2025 WA GIS Conference

For over 10 years, the WA DNR Nearshore Habitat Program (NHP) has been researching methods to transplant and restore populations of eelgrass, Zostera marina, in South Puget Sound. At a series of small research meadows, eelgrass has been transplanted using different combinations of methods and donor sources and each summer NHP staff conduct surveys of the test plots to assess their performance. In 2019, uncrewed aircraft systems (UAS or “drones”) were added to the suite of tools deployed at the sites, which has enabled estimates of total eelgrass shoots to be calculated by combining in situ density observations and area delineations based on the aerial imagery. Then in 2024, DNR announced plans to break ground on a project to remove the fish passage barrier near Joemma Beach State Park – the site of the largest of our eelgrass research meadows – and restore Whiteman Cove to a free-flowing tidal estuary. In anticipation of the project, NHP decided to expand our efforts to include RTK-enabled (real-time kinematic) drone surveys over the entire tidal flat, which enable the production of high-resolution digital elevation models using structure-from-motion photogrammetry software. These models allow DNR to track channel formation and sediment deposition in the restored system, and to observe in real time if there are any impacts from the project on the eelgrass research meadow nearby. This talk will present lessons learned over five years of monitoring transplanted eelgrass populations with high resolution drone imagery, the initial results of comparing the RTK drone-based elevation models of the restored estuary, and finally how these products are being shared with the public using web products such as ArcGIS Experience Builder.