Shoreline Change Analysis

Consistent documentation of shoreline change in communities that are subject to coastal or riverine erosion is a critical foundation for understanding both episodic and long-term changes that impact public health, safety, and well-being. This is also a necessary step toward estimating long-term erosion rates, which will ultimately enable local planners to have a better understanding of local vulnerabilities, support updated response and adaption, and make informed decisions about development and the relocation of at-risk infrastructure. Systematic observations of shoreline change serve to solve an existing problem that arises from the lack of critical baseline data necessary for informed hazard mitigation planning at the community level. GIS-based shoreline change analysis uses the USGS Digital Shoreline Analysis System (DSAS) to help calculate historical shoreline trends and identify areas of erosion and accretion.

DSAS imagery of Goodnews Bay, Alaska, showing regression rate from 1952-2016.

Shoreline change rates along a coastal barrier beach fronting Goodnews Bay, Alaska, with negative values on the Y axis corresponding to erosion.   The graph results of this analysis quantify shoreline change rates and elucidate long-term patterns of erosion and accretion along this portion of the coastline.