Final Report: Strategic Marsh Adaptation: Creating and Testing a New Decision-Support Tool

In an era of rising sea levels, costal land managers including land trust representatives, municipal planners, and others contributing to decisions about whether to develop or protect coastal parcels do not have viable means of evaluating future values on wetlands that will be created when sea levels rise. This project develops and tests a software modeling approach to help address this issue. The beta test used three parcels in Scarborough, Maine: Hampton Circle, Audubon, and Pine Point. It used a group of experts to 1) allocate initial values to these parcels for a range of ecosystem services and 2) create depth-benefit curves that estimate how those values would change with increasing water depth at each site. Experts estimated that the Hampton Circle site had the highest initial values across all services. But once sea level rise and topographic diversity was accounted for via use of the software tool (MAST – Marsh Adaptation Strategy Tool), what initially appeared to be the most valuable site became the least valuable. The analysis demonstrates the importance of being able to examine interactions among a diversity of ecosystem service values, local topography, and possible sea level rise, and demonstrates the utility of a new tool to support costal land management decisions before and during upland conversion to wetland.