Land cover change has been extreme in Puerto Rico since the 1950s and this has greatly affected streamflow on the island. Forest Service scientists developed models for mainland Puerto Rico, Vieques, and Culebra that simulated historic streamflows from 1953 to 2012 using static land-cover parameterizations based on different snapshots in time. The models then were run for the Río Piedras watershed using dynamic land cover parameterization that changed yearly from 1953 to 2012.. The results showed that by including land cover change in modeling efforts, Forest Service scientists can do a better job of accurately simulating streamflow for watersheds with a high amount of human-ecosystem interactions. These models help scientists understand how land-cover change affects streamflow and how humans might be affecting ecosystems.