Mapping Puget Sound bluffs and beaches

Mapping strategy

We used boat-based lidar and GPS topography data to produce 0.5-meter digital elevation models for beaches and bluffs at each of the sites we surveyed. These models afford us the opportunity to inventory and characterize the shoreline landscape affecting the nearshore ecosystem. These features include:

• Feeder bluff activity
• Beach slope and width
• Armoring position, length, and elevation relative to the back shore

Compared to airborne lidar, boat-based lidar provides a more advantageous view of the bluff face. It gives us the higher resolution data we need to gain insight about bluff failure, erosion mechanisms, and sediment transport processes. The near-horizontal "look angle" of the laser also successfully collects data lying under overhanging vegetation and over-water structures.

Using the data

In the future, repeat surveys will enable us to analyze changes in quantifying bluff sediment supply and marine riparian vegetation. This will help us gain a better understanding about the links between physical and ecological processes.