The Department of Labor Job Corps Center located in Arecibo, Puerto Rico was constructed at the base of a series of hills and just upstream of an area that constricts flow of runoff from the hills. This combination results in flash flooding that inundates the campus including numerous buildings and is characterized by high flows (1,700 cfs) and velocities high enough to strip asphalt from the roadways.
SAI developed a stormwater model using both 1-D and 2-D elements to represent the existing flooding conditions and evaluate the flow patterns and extents of the flooding. Model validation was conducted based on Tropical Storm Irene, which made landfall in 2011. In order to mitigate the flooding, SAI developed a series of design alternatives that involved converting a recreational area to impound the water on-site, restoring the natural flow condition by channelizing through the campus, and an underground option that impounded water offsite upstream of the Center and then conveyed the runoff underground through the site via large concrete box culverts. A NEPA study was conducted to identify and evaluate the potential impacts of the proposed design alternatives.
The underground alternative was selected as the preferred option, and SAI subsequently developed 3 additional phased underground designs, prepared conceptual construction plans, and conducted permitting coordination with local agencies. SAI's design eliminated structure flooding for the Center and reduced flows along the entrance road by 1,000 cfs during the 100-year storm event.
Shortly after the completion of the work, the Center suffered catastrophic damage from Hurricane Maria. As a result, SAI’s scope was modified to include master planning and site design to restore the campus, including civil and architectural design. This work is anticipated to be completed in 2020.