Improving tide gate use to reduce coastal threats
Tide gates—hinged doors between coastal estuaries and the ocean—often serve as a last line of defense to protect coastal residents and homes from floods. But improper gate management can cause lasting damage, harming wetlands that form natural buffers against storms and pollutants, and that are important nurseries for fish.
Designed to close during extreme high tides to prevent nearby properties from flooding, these gates are often kept closed. However, if too little seawater passes through a tide gate during a tidal cycle, the marsh begins to freshen, allowing an invasive marsh grass to displace local species. This grass fundamentally changes the marsh—a critical nursery habitat for fish like flounder—and is highly flammable, posing a fire risk to nearby homes. The lack of seawater exchange can also cause pollutants to build up in the marsh.
“As sea levels rise and extreme storms become common, thousands of coastal communities around the world are using tide gates. But there hasn’t been a lot of research into how to operate them sustainably,” says Brian Helmuth, a professor of marine and environmental science and public policy. An interdisciplinary team of CSI faculty—Helmuth, Mark Patterson, and Loretta Fernandez—is addressing that problem head-on.
They’ve partnered with the city of Revere, Massachusetts, and the National Oceanic and Atmospheric Administration on a three-year study to gather data and test operational strategies in three tide-gate-protected areas: a large urban-coastal marsh with a history of toxin exposure, a small urban marsh that’s used recreationally, and a pristine marsh.
The team is using these data, modeling tools, and stakeholder input to create a smartphone app and other decision support tools to help tide gate operators minimize the risks of fire, flooding, and pollution. The tools will offer guidance on when and how much to open the gates under different climate conditions.
“Our research will increase the resilience of coastal communities because existing tide gates will be better managed,” Helmuth says.
Author: CSI Staff