The National Assessment of Shoreline Change:

Introduction

The U.S. Geological Survey has generated a comprehensive data clearinghouse of digital vector cliff edges and associated rates of cliff retreat along the open-ocean California coast. These data, which are presented herein, were compiled as part of the U.S. Geological Survey's National Assessment of Shoreline Change Project.

Cliff erosion is a chronic problem along many coastlines of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information including rates and trends of coastal cliff retreat. There is also a critical need for these data to be consistent from one region to another. One objective of this work is to a develop standard, repeatable methodology for mapping and analyzing cliff edge retreat so that periodic, systematic, and internally consistent updates of cliff edge position and associated rates of erosion can be made at a national scale.

This data compilation for open-ocean cliff edges for the California coast is a separate, yet related study to Hapke and others, 2006 documenting shoreline change along sandy shorelines of the California coast, which is itself one in a series that includes the Gulf of Mexico and the Southeast Atlantic coast (Morton and others, 2004; Morton and Miller, 2005). Future reports and data compilations will include coverage of the Northeast U.S., the Great Lakes, Hawaii and Alaska. Cliff edge change is determined by comparing the positions of one historical cliff edge digitized from maps with a modern cliff edge derived from topographic LIDAR (light detection and ranging) surveys. Historical cliff edges for the California coast represent the 1920s-1930s time-period; the most recent cliff edge was delineated using data collected between 1998 and 2002. End-point rate calculations were used to evaluate rates of erosion between the two cliff edges. Please refer to our full report on cliff edge erosion along the California coastline at https://pubs.usgs.gov/of/2007/1133/ for additional information regarding methods and results (Hapke and others, 2007).

Data in this report are organized into downloadable layers by region (Northern, Central and Southern California) and are provided as vector datasets with accompanying metadata. Vector cliff edges may represent a compilation of data from one or more sources and the sources used are included in the dataset metadata. This project employs the Environmental Systems Research Institute's (ESRI) ArcGIS as it's Geographic Information System (GIS) mapping tool and contains several data layers (shapefiles) that are used to create a geographic view of the California coast. The vector data form a basemap comprising polygon and line themes that include a U.S. coastline (1:80,000), U.S. cities, and state boundaries.

GIS Data Layers

Data in this publication are intended to be integrated into a Geographical Information System (GIS). A GIS is defined as a system of hardware and software used to support the display, manipulation, and analysis of spatial data for mapping and data analysis. This integrated system provides researchers the ability to analyze and map the various datasets to help with research, and economic and social policy-making decisions regarding the environment.

All of the files necessary to conduct coastal cliff retreat analyses are provided. These include five GIS data layers (shapefiles) for each section of the California coast: one historical and one modern vector cliff edge, an offshore baseline used for generating shore-normal transects, shore-normal transects for cliff edge erosion rates, and transect/cliff edge intersection positions for cliff edge erosion rates as a point shapefile. The GIS data layers from this publication are cataloged below by region for easy access. Please refer to http://woodshole.er.usgs.gov/project-pages/dsas/ for information about the Digital Shoreline Analysis System (DSAS) used for the analysis of this data.

  Top of page

Data Files

Region	Layer Name and Description	Metadata	Files
Southern index map	socal1932_1934.shp - Vector shoreline derived from 1932-1934 source data	HTML, FAQ, text, xml	SCal.zip
	socal1998.shp - Vector shoreline derived from 1998 source data	HTML, FAQ, text, xml
	socal_baseline.shp - Offshore baseline for generating shore-normal transects	HTML, FAQ, text, xml
	socal_intersects.shp - Transect/Shoreline intersection positions associated with short-term rates	HTML, FAQ, text, xml
	socal_transects.shp - Shore-normal transects with associated short-term rates of shoreline change	HTML, FAQ, text, xml
Central index map	cencal1929_1935.shp - Vector shoreline derived from 1929-1935 source data	HTML, FAQ, text, xml	CCal.zip
	cencal1998_2002.shp - Vector shoreline derived from 1998-2002 source data	HTML, FAQ, text, xml
	cencal_baseline.shp - Offshore baseline for generating shore-normal transects	HTML, FAQ, text, xml
	cencal_intersects.shp - Transect/Shoreline intersection positions associated with short-term rates	HTML, FAQ, text, xml
	cencal_transects.shp - Shore-normal transects with associated short-term rates of shoreline change	HTML, FAQ, text, xml
Northern index map	norcal1928_1935.shp - Vector shoreline derived from 1928-1935 source data	HTML, FAQ, text, xml	NCal.zip
	norcal2002.shp - Vector shoreline derived from 2002 source data	HTML, FAQ, text, xml
	norcal_baseline.shp - Offshore baseline for generating shore-normal transects	HTML, FAQ, text, xml
	norcal_intersects.shp - Transect/Shoreline intersection positions associated with short-term rates	HTML, FAQ, text, xml
	norcal_transects.shp - Shore-normal transects with associated short-term rates of shoreline change	HTML, FAQ, text, xml
Base Layers	NOS80K - Medium resolution digital vector U.S. shoreline. Type: feature - polygon	HTML, FAQ, text, xml	nos80k.zip
	state_bounds - Internal U.S. state boundaries	HTML, FAQ, text, xml	state_bounds.zip
	cities - Cities and towns of the United States	HTML, FAQ, text, xml	cities.zip

  Top of page

References

Hapke, C.J., and Reid, D., 2007, The National assessment of shoreline change: Part 4, Historical coastal cliff retreat along the California coast: U.S. Geological Survey Open-file Report 2007-1133 (https://pubs.usgs.gov/of/2007/1133)

Hapke, C.J., Reid, D., Richmond, B.M., Ruggiero, P., and List, J., 2006, The National assessment of shoreline change; Part 3, Historical shoreline change and associated coastal land loss along sandy shorelines of the California coast: U.S. Geological Survey Open-file Report 2006-1219 (https://pubs.usgs.gov/of/2006/1219)

Morton, R.A., Miller, T.L., 2005, National assessment of shoreline change: Part 2, Historical shoreline change and associated land loss along the U.S. South East Atlantic coast: U.S. Geological Survey Open-file Report 2005-1401 (https://pubs.usgs.gov/of/2005/1401)

Morton, R.A., Miller, T.L. and Moore, L.J., 2004, National assessment of shoreline change: Part 1, Historical shoreline change and associated land loss along the U.S. Gulf of Mexico: U.S. Geological Survey Open-file Report 2004-1043 (https://pubs.usgs.gov/of/2004/1043)

All "National Assessment of Shoreline Change" Publications

The National Assessment of Shoreline Change: Part 4, Historical Coastal Cliff Retreat Along the California Coast
https://pubs.usgs.gov/of/2007/1133

The National Assessment of Shoreline Change: A GIS Compilation of Vector Cliff Edges and Associated Cliff Erosion Data for the California Coast (this page)
https://pubs.usgs.gov/of/2007/1112

The National Assessment of Shoreline Change: A GIS Compilation of Vector Shorelines and Associated Shoreline Change Data for the Sandy Shorelines of the California Coast
https://pubs.usgs.gov/of/2006/1251

National Assessment of Shoreline Change: Part 3, Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast
https://pubs.usgs.gov/of/2006/1219

National Assessment Of Shoreline Change: Part 2, Historical Shoreline Changes And Associated Coastal Land Loss Along The U.S. Southeast Atlantic Coast
https://pubs.usgs.gov/of/2005/1401

The National Assessment of Shoreline Change: A GIS Compilation of Vector Shorelines and Associated Shoreline Change Data for the U.S. Gulf of Mexico
https://pubs.usgs.gov/of/2004/1089

National Assessment of Shoreline Change: Part 1, Historical Shoreline Changes and Associated Coastal Land Loss Along the U.S. Gulf of Mexico
https://pubs.usgs.gov/of/2004/1043

Contacts

Cheryl Hapke
(401) 874-5532
chapke@usgs.gov
USGS Patuxent Wildlife Research Center
University of Rhode Island
317 Woodward Hall, Dept. of Geosciences
Kingston, RI 02881

Dave Reid
(831) 427-4759
dreid@usgs.gov
U.S. Geological Survey
Pacific Science Center
400 Natural Bridges Drive
Santa Cruz, CA 95060

Mark Borrelli
mborrelli@uri.edu
Department of Geosciences
University of Rhode Island
Kingston, RI 02881

  Top of page