Technology in Support of Shoreline Surveys for Characterizing Spatial Complexity

Abstract

There are numerous issues related to the management of shoreline development in Puget Sound. As shoreline property owners armor and protect their coastal property from erosion and slope failure, many natural processes are interrupted. This ongoing alteration of natural processes in the nearshore by anthropogenic uses is now thought to result in a less complex, more homogenous nearshore environment that has negative implications for species which use the nearshore for migration and spawning (Logsdon et al., 2011). The dynamic interactions of ecological functions for migrating salmon within units of the shoreline that have uniform physical controls on the transport of sediments (i.e. process units) are impacted by anthropogenic use. Changes in the physical structure of these process units, which create variety in shoreline complexity, are thought to be related to the observed decline in suitable habitat for salmon migration and spawning. Characterizing beach complexity will not only help address causes of the decrease in complexity itself, but also tie in the lack of suitable habitat affecting local salmon species. Several species of salmon in the Pacific Northwest are either in decline, or already represented in the federal Endangered Species Act. We developed a tethered remotely operated water surface vehicle as a technological addition, with a deployment protocol that is used to assess the nearshore environment of Puget Sound. This is accompanied by developmental designs and schematics of the sensor, along with the code necessary to duplicate the build process. Correlating the anthropogenic effects in the process unit to the decrease in beach complexity and therefore loss of suitable habitat for migrating and spawning Chinook, also known as King Salmon. Using the developed sensor within a process unit, we identified a correlation of habitat loss due to anthropogenic processes with sea grass changes, quantified the extent of armoring, landslides, and natural beaches visually as a percent. This deployment protocol may be used in the future to characterize a variety of beaches in reference to other species, in addition to the Chinook.