approximately 300 feet in length and 60 feet in width.
Dewatering plans include bottom stability analysis and recommend piezometer locations in accordance with USACE specification.
Key requirements of the dewatering specification were to lower and maintain the water table in pervious stratum to meet the required drawdown elevations within the confines of the TRS and operate recharge wells to maintain or restore the groundwater surface outside of the excavation where the groundwater surface has been lowered as a result of operation of the dewatering system inside the excavation.
One set of vibrating wire piezometers (a set consisting of 1 piezometer within the interior of the excavation, 2 piezometers immediately outside the excavation but within the project right of way, and 2 piezometers at the project right of way positioned in line with the interior piezometers) were installed at each TRS cell. Each piezometer were equipped with a wireless interface transmitting to a base station. Base stations were placed along the project alignment. The base stations transmitted all data via cellular modems to the monitoring software which can be accessed by a remote computer.
Seven inclinometers extending to depths of 100 feet below the existing ground surface were installed to evaluate lateral movement outside the excavation. Monthly readings and a data report were provided on a monthly basis.