8 HEADLINE MISSION: WATER SURFACE WATER THREE TIERS The first tier of the system, Owosina explains, is a network of flood control canals built by the U.S. government in the 1940s and 1950s to drain marshland for agriculture and development, supply fresh water to South Florida's growing cities, and drain stormwater following the area's infamous storms. Those main, or primary, canals are fed by secondary canals operated by counties, cities and special drainage districts, which in turn accept water from tertiary systems that homeowner associations use to drain their neighborhoods. Over the years, more people and more pavement have increased pressure on all three layers of the drainage system. And as high tides pushed saltwater inland through the canals, authorities added salinity barriers at the mouths of the waterways— gates that can be closed during high tides to prevent saltwater intrusion. The district can close the barriers to ward off rising tides that could push salinity inland during storms, Owosina notes. He adds that as important as it is to manage the primary canal system, it is every bit as vital to also manage the water flowing into the primary canals from the feeder canals upstream. As sea levels rise, it is important to predict how well those systems will perform in the future. Part of SFMWD's cooperation with stakeholders upstream is sharing the results of its Flood Protection Level of Service program, a deep assessment of the infrastructure that integrates information from current on-site inspections with detailed modeling of different future conditions, including sea level rise and weather scenarios. "The program will cover around the entire district, starting with the highest priority watersheds, determine the current level of services, compare it to design conditions, and subject it to different future conditions [in the models] with future land use and changes in sea level," Owosina says. "Does this structure continue to provide the same level of flood protection it was designed to provide? We're hoping to see that it is robust, or that you can tell at what level of sea level rise it becomes less effective and provides less flood protection so that necessary action can be taken proactively." Farmlands south of Lake Okeechobee in the Everglades Agricultural Area. Everglades restoration focuses on restoring water flow through this area. Tertiary canal systems allow for residential neighborhoods to drain their excess water. Water control facility under construction on the Zipprer Canal in Lake Kissimmee State Park.