Evaluating methods to obtain high resolution nearshore bathymetry and coastal topography for Puget Sound

The Washington State Department of Ecology Coastal Monitoring & Analysis Program performed a coastal topographic and bathymetric survey of Port Gamble Bay between March 9 and March 28, 2014. Boat-based topographic lidar was collected along the shoreline of the bay and multibeam bathymetric sonar was collected throughout the bay to obtain a seamless topographic-bathymetric surface with complete coverage of Port Gamble Bay. The survey was performed with a R2Sonic 2022 multibeam echosounder, an Optech ILRIS-HD-ER mobile laser scanner, and an Applanix POS MV 320 v5 receiving real-time kinematic positioning corrections. The Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX) performed a topographic and bathymetric lidar survey of Port Gamble Bay on September 4, 2014. The Coastal Zone Mapping and Imaging Lidar (CZMIL) system was used to obtain seamless coastal topographic-bathymetric coastal intertidal and nearshore coverage of Port Gamble Bay. The bathymetric depth coverage is limited to laser extinction, which is determined by water clarity. The availability of these two datasets provides the unique opportunity to compare data between high-resolution boat-based lidar and multibeam systems and the state-of-the-art airborne topo-bathy lidar system and also assess detection and resolution of specific features throughout a range of water depths across the nearshore important to habitat and restoration efforts. This effort provides a detailed comparison of coverage and resolution of nearshore features and will help clarify differences between these capabilities to aid in planning complementary efforts in coastal zone mapping and monitoring.