The city of Jacksonville’s Lower Eastside neighborhood has been plagued by localized flooding problems for many years. This project involved civil engineering services to correct this long-term infrastructure problem by developing a new stormwater collection system on seven key roadways in the area bounded by Spearing Street on the west, Seventh Street on the north, Harrison Street on the east and First Street on the south.
Improvements included new stormwater collection system mains ranging from 24- to 72-inch piping that traversed Van Buren Seventh and Fourth streets. The total project length was approximately 8,700 linear feet and included reconstructing the roadways, installing new curb and gutter and sidewalks, and designing and constructing new potable water and sanitary sewer lines.
This 152-acre project area was part of a larger city effort to improve drainage in a 536-acre drainage basin designated in the city’s master stormwater management plan as Upper Deer Creek.
This $6.8 million project was the last of three phases of drainage improvements. Phase 1 included improvements for neighborhoods north of Lower Eastside, and Phase 2 involved construction of a regional pond to attenuate and treat the stormwater from this project. The improvements are expected to have a life span of at least 50 years.
Hanson’s services included drainage design analysis, groundwater modeling, preparing final construction plans and an opinion of probable costs, construction assistance and reports that summarized all collected data, calculations, geotechnical surveys and dewatering impact mitigation. Using older construction plans, Hanson performed a brief study to identify flood-prone areas and determine a level of service that was feasible within the available budget. The study results were used to develop the design for the drainage improvements.
Because the entire roadway was to be reconstructed, Hanson coordinated with JEA to provide an economical opportunity to replace the agency’s aging utility lines concurrently with the city project. As a result, Hanson designed replacements for JEA’s water and gravity sewer lines. The JEA project involved construction of approximately 9,400 feet of 2- to 16-inch PVC water main and approximately 6,000 feet of 6- to 12-inch PVC gravity sewer within the project limits. The project included design for a hydraulic barrier to prevent contaminated groundwater from migrating onto the city’s right-of-way during construction dewatering activities. Completing both projects simultaneously minimized conflicts with the new stormwater collection system.
Because construction required deep excavation and roadway reconstruction, a detailed Maintenance of Traffic (MOT) plan was developed for the neighborhood streets. The MOT plan limited the amount of excavated area left open each night to provide residents access to homes.