The Development of a National-Scale Coastal Landform and Anthropogenic Classification Framework

Abstract:

The USGS has an ongoing National Assessment of Coastal Change Hazards project that provides data, analysis, and assessments of coastal change hazards on a national scale. As part of this effort, the USGS is developing a systematic comprehensive coastal landform classification system for the nation’s coast. The primary focus is a hierarchical characterization of natural landforms along the coast, but the framework also includes anthropogenic metrics. The framework is intended to be open-ended and adaptable based on availability and relevancy of data. The purpose of the framework is to provide a comprehensive organization for a vast and varied database of relevant geologic and anthropogenic information (both qualitative and quantitative) related to coastal change hazards.

The framework is divided geographically and is comprised of five units: 1) natural landform type (foreshore and backshore); 2) geology; 3) level of anthropogenic development; 4) engineering structures; and 5) beach nourishment. The units are categorically separated but are designed to be utilized in conjunction with each other to describe the makeup, character, and processes that may influence change along a given coastal area. For the natural landform types, the foreshore is defined as extending from the mean high water to the base of the backshore feature. The levels of anthropogenic development range from ‘none’ to ‘high intensity’ based on the data from the USGS National Land Cover Database.

A pilot implementation of the natural landform and anthropogenic development units of the framework was developed for the Mid-Atlantic region, from New York through Virginia. Initial queries of the database indicate that the primary foreshore landforms along the Mid-Atlantic coast are barrier island beaches (62%), mainland beaches (21%), and barrier spits (16%). Almost forty percent of this coastal region is categorized as having a medium or high intensity level of development.

The framework will allow users to access and extract relevant information about the coast and will provide a baseline system that can be populated and updated as new data becomes available. The classification database will provide a valuable resource to help inform the scientific and management communities about the relevant factors influencing coastal change hazards.