The GIWW is a safe shipping route for important cargo traffic along the Gulf Coast, but wind and wave action are eroding the shorelines. In some places, the GIWW is ten times wider than it was originally. This erosion ultimately leads to coastal marsh degradation and coastal land loss. Shoreline hardening using rock breakwaters is an effective tool to stop erosion and protect important coastal marsh. However, with a cost of more than $1 million/mile, and hundreds of miles of GIWW shoreline in need of protection, we needed a decision support tool to guide resource investment. Ducks Unlimited used the latest geospatial techniques to determine the areas most in need of shoreline protection. Now we can work with our partners to protect the most vulnerable and most important marshes with the limited resources available, delivering the most efficient and effective conservation possible.