Climate Connections: Coastal flooding

We have a problem. We live on an Island, and the sea is rising. Sea-level rise increases the height of storm waves, and thus causes more coastal flooding. A two-foot rise is predicted by the year 2050. That’s a lot of water.

The Island towns are in the process of updating their floodplain and wetlands bylaws to address current and future flooding (Chilmark doesn’t currently have a floodplain bylaw).

I have been studying climate change on the Island for almost 20 years, and my No. 1 recommendation to the towns as they update their bylaws is this: No new development in the flood zone. Flood zones are so named because they are susceptible to flooding. The current structures in the flood zone are already in harm’s way. It makes no sense to add more; it’s just asking for trouble.

The existing structures are at risk of damage and destruction. In addition, as buildings are damaged by flooding and storms, the storm-strewn debris becomes a public safety hazard. It costs the towns money to clean up the mess.

People who live and work in the flood zone are at risk. They can be trapped in place. If there is a medical emergency, even if the building is raised, ambulances cannot get there on flooded roads. There are already 1,126 structures in the Island’s FEMA-designated flood zone. The FEMA flood maps are the official maps used by insurers and building inspectors to identify at-risk structures. However, the FEMA maps are based on historic data, and do not address sea-level rise and increased flooding.

The state has issued more accurate flood maps, called the Massachusetts Coastal Flood Risk Model (MC-FRM). Another valuable mapping tool is called Storm Tide Pathways. More than 700 flood pathways are identified on the Vineyard map (bit.ly/stpapplaunch). I encourage the towns to use these maps when considering flood risks. They are illuminating.

A group of state floodplain specialists has developed a set of model floodplain and wetland bylaws to help guide the town updates. The model bylaws offer a menu of regulations for the towns to consider. The menu items are recommendations that can be applied to all or part of the flood zone.

Here is a brief sample of menu items:

• No new construction
• No new impervious hardscape, including patios, pools, and tennis courts
• Restrictions on hazardous-materials storage
• No new construction or expansion of seawalls and other hard structures that deflect or increase the velocity of wave action

These regulations are designed to protect both the public and the land that absorbs floodwater.

In addition to updating the bylaws, we as an Island community have to start a conversation about moving out of the flood zone. The process is called “managed retreat,” which is a terrible name, because in our society the word “retreat” is associated with loss and failure. In fact, retreating from the shore is the smart thing to do. Sea-level rise and flooding are only going to get worse.

You’ll be hearing more about the bylaw updates over the course of the year, as the towns plan public input sessions. Make your voice heard. The goal is to bring the updated bylaws before voters at the 2026 annual town meetings, so there is plenty of time to get it right!

Liz Durkee is the Martha’s Vineyard Commission’s climate change coordinator.