Noted as one of the City of St. Augustine’s “most ambitious public works projects”, the Riberia Street Rehabilitation project was a complete overhaul of its utility infrastructure, stormwater systems and surface construction.
The street itself is located in a narrow corridor through the Lincolnville Community on the west side of the St. Augustine peninsula. It runs through urban business and residential neighborhoods, ending at the Willie Galimore Recreation Center and City Public Works Facilities.
ETM was contracted by the City of St. Augustine to upsize and update the utilities under the roadway, provide stormwater drainage and treatment for runoff and reconstruct the one mile stretch of Riberia Street from King Street South to Cerro Street.
Under the contract, ETM was responsible for the roadway, utility and drainage design, as well as permitting and construction inspection for the reconstruction.
Replacing the Utility Infrastructure
While the Lincolnville community applauded the newly constructed roadway for its many improvements that made the street safer for vehicles, emergency services and pedestrians, the most beneficial improvements were made beneath the surface, to the utility system.
The Wastewater Treatment plant located on the south end of Riberia St. treats all of the city’s wastewater. The sanitary sewer force main to the treatment center runs directly under the corridor, which also holds the City’s water and gravity sewer lines and other utilities. Over the years, these lines had become old, prone to corrosion and too small to handle the increased volume that was needed for the city. The result was a decrease in quality and capacity for the community.
To fix the problem, ETM designed a replacement utility system that upsized the main sanitary force main from a 24 in. ductile iron pipe to a 36 in. PVC pipe, and upgraded the gravity sewer that ran alongside the force main from an 8 in. and 6 in. clay to 10 in. and 8 in. PVC.
Fixing the “Red Water” Problem
Over the years, many of St. Augustine’s cast iron water distribution lines have slowly corroded and rusted, leading to a large problem of “Red Water” -rust-colored water- that the city has been very intent on fixing.
Part of the Riberia Street Rehabilitation project was to update the waterlines from Cast Iron to PVC pipe, a corrosion-resistant material that would eliminate Red Water and improve water quality throughout St. Augustine. The existing 6 in. and 8 in. cast iron water mains were replaced with a new 12 in. PVC water main providing cleaner water and increased pressure.
Securing Funding for Stormwater Treatment
The underground treatment structures cost considerably more than a traditional storm water pond. To help secure funding for the additional cost, ETM submitted an application to the Florida Department of Environmental Protection for their 319 grant program. The City of St. Augustine won the grant and was awarded $450,000, which offset the cost of the structures.
Managing and Treating Stormwater
Flooding is a normal occurrence in St. Augustine. In fact, 90% of City residents live in a floodplain zone and see some flooding with just about every rainfall. It’s not uncommon for the roads to flood, especially if the rain coincides with peak tides.
The city’s old road infrastructure makes it even more susceptible to flooding. Riberia Street was one of these roads. The deteriorating condition, combined with a lack of a proper stormwater system, caused it to flood every time it rained, sometimes leaving the roadway covered for hours or even days.
The Riberia St. Rehabilitation Project sought to address the flooding issue by re-engineering the roadway design and providing a new stormwater system that would efficiently drain the road’s surface when it rained. An additional step in the design was to engineer a stormwater treatment system that would remove sediment, trash and debris, nutrients and metals from rainwater before it drained into the San Sebastian River.
To do this, ETM designed and installed strategically placed storm water inlets that could handle the large volume of storm water runoff produced by Riberia Street and the surrounding Lincolnville neighborhood. They then designed and placed stormwater conveyance systems to quickly transport any water drained from the roadway away from the surface.
Due to the lack of available property in the corridor, ETM proposed using underground treatment structures (shown below) instead of the more traditional stormwater ponds to address the treatment of stormwater runoff. These structures fit comfortably under the ground surface and maintains a low profile in the existing City right-of-way while separating the sediments, trash and other pollutants from the storm water before discharging to the river.
Reconstructing the Road (1 intersection with dedicated turning lane)
A final portion of the project was to reconstruct Riberia Street and complete its transformation from a rural two-lane road to an urban two-lane road with new curbs, gutters, enhanced lane markings, and a dedicated turning lanes at the Riberia/King, Riberia/Sebastian Harbor Drive and Riberia/Bridge Street intersections.
Because of St. Augustine’s historical significance, city archeologists were involved throughout the project to recover and preserve any items found that may have had historical value. However, no historically significant items were found during construction.