U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2006-1219

National Assessment of Shoreline Change Part 3: 

Historical Shoreline Change and Associated 

Coastal Land Loss Along Sandy Shorelines of the 

California Coast

Cheryl J. Hapke, David Reid, Bruce M. Richmond, Peter Ruggiero and Jeff List
National Assessment of Shoreline Change Part 3: 

Historical Shoreline Change and Associated 

Coastal Land Loss Along Sandy Shorelines of the 

California Coast

Cheryl J. Hapke1, David Reid2, Bruce M. Richmond2, Peter Ruggiero3, and Jeff List4

Open File Report 2006-1219

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. 

Government.

Hapke, C.J., Reid, D., Richmond, B.M., Ruggiero, P., and List, J., 2006, National assessment of shoreline change: Part 

3: Historical shoreline changes and associated coastal land loss along the sandy shorelines of the California coast: 

U.S. Geological Survey Open-file Report 2006-1219.

U.S. Department of the Interior

U.S. Geological Survey

1

U.S. Geological Survey, Coastal Field Station, Department of Geosciences, University of Rhode 

Island, Kingston, RI 02881

2

U.S. Geological Survey, Pacific Science Center, Santa Cruz, CA 95060

3

Dept. of Geosciences, Oregon State University, Corvallis, OR 97331

4

U.S. Geological Survey, Woods Hole Science Center, Woods Hole, MA 02543
Open-File Report 2006-1219   

Contents

EXECUTIVE SUMMARY......................................................................................................................................................1

INTRODUCTION...................................................................................................................................................................1

U.S. Geological Survey National Assessment of Shoreline Change.................................................................1

Disclaimer...................................................................................................................................................................2

Acknowledgments.....................................................................................................................................................2

THE ROLE OF STATE AND FEDERAL GOVERNMENTS..................................................................................................4

PRIOR NATIONAL AND CALIFORNIA COAST SHORELINE ASSESSMENTS ............................................................4

METHODS OF ANALYZING SHORELINE CHANGE.........................................................................................................5

Compilation of Historical Shorelines ......................................................................................................................5

Delineation of a Modern (Lidar-derived) Shoreline .............................................................................................5

Geographic Information System (GIS) Procedures .............................................................................................6

Calculation and Presentation of Rates of Change ...............................................................................................7

Beach Alterations and Shoreline Definitions that Influence Rates of Change ...............................................8

Human Activities............................................................................................................................................... 8

Shoreline Definitions........................................................................................................................................ 9

Estimating the proxy-datum bias and the bias uncertainty ..................................................................... 10

Uncertainties and Errors.........................................................................................................................................11

End-point (short-term) shoreline change error ........................................................................................ 13

Linear regression (long-term) shoreline change error............................................................................. 14

GEOLOGIC HISTORY AND SETTING ..............................................................................................................................15

General Geology of the California Coast..............................................................................................................15

Climate.......................................................................................................................................................................19

Coastal Processes...................................................................................................................................................20

Waves .............................................................................................................................................................. 20

Tides .............................................................................................................................................................. 21

Winds .............................................................................................................................................................. 22

Currents............................................................................................................................................................ 22

Littoral cells and transport directions ......................................................................................................... 22

Sand Sources .................................................................................................................................................. 23

GEOMORPHOLOGY OF THE CALIFORNIA COAST .......................................................................................................24

Cliffs .......................................................................................................................................................................24

Beaches.....................................................................................................................................................................24

Coastal Dune Complexes........................................................................................................................................26

Estuaries and Lagoons............................................................................................................................................26

General Characteristics of the California Coast Sections .........................................................................................27

Northern Section: Oregon Border to Tomales Bay ...........................................................................................27

Central Section: Tomales Bay to Point Conception............................................................................................30

Southern Section: Point Conception to the Mexican Border...........................................................................30
Open-File Report 2006-1219 ii

HISTORY OF INFRASTRUCTURE DEVELOPMENT .......................................................................................................30

HISTORICAL SHORELINE CHANGE ANALYSIS............................................................................................................33

Northern California..................................................................................................................................................33

Klamath Region ............................................................................................................................................... 33

Eureka Region.................................................................................................................................................. 34

Navarro Region ............................................................................................................................................... 36

Russian River Region ..................................................................................................................................... 40

Central California .....................................................................................................................................................42

San Francisco North Region......................................................................................................................... 43

San Francisco South Region......................................................................................................................... 43

Monterey Bay Region .................................................................................................................................... 47

Big Sur Region................................................................................................................................................. 50

Morro Bay Region........................................................................................................................................... 50

Santa Barbara North...................................................................................................................................... 54

Southern California..................................................................................................................................................56

Santa Barbara South Region ........................................................................................................................ 57

Santa Monica Region ................................................................................................................................... 57

San Pedro Region ........................................................................................................................................... 61

Oceanside Region........................................................................................................................................... 63

San Diego Region ........................................................................................................................................... 65

DISCUSSION AND FURTHER CONSIDERATIONS........................................................................................................67

Summary of Shoreline Changes............................................................................................................................67

Planned Updates and Related Research.............................................................................................................68

Influence of Human Activities ...............................................................................................................................68

REFERENCES......................................................................................................................................................................68
Open-File Report 2006-1219 iii

Figures

Figure 1. Index map of California showing the fifteen regions discussed in the text. ................................................................3

Figure 2. Example of a lidar profile from April 10, 1998 at Santa Cruz, California ........................................................................7

Figure 3. Examples of common conditions where transects are eliminated in the absence of 

four shoreline intersections. ................................................................................................................................................9

Figure 4. Major tectonic elements and geomorphic provinces of California ............................................................................16

Figure 5. Index map showing locations of place names discussed in Geologic History and Geomorphology section. .....17

Figure 6. Simplified geologic map of California ...............................................................................................................................18

Figure 7. General wave directions for central California based on offshore wave buoy data................................................20

Figure 8. Monthly mean sea level for selected tide gauges along the California coast...........................................................21

Figure 9. Map showing major littoral cell boundaries, coastal watersheds, and conceptual net longshore 

drift directions for the California coast.............................................................................................................................23

Figure 10. Average annual sand and gravel discharge from major rivers in California. ............................................................25

Figure 11. Sketch of common coastal landforms of California.......................................................................................................26

Figure 12. Beach profiles from Cowells Beach in Santa Cruz illustrating beach erosion over an El Niño winter 

and the subsequent recovery the following summer.....................................................................................................27

Figure 13. Map showing the major coastal dune complexes of California...................................................................................28

Figure 14A. Index map showing the four analysis regions in Northern California and various locations ..............................29

Figure 14B. Index map showing the six analysis regions in Central California and various locations ...................................31

Figure 14C. Index map showing the five analysis regions in Southern California and various locations ...............................32

Figure 15. Shoreline change rates for the Klamath region..............................................................................................................35

Figure 17. Shoreline change rates for the Eureka region................................................................................................................37

Figure 18. Spit and jetty on north side of Humboldt Bay Harbor in photograph taken in June 1987........................................38

Figure 19. Shoreline change rates for the Navarro region..............................................................................................................39

Figure 20. Photographs from 1972 (top) and 2002 (bottom) show the widening of the spit beach at the 

Ten Mile River mouth...........................................................................................................................................................40

Figure 21. Shoreline change rates for the Russian River region....................................................................................................41

Figure 22. Many of the large rivers in Northern California have well-developed sandy spits such as this one 

extending across the mouth of the Russian River..........................................................................................................42

Figure 23. Shoreline change rates for the San Francisco North region .......................................................................................44

Figure 24. Houses on the spit at Stinson Beach are partially buried by sand during an El Niño winter storm in 1983.........45

Figure 25. Shoreline change rates for the San Francisco South region.......................................................................................46

Figure 26. A riprap revetment protects an apartment building that overlooks a narrow beach near 

Pillar Point Harbor in a photograph taken in February, 2002 ........................................................................................47

Figure 27. Shoreline change rates for the Monterey Bay region...................................................................................................48

Figure 28. Aerial photographs of the Santa Cruz Yacht Harbor show the impoundment of sand against the 

constructed jetties...............................................................................................................................................................49

Figure 29. Shoreline change rates for the Big Sur region...............................................................................................................51

Figure 30. JP Burns waterfall shows the beach that formed as a result of the sediment added to the system 

from the 1983 landslide .......................................................................................................................................................52
Figures continued

Open-File Report 2006-1219 iv

Figure 31. Shoreline change rates for the Morro Bay region ........................................................................................................53

Figure 32. Development of a tombolo at Morro Rock after a causeway was built in the 1930s ..............................................54

Figure 33. Shoreline change rates for the Santa Barbara North region......................................................................................55

Figure 34. Photographs from January 1989 shows the well-developed dune field at Guadalupe Dunes ..............................56

Figure 35. Shoreline change rates for the Santa Barbara South region......................................................................................58

Figure 36. Dredging of spit at Santa Barbara Harbor......................................................................................................................59

Figure 37. Shoreline change rates for the Santa Monica region ..................................................................................................60

Figure 38. Oblique aerial photograph of a breakwater along the highly engineered Santa Monica coastline.....................61

Figure 39. Shoreline change rates for the San Pedro region.........................................................................................................62

Figure 40. Oblique aerial photograph of the Los Angeles Harbor.................................................................................................63

Figure 41. Shoreline change rates for the Oceanside region ........................................................................................................64

Figure 42. Narrow beach fronting tall coastal bluffs at Torrey Pines City Beach.......................................................................65

Figure 43. Shoreline change rates for the San Diego region.........................................................................................................66

Figure 44. Oblique aerial photograph of Zuniga Point and breakwater at the entrance to the San Diego Harbor...............67
Open-File Report 2006-1219   

Tables

Table 1. Providers and original sources of historical shorelines for each California region. ....................................................5

Table 2. Dates of compiled shorelines in different regions for selected periods.........................................................................6

Table 3. List of tide gauge measurements used to calculate mean high water elevation..........................................................8

Table 4. Absolute horizontal and vertical differences between high water and mean high water shorelines.....................10

Table 5. Maximum estimated measurement errors for California shorelines.............................................................................11

Table 6A. Average shoreline change rates for Northern California................................................................................................12

Table 6B. Average shoreline change rates for Central California...................................................................................................12

Table 6C. Average shoreline change rates for Southern California................................................................................................12

Table 7. Coastal cliff rock type along the California coast (from Runyan and Griggs, 2002). ...................................................19

Table 8. Estimated annual littoral drift rates and directions along the California Coast...........................................................24

Table 9A. Maximum and minimum shoreline change rates: Northern California .........................................................................34

Table 9B. Maximum and minimum shoreline change rates: Central California ............................................................................45

Table 9C. Maximum and minimum shoreline change rates: Southern California.........................................................................59
EXECUTIVE SUMMARY

Beach erosion is a chronic problem along many openocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened 

by erosion, there is increased demand for accurate information regarding past and present trends and rates of shoreline movement. There is also a need for a comprehensive 

analysis of shoreline movement that is consistent from one 

coastal region to another. To meet these national needs, the 

U.S. Geological Survey is conducting an analysis of historical shoreline changes along open-ocean sandy shores of the 

conterminous United States and parts of Hawaii and Alaska. 

One purpose of this work is to develop standard repeatable 

methods for mapping and analyzing shoreline movement so 

that periodic updates regarding coastal erosion and land loss 

can be made nationally that are systematic and internally consistent. In the case of this study, the shoreline being measured 

is the boundary between the ocean water surface and the 

sandy beach.

This report on the California Coast represents the first 

of two reports on long-term sandy shoreline change for the 

western U.S., the second of which will include the coast of 

the Pacific NW, including Oregon and Washington. A report 

for the Gulf of Mexico shoreline was completed in 2004 and 

is available at: http://pubs.usgs.gov/of/2004/1043/. This 

report summarizes the methods of analysis, interprets the 

results, provides explanations regarding long-term and shortterm trends and rates of change, and describes how different 

coastal communities are responding to coastal erosion. Shoreline change evaluations are based on comparing three historical shorelines digitized from maps, with a recent shoreline 

derived from lidar (Light Detection and Ranging) topographic 

surveys. The historical shorelines generally represent the 

following periods: 1800s, 1920s-1930s, and 1950s-1970s, 

whereas the lidar shoreline is from 1998-2002. Long-term

rates of change are calculated using all four shorelines (1800s 

to lidar shoreline), whereas short-term rates of change are 

calculated for only the most recent period (1950s-1970s to 

lidar shoreline). The rates of change presented in this report 

represent past conditions and therefore are not intended for 

predicting future shoreline positions or rates of change. Due 

to the geomorphology of the California Coast (rocky coastline 

instead of beach) as well as to data gaps in some areas, this 

report presents beach erosion rates for 45% of California’s 

1100 km of coast.

The average rate of long-term shoreline change for the 

State of California was 0.2±0.1 m/yr, an accretional trend. 

This is based on shoreline change rates averaged from 14,562 

individual transects, of which 40% were eroding. Of the 

transects on which the shoreline was eroding, the long-term

erosion rates were generally lowest in Southern California 

where coastal engineering projects have greatly altered the 

natural shoreline movement. On a regional scale, long-term

accretion rates were either equal to (Central California) or 

greater than (Northern and Southern California) the long-term

erosion rates, yielding the net accretional trend for the entire 

state. This accretional trend is most likely due to changes in 

the large volumes of sediment that are added to the system 

from large rivers and to the impact from coastal engineering 

and beach nourishment projects.

The average rate of short-term shoreline change for 

the state was erosional. The net short-term rate as averaged 

along 16,142 transects was -0.2±0.4 m/yr. Of the transects 

used to measure short-term change, 66% had erosional trends. 

In addition erosion rates were higher in the short-term period, 

possibly related to the localized artificial nourishment that 

occurred over much of the 20th century but that has recently 

slowed or stopped (Flick, 1993; Wiegel, 1994). Short-term

accretion rates were highest in Northern California where the 

overall magnitudes of shoreline change are systematically 

higher than in Central and Southern California. The most 

stable (low erosion and accretion rates) California beaches 

were most commonly found in Central California. 

Seawalls and/or riprap revetments have been constructed 

in all three sections of California, although many of these 

structures were built to protect houses and infrastructures 

from the erosion of coastal cliffs and bluffs rather than to 

protect against long-term beach erosion. California permits 

shoreline stabilization structures where homes, buildings or 

other community infrastructure are imminently threatened by 

erosion. 

A second California report that is following this publication will include analyses and reports on long-term coastal 

cliff erosion, as this hazard is of equal or greater concern 

to coastal communities in many areas along the California 

Coast.

INTRODUCTION

U.S. Geological Survey National Assessment of 

Shoreline Change

Sandy ocean beaches represent some of the most popular 

tourist and recreational destinations in the United States, 

and also constitute some of the most valuable real estate 

in the country. These changing and ephemeral interfaces 

between water and land are the sites of intense residential and 

commercial development even though they are frequently 

subjected to a range of natural hazards that can include flooding, storm impacts, coastal erosion and tsunami inundation. 

Because population and economic trends have made the 

coasts so valuable, the U.S. Geological Survey (USGS) is 

conducting a National Assessment of Coastal Change HazOpen-File Report 2006-1219   
ards. One component of this effort, the National Assessment 

of Shoreline Change, documents changes in shoreline position as a proxy for coastal change. Shoreline position is one 

of the most commonly monitored indicators of environmental change (Morton, 1996), and it is easily understood by 

those who are interested in historical movement of beaches.

A principal purpose of the USGS shoreline change 

research is to develop a repeatable surveying methodology 

so that shorelines for the continental U.S., and portions of 

Hawaii and Alaska, can be periodically and systematically 

updated in an internally consistent manner. In addition, new 

methods for developing datum-based shorelines and assessing coastal change can provide the opportunity to achieve 

more comprehensive assessments of error in the future. 

The primary objectives of this effort are: (1) to develop and 

implement improved methods of assessing and monitoring 

shoreline movement, (2) to obtain a better understanding 

of the processes controlling shoreline movement, and (3) to 

enter into partnerships to facilitate data dissemination. 

Achieving these ongoing objectives requires research 

that (1) examines the original sources of shoreline data 

(maps, air photos, global positioning system (GPS), lidar), 

(2) evaluates the utility of different shoreline proxies 

(geomorphic feature, water mark, tidal datum, elevation 

contour) including the errors associated with each method, 

(3) investigates the bias and potential errors associated 

with integrating different shoreline proxies from different 

sources, (4) develops standard uniform methods of shoreline 

change analysis, (5) determines the effects of human activities on shoreline movement and rates of change, and (6) 

investigates alternative mathematical methods for calculating historical rates of change and forecasting future rates of 

change.

This report summarizes historical changes in the 

California sandy shoreline, both accretion and erosion, but 

emphasizes the erosion hazard because of its impacts on 

natural resources and the economy. The descriptions of 

coastal land loss for each region (Figure 1) within the state 

provide a more comprehensive view of coastal processes 

and key references that can be used to learn more about 

coastal change in a regional context.

Disclaimer

Results of the National Assessment of Shoreline 

Change are organized by coastal regions. This report for 

California is part of a series of reports that will include 

text summarizing methods, results, and implications of the 

results in addition to maps, via Internet Map Server (IMS), 

illustrating rates of shoreline change. Rates of shoreline 

change are being published for the purpose of regional 

characterization. The shoreline change results and products 

prepared by the USGS are not intended for comprehensive 

detailed site specific analysis of shoreline movement, nor 

are they intended to replace any official sources of shoreline 

change information identified by local or state government 

agencies, or other federal entities that are used for regulatory 

purposes. Rates of shoreline change presented herein may 

differ from other published rates, and differences do not 

necessarily indicate that the other rates are inaccurate. Some 

discrepancies are expected, considering the many possible 

ways of determining shoreline positions and rates of change, 

and the inherent uncertainty in calculating these rates. Rates 

of shoreline change presented in this report represent shoreline movement under past conditions. The results are not 

intended for predicting future shoreline positions or future 

rates of shoreline change.

This publication was prepared by an agency of the 

United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes 

any legal responsibility for the accuracy, completeness, or 

usefulness of any information apparatus, product, or process 

disclosed in the report, or represents that its use would not 

infringe privately owned rights. Reference to any specific 

commercial product, process, or service by trade name, 

trademark, manufacturer, or otherwise does not necessarily 

constitute or imply its endorsement, recommendation, or 

favoring by the United States Government or any agency 

thereof. Any views and opinions of authors expressed herein 

do not necessarily state or reflect those of the United States 

Government or any agency thereof.

Acknowledgments

This report was made possible by the hard work and 

generous cooperation of many individuals. We owe a debt 

of gratitude to Mike Rink (NOAA) and Paul Frascione 

(Information Manufacturing Corporation) for providing 

digital historical shorelines and scans of selected T-sheets, 

and David Doyle (NOAA) for providing datum corrections 

so that T-sheets could be rectified before they were digitized 

by the USGS. An enthusiastic and untiring USGS team 

was responsible for developing the methods and computer 

codes for calculating operational mean high water elevations 

and extracting the lidar shorelines. The lidar research and 

development team included Abby Sallenger, Jeff List, Karen 

Morgan, Eric Nelson, Hillary Stockdon, and Kathy Webber. 

Tara Miller and Kathy Webber provided invaluable help in 

data processing and analysis. Rob Thieler worked closely 

with TPMC Environmental Services to develop and improve 

the Digital Shoreline Analysis System (DSAS) code for 

shoreline change measurement. Brian Spear (UCSC) and 

Evan Lindenbach (UCSC) provided assistance by digitizing 

shorelines and cliff edges, georectifiying maps and preparing metadata. Bruce Rogers provided valuable assistance in 

the drafting of figures, and Ben Melosh (UCSC) helped with 

background data compilation. Ann Gibbs provided excellent 

advice and input regarding data presentation. Comments 

from and discussions with Ed Thornton, Bob Guza, Dick 

Seymour, Bob Wiegel, Mark Crowell, Lesley Ewing, Bob 

Morton and Sam Johnson were also very helpful. Finally, a 

Open-File Report 2006-1219   
Figure 1. Index map of California showing the fifteen regions discussed in the text.

California Analysis Regions

Northern California

 1 Klamath

 2 Eureka

 3 Navarro

 4 Russian River

Central California

 5 San Francisco North

 6 San Francisco South

 7 Monterey Bay

 8 Big Sur

 9 Morro Bay

 10 Santa Barbara North 

Southern California

 11 Santa Barbara South

 12 Santa Monica

 13 San Pedro

 14 Oceanside

 15 San Diego

Klamath 1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

0 30 60 120 180 240

Kilometers

San Francisco

Los Angeles

Eureka

Open-File Report 2006-1219   
detailed review by Gary Griggs was invaluable and greatly 

improved the report.

THE ROLE OF STATE AND FEDERAL 

GOVERNMENTS

One reason for conducting this National Assessment 

of Shoreline Change is that there is no widely accepted 

standardized method of analyzing shoreline changes. Each 

state or region has its own data needs and coastal zone management responsibilities (e.g. construction set-back lines), 

and therefore different techniques and standards are used to 

compile shorelines and to calculate rates of shoreline movement. Consequently, existing calculated rates of shoreline 

change and projected shoreline positions are inconsistent 

from state to state and even within states, such as in California, and cannot be compared directly. These inconsistencies were clearly demonstrated by the Federal Emergency 

Management Agency (FEMA) sponsored erosion studies 

(Crowell and Leatherman, 1999) that were used as the basis 

for evaluating erosion hazards (The Heinz Center, 2000). 

Within California, the FEMA sponsored erosion studies 

only addressed coastal cliff erosion, not sandy shoreline erosion. The USGS National Assessment of Shoreline Change 

represents the first time that shorelines from original data 

sources have been compiled and rates of shoreline change 

have been calculated on a national scale using internally 

consistent methods. The results of this analysis allow direct 

comparison of rates of change from one coastal segment to 

another and form the basis for future comparison of shoreline position.

Several federal agencies (USGS, FEMA, NOAA, U.S. 

Army Corps of Engineers (USACE) have regulatory or 

administrative responsibilities pertaining to shorelines. Yet 

these responsibilities are quite different, requiring different approaches and offering substantial opportunities for 

cooperation. For example, the USACE is authorized and 

funded by Congress to report on the economic and environmental implications of shoreline change and the costs of 

erosion mitigation. Their National Shoreline Management 

Study (Stauble and Brumbaugh, 2003) is being conducted 

using existing shoreline data. The USGS will share data and 

information, such as the lidar-derived shoreline and rates of 

change, in support of their effort. NOAA has the mandate 

to establish the official shoreline boundary for the nation 

using tidal datums. Their emphasis is on safe navigation and 

using the shoreline to generate nautical charts. NOAA also 

has a developing program (V datum), which will greatly 

assist other agencies in establishing alternative shorelines 

for a variety of purposes where the official shoreline is 

inappropriate. FEMA is authorized and partially funded by 

Congress to map coastal (and riverine) flood hazard areas. 

These maps and associated information are used for flood 

risk assessment, floodplain management, and setting insurance rates through the National Flood Insurance Program 

(NFIP). Because of perceived deficiencies in the way the 

NFIP considers coastal erosion, Congress authorized FEMA 

to report on the economic impact of erosion hazards on 

coastal communities, and on the NFIP. To accomplish this, 

FEMA contracted state agencies and academic researchers 

to conduct a pilot study of erosion hazards that included 

shoreline change data for limited geographic areas. The 

USGS is responsible for conducting research pertaining to coastal change hazards including shoreline change, 

understanding the processes that cause coastal change, and 

developing models to predict future change. The USGS is 

the only government agency that has a dedicated program 

to monitor coastal change into the future using consistent 

methods nationwide. Such a program is critically important 

to assess national issues, such as the coastal impacts of sea 

level rise.

PRIOR NATIONAL AND CALIFORNIA 

COAST SHORELINE ASSESSMENTS

There are very few studies of regional sandy shoreline 

erosion for California. The USACE (1971) conducted the 

first national assessment of coastal erosion that included 

California. That study identified areas of critical and noncritical erosion on the basis of economic development and 

potential for property loss, but rates of shoreline movement 

were not quantified. Numerous analyses have been conducted for specific sites by private consultants or contractors, or cities and counties where erosion rates have been 

required for regulatory or management purposes. Some 

of these analyses were incorporated into Dolan and others 

(1985), and Griggs and Savoy (1985), where rates of change 

were presented on maps, and the long-term trends of erosion 

and accretion were summarized in an accompanying text. 

The Griggs and Savoy (1985) compilation has recently been 

updated (Griggs and others, 2005a), although most of the 

erosion hazards addressed therein pertain to coastal cliff and 

bluff erosion, with the exception of Southern California.

Since these earlier works, methods of obtaining, 

analyzing, displaying, and storing shoreline data have 

improved substantially, and coastal change has continued. 

Furthermore, coastal scientists have not agreed on standard 

methods for analyzing and reporting shoreline changes, 

nor have they identified rigorous mathematical tests that 

are widely accepted for quantifying the change and associated errors. Consequently, there are critical needs for (1) a 

nationwide compilation of reliable shoreline data including 

the most recent shoreline position, and (2) a standardization 

of methods for obtaining and comparing shoreline positions 

and mathematically analyzing the trends.

Open-File Report 2006-1219 
METHODS OF ANALYZING 

SHORELINE CHANGE

Compilation of Historical Shorelines

Coastal scientists in U.S. universities and government 

agencies have been quantifying rates of shoreline movement 

and studying coastal change for decades. Before GPS and 

lidar technologies were developed, the most commonly used 

sources of historical shoreline position were NOAA Topographic Sheets (T-sheets, see Shalowitz, 1964) and aerial 

photographs. Ideally, extraction of shoreline position from 

these data sources involves geo-referencing and removing 

distortions from maps or aerial photographs, followed by 

digitizing shoreline position. Depending on coastal location, data source, and scientific preference, different proxies 

for shoreline position are used to document coastal change, 

including the high water line (for discussion of the high 

water line (HWL) see Shalowitz, 1964), wet-dry line, vegetation line, dune toe or crest, toe or berm of the beach, cliff 

base or top, and the line of mean high water (MHW). 

The USGS National Assessment of Shoreline Change 

analysis for California incorporates shoreline positions from 

4 time periods and three unique data sources. To maintain consistency at a national scale, these four periods are 

mid- to late1800s, 1920s-1930s, 1950s-1970s, and post1997. Several organizations have provided the USGS with 

digital maps and/or shoreline data (Table 1). The historical 

shorelines from the 1850-1890s and 1920s-1930s were digitized from scanned and georeferenced historical T-sheets. 

In addition, shorelines were digitized from USGS Digital 

Raster Graphic (DRG) maps where data gaps in the T-sheets 

existed, as these were the only source of shoreline data that 

could be located for the data gap areas. These occurred 

for the third period (1950s-1970s) for most of Central and 

Northern California. The modern (post-1997) shoreline 

represents a MHW elevation derived from lidar data.

Shorelines were compiled for the state following 

the guidelines established for selected periods (mid- to 

late 1800s, 1920s-1930s, 1950s-1970s, and post-1997) as 

closely as possible. Table 2 lists the final range of years 

(and months where known) for shorelines compiled for each 

period by region.

Delineation of a Modern (Lidar-derived) 

Shoreline

The most recent shoreline used in this National Assessment (post-1997) was derived from lidar (Light Detection and Ranging) data. The USGS, in collaboration with 

NASA, has been using the NASA Airborne Topographic 

Mapper (ATM) to map coastal areas since 1997 (Krabill 

and others, 2000; Sallenger and others, 2003). The ATM 

surveys ground elevation using an elliptically rotating bluegreen laser. GPS (global positioning system) positions and 

inertial navigation systems are used to correct for aircraft 

pitch, roll, and heading, providing ground elevations with 

accuracies of about ±15 cm (Sallenger and others, 2003). 

The lidar surveys used to extract shorelines for this report 

were conducted either in 1998 or 2002 (Table 2). 

To compare with historical shorelines, an operational 

MHW shoreline was extracted from the lidar surveys using 

a method developed by Stockdon and others (2002) (Figure 2). Shorelines were extracted from cross-shore profiles which consist of bands of lidar data 10 m wide in the 

alongshore direction and spaced every 20 m along the coast. 

A least-squares linear regression line is passed through 

the 2-D cluster of data that encompasses the operational 

MHW datum (Table 3) and is limited to the seaward-sloping 

foreshore. The regression equation is then used to derive the 

horizontal intersection of the operational MHW datum with 

the profile, giving the shoreline position for that profile. 

Repeating this procedure at successive profiles 20 m apart 

generates points that can be connected to create a continuous shoreline. 

Table 1. Providers and original sources of historical shorelines for each California region.

Section Organization Original Data Source Spatial Coverage

Northern 

California

NOAA Coastal Services Center NOAA T-sheets

U.S. Geological Survey DRGs Oregon Border to Tomales Point

NOAA Vectorization Project NOAA T-sheets

Central 

California

NOAA Coastal Services Center Scanned NOAA T-sheets Tomales Point to El Capitan Beach NOAA Vectorization Project NOAA T-sheets

U.S. Geological Survey DRGs Tomales Point to Point Estero

Southern 

California

NOAA Coastal Services Center Scanned NOAA T-sheets

El Capitan Beach to Mexico Border

NOAA Vectorization Project NOAA T-sheets

Open-File Report 2006-1219 
To determine the operational MHW elevation, California was divided into 3 sections (Northern, Central and 

Southern California). For each section, the operational 

MHW elevation represents an average of MHW elevations 

from individual open-ocean or near open-ocean tide gauges 

(Weber and others, 2005). A list of tide gauges and MHW 

elevations used in each section is presented in Table 3. The 

lidar-extracted MHW shoreline is not necessarily the same 

as a MHW shoreline surveyed by a licensed land surveyor. 

This is because the operational MHW elevation used for the 

lidar shoreline is an average of the MHW elevations at several tide gauges. Furthermore, the lidar-extracted shoreline 

is intended only as a reference feature for measuring shoreline change. It is not intended to establish legal boundaries.

Because inland bays generally are not suitable sites 

for extraction of a lidar shoreline and because this report 

focuses on the open-ocean coasts, extensive bay areas such 

as San Francisco and Tomales Bay shorelines were not 

included in the shoreline change analysis. Also, lidar data 

were not available for all sandy beaches in California; gaps 

exist in Northern California along the sandy shorelines near 

Arcata and Eureka, as well as along a stretch of coast around 

San Simeon and Cambria in Central California. When lidar 

data are available for these gaps, the shoreline change analyses will be conducted and provided as on-line updates and in 

future reports.

Geographic Information System (GIS) 

Procedures

NOAA T-sheet indexes were used to determine T-sheet 

availability for shorelines that were not already available as 

ESRI ArcGIS shapefiles. T-sheets were then requested from 

NOAA and received as scanned TIF images. Existing digital 

shorelines for each period were compiled and a quality 

assessment was performed.

Scanned TIF image T-sheets were rectified using Erdas 

Imagine geographic imaging software by placing at least 

6 well-spaced ground control points (GCPs) on selected 

T-sheet graticules in geographic coordinates. Some Tsheets produced before 1930 required additional coordinate 

transformation information from NOAA to convert from 

the United States Standard Datum (USSD) to the North 

American Datum of 1927 (NAD27). The datum transformation was applied to T-sheet graticule coordinates prior to 

rectification. Total Root Mean Square (RMS) error for the 

rectification process was maintained below 1 pixel, which is 

approximately 4 m at a scale of 1:20,000 and approximately 

1.5 m at a scale of 1:10,000. Typically the resulting RMS 

was much lower than one pixel. Newly geo-referenced Tsheets were loaded in ArcGIS and shorelines were digitized. 

All shoreline vectors were converted to the Universal Transverse Mercator (UTM) projection with the North American 

Datum of 1983 (NAD83).

Table 2. Dates of compiled shorelines in different regions for selected periods.

 Region

Selected Periods 

1800s 1920s - 1930s 1950s - 1970s month post-1998 month

Klamath 1859-1870 1926-1929 1955-1964 June, July 2002 Sept.

Eureka 1854-1870 1929 1956-1968 June, July, Aug. 2002 Sept.

Navarro 1870-1874 1929-1935 1957-1968 n/a 2002 Oct.

Russian River 1862-188 1929-1930 1952-1971 July, Nov. 2002 Oct.

San Francisco N 1853-1862 1929-1931 1952 July 1998 Apr.

San Francisco S 1853-1900 1929-1932 1946-1953 June, July, Aug. Oct. 1998 Apr.

Monterey Bay 1853-1910 1932-1933 1945-1952 July, Aug. 1998 Apr.

Big Sur 1876-1891 1933-1934 1947-1976 Mar., May, June 1998/2002 Apr./Oct.

Morro Bay 1871-1887 1934 1947-1976 Mar. 1998/2002 Apr./Oct.

Santa Barbara. N 1869-1888 1933-1934 1976 Mar. 1998 Apr.

Santa Barbara S 1855-1871 1932-1934 1974-1976 Feb., Mar., Oct. 1998 Apr.

Santa Monica 1857-1877 1933 1972-1974 Mar. 1998 Apr.

San Pedro 1859-1885 1920-1934 1971-1974 Mar. 1998 Apr.

Oceanside 1886-1889 1933-1934 1972 Mar. 1998 Apr.

San Diego 1852-1889 1933 1972 Mar. 1998 Apr.

Open-File Report 2006-1219   
Shorelines from all sources were merged to produce 

a single shoreline for each of the 4 time periods by section of California (Northern, Central and Southern). Final 

shorelines were coded with 6 attribute fields (ID, Type, 

Date, Description, Source, and Accuracy) to prepare for 

calculating shoreline change rates with the Digital Shoreline 

Analysis System (DSAS; Thieler and others, 2003). 

Calculation and Presentation of Rates of 

Change

Rates of long-term shoreline change were generated in 

a GIS with the Digital Shoreline Analysis System (DSAS), 

an ArcGIS tool developed by the USGS in cooperation with 

TPMC Environmental Services. The tool is designed to 

efficiently lead a user through the major steps of shoreline 

change analysis. This ArcGIS tool contains three main components that define a baseline, generate orthogonal transects 

at a user-defined separation along the coast, and calculate 

rates of change (linear regression, endpoint rate, average 

of rates, average of endpoints, jackknife). The extension 

utilizes Visual Basic scripts to develop transects and rates, 

and uses the Visual Basic programming environment to 

automate and customize the user interface.

Baselines were constructed seaward of, and parallel 

to, the general trend of the four shorelines. The coastline of 

Figure 2. Example of a lidar profile from April 10, 1998 at Santa Cruz, California for (a) the entire cross-shore region and (b) an 

expanded view of the foreshore region. (a) Laser returns off of the water’s surface are seen as green symbols seaward of x = 230 m. 

Blue symbols indicate data points within ± 0.5 m of the operational MHW datum. Red symbols indicate data points along the cliff face 

and top. (b) The asterisk marks the cross-shore position of the operational MHW shoreline on the foreshore. The horizontal error bar 

represents the 95% confidence interval about the estimate. After Stockdon and others (2002).

0 100 200 300 400 500 600

-2

0

5

10

15

20

25

30

cross-shore position (m)

elevation (m) NAVD88

(a) MHW +/ 0.5m

MH W

194 196 198 200 202 204 206

-0.4

-0.2

0

0.4

0.8

1.2

1.4

1.6

cross-shore position (m)

elevation (m) NAVD88

(b) MHW +/ 0.5m

shoreline

95% confidence interval

*

*

Cliff

Pacific Ocean Beach

Open-File Report 2006-1219   
California, and hence the baselines, are curvilinear. Using 

DSAS, transects were spaced 50 m apart. Transects were 

manually eliminated to prevent calculation of rates in areas 

where less than four shorelines were intersected. Fewer than 

four shorelines can result from one or more of the following 

conditions (Figure 3): 1) the position of a river mouth has 

changed or migrated, 2) shoreline segments were missing 

(data gaps), 3) a harbor or other coastal structure eliminated 

one or more of the shorelines, and 4) no lidar shoreline is 

available for rocky coasts. 

Long-term rates of shoreline change were calculated 

at each transect using a linear regression applied to all four 

shoreline positions from the earliest (1800s) to the most 

recent (derived from lidar). Linear regression was selected 

because it has been shown to be the most statistically robust 

quantitative method when a limited number of shorelines 

are available (Crowell and others, 1997). It is also the most 

commonly applied statistical technique for expressing shoreline movement and estimating rates of change (Crowell and 

Leatherman, 1999). Short-term rates of shoreline change 

were calculated using the endpoint method comparing the 

1970s and most recent (lidar-derived) shoreline positions. 

Long-term rates and short-term rates of shoreline change, as 

defined here, are used throughout the report. 

Beach Alterations and Shoreline Definitions 

that Influence Rates of Change

Human Activities

Attempts to stabilize the shore can greatly influence 

rates of shoreline change. Activities such as beach nourishment or emplacement of shoreline stabilization structures tend to alter coastal processes, sediment transport, 

and shoreline position. For example, beach nourishment 

artificially causes rapid, temporary shoreline accretion. 

Depending on the frequency of beach nourishment, the 

placement of large volumes of sand on the beach will bias 

the rates of observed shoreline change toward accretion 

or stability, even though the natural beach, in the absence 

of nourishment, may have an erosional trend. In addition, 

the emplacement of shoreline protection structures such as 

seawalls, bulkheads and revetments can result in both active 

and passive erosion of the beach. In the case of passive 

erosion, the back beach area is fixed by the structure, and 

the beach in front gradually narrows. Eventually erosion 

will cease (until the structure fails), thus indicating a stable 

shoreline in the shoreline change record. Active erosion 

associated with shoreline protection structures refers to 

the acceleration of shoreline erosion in front of a structure 

caused by the alteration of wave, tide and current patterns.

Clayton (1991), Flick (1993) and Wiegel (1994) provide a summary of identifiable beach nourishment projects 

on the U.S. West Coast that had been conducted up to the 

late 1980s. These records were used to identify shoreline 

segments that had been influenced by beach nourishment. 

Only projects that pre-date the lidar shoreline were included. 

There is no distinction made between large volume, continuous projects and small volume, finite projects. According 

to Flick (1993), Wiegel (1994), and many others, beaches 

along the coast of Southern California were extensively 

nourished from the early part of the 20th-century through 

the mid-1970s. Nourishment programs became far less 

frequent in the post-1970s era. 

Differentiating between natural rates of erosion and the 

influences of beach nourishment is difficult because studies 

have not been conducted to specifically address this issue. 

In addition, available data may be inadequate to address this 

question because there are not enough shoreline positions 

immediately before, after, and between nourishment projects. Human responses to shoreline erosion, including beach 

Table 3. List of tide gauge measurements used to calculate mean high water elevation.

Site Name MHW above 

NAVD88 (m)

Average of 

MHW

Northern 

California

Crescent City, CA 1.80

Trinidad Bay, CA 1.76 1.81

Arena Cove, CA 1.52

Central 

California

Arena Cove, CA 1.52

1.46

Point Reyes, CA 1.49

Monterey Harbor, CA 1.40

San Simeon, CA 1.43

Southern 

California

Port San Luis, CA 1.37

1.33

Santa Barbara, CA 1.35

Rincon Island, CA 1.34

Santa Monica, CA 1.35

Huntington Beach, CA 1.32

La Jolla, CA 1.28

Imperial Beach, CA 1.33

Open-File Report 2006-1219   
nourishment and emplacement of structures, are included in 

the discussion of the results of the shoreline change analysis.

Shoreline Definitions

Inclusion of a lidar-derived shoreline represents a new 

approach to the investigation of shoreline change. The three 

pre-lidar historical shorelines come from topographic maps 

that use the HWL as the shoreline proxy. For more than 

150 years, the HWL has served as the most commonly used 

shoreline because it could be visually identified in the field. 

With advanced technologies, such as GPS and lidar, it is 

now possible to objectively define the shoreline on the basis 

of an elevation or a tidal datum, such as MHW. Changing 

the shoreline definition from a proxy-based physical feature 

that is uncontrolled in terms of an elevation datum (HWL) 

to a datum-based shoreline defined by an elevation contour 

(MHW) has important implications with regard to inferred 

changes in shoreline position and calculated rates of change. 

Morton and others (2004) first compiled published 

and unpublished data to evaluate the horizontal and vertical differences in HWL determined from beach profiles, 

aerial photographs, or GPS surveys, and the MHW derived 

from beach profiles, GPS surveys, or lidar surveys. We 

have updated this to include the most recent available 

analyses (Table 4). The HWL and MHW positions were 

established at the same time, or within a few weeks of one 

another at multiple sites around the U.S. where the beach 

and wave characteristics are diverse. Comparing these HWL 

and MHW positions assumes that the observed proxydatum offsets are entirely artifacts of shoreline definition 

and are not related to actual changes in the beach profile 

due to sediment transport (erosion or accretion processes) 

between the survey dates. This is a relatively safe assumption considering the short intervals between surveys or the 

knowledge that a particular shoreline segment is relatively 

stable. Moore and others (2006) avoided the need for this 

assumption by deriving HWL and MHW shorelines from 

aerial photography and lidar data collected during the same 

tidal cycle. 

Table 4 shows that average absolute horizontal and 

vertical offsets between the HWL and MHW range from a 

few meters to more than 50 m, and vertical offsets can be as 

much as 2 m. Most of the horizontal offsets are less than 20 

landward

seaward

landward

seaward

A River Mouths B Missing Data

C Coastal Structures D Rocky Coastline

offshore baseline offshore baseline

offshore baseline offshore baseline

Shorelines Transects

eliminated

1800s used for calculation

2000s

1970s

1930s

transect/shoreline

intersection

Figure 3. Examples of common conditions where transects are eliminated in the absence of four shoreline intersections.
m, and most of the vertical offsets are less than 1 m. Offsets 

are typically greatest on relatively flat beaches where high 

waves produce high wave runup (i.e. southwest Washington). Conversely, offsets are least where beaches are relatively steep and wave runup is low. For the data analyzed 

by Morton and others (2004), the MHW was seaward of 

the HWL on virtually all of the transects (Table 4). This 

nearly systematic horizontal offset between the HWL and 

the MHW causes shoreline positions and calculated rates of 

change to imply slower erosion, a change from erosion to 

accretion, or faster accretion than actual shoreline movement can account for. 

The recent study by Moore and others (2006) illustrated that overall, the importance of incorporating a 

proxy-datum offset into shoreline change analysis depends 

on several factors including the magnitude of the offset, the 

length of time over which rates are being measured and the 

statistical significance of the shoreline change rates. This 

proxy-datum offset is particularly important when averaging 

shoreline change rates alongshore. Since the proxy-datum 

offset is a bias, virtually always acting in the same direction, 

the error associated with the apparent shoreline change rate 

shift does not cancel during averaging and it is important to 

quantify the bias in order to account for the rate shift. The 

shoreline change rates presented in this report have been 

calculated by accounting for the proxy-datum bias using the 

methodology described below.

Estimating the proxy-datum bias and the bias 

uncertainty

Comparison of HWL shorelines and a MHW datumbased shoreline for a single-day survey on Assateague 

Island (Moore and others, 2006) revealed an average horizontal offset between shoreline indicators of 18.8 m (Table 

4). Vertical offsets were also substantial and were strongly 

correlated with foreshore beach slope. A simple total water 

level model, that combines the effects of tidal variations 

and wave runup, (Ruggiero and others, 1996; Ruggiero 

and others, 2001; Ruggiero and others, 2003) successfully 

reproduced these vertical offsets suggesting that the proxydatum offset is primarily governed by wave runup. In order 

to estimate the proxy-datum bias for the State of California 

we use the approach outlined in Moore and others (2006) 

with the improvement of including the wave runup formula1 Simultaneous measurement of HWL and MHWL at beach profiles coordinated with tide gauge measurements

2 Video camera projections of HWL for 111 days during a three-year period and MHWL from generalized beach profiles

3 Nearly simultaneous aerial photographs (HWL) and GPS surveys (MHWL) 

4 Nearly simultaneous GPS (HWL) and lidar surveys (MHWL)

Table 4. Absolute horizontal and vertical differences between high water and mean high water shorelines (modified from Morton 

and others, 2004).

Location Survey Date 

HWL

Survey Date 

MHWL

Length 

of Shore 

(km)

No. of 

Observations

Average 

Horizontal 

Offset (m)

Average 

Vertical 

Offset 

(m)

% MHWL with 

Seaward Offset Data Source or Reference

Galveston Is., TX1

01-27-95 01-27-95 Point 1 18 0.6 100

Morton and Speed, 1998

North Padre Is., TX1

08-16-95 08-16-95 1.6 6 8 0.4 100

09-14-95 09-14-95 1.6 6 8 0.2 100

09-28-95 09-28-95 1.6 6 12 0.2 100

10-06-95 10-06-95 1.6 6 6 0.3 100

Duck, NC2

1994-19962 Point 111 40 2.0 100 Pajak and Leatherman, 2002

Klipsan, WA3 05-26-99 05-28-99 3.0 171 22 0.5 100

Ruggiero and others, 2003

09-21-99 09-24-99 3.0 171 52 0.8 100

Ocean Shores, WA3

05-26-99 05-28-99 4.0 200 23 1.0 100

07-27-99 07-22-99 4.0 200 8 0.2 100

05-06-01 05-07-01 4.0 200 30 1.0 100

Oysterville, WA3

09-21-99 09-10-99 3.5 201 49 0.9 100

Assateague Is., 

MD/ VA4

03-16-98, 03-17-98 04-03-98 58.6 1172 11 0.7 99

National Park Service (M. Duffy) 09-29-99, 10-28-99 10-01-99 60.0 1200 20 1.6 100

06-13-01, 06-14-01 06-05-01 52.4 1049 8 0.6 92

10-01-02 09-12-02 47.7 953 22 1.4 98

Coastal Research and 

Engineering, Inc. (M. Byrnes)

05-06-02 05-06-02 47 470 18.8 1.2 – 1.3 100 Moore and others, 2006

Open-File Report 2006-1219 10
tion of Stockdon and others (2006). The horizontal offset 

between HWL and MWH shorelines can be estimated by:

Equation (1)

where ZT is the tide level, tan b is the beach slope, Ho is the 

deepwater significant wave height, and Lo is the deep-water 

wave length given by linear theory as gT2/2p, where g is the 

acceleration due to gravity and T is the peak wave period. 

In order to calculate the bias, as well as the bias uncertainty, for this regional shoreline change analysis, long-term 

best estimates and measures of uncertainty are derived for 

beach slope, wave height, wave length, and tide level. The 

best estimate for beach slope was derived by averaging 

individual lidar transect slope estimates within 1-km blocks 

along the coast. We take the long-term mean wave height 

and length to be the best estimate to use in the bias calculation. The long-term mean wave height is derived from 

USACE Wave Information Studies (WIS) hindcasts while 

the long-term mean wave length is derived from long-term 

buoy records (NDBC and CDIP) along the California Coast. 

Finally, the best estimate of the tide level responsible for 

generating HWL shorelines is taken as the elevation of 

MHW (see Table 3) (Weber and List, 2005). The measures of uncertainty for the beach slope, wave height, and 

wave length are estimated as the difference between the 

95% exceedance statistic and the 50% exceedance statistic 

of the cumulative distributions. This gives a 90% confidence interval on each of the cumulative distributions. The 

uncertainty of assuming that the tide responsible for leaving 

HWL-type shorelines was at MHW is calculated simply by 

MHHW-MHW 

The proxy-datum bias, and the associated uncertainty, 

is calculated at each of the 1-km blocks in which the average beach slope has been calculated. The nearest WIS 

station, wave buoy, and tide gage to each individual 1-km 

block were used in the application of Equation 1. Once 

the bias was calculated, it was incorporated into DSAS and 

applied on a transect-by-transect basis, so that the estimated 

bias is removed from the final long- and short-term shoreline change rates. The bias, averaged over 815 1-km sections of the California coast, was approximately 18 m with 

an average uncertainty of approximately 8.7m.

Uncertainties and Errors

Documented trends and calculated rates of shoreline 

change are only as reliable as: (1) measurement errors 

that determine the accuracy of each shoreline position, (2) 

sampling errors that account for the variability of shoreline 

position, and (3) statistical errors associated with compiling and comparing shoreline positions. Anders and Byrnes 

(1991), Crowell and others (1991), Thieler and Danforth 

(1994), and Moore (2000), provided general estimates of 

the typical measurement errors associated with mapping 

methods and materials for historical shorelines, registry of 

shoreline position relative to geographic coordinates, and 

shoreline digitizing. 

For this analysis we report estimates of individual 

shoreline position uncertainty (Table 5) and shoreline 

change uncertainty for the regional averages presented in 

Table 6A-C. Uncertainties associated with shoreline change 

on individual transects can be calculated using similar methods as are used for the regional averages as discussed below 

for both long- and short-term analyses. 

The largest shoreline position errors were errors of 

±10 m, which were attributed to scales and inaccuracies 

in the original surveys (T-sheets) and typical positioning 

errors associated with DRGs (±15 m). Stockdon and others 

(2002) provided estimates of GPS positioning errors (±1 

m) and regression errors (±1.5 m) associated with derivation of the MHW elevation from the lidar data. A previously unreported error term in shoreline change analyses 

is the uncertainty in HWL shorelines due to variations in 

water levels. Our estimates of the uncertainty associated 

with the proxy-datum bias in effect quantify this error term 

for the first time. Following the methodology of Taylor 

(1997), Equation 1 was used to translate the estimates of 

the uncertainty of each parameter into an estimate of the 

uncertainty of the proxy-datum bias. Equation 1 can also be 

used to demonstrate that the uncertainty of the proxy-datum 

bias is equivalent to the uncertainty in any individual HWL 

shoreline.

Sampling errors relating to the local short-term variability of true shoreline positions (Morton, 1991; Douglas 

Table 5. Maximum estimated measurement errors for California shorelines.

Measurement Errors (m) Time Period*

1 2 3a 3b 4

Georeferencing (Eg) 4 4 4 4 --

Digitizing (Ed) 1 1 1 1 --

T-sheet survey/T-sheet, DRG position (Et) 10 10 3 15 --

Shoreline position uncertainty (Eo) 8.7 8.7 8.7 8.7 1.5

Total shoreline position error (Esp) (m) 13.9 13.9 10.1 17.8 1.5

Annualized short-term rate error (m/yr) 0.4

*Time periods: 1=1800s; 2=1920s-1930s; 3a=1970s; 3b=1950s; 4=post-1997

Open-File Report 2006-1219 11
Open-File Report 2006-1219 12

Table 6A. Average shoreline change rates for Northern California

Table 6B. Average shoreline change rates for Central California

Table 6C. Average shoreline change rates for Southern California

Note: LT = long-term; ST = short-term

Note: LT = long-term; ST = short-term

Note: LT = long-term; ST = short-term

No. of Transects Average of Rates (m/yr) Erosion Rate (m/yr) % Erosion Accretion Rate (m/yr) % Accretion

Analysis 

Region

LT ST LT ST LT ST LT ST LT ST LT ST

Klamath 1430 1573 0.7+0.1 0.4+0.4 -0.4+0.1 -0.6+0.4 25 48 1.0+0.1 1.3+0.4 75 52

Eureka 493 652 0.7+0.2 0.4+0.4 -0.2+0.3 -0.9+0.4 4 51 0.7+0.2 1.8+0.4 96 49

Navarro 608 656 0.1+0.1 0.0+0.4 -0.1+0.1 -0.5+0.4 28 50 0.2+0.1 0.6+0.4 72 50

Russian River 435 483 0.2+0.1 0.4+0.4 -0.2+0.1 -0.4+0.4 28 35 0.3+0.1 0.8+0.4 72 65

No. California 2966 3364 0.5+0.1 0.3+0.4 -0.3+0.1 -0.6+0.4 23 47 0.7+0.1 1.2+0.4 77 53

No. of Transects Average of Rates (m/yr) Erosion Rate (m/yr) % Erosion Accretion Rate (m/yr) % Accretion

Analysis Region LT ST LT ST LT ST LT ST LT ST LT ST

San Francisco N 902 1039 0.1+0.1 -0.5+0.4 -0.2+0.1 -0.7+0.4 46 81 0.3+0.1 0.5+0.4 54 19

San Francisco S 1125 1150 -0.2+0.1 -0.5+0.4 -0.4+0.1 -0.7+0.4 76 81 0.1+0.1 0.5+0.4 24 19

Monterey Bay 1013 1031 -0.2+0.1 -0.6+0.4 -0.6+0.1 -0.8+0.4 41 77 0.4+0.1 0.3+0.4 59 23

Big Sur 512 533 0.0+0.1 -0.2+0.4 -0.1+0.1 -0.5+0.4 39 65 0.2+0.1 0.4+0.4 61 35

Morro Bay 447 458 0.1+0.1 -0.7+0.4 -0.1+0.1 -1.0+0.4 35 80 0.3+0.1 0.4+0.4 65 20

Santa Barbara N 1983 2267 0.0+0.1 -0.6+0.4 -0.2+0.1 -1.0+0.4 56 80 0.2+0.1 0.9+0.4 44 20

Central California 5982 6478 0.0+0.1 -0.5+0.4 -0.3+0.1 -0.8+0.4 53 79 0.2+0.1 0.6+0.4 47 21

No. of Transects Average of Rates (m/yr) Erosion Rate (m/yr) % Erosion Accretion Rate (m/yr) % Accretion

Analysis Region LT ST LT ST LT ST LT ST LT ST LT ST

Santa Barbara S 1692 1760 0.1+0.1 -0.5+0.4 -0.2+0.1 -1.2+0.4 56 72 0.5+0.1 1.1+0.4 44 28

Santa Monica 1319 1504 0.4+0.1 -0.1+0.4 -0.1+0.1 -0.5+0.4 31 60 0.7+0.1 0.9+0.4 69 40

San Pedro 605 925 0.5+0.1 0.5+0.4 -0.3+0.2 -0.5+0.4 12 35 0.6+0.1 1.0+0.4 88 65

Oceanside 1561 1587 0.2+0.1 -0.1+0.4 -0.1+0.1 -0.6+0.4 31 67 0.3+0.1 0.9+0.4 69 33

San Diego 437 524 0.9+0.1 -0.8+0.4 -0.1+0.1 -1.0+0.4 21 90 1.2+0.2 0.5+0.4 79 10

So. California 5614 6300 0.3+0.1 -0.1+0.4 -0.2+0.1 -0.8+0.4 36 64 0.6+0.1 0.9+0.4 64 35
and Crowell, 2000) are less well known. Along the California coast, as in many locales worldwide, there is pronounced 

cyclical erosion and accretion of the shoreline. This 

variability is driven by variations in wave conditions from 

summer to winter, years with severe versus average storms 

or swells, and episodic events like El Niños or hurricanes. 

In addition, the seasonal shoreline variability also has a high 

spatial variability, depending on the orientation of the coast 

with respect to the wave direction and effects of refraction 

or reflection from headlands, offshore islands and manmade 

structures. As a result, an uncertainty term quantifying seasonal shoreline variability for regionally averaged shoreline change rates is a rough estimate at best. Site specific, 

temporally dense data are required to evaluate short-term 

shoreline variability. The lack of reliable high frequency 

data regarding short-term variability (of true shoreline 

position) at most coastal sites limits the ability to quantify 

this uncertainty into the overall shoreline position uncertainty. Studies that do exist for California (Shepard, 1950; 

Bascom, 1954; Johnson, 1971) focus on changes in beach 

width or profile. An estimate of the variability in the position of the MSL intersect on the beach from eleven profile 

envelopes from La Jolla (Shepard, 1950) is approximately 

9 m. In Monterey Bay, similar qualitative estimates from 9 

profiles, surveyed over 15 years (Dingler and Reiss, 2002), 

suggests an average variability envelope of the MHW of 

approximately 40 m. However, these data include both the 

1982-83 and 1997-98 El Niños and thus incorporate extreme 

conditions. One of the most extensive records to date is 

the 20-year record of beach profiles surveyed by the Army 

Corps of Engineers at Duck, N.C. Using 460 shoreline positions from the Duck profile data, Barton and others (2003) 

showed that the envelope of shoreline positions around a 

relatively stable shoreline was about ±20 m. 

Due to the lack of accurate, systematic data regarding 

the seasonal variation of the shoreline along the California 

coast, the error values reported here do not include an uncertainty term for the seasonal shoreline position variability in 

the quantification of errors associated with the regionally 

averaged shoreline change rates. For the long-term shoreline 

change analysis we assume that the seasonal variability in 

each shoreline is random and uncorrelated to the others and 

that the regression error will account for this uncertainty 

(see Linear regression (long-term) shoreline change error

below). For the short-term analysis it is likely, at least 

in Northern and Central California, that due to the length 

of time over which our rates are calculated, the seasonal 

variability uncertainty term has a negligible impact on the 

total error value. In Northern and Central California, the 

shorelines from the most recent historical shoreline DRGs 

are based on aerial photographs from the 1940s and 1950s. 

Table 2 includes not only the years of the data sources, but 

also the months of the photography on which the T-sheet 

maps were based for the most recent historical shoreline. In 

Southern California nearly all of the source data are from 

the winter months, as is the lidar data. Therefore, the seasonal variability term is again assumed not to have a measurable impact on the error term for the regionally averaged 

rates presented in this report. Independent comparisons of 

our shoreline change results with published rates in Southern Monterey Bay (Thornton and others, 2006) are in close 

agreement, even in the short-term. However, we recommend 

that anyone using the data associated with this report for 

a more site-specific analysis incorporate an error term to 

account for seasonal shoreline position variability.

Estimates of the maximum positional errors for this 

study are provided in Table 5 to show how each error contributes to inaccuracy in the shoreline position. The annualized error for short-term shoreline change is calculated and 

subsequently incorporated into the shoreline change rate 

calculations as outlined below. The uncertainty on the shortterm (end-point) rates, using a best estimate for California 

shorelines is ±0.4 m/yr (Table 5 and Table 6A-C). 

End-point (short-term) shoreline change error 

The total error for the end-point shoreline change rate, 

(Esp)(Equation 2), is calculated by taking the square root of 

the sum of the squares (or adding in quadrature) of: georeferencing error (Eg), digitizing error (Ed), T-sheet survey or 

DRG error (Et), and shoreline position error (Ep), similar 

to the methods outlined by Crowell and others (1993). 

Values for each of the error terms are given in Table 5. 

The georeferencing error represents the elected maximum 

acceptable RMS error for T-sheets at a scale of 1:20,000 

in this study. The georeferencing error is applied to the 

historical shorelines that are derived from T-sheets only. 

The digitizing error reflects the maximum error specified in 

past studies (Anders and Byrnes, 1991; Crowell and others, 

1991; Moore, 2000), and is applied to the historical shorelines only. The maximum T-sheet survey error, determined 

by Shalowitz (1964), incorporates all of the errors associated with the mapping process including distance to rodded 

points, plane table position, and identification of the HWL. 

The maximum DRG error is the stated accuracy of USGS 

Topographic Quadrangle maps from which the DRGs are 

derived; National Map Accuracy Standards give ±15 m as 

the maximum acceptable error. The T-sheet survey error 

is applied to all historical shorelines; however, note that 

the error associated with the 1950s-1970s era T-sheets is 

considerably lower than the older T-sheets; this difference is 

based on findings by Ruggiero and others (2003), as well as 

the fact that more recent shorelines are derived from aerial 

photos or other sources. Shoreline position error is the 

maximum error associated with the derivation of the lidar 

shoreline (Stockdon and others, 2002) for lidar data and the 

average bias uncertainty (8.7 m) for the historical shoreOpen-File Report 2006-1219 13
lines. Thus, the total shoreline position error as shown in 

Table 5 for each shoreline is expressed by:

 Equation (2)

A separate Esp is calculated for each period. For the shortterm shoreline change rates only these values can be combined and annualized to provide an error estimation for the 

shoreline change rate at any given transect. The annualized 

error (Ea) is expressed by:

Equation (3)

For determining short-term uncertainty error at a 

specific location (at an individual transect) we can add the 

uncertainty terms from Table 5 to get a total uncertainty of 

the shoreline change rate at a given location. Dividing this 

total by the time between shoreline dates provides the error 

on the short-term change rate at that location.

Linear regression (long-term) shoreline change 

error

Linear regression is the most commonly applied 

statistical technique for expressing shoreline movement and 

estimating rates of change (Crowell and Leatherman, 1999) 

where there are a statistically valid number of samples. 

Because linear regression fails to recognize the potential for 

temporal differences in trend (trend reversals) and accelerations or decelerations (Morton, 1991; 1996), average trends 

and rates of shoreline change in this study were calculated 

for both long-term (entire period) and short-term (most 

recent) time scales. Long-term rates of shoreline change 

were determined at each transect by taking the slope of the 

regression line applied to all four shoreline positions. The 

resulting rates are reported in units of m/yr (Table 6A-C). 

Uncertainties for the average shoreline change rates are 

reported as the ± values in Table 6A-C. 

Two uncertainty terms arise in the calculation of the 

long-term shoreline change rates. The first term is the 90% 

confidence interval of the linear regression shoreline change 

rate for each transect. The second term arises from the 

uncertainty in our best estimates of the proxy-datum offsets. 

We calculate linear regression slopes using shoreline data 

that has been adjusted based on our best estimate of the 

proxy-datum bias as well as data that has been adjusted 

according to our best estimate of the ± the bias uncertainty. 

From this analysis we get a best estimate of the shoreline 

change rate and an uncertainty of the rate due to the bias 

uncertainty. At each transect we can add the regression 

error and the proxy-datum bias uncertainty error to get a 

total uncertainty of the shoreline change rate at a given location.

However, in terms of calculating regionally-averaged shoreline change rate uncertainties the two terms 

discussed above need to be treated differently. Because 

the 90% confidence interval on the linear regression of 

each transect is assumed to be random and independent, 

when averaged over many transects the resulting average 

uncertainty associated with this term can be quite small; the 

greater the number of transects over which the uncertainty 

is averaged, the smaller the uncertainty on the average rate. 

However, for the second term we need to account for the 

fact that the proxy-datum offset is a bias and always acts in 

one direction. Therefore, the regionally averaged shoreline 

change rate uncertainty associated with the proxy-datum 

bias is simply the average value of the error resulting from 

the uncertainty of the proxy-datum bias. The regionally 

averaged total shoreline change uncertainty terms can be 

expressed by:

Equation (4)

where U is the alongshore averaged shoreline change rate 

uncertainty, C is the linear regression 90% confidence interval, B is the shoreline change rate uncertainty associated 

with the proxy-datum bias, and n is the number of transects 

included in average. 

Field observations and prior studies of shoreline movement within each analysis region in California suggest that 

the trends and relative rates of change presented in this 

study are as accurate as the methodology allows. Reliability 

of the mapped results increases as both the persistence of 

the trend and the magnitude of the rates increase. Stated 

another way, confidence in the analytical results is greatest 

where the rates of shoreline erosion or accretion are high 

and the trend has persisted for decades. On the other hand, 

confidence in the absolute results decreases where the shoreline is relatively stable and the rates of change are low. This 

is because minor differences in historical or lidar shoreline 

positions can substantially alter the regression line and the 

calculated results. Data confidence also decreases in areas 

where frequent trends reversals occur.

Advanced technology such as GPS and lidar can better 

constrain shoreline positions, reduce the methodological 

errors, and improve the accuracy (reduce the error) of future 

shorelines. Establishing a datum-based shoreline (lidar 

derived MHW) as the standard for comparison provides, for 

the first time, the ability to perform an error analysis that is 

both quantitative and meaningful, in terms of its application. 

In the future, each electronic MHW shoreline could be presented with an accompanying error bar that would define the 

alongshore envelope of confidence. Subsequent shorelines 

Open-File Report 2006-1219 14
and associated confidence envelopes would provide a more 

precise basis for determining the statistical significance of 

observed shoreline change. Unfortunately, the use of lidar 

or any other shoreline mapping technology will still require 

distinguishing between short-term variability in shoreline 

position and the long-term trend of shoreline change.

GEOLOGIC HISTORY AND SETTING

California straddles the boundary between the Pacific 

and North American tectonic plates (Figure 4). The diverse 

landscape and complex geology of the California coast is 

largely a result of the interactions between these plates. 

Lateral movement between the two plates occurs along the 

San Andreas Fault Zone (SAFZ), which extends nearly 

1300 kilometers from the Gulf of California to Shelter Cove 

near Point Delgada in Humboldt County (Figure 5). Lateral 

movement on the fault zone averages 2.5-3 cm/yr (Harden, 

1998) with a total accumulated displacement from slip during earthquakes and aseismic creep of at least 560 kilometers since lateral movement began about 15-25 million years 

ago.

Inman and Nordstrom (1971) recognized the importance of tectonic setting to the development of coasts 

worldwide. They developed a coastal classification scheme 

based upon the position of a given coast relative to plate 

movement. Within this classification scheme they recognized three first-order classes: collision coasts, trailingedge coasts, and marginal sea coasts. Collision coasts (i.e. 

active margins) are characterized as being relatively straight 

and mountainous, having the presence of coastal cliffs and 

raised marine terraces, and bordered by narrow continental 

shelves. Coastal watersheds are typically steep and undergo 

high rates of erosion. Although the California coast south 

of Cape Mendocino presently borders a transform margin 

dominated by lateral movement, and is therefore not strictly 

collision controlled, it maintains many of the characteristics of a collision coast. Between Cape Mendocino and the 

Oregon border, the coast is a collision coast.

Movement along the SAFZ has created three broad 

geomorphic provinces (Figure 4) along the coast: Coast 

Ranges, Transverse Ranges, and Peninsular Ranges (California Geological Survey, 2002a). The northwest trending 

Coast Ranges run roughly parallel to the SAFZ and extend 

from the Oregon border in the north to the east-west trending Transverse Ranges in the south. The Coast Ranges 

are composed mostly of uplifted Mesozoic and Cenozoic 

marine sedimentary rocks that typically form a terraced and 

wave-cut coastline. The range is broken by the depression 

forming San Francisco Bay. 

The Transverse Ranges trend roughly east-west and 

lie oblique to the general northwest trend of the California 

coast. They extend from the San Bernardino Mountains to 

the offshore islands of San Miguel, Santa Rosa, and Santa 

Cruz. Intense north-south compression from SAFZ movement has resulted in very high uplift rates in this region 

(California Geological Survey, 2002a). Tertiary sedimentary rocks are the dominant rock type of the Transverse 

Ranges along the coast.

The Peninsular Ranges extend from the Transverse 

Ranges to the Mexican border, and, like the Coast Ranges, 

trend in a northwest direction. Along the coast they are 

composed mostly of Tertiary sedimentary rocks and further 

inland are characterized by Sierra Nevada-type rocks including granitics and older metamorphic rocks (Figure 6). The 

Los Angeles basin and offshore islands of Santa Catalina, 

Santa Barbara, San Clemente, and San Nicolas are considered part of the province.

To summarize, the features of the California coast 

have formed over millions of years of interaction between 

two large tectonic plates that continues today. Proximity to an active tectonic margin results in features such as: 

diverse rock types in close juxtaposition, high relief, high 

erosion rates of the land surface, and high rates of sediment 

supply to the coast. Block uplift and subsidence between 

high-angle reverse faults occur within the broader transform 

margin scenario. Segmentation of the coast through these 

types of vertical crustal movements, as well as horizontal 

(strike-slip) displacement forms important structural foundations for coastal sedimentary environments.

General Geology of the California Coast

The diverse morphology of the California coast 

is primarily a result of the local geology where lithology, 

geologic structure, and vertical tectonic movement play a 

prominent role in the configuration of the coast. Figure 6 is 

a generalized geologic map showing the major rock types 

of California (California Geologic Survey, 2002b). Tertiary 

and Mesozoic sedimentary rocks are clearly the dominant 

coastal rock type; they are mostly marine in origin and 

represent sediment deposition, lithification, and uplift along 

the Pacific-American plate subduction / transform boundary. The Mesozoic rocks, which include the Franciscan 

Complex, are typically sandstone and shale from oceanic 

crust and deeper marine settings. The Tertiary rocks such 

as those of the Monterey Formation tend to be sandstone, 

shale, and conglomerate from more shallow marine environments closer to the continental margin. Crystalline rocks 

are also present along the coast and are most common near 

San Francisco and Monterey.

The strength of the rocks exposed along the coast is 

a critical parameter in determining the erodability of the 

coast (Benumoff and others, 2000; Hapke, 2005). Stronger 

rocks form prominent headlands that resist erosion and often 

form natural boundaries to littoral and aeolian transport. 

Weaker rocks erode more quickly and form embayments 

where coastal sediment may accumulate. Monterey Bay is 

an excellent example of an embayed coast where resistant 

rocks in Santa Cruz and Monterey (Figure 5) form headlands and the interior of the bay is backed by easily eroded 

Open-File Report 2006-1219 15
Figure 4. Major tectonic elements and geomorphic provinces of California (modified from California Geological Survey, 2002a and 

CGS website: (http://www.consrv.ca.gov/cgs/information/publications/teacher_features/faults.htm).

GREAT

VALLEY

MODOC

PLATEAU

BASIN &

RANGE

BASIN & R.

BASIN

SIERRA

NEVADA

MOJAVE DESERT

COLORADO

DESERT

PENINSULAR

RANGES

COAST

RANGES

TRANSVERSE

RANGES

KLAMATH

MOUNTAINS

CASCADE

RANGE

&

R.

200 km

NORTH AMERICAN PLATE

San Andreas Fault

PACIFIC PLATE

N

San Francisco

Los Angeles

Open-File Report 2006-1219 16
Figure 5. Index map showing locations of place names discussed in Geologic History and Geomorphology section.

Ventura

River

Pt. San Diego

Loma

Silver Strand Beach

San Dieguito R.

San Diego R.

Santa Ynez R.

Santa Maria River

Santa

Barbara

Santa Maria

San Luis

Obispo

Los

Angeles

Palos Verdes

Point

Santa

Monica

L.A.

R.

Crescent

City

Mad R.

Eel River

Little R.

Monterey Bay Pajaro R.

Salinas

Channel Islands

Pt. Conception

Ft. Bragg

San

Jose

Santa Cruz

Monterey

Ventura

Eureka

250 km

N

C A L I F O R N I A

Smith R.

Ten Mile R.

Pt. Arena

Shelter

Cove

Pt. Reyes

Humboldt Bay

Tomales Bay

Bolinas Lagoon

Bodega Bay

San Franciso Bay

Elkhorn Slough

Pt. Sur

Morro Bay

Oxnard

La

Jolla

OREGON

CALIFORNIA

Sacramento

River

San

Joaquin

River

Santa Ana River

Santa

Clara R.

Ventura R.

San Bernadino Mountains

Bodega Head

Marin Headlands

San Francisco

Devils Slide

Santa Ynez

Mtns.

Estero Bay

Pt. Delgada

Pt. Sal

Pt. Arguello

Imperial Beach

San Gabriel

River

River

0

P A C I F I C O C E A N

San Luis

Range

Delgada

Canyon

Mendocino

Canyon

Mattole Canyon

Monterey Canyon Carmel

Canyon

Partington Canyon

Hueneme Canyon

Redondo Canyon

Scripps Canyon

La Jolla Canyon

Mugu Canyon

Mission Bay

Newport

Canyon

Open-File Report 2006-1219 17
Alluvium

Sedimentary rocks

Volcanic rocks

Crystalline rocks

EXPLANATION

200 km

San Andreas Fault

PACIFIC PLATE

NORTH AMERICAN PLATE

N

Figure 6. Simplified geologic map of California (modified from California Geological Survey generalized geologic map available online at: http://www.consrv.ca.gov/cgs/rghm/rgm/index.htm).

Open-File Report 2006-1219 18
Quaternary shallow marine, aeolian, and fluvial deposits. 

Coastal cliffs tend to be either high, steeply-dipping coastal 

mountains that plunge directly into the sea, or, broad nearplanar marine terraces.

Marine terraces are prominent features for much of 

the California coast and are best developed where uplifted 

marine clastic rocks form the bedrock. Terrace preservation 

varies from moderate to poor in the other rock types that 

form coastal slopes including metamorphic, granitic, and 

ophiolitic terranes. Marine terraces form when coastal cliff 

retreat generates wave-cut platforms, most notably during 

sea-level highstands, and are preserved as a slightly seaward-sloping planar surface during tectonic uplift (Anderson 

and others, 1999). Local uplift rates, duration of marine planation, and terrace composition determine the width and elevation of the terraces - they are typically 10s of meters high 

and 100s of meters wide. The terrace surface often contains 

beach, dune, or alluvial deposits and when combined with 

terrace erosional material they can provide an important 

component of sediment contribution to the coast. Weaker 

rock types with an abundant sand component may contribute a significant amount of sediment to the beach system (up 

to ~10-30%; Hearon and Willis, 2002; Inman and Masters, 1991; Runyan and Griggs, 2002). Table 7 shows the 

approximate amount of different rock types for the cliffed 

portion of the California coast (~72% of the 1760 km long 

coast). Cliff retreat rates vary dramatically from very low in 

granitic terranes to several meters per year in cliffs formed 

in poorly-consolidated sediment. In addition to providing 

sediment to the coast, marine terraces are important features 

because of their low surface relief and proximity to the 

ocean they are the sites of numerous developments along the 

California coast (Griggs and others, 2005c). 

Climate

The climate of California is strongly influenced by 

a persistent zone of high pressure in the north Pacific, a 

southerly flowing cold water ocean current, and the Sierra 

Nevada mountains, which block the continental air from 

affecting the coastal climate. During the summer months the 

northward migration of the semi-permanent North Pacific 

High diverts most storm tracks to the north. California 

seldom receives rain from Pacific storms during the summer 

but coastal fog is widespread. Cold upwelling waters at the 

surface come into contact with the relatively warm moist air 

from the Pacific causing massive fog banks to form. During the winter the North Pacific High migrates southward 

directing storms towards California. Occasionally storms 

will arrive from the southwest and are accompanied by 

relatively warm temperatures and heavy rains (often referred 

to as the pineapple express). Average annual precipitation 

varies dramatically from north to south with 80 inches and 

above in the north and only about 10 inches reaching the 

San Diego area.

The seasonal weather patterns are modified during El 

Niño and La Niña events. During El Niños California’s 

climate is typically characterized by above normal rainfall, warmer sea-surface temperatures, and large waves 

from Pacific-generated storms often resulting in increased 

beach erosion. The 1997-98 ENSO (El Niño – Southern 

Oscillation) was a significant climatic event responsible 

for widespread coastal flooding and beach loss (USGS/

UCSC/NASA/NOAA Collaborative Research Group, 

1998). La Niñas are generally accompanied by colder ocean 

temperatures, drier conditions, and less severe storms. El 

Niño’s and La Niña’s generally last for 6 to 18 months and 

their occurrence and intensity are related to longer term 

atmospheric variations termed the Pacific Decadal Oscillation (PDO). The PDO is an ENSO-like phenomenon 

that lasts for 20 to 30 years and consists of warm and cool 

phases (Zhang and others, 1997). The cool phase, which is 

likened to an extended La Niña, is characterized by a cool 

wedge of lower than normal sea-surface heights and ocean 

temperatures in the eastern equatorial Pacific resulting in 

cooler temperatures and lower rainfall in California. Conditions during the warm phase are reversed and are similar 

to extended El Niño conditions. Because phases tend to 

last between 20-30 years, with the last warm phase starting 

in 1977, some believe that we have entered a cool phase 

marked by the inception of the 1998/99 La Niña event as 

discussed in Hare and Mantua (2002). 

Table 7. Coastal cliff rock type along the California coast (from Runyan and Griggs, 2002).

Rock Type Km of Coast % of Cliffed Coast

Pliocene Marine 688 39%

Unconsolidated Quaternary 480 28%

Miocene, Oligocene, Tertiary and Cretaceous Marine 335 19%

Older Metamorphic & Sedimentary (Franciscan) 177 10%

Granitic 53 3%

Tertiary and Miocene Volcanic 18 1%

Open-File Report 2006-1219 19
Coastal Processes

Waves

Waves and currents are the primary forces that move 

sediment in the littoral zone and annual wave height variations are responsible for seasonal erosion and accretion 

patterns. Wave characteristics along the California coast 

depend on weather patterns, geographical effects such as 

offshore islands, storm climatology, coastline orientation 

and local bathymetry. The offshore wave climate of California is characterized by four regimes (Figure 7): Northern 

Pacific swell, Southern Hemisphere swell, northwest wind 

waves, and by locally driven seas (Storlazzi and Wingfield, 

2005). North Pacific swell is generated by extra tropical 

storms, mid-latitude low-pressure systems, and cold fronts 

that originate in the North Pacific. Southern swell is dominant in the summertime and generated by winter storms in 

the Southern Hemisphere. Northwest wind waves generated by daily sea breeze conditions are more common in the 

northern part of the state and are strongest in the spring and 

early summer months. Local seas are driven by wind and 

storms along the coast. Given the variety of local and seasonal variations in wave climate, the predominant direction 

of nearshore sediment transport along the California coast 

is from north-to-south (Hearon and Willis, 2002). Wave 

climate varies along the California coast and can regionally summarized as follows (after Storlazzi and Wingfield, 

2005):

In northern California the average wave height is 

greatest from November to February and averages about 3 

m, with approximately 20% of the time wave heights are 

greater than 4 m. Summer wave heights are smaller with 

mean values around 1.8 m with waves higher than 4 m being 

extremely rare. Early winter is the most common time for 

waves to exceed 6 m. During El Niño winter months mean 

annual wave heights are 0.3 m – 1.2 m greater than normal 

winter months. El Niño driven storms typically approach 

from the west or southwest and may cause local littoral drift 

to the north – counter to the predominant southerly drift. La 

Niña winter months have slightly higher than average wave 

height values of 0.1 m – 0.4 m whereas during the summers 

wave heights are smaller than average. 

Central California is a transition zone between harsh 

stormy waves of the northeast Pacific and milder conditions 

of Southern California. North Pacific Swell is the largest 

swell to impact the region with heights between 2m – 10m 

and periods ranging between 10 – 25 seconds. These waves, 

which are generated by storms in the North Pacific, occur 

most commonly between October and May. Northwest 

wind waves are generated from sea breeze and are dominant 

from April to October. The height of these waves typically varies between 1 and 4 meters with a period of 3 to 10 

seconds. Southern Swell occurs between April and October 

and typical wave heights range from 0.3 – 3 m with a period 

of 10 – 25 seconds. Local wind-driven waves are generated 

by storms passing through central California. They generally occur between October and April with typical heights 1 

and 4 meters and periods of 3 to 10 seconds. 

In southern California peak wave heights are 

greatest from November to February and average about 

2.4 m during this time. In the summer wave heights are 

smaller with mean values around 1.8 m. Waves greater than 

four meters occur about 11% of the time at Point Conception (Figure 5) and are most common during the month of 

March. Waves that damage the Southern California coast 

originate from extra-tropical storms in the northeast Pacific 

or Southern Hemisphere, although the second case is rare 

(Newberger, 1982). During El Niño winter months, wave 

heights at Point Conception are 0.7 m above average. In 

general, the southern region of the West Coast experiences 

more storms and higher wave energy during ENSO events 

(Seymour, 1998). Wave conditions along the southern California coast are extremely variable due to coastal configuration, bathymetry, orientation of coastline and the presence 

of several large offshore islands. Wave height measurements can be substantially different over distances of a few 

miles (Newberger, 1982). The Channel Islands block waves 

approaching from the south and Point Conception blocks 

waves from the north. Waves that propagate into the channel are severely refracted by irregular shallow bathymetry, 

producing large spatial variations in swell wave height and 

direction (Guza and O’Reilly, 2001). Figure 7. General wave directions for central California based 

on offshore wave buoy data (modified from Storlazzi and Wingfield, 2005).

Open-File Report 2006-1219 20
Tides

California has a mixed semidiurnal tidal regime of 

two unequal high and low tides a day with total open-coast 

elevation changes of about 2.1 m in Crescent City and 1.6 m 

in La Jolla (Figure 5). The two daily high and low tides are 

unequal in amplitude with the lower-low tide of the day usually following the higher-high. The monthly tidal variations 

are dominated by the spring-neap cycle with spring tides 

occurring during full and new moons and neap tides occurring during half moons. The highest monthly tides during 

summer and winter months are higher than the highest tides 

in fall or spring. Tide ranges increase from the south to 

north along the coast and higher tide ranges occur in San 

Diego and San Francisco Bays than in adjacent open coast 

areas (Flick, R.E., 1998). 

Tidal range influences beach processes along the 

California coast because it determines the extent of beach 

exposure and inundation throughout the tidal cycle. Especially crucial to beach erosion episodes are the timing and 

height of the highest tides in conjunction with the maximum 

wave height and surge developed during storms. Comparisons between impacts of the 1982-83 and 1997-98 El 

Niño storms on California’s coast (Storlazzi and Griggs, 

1998; Storlazzi and others, 2000) show that greater damage occurred in the 1982-83 event, in part, because the 

high tides were slightly higher and peak waves coincided 

with maximum high tides. The differences in tidal height 

between these two El Niño winters is primarily due to the 

4.4yr lunar perigee cycle with a small contribution from 

the 18.6 year lunar node cycle (Flick, 1998). This cycle 

enhanced peak high tides in 1982-83, 1986-87, 1990-91, 

1995-96, and 1999-2000. 

Long-term trends in California tide records are 

consistent with the general rise in mean sea level over 

the last century recorded throughout the world. Figure 

8 shows long-term trends in mean sea level for selected 

California tide gauges as reported by the National Ocean 

Service (http://140.90.121.76/sltrends/sltrends_states.

shtml?region=ca), and analyzed by Flick and others (2003). 

Both San Francisco and San Diego exhibit about 20 cm of 

sea-level rise over 93 years whereas Los Angeles exhibits a 

lower total rise of only 6 cm over 76 years. Crescent City, 

an exception to the sea-level rise trends, shows a relative 

sea-level fall of 3.2 cm over 66 years that is most likely the 

result of local tectonic uplift.

1906

1900 1920 1940 1960 1980 2000

-20

20

-40

40

Centimeters

0

SAN DIEGO

Total SLR = 20 cm

1900 1920 1940 1960 1980 2000

-20

20

-40

40

Centimeters

1923

0

LOS ANGELES

Total SLR = 6 cm

CRESCENT CITY

Total SLR = -3.2 cm

1900 1920 1940 1960 1980 2000

-20

20

-40

40

Centimeters

1860 1880

1854

1906

0

SAN FRANCISCO

Total SLR = 20 cm

0

1900 1920 1940 1960 1980 2000

-20

20

-40

40

Centimeters

1933

Figure 8. Monthly mean sea level for selected tide gauges along the California coast. Mean sea-level trends, based on the total sea 

level rise (SLR) for each site are: Crescent City – 0.48 mm/yr, San Francisco +2.13 mm/yr, Los Angeles +0.84 mm/yr, and San Diego 

+2.15 mm/yr. Data are from the National Ocean Service.

Open-File Report 2006-1219 21
Winds

Winds are important for generating waves that 

drive littoral sediment transport and for blowing sand off 

beaches resulting in potential sand loss from the littoral 

system. The wind climate of California is strongly influenced by the North Pacific High that creates a predominant 

northwesterly air flow over most of the state. The intensity 

and position of the North Pacific High often determines the 

direction and strength of winds affecting coastal California. 

The North Pacific High is stronger and located more northerly during summer months and moves south and weakens 

during winter months, allowing storms to reach the state. 

Coastal wind flow is predominantly parallel to the coast 

either from the northwest or the southeast. When winds are 

from the northwest, flow is along the coast but Ekman transport induces an onshore component, which is strengthened 

by local sea breezes (Zhiqian and others, 1997). Associated 

with northwest winds is the creation of a jet effect in the 

vicinity of some of the more prominent headlands. Strong 

jets of air and large eddies are projected around headlands 

such as Point Reyes, Point Sur, and Point Arguello (Figure 

5). Wind speeds in the immediate vicinity of these major 

headlands can be two or three times as great as the wind 

flow at nearby areas. 

In general, wind flow from the north is more aligned 

with the coast, the strongest flow is pushed offshore, and 

there is usually no associated daily sea breeze. During 

strong northern flows high wind speeds extends over a large 

area from Northern California to Point Conception. During 

northeast or east flow conditions the along-coast variability 

is significantly larger and winds are weaker (Zhiqian and 

others, 1997).

These wind patterns are altered by the passage 

of Pacific storms most of which arrive in the winter. As 

a storm approaches, the cold fronts are marked by strong 

easterly or southeasterly winds that can reach speeds of 50 

km/hr or more. After the storm passes winds turn toward 

the southwest. With the passage of the rare warm front, 

storm winds can reach 30 – 40 km/hr. In Southern California, after the passage of a cold front, Santa Ana winds will 

often blow down from the north to northeast. These winds 

are sometimes extremely intense and can blow between 90 

to 145 km/hr and extend 160 kilometers seaward. Although 

it is rare, when Santa Ana winds blow during the summer 

they produce hot and dry conditions that increase the fire 

danger.

Currents

The California current system forms the eastern edge 

of the North Pacific gyre and is primarily driven by wind 

stress patterns over the North Pacific Ocean (California 

Coastal Commission, 1997). Changes of the ocean circulation pattern are caused by the interactions between the 

sub-tropical high pressure cell over the North Pacific and 

the atmospheric thermal low over California and Nevada. 

The interaction between these pressure regions results in a 

dominant southward-directed wind along the coast of California in spring and summer driving the California Current 

towards the equator (Hickey, 1979). Maximum southward 

wind along the California coast occurs between Cape Mendocino and San Francisco in the spring (Nelson, 1977). The 

associated Ekman transport moves water perpendicularly 

away from the coast allowing cold, nutrient-rich waters to 

upwell from the deep (Newberger, 1982). 

During the late fall and early winter southward winds 

weaken, reducing upwelling and allowing a near-shore, 

northward-flowing current north of Point Conception called 

the Davidson Current, to prevail (Hickey, 1979). In the 

Southern California Bight (coastal Southern California and 

offshore waters) a counter-clockwise eddy occurs called the 

Southern California Countercurrent. It is a northwestwardflowing current south of Point Conception and inshore from 

the Channel Islands. The current runs shore parallel until it 

reaches Point Conception where one branch flows southwest 

joining the California Current and the other branch continues northward as a narrow countercurrent (Newberger, 

1982). The Southern California Counter current occurs in 

all seasons but is best developed in winter (Maloney and 

Chan, 1974).

Littoral cells and transport directions

The prevailing southerly transport direction for California littoral sediment is driven by North Pacific swell 

and northwest wind waves (see Figure 7). There are local 

reversals in this prevailing direction due to orientation of the 

coast and/or southerly wave events. Littoral cells are segments of the coast with distinct sediment sources, defined 

longshore transport pathways, and sinks where the sediment 

is removed from the littoral system. Conceptually, the cell 

boundaries delineate an area where the sediment budget can 

be balanced for quantitative analysis. Southern California 

littoral cells were first defined by Inman and Chamberlain 

(1960) and statewide littoral cells were identified by Habel 

and Armstrong (1978). In California the cells are typically bound by either prominent rocky headlands that block 

littoral transport around them, or, submarine canyons that 

cross the continental shelf to a shallow enough depth as to 

intercept alongshore moving sediment. Submarine canyons 

are clearly the largest sink for beach sand loss in California 

with an estimated removal from some of the larger canyons 

at: Scripps and La Jolla – 270,000 m3/yr, Mugu – 765,000 

m3/yr and Monterey – 230,000 m3/yr (Griggs and others, 

2005b). Once sediment enters the submarine canyon system 

it is permanently lost from the littoral system. Another large 

sediment sinks are coastal dune fields where wind-blown 

sand is removed from the active littoral system. However, 

unlike submarine canyons, subsequent erosion of the dunes 

can re-supply adjacent beaches with sand. Figure 9 shows 

Open-File Report 2006-1219 22
the boundaries of littoral cells and coastal watersheds along 

the California coast. The boundaries between many of 

these cells, however, and the amounts and rates of sediment 

transport are poorly understood. Long-term harbor dredge 

records are one of the best long-term sources of longshore 

transport rates (Table 8) where harbor dredging is undertaken. 

Sand Sources

The primary sources of coastal sediment for California 

are the fluvial drainage systems that reach the coast. These 

systems range from short, steep, ephemeral streams that 

deliver a wide mix of sediment grain sizes, to more mature 

rivers which often have well-developed estuaries. California’s coastal streams have exceptionally high sediment loads 

due to the steep landscapes, geologically young and tectonically active terrain, and, in central and Southern California, 

Figure 9. Map showing major littoral cell boundaries, coastal watersheds, and conceptual net longshore drift directions for the California coast, modified from Habel and Armstrong (1977), Griggs and others (2005b), and U.S. Army Corps of Engineers (2003). 

Open-File Report 2006-1219 23
relatively sparse vegetation cover (Willis, 2002a). Sediment 

yield per size of drainage basin for California rivers is typically very high when compared to other regions of the U.S. 

Estimated sand and gravel discharge for the major 

California streams that enter the open coast is shown in 

Figure 10. Average annual bedload discharges range from 

a few thousand m3/yr for the smaller creeks to nearly 3 

million m3/yr for the Eel River in northern California (Willis, 2002a and b) (Figure 5). These estimates should be 

considered maximum estimates of beach-quality material 

supplied from coastal streams because of numerous uncertainties and assumptions, and the fact that they include 

sand finer than 0.125 mm which is unlikely to remain in an 

energetic beach environment. In addition to the rivers shown 

in Figure 10, the large Sacramento and San Joaquin Rivers 

empty into San Francisco Bay (Figure 5), the largest estuary 

on the west coast. A large ebb-tidal delta has formed at the 

entrance to the bay. Numerous smaller ungauged streams 

also reach the coast and can supply significant amounts of 

sediment because of their steep, easily erodible watersheds 

(Willis, 2002b). On average 70 to 95% of the beach sand 

in California is derived from coastal streams (Runyon and 

Griggs, 2002; Willis, 2002a). In general, sand and gravel 

discharges from coastal watersheds decrease from north to 

south (primarily rainfall controlled), although the Transverse Range has a relatively high sediment discharge (lithology and vegetation controlled). Infrequent severe floods are 

thought to be responsible for delivering the majority of sediment to the coast and a single large storm can deliver more 

sand to the beaches than years of low to moderate rainfall. 

In addition, sediment discharge during extreme events can 

lead to open-coast ephemeral delta formation (Richmond, 

1988) and delivery of abundant coarse-grained sediment. 

El Niño years are typically times of significant sediment 

introduction to the coast because of increased likelihood of 

extreme rainfall events (Inman and Jenkins, 1999).

Coastal cliffs are the next major source and sand supply varies with cliff lithology and strength. In some areas 

such as the Oceanside littoral cell, the coastal bluffs have 

been found to be a major source of beach sand (Young 

and Ashford, 2006). Softer cliffs composed of coastal sand 

deposits provide the most beach quality sediment when 

eroded. Subordinate sources of coastal sediment include 

marine planation of submerged rock, material of biologic 

origin such as shells, and possibly onshore transport of relict 

shelf sediment. 

GEOMORPHOLOGY OF THE 

CALIFORNIA COAST

The California coast encompasses a wide range of 

coastal landforms a product of complex geology and 

dynamic coastal processes. Coastal landforms include steep 

cliffs, uplifted terraces, beaches, dunes, barrier spits, estuaries and lagoons (Figure 11). 

Cliffs

Nearly three-fourths of the California coastline are 

backed by cliffs which fall into two broad general categories: high steep cliffs and marine terraces. High cliffs occur 

where mountains directly border the coast such as along the 

Big Sur coast and most of northern California. The high 

cliffs may be hundreds of meters or more in height, they 

occupy about 13% of the California coastline, and are typically composed of more resistant rock types such as granite 

and rocks of the Franciscan Complex (Griggs and Patsch, 

2004). Marine terraces and coastal bluffs, which were discussed earlier, form about 60% of the remaining coast and 

are common from Mendocino to San Diego. Where tectonic 

uplift has persisted, multiple terraces are often preserved.

Beaches

Beaches are ubiquitous features of the California coast 

and are important for a number of reasons: a) they act as a 

natural buffer that protects coastal land during storms, b) 

they are a valuable recreational and economic resource, and 

c) they provide habitat such as nesting sites for the endangered snowy plover and haul-outs for protected marine 

mammals. California beaches are not as long and continuous as those along passive margins (e.g. the U.S. South 

Atlantic and Gulf coasts) in part because the young and 

steep nature of the coast has not allowed enough geologic 

time for extensive sandy coastal plains to develop. Beach 

types found in California include pocket beaches, long 

expanses of linear to gently curved beaches, barrier spit 

beaches at stream mouths, and cuspate headlands. Pocket 

beaches are bound by headlands, and occur in both small 

stream valley and cliffed-coast settings. Pocket beaches 

are probably the most common beach type in California, 

although their total length is smaller than the total length of 

California’s linear beaches. Long expanses of beach typically front the major dune complexes, larger stream valleys, 

and coastal plain or concaved areas (e.g. Monterey Bay and 

Table 8. Estimated annual littoral drift rates and directions 

along the California Coast (after Griggs and others, 2005b).

Location Annual Rate (m3) Direction

Santa Cruz 230,000 East

Santa Barbara 230,000 East

Ventura 460,000-765,000 Southeast

Santa Monica 210,000 Southeast

Oceanside 270,000 South

Open-File Report 2006-1219 24
Santa Monica Bay). Cliffed coastlines can be fronted by 

both permanent and seasonal beaches. Permanent beaches 

occur where there is abundant sediment supply, both alongshore and offshore. Seasonal beaches, which typically are 

present in the summer months and are lost during winter 

months, are common along exposed coasts with a limited 

offshore supply of sand. 

Because of the relatively high wave energy and a 

steeper and narrower continental shelf along the California 

coast, pronounced deltas do not form. Instead, barrier spits 

and ebb and tidal bars develop where the streams reach the 

sea. Beaches that form at the mouths of stream valleys and 

embayments are typically a mixture of both fluvial- and 

littoral-derived sediment (mostly sand). The barriers are 

typically barren to sparsely vegetated indicating an unstable 

substrate prone to occasional marine overwash and breaching. Seasonal changes in wave climate and rainfall result in 

a concomitant change in barrier style. In winter, periods of 

high waves and heavy rainfall cause overwash and channelization of the barrier spits, reducing their overall size. 

During the summer months, there are smaller waves and 

low precipitation and the barrier spits may completely block 

stream mouths due to reduced stream flow and beach accretion.

Seasonal beach change in California is caused by 

annual variations in wave climate that produce narrow 

beaches during winter months and wide beaches during the 

calmer summer months (Dingler and Reiss, 2002). Dramatic beach erosion, both in rate and amount, occurs during 

large storms. Subsequent recovery is less rapid, often 

0 1,000 1,200 1,400 3,000

137

1,275

256

525

40

2,900

178

77

160

140

7

43

46

374

25

29

199

200 400 600 800

46

265

78

912

50

26

2

59

45

96

12

23

31

31

10

5

32

Smith R.

Klamath R.

Redwood Cr.

Little R.

Mad R.

Eel R.

Mattole R.

Noyo R.

Navarro R.

Russian R.

Pescadero Cr.

San Lorenzo R.

Pajaro R.

Salinas R.

Carmel R.

Arroyo Grande

Santa Maria R.

San Antonio Cr.

Santa Ynez R.

Ventura R.

Santa Clara R.

Calleguas Cr.

Malibu Cr.

Ballona Cr.

Los Angeles R.

San Gabriel R.

Santa Ana R.

San Diego Cr.

San Juan Cr.

Santa Margarita R.

San Luis Rey R.

San Dieguito R.

San Diego R.

Tijuana R.

Average annual sand and gravel discharge (1000 * m3/yr)

0 200 400 600 800 1,000 1,200 1,400 3,000

Figure 10. Average annual sand and gravel discharge from major rivers in California.

Open-File Report 2006-1219 25
requiring several months for the beach to achieve its prestorm configuration. Beaches without an abundant offshore 

sand supply take much longer to recover (Brown and others, 

1998). Figure 12 illustrates the seasonal change in beach 

profile shape during the intense 1997-98 El Niño winter 

season at Cowells Beach in Santa Cruz.

Coastal Dune Complexes

Cooper (1967) mapped the coastal dunes of California and recognized that coastal dune complexes are best 

developed where there is: a) a nearby source of fluvial-supplied sediment, b) a structural high at the coast, such as 

a headland, to trap littoral drift or a low-relief stretch so 

dunes can migrate inland, and, c) strong consistent onshore 

winds. Orme (1992) further noted that dune fields are best 

preserved in coastal areas that have undergone net tectonic 

subsidence or limited uplift in the Quaternary. Aeolian 

deposits are often interbedded with fluvial and nearshore 

facies and the larger complexes represent multiple episodes 

of dune building. In many areas the modern dunes represent 

surficial deposits overlying older, and larger, dune systems. 

There is some indication (Orme, 1992) that significant 

coastal dune building occurs at lower sea-level positions 

when large quantities of sand are exposed on the emergent 

continental shelf. 

Modern dune building removes sediment from the littoral supply; in some places this can be a substantial portion 

of the littoral sediment budget. For example, it has been 

estimated that about 150,000 m3 of sand are blown inland 

each year along the 55 km stretch of coastline from Pismo 

Beach to Point Arguello (Figure 5) (Griggs and others, 

2005c). Where the present coastline is undergoing retreat, 

such as in southern Monterey Bay, the dunes are reworked 

and supply sediment to the beach. The major dune complexes of California are shown in Figure 13 along with their 

effective wind directions. 

Estuaries and Lagoons

U.S. West Coast estuaries and coastal lagoons typically form in drowned-stream valleys cut below the level of 

the uplifted coastal plain (Peterson and Phipps, 1992) or in 

subsiding coastal blocks. Four general types of estuarine/

lagoon embayments occur in California: a) large embayments with high freshwater inflow, b) large embayments 

with relatively low freshwater inflow, c) large freshwater 

bodies with limited intertidal environments, and, d) ephemeral streams with limited estuarine environments. 

The largest California estuary is the San Francisco Bay 

system that forms the outlet for the contiguous SacramentoSan Joaquin Delta watershed. This is a large embayment 

(~4,100 km2) with high freshwater inflow that drains more 

than 40% of the land area of the State of California (Chin 

and others, 2004). Bay environments include marshes, 

intertidal mudflats, and subtidal channels. The remainder of 

estuaries in California are much smaller in size but typically 

contain the same depositional environments. 

Embayments currently with low fluvial input, such as 

Bolinas Lagoon, Drakes Estero, Tomales Bay, Bodega Bay, 

Spit

Landslide

Elevated terraces

Pocket

beaches

Dune

field

Spit

High relief

coastal slope Elevated marine terrace 

with thin, sandy 

beach deposits

Coastal cliff

Estuary

Lagoon

Figure 11. Sketch of common coastal landforms of California.

Open-File Report 2006-1219 26
Elkhorn Slough, and Morro Bay (Figure 5), appear to be 

structurally controlled depressions not presently connected 

to a major fluvial source. In these examples, the embayment 

size is large compared to present stream discharge. Embayment downcutting was probably enhanced during lower sealevel stands and the subsequent period of higher Holocene 

sea level resulted in bay infilling. At present, many of the 

morphologic bay features appear to be tidally controlled.

The major rivers of California are typically characterized by relatively high flow but narrow confined estuaries. 

These drainages are characterized by well-defined stream 

channels entering a restricted coastal depositional plain, 

and the location of the stream mouth is often controlled 

by a geologic feature such as a resistant headland. Intertidal environments are relatively limited in size because of 

extensive floodplain deposition (abundant sand). The rivers 

are the main suppliers of sand to the California coast (Figure 

10). Fine-grained sediment typically bypasses the coastal 

zone and is deposited in deeper water. Ephemeral streams 

are similar to the larger rivers but on a smaller scale.

General Characteristics of the 

California Coast Sections

Northern Section: Oregon Border to Tomales 

Bay

The coast of Northern California (Figure 14A) can be 

characterized as a rugged landscape with high rainfall and 

low population. Steep coastal cliffs dissected by numerous streams result in high sediment loads delivered to the 

coast. Franciscan Complex rocks are common and the more 

resistant units often result in an irregular coast with steep 

cliffs, small offshore islands and sea stacks. Barrier spits 

and beaches are common features at stream valleys and 

embayments with the largest barrier in the region extending 

across Humboldt Bay. Large dune complexes occur south 

of Smith River, between the Little and Eel Rivers, and south 

of Tenmile River (Figure 13). Other large dune fields are 

present north of headlands at Point Arena and Bodega Head, 

and at the entrance to Tomales Bay (Figure 5). Marine 

terraces and wave-cut bluffs are common between the areas 

dominated by the steep mountain cliffs. The terraces south 

of Cape Mendocino are Holocene features that are undergoing rapid uplift. According to Savoy and others (2005), as 

much as 1 m of uplift occurred during a single earthquake 

in 1992 along the Cascadia subduction zone. The heads of 

Mattole and Delgada submarine canyons reach into shallow 

water where they can intercept littoral transport.

-5

-4

-3

-2

-1

0

1

2

3

4

5

0 50 100 150 200 250 300

Distance (m)

Elevation (m)

10/15/97

2/9/98

10/26/98

Figure 12. Beach profiles from Cowells Beach in Santa Cruz illustrating beach erosion over an El Niño winter and the subsequent 

recovery the following summer. The dashed gray line is the MHW elevation. From unpublished USGS data.

Open-File Report 2006-1219 27
San Diego Pt. Loma 

Silver Strand Beach 

Del Mar 

San Dieguito R. 

Sweetwater R. 

San Diego R. 

Los Angeles 

Palos Verdes Point 

Santa Monica L.A.

R.

Eureka Crescent City 

Mad R. 

Eel R. 

Little R. 

N.19W. 

Santa Cruz 

Monterey

Monterey Bay 

Pajaro R. 

Salinas R. 

N.88W. 

N.53W. 

San Pedro Channel 

San Luis Obispo 

Santa Ynez R. 

N.60W. 

Santa

Maria

Santa

Maria R.

N.42W. 

N.39W. 

N.45W. 

Pt. Conception 

Purisima Pt. 

Ft. Bragg 

San Francisco 

San Jose 

Santa Cruz 

Monterey

Santa Barbara 

Ventura 

Eureka

Santa Maria 

San Luis Obispo 

0 50 km 

100 km 

50 km 

50 km 

50 km 

N

C A L I F O R N I A 

A

A

B

B

C

C

D

D

Figure 13. Map showing the major coastal dune complexes of California (modified from Cooper, 1967).

Open-File Report 2006-1219 28
Klamath Region

1 Oregon Border

2 Smith River

3 Crescent City

4 Crescent City Harbor

5 Gold Bluffs Beach

6 Klamath River

7 Redwood State Park

8 Ossagon Creek 

9 Big Lagoon County Beach

10 Patrick's Point

Navarro Region

21 Point Delgada 

22 Sinkyone Wilderness State Park

23 DeHaven Creek Beach

24 Westport-Union Landing State Beach

25 Ten Mile River 

26 Mac Kerricher State Park

27 Fort Bragg

28 Nova Harbor

29 Mendocino

30 Manchester Beach State Park

31 Point Arena

Russian River Region

32 Gualala River

33 Russian River

34 Sonoma Coast State Beach

35 Salmon Creek Beach

36 Bodega Head

37 Dillon Beach

38 Tomales Point

Eureka Region

11 Trinidad Head

12 Little River

13 Little River State Beach

14 Mad River

15 Arcata 

16 Eureka

17 Humbolt Bay Harbor

18 Eel River State Wildlife Area

19 Eel River

20 Cape Mendocino

0 12.5 25 50 75 100

Kilometers

1

10

6

3

4

2

5

8

9

11

20

19

14

12

17 16

13

18

21

31

27

29

28

25 26

24

30

22

23

38

32

33

35

36 37

34

7

15

Pacific Ocean

Figure 14A. Index map showing the four analysis regions in Northern California and various locations as discussed in the text.

Open-File Report 2006-1219 29
Central Section: Tomales Bay to Point 

Conception

Central California (Figure 14B) is the most diverse 

coastal region of the state having characteristics of both the 

north and south regions plus a few unique features of its 

own. This section represents the transition zone between the 

relatively wet and high wave energy north and the drier and 

lower wave energy southern section. Unique embayments 

at Tomales, San Francisco, Monterey, and Morro-Estero 

Bays (Figure 5) form natural harbors along the rugged 

coastline. Marine terraces and coastal bluffs are well developed south of Point Reyes, in the Monterey Bay region, 

parts of the southern Big Sur coast, and stretches along the 

San Luis Obispo County coast. High relief coastal slopes 

occur at the Marin Headlands and Devils Slide north and 

south of San Francisco respectively, and along most of the 

Big Sur coast. Between Morro Bay and Point Conception, 

coastal mountains of the San Luis Range, Point Sal Ridge, 

and the Santa Ynez Mountains of the western Transverse 

Ranges alternate with intervening basins forming the greater 

Santa Maria basin. There are large dune complexes at Point 

Reyes, southern Monterey Bay, Morro Bay, and near the 

mouths of the Santa Maria and Santa Ynez Rivers (Figure 

5). The Santa Maria and Santa Ynez Rivers are presently 

dammed resulting in a significant reduction of sediment 

reaching the coast from past conditions. The heads of Monterey, Carmel, and Partington submarine canyons lie just 

offshore where they are thought to be major sinks for beach 

sand moving alongshore.

Southern Section: Point Conception to the 

Mexican Border

The coast of Southern California, extending from 

Point Conception to the Mexican border (Figure 14C), is 

markedly different from the rest of the state. Point Conception marks a dramatic change in coastal orientation due to 

tectonic movement along the Transverse Ranges that has 

resulted in an east-west trending coast. Further south, the 

coast gradually returns to the northwest-southeast trend. 

Coastal cliffs and marine terraces are widespread and are 

typically fronted by narrow beaches. Unusual boulder 

deltas occur in the Santa Barbara area, notably at El Capitan 

and Rincon (Figure 5), and are thought to be remnant flood 

deltas at the mouths of steep mountain creeks. The largest river in this section in this section is the Santa Clara 

River with an estimated average annual sand and gravel 

discharge of 912,000 m3 (Figure 10). Other notable rivers 

are the Ventura, Los Angeles, and Santa Ana. There are 

a number of submarine canyons with heads near the littoral zone, including: Mugu, Hueneme, Redondo, Dume, 

Newport, Scripps, and La Jolla canyons (Figure 5). The 

narrow coastal plains of the Santa Barbara area are replaced 

by broader plains in Ventura-Oxnard, Santa Monica - Los 

Angeles Basin, and Mission Bay to Imperial Beach. The 

dune complexes are not as well developed as those in the 

rest of the state but moderately large dune fields occur near 

Oxnard, north of Palos Verdes, and at Silver Strand - Imperial beaches (Figure 5). This section is the most urbanized 

stretch of coast in California.

HISTORY OF INFRASTRUCTURE 

DEVELOPMENT

The first European to visit the coast of California is 

widely held to be Juan Rodriguez Cabrillo, a Portuguese 

explorer who is credited with the “discovery” of California in 1542. The first permanent European settlement was 

established in what is now San Diego in 1769. Settlement 

of the coastal areas proceeded slowly in California, partly 

because of the dangerous nature of the Pacific coastal 

waters, and partly because access from inland was inhibited 

by the steep and rugged terrain. Northern California was 

settled primarily by Russian fur traders, and most coastal 

development in the State was restricted to large natural harbors such as San Diego Bay, Monterey Bay, San Francisco 

Bay and Humboldt Bay.

By 1850, the total population of California was only 

93,000. Population grew over the years, but there was an 

explosion following World War II; the State’s population 

increased from 10 to 20 million between 1950 and 1970 

(Pincetl, 2004) and in 2005 is about 36 million. Today, 

California is the most populous state in the union, and it is 

estimated that 80% of California residents live within 50 km 

of the coast (Griggs, 1994). 

Much of the coast of Central and Northern California is 

very rugged, inaccessible and therefore undeveloped. This 

results in the focusing of developmental pressures over a 

smaller percentage of the coast resulting in variations in 

coastal hazards. Along much of the Northern California 

coast, the most important coastal hazards are large landslides that can damage coastal roads, and the rapid retreat of 

coastal cliffs where community infrastructure exists at the 

top or base of the cliff. Central California has a mixture of 

hazards; in addition to large coastal landslides and coastal 

cliff erosion, there are linear stretches of sandy shoreline 

that have been developed with homes and infrastructure. 

Southern California, which has the greatest percent of sandy 

shorelines also has the greatest percent of coastal armoring, engineering structures and nourishment programs. The 

wide, sandy beaches that exist today in Southern California 

were created and are maintained through a variety of coastal 

engineering projects and nourishment programs (Flick, 

1993).

Practices such as damming coastal rivers and building 

various coastal engineering structures (groins, jetties and 

breakwaters) may be adversely affecting beach resources. 

During the post-World War II building boom, many homes 

Open-File Report 2006-1219 30
Figure 14B. Index map showing the six analysis regions in Central California and various locations as discussed in the text.

Monterey Bay

0 12.5 25 50 75 100

Kilometers

San Francisco North

1 Tomales Point

2 Point Reyes

3 Bolinas

4 Stinson Beach

5 Rodeo Beach

6 Point Bonita

San Francisco South

7 San Francisco

8 Ocean Beach

9 Mussel Rock

10 San Francisco Bay

11Pacifica

12 Point San Pedro

13 Half Moon Bay

14 Pillar Point Harbor

15 Tunitas Beach

16 Ano Nuevo

17 Davenport

Monterey Bay Region

18 Wilder Ranch State Park

19 Santa Cruz Main Beach

20 San Lorenzo River 

21 Santa Cruz Harbor

22 Twin Lakes State Beach

23 Capitola Beach

24 Pajaro River 

25 Salinas River

26 Indian Head Beach

27 Del Monte State Beach

Big Sur Region

28 Point Pinos 

29 Carmel River 

30 Carmel City Beach

31 Little Sur River

32 Point Sur

33 Pfeiffer Beach

34 Cape San Martin

Morro Bay Region

35 San Carporforo Creek

36 Point Sierra Nevada

37 San Simeon 

38 Cambria

39 Cayucas

40 Morro Bay

41 Morro Bay Harbor

42 Morro Strand State Beach

43 Montana De Oro State Park

44 Point Bachon

Santa Barbara North Region

45 Point San Luis

46 Avila Beach

47 Port San Luis

48 Pismo State Beach

49 Oceano 

50 Guadalupe Dunes

51 Purisima Point

52 Vandenberg AFB

53 Point Arguello

54 El Capitan State Beach

1

5

6

2

3

4

10

17

13

7

11

14

8

12

9

15

16

18

17

21

20

19 22

23

26

24

25

28

34

29 30

31

32

33

44

42

43

37

38

39

40

35

36

41

45

54

46

48

47

49

50

52

53

51

Pacific Ocean

Open-File Report 2006-1219 31
and communities were established on or near the coast, with 

houses often built on the sand, especially in Southern and 

parts of Central California. Eventually these homes were 

threatened by shoreline erosion, and the response was frequently to construct some type of protection structure. The 

California Coastal Act was passed in 1976, and with it the 

California Coastal Commission was formed. The Coastal 

Act requires statewide regulation and planning for coastal 

development, but also allows local governments to implement policies for coastal erosion hazard mitigation. The 

Coastal Commission has slowed the widespread emplacement of shoreline protection structures, but the Coastal Act 

states that such structures shall be permitted to protect existing development if it is threatened by erosion.

The post-World War II rapid increase in population 

and construction also coincided with a period of relative 

climatic quiescence on the West Coast. The period from 

the 1940s through the early 1970s had no major El Niño 

events and average or below average number of damaging 

coastal storms (Storlazzi and Griggs, 2000). Rapid building took place near the coast during this time because it 

was considered desirable and not a high-hazard zone. This 

period also coincided with the development of several major 

coastal engineering projects in Southern California, which 

resulted in the addition of large volumes of sand to the 

beach systems. In the mid-1970s, the West Coast entered 

into a climatic period when the intensity and number of 

severe storms substantially increased. The destructive El 

Niño winters of 1982-83 and 1997-98 are evidence of this 

stormier period. Widespread damage to both public and 

private property occurred during those winters. According 

to Griggs and Fulton-Bennett (1988), total losses during the 

Figure 14C. Index map showing the five analysis regions in Southern California and various locations as discussed in the text.

Santa Barbara South Region

1 El Capitan State Beach

2 Isla Vista

3 Goleta Point

4 Santa Barbara

5 Santa Barbara Harbor

6 Sandyland Beach

7 Carpenteria

8 Rincon Point

9 Ventura 

10 Ventura Harbor

11 Buenaventura Beach

12 Oxnard

13 Oxnard Harbor

14 Port Hueneme

15 Ormond Beach

16 South Beach

Santa Monica Region

17 Solromar

18 Leo Carillo State Beach

19 Trancas Beach

20 Point Dume

21 Amarillo State Beach

22 Malibu

23 Malibu Point

24 Marina Del Rey Harbor

25 Manhattan Beach

26 Dockweiler State Beach

27 Hermosa Beach

28 Redondo Beach

29 King Harbor

30 Point Vincente

San Pedro Region

31 Point Fermin

32 Los Angeles River

33 Los Angeles Harbor

34 Long Beach

35 Santa Ana River

36 Seal Beach

37 San Gabriel River

38 Bolsa Chica State Beach

39 Huntington Beach

40 Newport Beach

41 Newport Bay Harbor

42 Salt Creek Beach

43 Dana Point Oceanside Region

44 San Juan Creek

45 San Clemente

46 Doheny State Beach

47 San Onofre State Beach

48 Santa Margarita River

49 Oceanside

50 Oceanside Harbor

51 Del Mar

52 Torrey Pines City Beach

53 Point La Jolla

Mission Bay Region

54 Pacific Beach 

55 Mission Beach

56 Misson Bay

57 Coronado Island

58 Zuniga Point

59 Point Loma

60 San Diego Bay

61 Silver Strand 

Pacific Ocean

Santa Monica Bay

1 2 4

9

12

3 5 6 7

8

10

13

14

11

15

16

0 12.5 25 50 75 100

Kilometers

20

30

22

25

28

24

17

18 19 21 23

27

26

29

31

41

33

34 32

37 35

36

39 38

40

43

42

53

45

49

51

50

46 47

48

44

52

59

56

61

60

54

55

58

q

57

Open-File Report 2006-1219 32
winter of 1982-83 reached $200 million (in 2006 dollars), 

and numerous houses, businesses and existing coastal protection structures were damaged.

HISTORICAL SHORELINE CHANGE 

ANALYSIS

This section presents the results of the California sandy 

shoreline (herein referred to as shoreline) change analysis 

and discusses, where applicable, the effects of engineering 

structures and beach nourishment programs on the rates of 

shoreline change. Each California section (Northern, Central 

and Southern) is subdivided into regions (Figure 1), which 

are based broadly on littoral cells and breaks in data coverage. Tables 6A-C summarize both long-term and short-term 

average rates of shoreline change within each region. Additionally, Tables 7A-C present the maximum and minimum 

erosion and accretion rates for each region in California. 

The description of shoreline change includes information and discussion on human-induced changes. Most of the 

substantial erosion/accretion trends and/or reversals in trend 

are related to human intervention within the natural coastal 

system; these are virtually inseparable topics of discussion. 

In California, shorelines are eroding primarily because of an 

increase in storm intensity, sea-level rise, climatic changes, 

and as a consequence of human activities that disrupt the 

natural sediment supply. 

In the discussions below, rates are referenced from 

Tables 6A-C and 7A-C, where shoreline change rates are 

presented as the region-average net rate for the long-term

(1800s-1998/2001) and short-term (1950s/70s – 1998/2001) 

analysis, as well as by the magnitude of the erosion-only 

and accretion-only rates. Errors and uncertainty values 

are not shown in the text for clarity; refer to Table 6A-C 

for these values. To compare how net trends and rates 

may have changed from the long-term to the short-term, 

a statistical t-test was performed to determine whether the 

long-term and short-term rates were significantly different 

from one another at the 90% confidence interval. The t-test 

results found that in all regions except the San Pedro region, 

the change from long-term to short-term was statistically 

significant. Within the remaining 14 regions, the net shoreline change rate became more erosional from the long-term 

to the short-term with the exception of the Russian River 

region.

The average net rate of long-term shoreline change for 

California was 0.2 m/yr, an accretional trend. This is based 

on shoreline change rates averaged from 14,562 individual 

transects, of which 40% were eroding. Our analysis found 

that the only regions in California that experienced longterm negative net shoreline change were in Central California (San Francisco South and Monterey Bay regions), both 

with region-averaged rates of –0.2 m/yr (Table 6B). The 

highest region-averaged net rate was measured in the San 

Diego region (0.9 m/yr). Overall, Central California had 

the lowest overall net long-term shoreline change, likely 

because of the lack of major coastal engineering projects, 

such as those that result in more accretional rates in Southern California by adding sediment to the littoral system. In 

addition, the high volumes of sediment input from rivers 

likely contribute to the lower overall erosional trend in 

Northern California. When the erosion versus accretion 

rates were separated out, the average long-term erosion rate 

for the state was found to be –0.2 m/yr. 

The average net rate of short-term change for California was -0.2 m/yr, based on 16,142 transects, along which 

66% were eroding. Negative (erosional) net short-term

shoreline change was measured in 10 of the 15 regions. For 

those transects along which erosion was recorded, the average short-term erosion rate was -0.8 m/yr. The short-term

average erosion rates were highest in Central California 

(Table 6B).

It is important to keep in mind that the change rates 

discussed in this report represent change measured through 

the date that the lidar was collected and thus may not reflect 

the most recent trends in shoreline change. In addition, 

although erosion rates in some areas are relatively low, 

many of California’s beaches are narrow and even a small 

amount of local erosion may present serious hazards to the 

coastal resources and community infrastructure in a given 

area. 

Northern California

The Northern California analysis extends from the Oregon border to Tomales Bay, a distance of approximately 550 

km (Figure 1). For the presentation of the shoreline change 

analysis Northern California was divided into four regions: 

Klamath, Eureka, Navarro and Russian River (Figure 14A). 

Much of Northern California is highly crenulated, 

rocky coastline with small sections of pocket beaches, 

except for near major river mouths such as the Klamath, 

Smith, Eel and Russian Rivers, and a few areas where steep 

coastal cliffs are fronted by narrow beaches. As a result 

of this geomorphology, there were many gaps in the data; 

the long-term change was measured along only 148 km of 

the shoreline, and short-term change over 168 km. Both 

long-term (0.5 m/yr) and short-term (0.3 m/yr) net shoreline 

change rates were accretional when averaged over all of the 

Northern California transects. Of the 2,966 transects along 

which long-term shoreline change was measured, 23% had 

erosional trends, with an average erosion rate of –0.3 m/yr 

(Table 6A). For the short-term analysis, the percent of 

beach eroding more than doubles, increasing to 47% and the 

average short-term erosion rate was –0.6 m/yr.

Klamath Region

The Klamath region covers approximately 112 km of 

coastline and extends from the Oregon border to Patrick’s 

Open-File Report 2006-1219 33
Point (Figure 1). This region lies within the Smith and 

Klamath littoral cells (Figure 9), where rivers of the same 

names supply abundant sediment to the beach systems. The 

coastline here is sparsely developed, except for the area 

around Crescent City, and includes long stretches of State 

and National Park lands. The only significant engineering 

structures are the breakwaters protecting the Crescent City 

Harbor. According to Clayton (1991) there is harbor sand 

by-passing every several years; however the frequency 

is not consistent. In addition, the harbor was dredged in 

the 1970s, and material was placed north of the harbor to 

attempt to slow chronic bluff erosion (Savoy and others, 

2005).

For the Klamath region, long-term change rates were 

measured along 71.5 km of shoreline. The net long-term 

rate, averaged over 1,430 transects, was 0.7 m/yr. Along 

those transects with a long-term erosional trend, the average 

erosion rate was –0.4 m/yr and was found along 25% of the 

coast. The average long-term accretion rate, which occurred 

along 75% of the coast in this region, was 1.0 m/yr (Table 

6A). The long-term accretion rate in the Klamath region 

was the highest in Northern California. The maximum 

long-term erosion rate (-1.2 m/yr) occurred on the shoreline 

of a dynamic spit that extends across much of the Klamath 

River mouth (Table 9A).

The average short-term net shoreline change rate in the 

Klamath region is accretional (0.4 m/yr). Forty-eight percent of the coast along which short-term shoreline change 

was measured was erosional, and the average erosion rate 

was -0.6 m/yr. The remaining 52% of the measured coast in 

this region had a short-term accretion rate of 1.3 m/yr. The 

highest short-term erosion rate, -2.6 m/yr, was along Big 

Lagoon Beach, north of Patrick’s Point (Table 9A; Figure 

15). This area was heavily impacted during the 1982-83 El 

Niño winter storms (Figure 16), which may have influenced 

the short-term erosion rate.

The rate of net shoreline change in the Klamath region 

decreased from the long-term (0.7 m/yr) to the shortterm (0.4 m/yr), and the percent of the coastline eroding 

increased from 25% in the long-term to 48% in the shortterm (Table 6A). 

North of the Crescent City Harbor, shoreline change 

becomes increasingly erosional in both the long- and shortterm periods (Figure 15) near the harbor as opposed to areas 

further north. The highest accretion rates north of Crescent 

City were located immediately south of the Smith River 

mouth where there are extensive dune systems. There were 

local increases in the rates of accretion adjacent to the north 

and south breakwaters of the Crescent City Harbor (Figure 

15). This area is composed of broad tidal flats, and the high 

rates may have been a function of the tide level when the 

shoreline data were collected.

South of the Klamath River mouth, the magnitude of 

shoreline change increased substantially. At the northern 

end of Redwood State Park where Ossagon Creek empties 

onto the beach at Gold Bluffs Beach, the highest accretion 

rates in the State were observed (4.8 m/yr long-term and 7.3 

m/yr short-term). While most of the high accretion rates 

in other parts of the State were associated with engineering 

structures or beach nourishment, the accretion rates here 

were apparently natural.

Eureka Region

The Eureka region, which begins 6 km south of Trinidad Head and extends 74 km south to Cape Mendocino 

(Figures 14A and 17) falls within the Eureka littoral cell. 

Most of the coastline consists of sandy beaches as compared 

with the other Northern California regions. Long, linear 

beaches, dunes systems and spits have formed through 

deposition of sand by the Eel, Mad and Little Rivers. While 

still sparsely developed by California standards, the Eureka 

Region Long-term

(m/yr)

Location Short-term

(m/yr)

Location

Klamath

 Max. erosion -1.2 Klamath River mouth, south side -2.6 Big Lagoon Beach, 3.0 km north of 

Patrick’s Point

 Max. accretion 4.8 Gold Bluffs Beach, Prairie Creek 

Redwoods State Park 7.3 Gold Bluffs Beach, Prairie Creek Redwoods State Park

Eureka

 Max. erosion -0.4 Eel River mouth, south side -2.7 North Spit Beach, 0.8 km north of 

Humboldt Bay jetty Max. accretion 2.5 Little River mouth, south side 4.7 Little River mouth, south side

Navarro

 Max. erosion -0.6 DeHaven Creek Beach -1.4 DeHaven Creek Beach

 Max. accretion 0.7 Ten Mile Beach, 0.6 km south of the

Ten Mile River mouth 3.3 Ten Mile Beach, north side of Ten Mile River mouth

Russian River

 Max. erosion -0.7 Sonoma Coast State Beach, 1.3 km 

south of Russian River mouth -1.6 Sonoma Coast State Beach, 1.5 km south of the Russian River mouth

 Max. accretion 1.8 Dillon Beach 3.5 Dillon Beach

Table 9A. Maximum and minimum shoreline change rates: Northern California

Open-File Report 2006-1219 34
Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km )

0

10

20

30

40

50

60

70

80

90

100

110

Shoreline Change: Klamath Region

Crecsent City Harbor

Klamath River Cell Smith River Cell

Patrick’s Point

Oregon border

Accretion Erosion

Smith River mouth

Point Saint George

Klamath River mouth

Gold Bluffs Beach

Redwood Creek

Dry Lagoon

State Park

Big Lagoon Beach

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 15. Shoreline change rates for the Klamath region. The maximum long-term erosion rate 

was -1.2 m/yr on the south side of the Klamath River mouth, and the maximum short-term erosion 

rate of -2.6 m/yr was measured at Big Lagoon County Park Beach.

Open-File Report 2006-1219 35
region, which includes the towns of Arcata and Eureka, is 

the most developed and populous coastal area of the Northern California regions. Humboldt Bay Harbor lies between 

Eureka and a seaward barrier spit and is the largest harbor 

in Northern California; jetties were constructed there in the 

1800s to keep a channel in the spit open for boat traffic. 

North Spit and South Spit now converge at the Humboldt 

Bay jetties; unfortunately there is a gap in the lidar data for 

the spits, except immediately adjacent to the jetties. Therefore, we were unable to calculate long- or short-term rates 

for 18 km of sandy shoreline along the spits. 

The long-term net shoreline change rate for the Eureka 

region was 0.7 m/yr, an accretional trend similar to that 

measured for the Klamath region. Virtually all of the shoreline was accreting at a long-term average rate of 0.7 m/yr, 

observed along 96% of the measured shoreline. The average 

long-term erosion rate for the Eureka region is -0.2 m/yr 

(Table 6A). Of the total 24.7 km of sandy shoreline that 

was measured, long-term erosion occurred along only 4% of 

the coast. The highest erosion rates were measured on either 

side of the Eel River mouth, where a maximum long-term 

rate of -0.4 m/yr, was observed (Table 9A). 

Short-term net average shoreline change rates for the 

Eureka region, measured along 32.6 km of coastline, were 

0.4 m/yr, a less accretional trend from the long-term rates. 

The average short-term erosion rate was -0.9 m/yr (Table 

6A) and was measured along 51% of the analyzed coast. 

The average short-term accretion rate, 1.8 m/yr, was the 

highest average accretion rate in the State, and was measured along 49% of the analyzed coast.

Short-term change rates varied along coast, and were 

predominantly erosional near the Mad River, the North Spit 

of Humboldt Bay, and south of the Eel River. The maximum erosion rate (-2.7 m/yr) in this region was along North 

Spit Beach, immediately north of the Humboldt Bay jetty 

(Figure 18).

The highest accretion rates (both long- and short-term) 

occurred in the northern portion of the region, on the south 

side of the mouth of the Little River (Figure 17; Table 9A), 

along Little River State Beach. The beach here is backed 

by a substantial dune system. Similarly, in the southern part 

of the region, within the Eel River State Wildlife area, there 

was a strong accretional trend in both long- and short-term 

rates in an area that is backed by substantial dunes. 

Navarro Region

The Navarro region extends along 207 km of coastline and contains both the Ten Mile and Navarro littoral 

cells (Figure 9). This section begins approximately 11 km 

south of Point Delgada and ends at Point Arena (Figures 

14A and 19). The towns of Fort Bragg and Mendocino are 

Figure 16. Bluff erosion at Big Lagoon Beach after an El Niño storm in the winter of 1983 (photo: Gary Griggs, UCSC).

Open-File Report 2006-1219 36
Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km )

10

20

30

40

50

60

70

Shoreline Change: Eureka Region

Humboldt Bay

Eureka Cell

Little River

State Beach

Accretion Erosion

Mad River mouth

Eel River mouth

Eel River State 

WIldlife Area

Mad River

Beach

Cape Mendocino

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 17. Shoreline change rates for the Eureka region. The maximum long-term erosion rate 

was -0.4 m/yr on the south side of the Eel River mouth, and the maximum short-term erosion 

rate of -2.7 m/yr was measured along North Spit Beach.

Open-File Report 2006-1219 37
located within the Navarro region; otherwise, this stretch 

of coastline is very rugged, inaccessible, and there is little 

development. The only major coastal engineering structure 

along this coast is the breakwater at the Noya Harbor, on the 

south side of Fort Bragg. With a few exceptions, the coast 

in the Navarro region is crenulated and rocky with steep 

cliffs; there are some scattered pocket beaches and occasional narrow beaches fronting the cliffs that generally are 

not passable at high tide. Exceptions include the extensive 

beach and dune system south of the Ten Mile River mouth 

(Mac Kerricher State Park) (Figure 20), and several beaches 

formed in the vicinity of larger creek mouths, such as Westport-Union Landing State Beach, and Manchester Beach 

State Park (Figure 14A). 

Of the 207 km of coastline in this region, only 31.5 km 

had measurable sandy shorelines for our long-term analysis, 

due primarily to the lack of continuous beaches. The net 

long-term shoreline change was accretion that averaged 0.1 

m/yr. This rate was much lower than the average rates for 

the Eureka and Klamath regions discussed above. Along 

those transects where erosion was measured, the average 

long-term erosion rate was -0.1 m/yr, averaged along 28% 

of the coast (Table 6A). Long-term accretion, measured 

along 72% of the coast, averaged 0.2 m/yr. The maximum 

long-term erosion rate (-0.6 m/yr) was located within 

DeHaven Creek Beach north of Fort Bragg (Table 9A). 

Long-term accretion rates reached a maximum of 0.7 m/yr 

along Ten Mile Beach south of the Ten Mile Rive mouth.

Net short-term shoreline change, as averaged along 

32.8 km of coastline, was found to be undetectable at the 

significant figures appropriate for this analysis and therefore 

are reported as 0.0 m/yr in Table 6A. Of the measurable 

stretches of sandy shoreline, 50% eroded and 50% accreted. 

The average short-term erosion rate was –0.5 m/yr, and 

the accretion rate was 0.6 m/yr. The maximum short-term 

erosion rate of -1.4 m/yr occurred at DeHaven Creek Beach 

(Table 9A), and the maximum short-term accretion rate of 

3.3 m/y occurred just north of the Ten Mile River mouth 

(Figure 19).

The maximum long- and short-term erosion rates in 

the Navarro region are both found along isolated narrow 

beaches in the northern half of the region. These beaches 

are difficult to access and no development is threatened as 

a result of the higher erosion rates. Both long- and shortterm maximum accretion rates were near the Ten Mile River 

mouth north of Fort Bragg. The high long- and short-term 

accretion rates were likely related to the large volumes of 

sand discharged by the Ten Mile River (Merritts and others, 

2005).

Figure 18. Spit and jetty on north side of Humboldt Bay Harbor in photograph taken in June 1987. North is to the left 

in the photograph. (photo: Copyright © 2002-2005 Kenneth & Gabrielle Adelman, California Coastal Records Project, 

www.californiacoastline.org)

Open-File Report 2006-1219 38
Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km )

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Shoreline Change: Navarro Region

Ten Mile River mouth

Navarro River Cell

Ten MileRiver Cell

Point Arena

Accretion Erosion

Sinkyone

Wilderness

State Park

Ten Mile Beach

DeHaven Creek Beach

Navarro River mouth

Manchester Beach

 State Park

Fort Bragg

Mendocino

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 19. Shoreline change rates for the Navarro region. The maximum long-term erosion rate 

was -0.6 m/yr at DeHaven Creek Beach, and the maximum short-term erosion rate of 1.4 m/yr 

was also measured at DeHaven Creek Beach.

Open-File Report 2006-1219 39
Russian River Region

The Russian River region begins 12 km south of Point 

Arena along a remote, rocky stretch of coastline that has 

little development, and extends 155 km south to Tomales 

Point (Figures 14A and 21). Similar to the other regions in 

Northern California, there are few linear stretches of sandy 

shoreline, especially in the northern half of the region. The 

Figure 20. Photographs from 1972 (top) and 2002 (bottom) show the widening of the spit beach at the Ten Mile 

River mouth. Also note the increased vegetation on the dunes. (photo: Copyright © 2002-2005 Kenneth &Gabrielle 

Adelman, California Coastal Records Project, www.californiacoastline.org).

Open-File Report 2006-1219  40
Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km )

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

Shoreline Change: Russian River Region

Gualala River mouth

Russian River 

Cell

Accretion Erosion

Black Point Beach

Russian River mouth

Sonoma Coast

State Beach

Bodega Bay

Dillon Beach

Bodega Bay 

Tomales Point

Cell

Salmon Creek Beach

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 21. Shoreline change rates for the Russian River region. The maximum long-term erosion 

rate was -0.7 m/yr on Sonoma Coast State Beach, and the maximum short-term erosion rate of 

-1.6 m/yr was also measured along a remote beach along Sonoma Coast State Beach.

Open-File Report 2006-1219  41
most extensive beaches are formed near large rivers such as 

the Gualala and the Russian Rivers (Figure 21). In addition, 

a wide sandy beach and dune system exist at Salmon Creek 

Beach just north of Bodega Head. The Russian River region 

contains both the Russian River and Bodega Bay littoral 

cells.

Of the 155 km of coast in this region, we were only 

able to measure long-term shoreline change along 21.8 km, 

primarily because of the lack of linear beaches; we did not 

measure shoreline change rates on pocket beaches smaller 

than 0.5 km in length. The average net long-term shoreline change rate for the Russian River region was 0.2 m/yr. 

Average long-term erosion was -0.2 m/yr and occurred 

over only 28% of the coast (Table 6A). Similar to the other 

regions in Northern California, a much higher percentage 

of the coast is accreting in the long-term than eroding. The 

average long-term accretion rate for the Russian River 

region was 0.3 m/yr and was observed along 72% of the 

coast. The maximum long-term accretion rate, 1.8 m/yr, was 

at Dillon Beach, and the maximum long-term erosion rate of 

-0.7 m/yr was along Sonoma Coast State Beach (Figure 22; 

Table 9A).

Net short-term shoreline change averaged 0.4 m/yr, 

measured along 24.1 km of the coast. Short-term erosion 

occurred along 35% of the coast, and the average rate was 

–0.4 m/yr (Table 6A). This is the lowest percentage of 

eroding coastline of the four Northern California regions. 

The average short-term accretion rate was 0.8 m/yr.

The maximum short-term accretion rate (3.5 m/yr) was 

at Dillon Beach (Figure 22; Table 9A) and the highest shortterm erosion rate (–1.6 m/yr) occurred along Sonoma Coast 

State Beach ~1.5 km south of the Russian River mouth.. 

Sandy shorelines in the northern 100 km of this region 

are rare and occur only where small pocket beaches form 

at the mouths of rivers and creeks. Overall the shoreline 

change was accretional; the highest erosion rates were near 

the Russian River. This is the only region in the state in 

which the average rate of net shoreline change increased 

from the long-term to the short-term.

Central California

The Central California section begins approximately 5 

km south of Tomales Point in Point Reyes National Seashore (PRNS) and extends south to El Capitan State Beach, 

just north of Santa Barbara, a total distance of approximately 740 km (Figure 14B). Central California is divided 

into six regions including San Francisco North, San Francisco South, Monterey Bay, Big Sur, Morro Bay and Santa 

Barbara North. The average net long-term shoreline change 

rate for Central California was found to be undetectable at 

the significant figures appropriate for this analysis and is 

reported as 0.0 m/yr. In the short-term, however, the average net rate is strongly erosional (-0.5 m/yr). 

There are many gaps in our analysis along this coast, as 

much of the shoreline is rocky with isolated pocket beaches; 

Figure 22. Many of the large rivers in Northern California have well-developed sandy spits such as this one 

extending across the mouth of the Russian River (photo: Copyright © 2002-2005 Kenneth & Gabrielle Adelman, 

California Coastal Records Project, www.californiacoastline.org).

Open-File Report 2006-1219  42
there are a few continuous linear beaches such as in the 

Monterey Bay region. Coastal engineering structures and 

nourishment projects are limited to small harbor construction (e.g. Port San Luis, Santa Cruz) and some harbor bypassing. Numerous seawalls and revetment exist along the 

coast but these are primarily related to issues of coastal cliff 

erosion mitigation, not to protect structures from erosion of 

the sandy shoreline. 

San Francisco North Region

The San Francisco North region is 93 km long and 

includes the Point Reyes, Drakes Bay and Bolinas Bay littoral cells (Figure 9). This is primarily a rocky coastline, with 

narrow beaches backed by high coastal cliffs, small isolated 

pocket beaches between rocky headlands, and an expansive 

dune field at Point Reyes. There are two very small, developed sections of the coast in this region at Bolinas and Stinson Beach. Due to a data gap in the 1800s-era t-sheets we 

have no long-term shoreline change rates for either of these 

areas. Other than these two areas, the coast here is undeveloped and remote, and falls entirely within either PRNS or 

the Golden Gate National Recreation Area (GGNRA).

Net long-term shoreline change rates in this region, 

averaged along 45.1 km of coast, were low and averaged 

0.1 m/yr (Table 6B). Forty-six percent of the shoreline 

was eroding in the long-term at an average rate of –0.2 

m/yr. Long-term accretion rates of 0.3 m/yr occurred along 

54% of the coast. The highest and lowest long-term rates 

occurred north of Point Reyes Headland where the longterm trend was largely accretional (Figure 23). However, 

the maximum long-term erosion rate for the San Francisco 

North region of -0.5 m/yr was at Limantour Beach, which is 

north of Point Reyes (Table 9B).

Net average short-term shoreline change rates were 

measured along 51.9 km of coastline, and the average 

change rate was –0.5 m/yr. Eighty-one percent of the coast 

was eroding (short-term) with the rate of erosion averaging 

–0.7 m/yr. Short-term accretion rates, averaging 0.5 m/yr, 

occurred along only 19% of the coast. 

Short-term shoreline change trends north of Point 

Reyes Headland (Figure 23) were highly variable with 

accretion dominant in the north, changing to predominantly 

erosion in the south. The maximum short-term erosion rate 

of -3.1 m/yr was measured at Point Reyes Beach (Figure 

23). This trend is driven by the position of the most recent 

(lidar) shoreline and may indicate a rotation of the beach 

during the 1997-98 El Nino where the dominant littoral 

transport changed directions from southward to northward 

in many local areas.

In the San Francisco North region, the long- and 

short-term shoreline change rates were significantly different; there was an overall shift from a net shoreline change 

trend that was 0.1 m/yr in the long-term to a net shoreline 

change rate that was strongly erosional (-0.5 m/yr) in the 

short-term. In addition, the percent of coastline along which 

erosion was measured increased from 46% in the long-term

to 81% of the short-term. 

As demonstrated in Figure 23, from Point Reyes 

headland to Point Bonita, the sandy beaches were relatively 

stable in the long-term. In the short-term, this section of 

beach as primarily erosional, with a few localized exceptions (i.e south of Drakes Estero). The short-term erosion 

rates at Stinson Beach were the highest of those measured 

in the southern portion of the San Francisco North region. 

Winter storm waves frequently inundate Stinson Beach, 

moving large volumes of sand, and threatening homes built 

on the sand spit. Figure 24 shows a house buried by sand 

that had been eroded from a location further north. Riprap 

has been emplaced in many areas to protect the houses from 

beach erosion (Savoy and others, 2005).

San Francisco South Region

The San Francisco South region is 115 km long and 

extends from the mouth of San Francisco Bay to Davenport 

(Figures 14B and 25). The northern coast in this region 

is urban and includes San Francisco, Pacifica and Half 

Moon Bay; the southern half is largely undeveloped and 

agricultural. The San Francisco littoral cell is within this 

region (Figure 9). The geomorphology of the coastline is 

variable, with linear beaches backed by dunes, steep cliffs 

with narrow fronting beaches, rocky coast with small pocket 

beaches, and steep, high-relief coast with no sandy shoreline. There are no known beach nourishment projects in 

this region, although a dredge spoil deposit offshore may 

be contributing material to the beach (Barnard and Hanes, 

2006). Additionally, wind-blown sand is regularly removed 

from the inland side of the dunes and from the adjacent 

highway and added to the south end of the beach (Wiegel, 

2002). The most notable coastal engineering structures are 

the O’Shaughnessy and Great Highway seawalls along 

Ocean Beach in San Francisco and the Pillar Point Harbor at 

Half Moon Bay. 

For this analysis we calculated net average long-term

shoreline change rates for 56.3 km of coastline, and the 

average rate was –0.2 m/yr. Long-term erosion occurred 

along 76% of the coast at an average long-term rate of 

–0.4 m/yr. For the 24% of the coast along which accretion 

occurred, the long-term average accretion rate was 0.1 m/yr. 

The maximum long-term accretion rate (0.4 m/yr) in this 

region was located 0.25 km south of Mussel Rock, and the 

maximum long-term erosion rate of –1.8 m/yr occurred on 

the north side of Point Año Nuevo (Figure 25; Table 9B).

Net short-term shoreline change, with an average rate 

of –0.5 m/yr, was measured along 57.5 km of coast in the 

San Francisco South region. Along the portions of coast 

where the short-term shoreline change was erosional, the 

rate was –0.7 m/yr, averaged over 81% of the coast. The 

average short-term accretion rate was 0.5 m/yr. 

Short-term change trends in the central portion of this 

region are more variable than the long-term trends; erosion 

Open-File Report 2006-1219  43
Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km)

10

20

30

40

50

60

70

80

90

Point Reyes Beach

Driftwood Beach

Point Reyes Headland

Shoreline Change: San Francisco North

Drakes Estero Mouth

Bolinas Bay Cell Drakes Bay Cell

Stinson Beach

Bolinas Point

Point Bonita Rodeo Beach

Accretion Erosion

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 23. Shoreline change rates for the San Francisco North region. The maximum longterm erosion rate was -0.5 m/yr on Limantour Beach east of Drakes Estero; the maximum shortterm erosion rate of –3.1 m/yr was measured at Point Reyes Beach just north of Point Reyes.

Open-File Report 2006-1219  44
was relatively high north and south of Pillar Point Harbor 

(Figure 26) where the breakwater disrupts the natural transport of sand and focuses wave energy at the south end of the 

breakwater. The maximum short-term accretion rates were 

found along the central area, where they reach a maximum 

of 2.2 m/yr at Tunitas Beach (Figure 25). The maximum 

short-term erosion rate, -2.6 m/yr, was along the north side 

of Point Ano Nuevo.

Both the long-term and short-term net trends were erosional, and the rates more than doubled from the long-term 

to the short-term. The percents of coast eroding and accreting were similar in both the long-term and the short-term 

(Table 6B). Along Ocean Beach, both were relatively stable 

at the very northern end of the beach adjacent to the mouth 

of San Francisco Bay. However, both long-term and shortterm rates became strongly erosional to the south except 

immediately north and south of Mussel Rock. 

The long- and short-term maximum erosion rates (-1.8 

m/yr and –2.6 m/yr, respectively; Table 9B) were observed 

immediately north of Point Año Nuevo. This area of rapid 

erosion was adjacent to a former sand spit that connected 

Año Nuevo Island to the mainland (Griggs and others, 

2005). The spit was breached sometime in the late 1800s, 

providing a path for the transport of sand to the south.

Figure 24. Houses on the spit at Stinson Beach are partially buried by sand during an El Niño 

winter storm in 1983 (photo: Gary Griggs, UCSC).

Region Long-term

(m/yr) Location Short-term(m/yr) Location

San Francisco N

 Max. erosion -0.5 Limantour Beach, 2.5 km east of Drakes 

Estero -3.1 Pt Reyes Beach, immed. north of Pt Reyes

 Max. accretion 1.0 Pt Reyes Beach, 9 km north of Pt Reyes 0.9 Pt Reyes Beach, 12 km south of Tomales Pt.

San Francisco S

 Max. erosion -1.8 North side of Pt. Año Nuevo -2.6 North side of Pt. Año Nuevo

 Max. accretion 0.4 0.25 km south of Mussel Rock 2.2 Tunitas Beach

Monterey Bay

 Max. erosion -1.3 Indian Head Beach, Marina -2.4 Seaside, 3 km north of Laguna Del Ray Max. accretion 1.2 Salinas River State Beach 1.8 Twin Lakes Beach, 0.3 km east of harbor

Big Sur

 Max. erosion -0.8 North end of Carmel River State Beach -1.7 Carmel City Beach Max. accretion 0.7 JP Burns Landslide, Big Sur Coast 2.4 Pfeiffer Beach

Morro Bay

 Max. erosion -0.6 South of Ragged Pt. – narrow pocket beach -3.4 Montana De Oro State Park

 Max. accretion 1.5 Immed. north of Morro Rock 1.2 Morro Bay, 800 m south of breakwater

Santa Barbara N

 Max. erosion -1.1 Guadalupe Dunes, SLO Co. -6.7 Guadalupe Dunes, SLO Co. Max. accretion 1.1 Vandenberg Air Force Base 4.7 Vandenberg Air Force Base

Table 9B. Maximum and minimum shoreline change rates: Central California

Open-File Report 2006-1219  45
Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km)

10

20

30

40

50

60

70

80

90

100

110

San Francisco Cell

Ocean Beach

Point San Pedro

Pillar Point Harbor 

Tunitas Beach

Point Ano Nuevo

Davenport

Half Moon Bay 

Cell

Shoreline Change: San Francisco South

San Francisco Bay entrance

Accretion Erosion

Mussel Rock

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 25. Shoreline change rates for the San Francisco South region. The maximum long-term 

erosion rate was –1.8 m/yr on the north side of Point Año Nuevo; the maximum short-term erosion 

rate of -2.6 m/yr was also measured on the north side of Point Año Nuevo.

Open-File Report 2006-1219  46
Monterey Bay Region

The Monterey Bay region begins approximately 2 km 

north of Davenport in Santa Cruz County and extends 75 

km to Del Monte State Beach in Monterey (Figures 14B 

and 27). This region includes the Santa Cruz and Southern 

Monterey Bay littoral cells, and is characterized by a variable coast that includes rocky points and pocket beaches, 

cliffed coastline with narrow fronting beaches, and linear 

beach and dune systems. Development varies from urban 

(city of Santa Cruz and environs) to rural/agricultural. The 

Santa Cruz Small Craft Harbor, built in the early 1960s, currently has an active entrance channel dredging programs and 

the sand is placed downcoast from the harbor mouth. One 

beach in this region, Capitola, is down-coast from the Yacht 

Harbor and has been nourished.

The total length of sandy shoreline along which longterm change was measured in the Monterey Bay region is 

50.7 km. The average net long-term shoreline change rate 

was -0.2 m/yr. Along the 41% of the coast that had a longterm erosional trend, the average rate was -0.6 m/yr. Longterm accretion occurred along 59% of the sandy shoreline, 

and had an average rate of 0.4 m/yr (Table 6B). 

Long-term shoreline change throughout the central 

portion of the Monterey Bay was accretional. However, in 

the northern portion of the bay near the Santa Cruz Yacht 

Harbor, the shoreline change trend shifts from accretional 

west of the harbor to erosional east of the harbor (Figure 

27). The effects of the harbor appear to diminish south of 

Capitola State Beach, where the change rates are strikingly 

uniform. In the southern part of Monterey Bay there was 

a noticeable shift in the long-term shoreline change trend 

from strongly accretional in the north to erosional in the 

south (Figure 27). Both the maximum long-term accretion 

and erosion rates were measured in the southern area (Table 

9B). The maximum long-term erosion rate of -1.3 m/yr 

occurred at Indian Head Beach, and the maximum accretion 

rate (1.2 m/yr) occurred further south at Salinas River State 

Beach (Figure 27). 

The net short-term shoreline change rate in the Monterey Bay region was –0.6 m/yr, measured over 51.5 km of 

coast. Along those portions of the coast that had an erosional trend, the average rate was –0.8 m/yr, and occurred 

along 77% of the coast. The average short-term accretion 

rate, 0.3 m/yr, is the lowest in the Central California region.

The maximum short-term accretion rate (1.8 m/yr) 

was measured just south of the harbor on Twin Lakes State 

Beach (Figure 27; Table 9B). This maximum is likely due 

to material that was dredged from the harbor channel every 

winter and spring and placed on or just offshore of this 

beach (Griggs and Johnson, 1976; Wiegel, 1994). In the 

northern part of the Bay, the large pulse of short-term accretion near Capitola Beach was the result of beach nourishment projects. This project was implemented shortly after 

the harbor jetties were built to compensate for the disrupted 

downcoast transport of sand (Griggs and Johnson, 1976; 

Clayton, 1991). 

The northernmost portion of the Monterey Bay region 

is primarily a rocky coastline with scattered small pocket 

beaches; therefore, there is little sandy shoreline along 

which to measure change. The first continuous stretches 

of beach in this region are associated with the San Lorenzo 

River mouth at Main Beach in Santa Cruz (Figure 27). The 

net average rates of change in the Monterey region were 

significantly different, and there were distinct trends in the 

rates of change from the long-term to the short-term. The 

net average change rate more than doubles from the longterm (-0.2 m/yr) to short-term net change of -0.6 m/yr. In 

addition, the percent of coast experiencing erosion increased 

by 36%. This trend suggests that the Monterey Bay region 

is undergoing a shift to overall increased erosion in the more 

recent time period.

Figure 26. A riprap revetment protects an apartment building 

that overlooks a narrow beach near Pillar Point Harbor in a 

photograph taken in February, 2002. Note that the beach (background) with no revetment is much wider (photo: Gary Griggs, 

UCSC).

Open-File Report 2006-1219  47
Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km)

10

20

30

40

50

60

70

80

Wilder Ranch State Park

Main Beach

Santa Cruz Yacht Habor

Capitola State Beach

Pajaro River mouth

Santa Cruz Cell Southern Monterey Bay Cell

Salinas River 

State Beach

Laguna Del Ray

Shoreline Change: Monterey Bay

Accretion Erosion

Twin Lakes Beach

Seaside

Indian Head Beach

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

San Lorenzo River mouth

Salinas River mouth

Figure 27. Shoreline change rates for the Monterey Bay region. The maximum long-term erosion rate was -1.3 m/yr on Indian Head Beach near Marina. The maximum short-term erosion 

rate of –2.4 m/yr was measured near Seaside.

Open-File Report 2006-1219  48
In general, in the northern postion of the bay, the longterm and short-term trends of accretion gradually increased 

to the southeast where sand is impounded against the northwestern Yacht Harbor jetty (Figure 28). In the Southern 

Monterey Bay, accretional trends to the north gradually 

shifted to erosional trends to the south. The general area 

where erosion becomes more predominant corresponds to 

the portion of coast where sand mining practices throughout 

the 20th century removed large volumes of sand from the 

Figure 28. Aerial photographs of the Santa Cruz Yacht Harbor show the impoundment of sand 

against the constructed jetties. The top photo is from 1963, one year after the jetties were 

constructed. The bottom photo is from 1987, and shows a now wide, sandy beach (Seabright 

Beach) on the upcoast side of the jetty (photos: Santa Cruz Harbor Master’s Office).

Open-File Report 2006-1219  49
beach and dunes (Griggs and Patsch, 2005; Thornton and 

others, 2006). 

Big Sur Region

The Big Sur region extends along 165 km of largely 

remote and rugged coastline from Point Piños in the north 

to near Cape San Martin in the south (Figures 14B and 29). 

The littoral cells within this region are the Carmel River cell 

and the Point Sur cell (Figure 9). This region includes the 

development associated with Monterey and Carmel in the 

north; the remainder of the coast is essentially undeveloped. 

The primary hazards along this coast are large landslides 

that threaten roads and small development. The only sandy 

shorelines are along small pocket beaches and the extensive beach and dune system at the mouth of the Little Sur 

River extending to Point Sur. There are no known coastal 

engineering structures or beach nourishment projects. Due 

to the lack of linear stretches of sandy shoreline, we were 

able to measure shoreline change along only 27 km of the 

Big Sur region. 

The net long-term average shoreline change rate was 

found to be undetectable at the significant figures appropriate for this analysis and is reported as 0.0 m/yr in Table 6B. 

The average long-term erosion and accretion rates were both 

low (-0.1 and 0.2 m/yr, respectively), but accretion occurred 

over a much higher percent of the shoreline, 61% versus 

39% for the eroded areas. The maximum long-term erosion 

rate (-0.8 m/yr) was measured in the northern portion of 

the region at the southern end of Carmel River State Beach 

(Figure 29). 

In the short-term, the net average shoreline change rate 

is was -0.2 m/yr. Short-term erosion occurred along 65% 

of the coast, with rates averaging –0.5 m/yr. Short-term 

accretion rates averaged 0.4 m/yr. Similar to the maximum 

long-term erosion rate, the maximum short-term erosion rate 

was in the northern portion of the region at Carmel River 

State Beach and Carmel City Beach (Figure 29) where the 

maximum short-term erosion rate was –1.7 m/yr (Table 

9B). Pfeiffer Beach, which is approximately 13 km south of 

Point Sur, had the maximum short-term accretion rate (2.4 

m/yr) in this region.

Beaches along the Big Sur region are widely scattered 

and typically occur only at or near the mouths of rivers and 

creeks. The longest continuous stretches of beach are near 

the Little Sur River mouth and the dune system at Point 

Sur (Figure 29) where there is adequate sand supply. The 

highest long-term accretion rate was at the site of the Julia 

Pfeiffer-Burns landslide, which occurred in 1983. As a 

result of the landslide, a small beach was created where 

none had existed before (Hapke, 2005; Figure 30). Overall, 

the net shoreline change rate for the Big Sur region became 

more erosional from the long-term to the short-term.

Morro Bay Region

The Morro Bay region is 105 km long, includes the 

section of coast from San Carporforo Creek in the north to 

Point Bachon in the south (Figures 14B and 31) and falls 

within the Morro Bay littoral cell. This is a lower relief 

coast than the Big Sur region to the north, with stretches of 

rocky coastline with no beaches, low cliffs backing narrow 

beaches, as well as several linear beach and dune systems. 

The largest dunes are in the southern part of the region at 

Morro Strand State Beach and Montana De Oro State Park 

(Figure 14B). Shoreline change (both long-term and shortterm) was measured along only 22.3 and 22.9 km of coast 

respectively, partly due to the rocky nature of the coastline, 

and partly due to gaps in the lidar data. The Morro Bay 

region is moderately developed with the developed sections 

of coast concentrated in the southern areas. The towns of 

San Simeon, Cambria, Cayucas and Morro Bay are within 

this region.

In the Morro Bay region, the net average long-term

shoreline change rate of 0.1 m/yr was the one of the highest 

(most accretional) in Central California (the San Francisco 

North region also had a net long-term rate of 0.1 m/yr) 

(Table 6B). Accretion was measured along 65% of the 

coast, and the average rate of the accreting sections was 

0.3 m/yr. Where the beach was eroding, the rates averaged 

–0.1 m/yr. The maximum long-term erosion rate (-0.6 m/yr; 

Table 9B) was measured in the northern part of the region 

along a small, unnamed pocket beach.

The average short-term shoreline change rate, -0.7 

m/yr, was the most erosional net change rate in Central California. Where the beach was eroding (80% of the coast), the 

short-term erosion rates averaged -1.0 m/yr, the highest in 

Central California. The short-term accretion rates averaged 

0.4 m/yr. 

Shoreline change rates in the Morro Bay region were 

highly variable in both the long-term and short-term (Figure 

31). Beaches in the southern portion of the region were 

largely stable in the long-term, but becoming highly erosional in the short-term, suggesting a more recent disruption 

of the sand supply in this area. Figure 32 shows an area 

of long-term beach accretion at Morro Rock, which is the 

site of the highest accretion rate (1.5 m/yr) in the Morro 

Bay region. This high accretion was related to the trapping 

of sand up coast from the Morro Bay harbor breakwater 

and the Morro Rock causeway, which was built during the 

1930s – 1940s. The maximum short-term accretion rate 

was located just downcoast of the breakwater (1.2 m/yr) 

(Figure 31; Table 9B). For the long-term period, beaches 

along the Montana De Oro shoreline were stable; however 

in the short-term, this area eroded rapidly, and included the 

maximum short-term erosion rate of –3.4 m/yr.

Open-File Report 2006-1219  50
Figure 29. Shoreline change rates for the Big Sur region. The maximum long-term erosion rate was 

-0.8 m/yr on the north end of Carmel River State Beach. The maximum short-term erosion rate of -1.7 

m/yr was measured at Carmel City Beach.

Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km)

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

Pfeiffer Beach

Cape San Martin

Willow Creek Beach

Shoreline Change: Big Sur Region

Asilomar State Beach Point Pinos

Carmel City Beach

Carmel River State Beach

Point Sur

Little Sur River Beach

Julia Pfeiffer Burns Landslide site

Kirk Creek Beach

Carmel River Cell Point Sur Cell

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Open-File Report 2006-1219  51
A

B

Figure 30. JP Burns waterfall shows the beach that formed as a result of the sediment added to the system 

from the 1983 landslide. a) photo taken July 10, 1963 shows waterfall pouring directly into the ocean (from photo 

archives, Caltrans), b) photo taken June 10, 2003 shows water now pouring on to a beach (photo: Cheryl Hapke, 

USGS).

Open-File Report 2006-1219  52
Cayucas State Beach

Morro Bay Cell

Shoreline Change: Morro Bay Region

Piedras Blancas Point

Morro Strand 

State Beach

Shoreline change rate (m/yr)

Distance along shore (km)

San Carporforo Creek Beach

Point Sierra Nevada 

San Simeon Point

Point Estero

Morro Rock

Montana De Oro

State Park

Point Bachon

Accretion Erosion

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 31. Shoreline change rates for the Morro Bay region. The maximum long-term erosion rate 

was -0.6 m/yr along a narrow pocket beach south of Ragged Point. The maximum short-term erosion rate of –3.4 m/yr was measured at Montana De Oro State Park.

Open-File Report 2006-1219  53
Santa Barbara North

The Santa Barbara North region extends for 186 km 

from Point San Luis in the north to El Capitan State Beach 

in the south (Figures 14B and 33). The division between the 

Santa Barbara North and South regions is the transition from 

UTM Zone 10 (northwest) to UTM Zone 11 (southeast), 

and was necessitated by our analysis techniques. The Santa 

Barbara North region contains the Santa Maria River and 

Santa Ynez River littoral cells along with the northern half 

of the Santa Barbara cell (Figure 14B). Much of the coast is 

rugged and remote, and not highly developed. An exception is the area extending from Avila Beach to Pismo State 

Beach where some seawalls and riprap have been emplaced 

to protect coastal roads and buildings from cliff erosion. In 

addition there is a small harbor and breakwater at Port San 

Luis. The coast is predominantly cliffed with small pockets 

beaches or narrow linear beaches. However, linear stretches 

of wide beaches are present from Pismo State Beach south 

through the expansive beach and dune systems at Oceano 

and Guadalupe Dunes (Figure 34) and within Vandenberg 

Air Force Base, which occupies more than 60 km of coastline in the region. There are no known beach nourishment 

projects in this region (Clayton, 1991; Wiegel, 1994).

Ninety-nine point two kilometers of shoreline were 

measured in this region and the long-term net shoreline 

change rate was found to be undetectable at the significant 

figures appropriate for this analysis and is reported as 0.0 

m/yr in Table 6B. Long-term erosion was measured along 

A

B

Figure 32. Development of a tombolo at Morro Rock after a causeway was built in 

the 1930s. Top photo was taken in 1936 just after the completion of the causeway. 

The postcard (lower image) is from the 1950s and shows a sandy tombolo leading out 

to Morro Rock (photos: http://morro-bay.com/morro-rock/).

Open-File Report 2006-1219  54
Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km)

Santa Maria RIver Cell

Avila State Beach

Santa Ynez River Cell

Shoreline Change: Santa Barbara North Region

Point San Luis

Pismo State 

Beach

Guadalupe Dunes

Point Sal

Purisima Point

Ocean Beach 

County Park

Vandenberg Air Force Base

Point Arguello

Santa Barbara Cell

Point Conception

El Capitan Beach State Park

Gaviota Beach

Accretion Erosion

Santa Ynez River

Santa Maria River

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 33. Shoreline change rates for the Santa Barbara North region. The maximum long-term erosion rate was -1.1 m/yr at Guadalupe Dunes; the maximum short-term erosion rate of -6.7 m/yr was 

also measured at Guadalupe Dunes, and was the highest short-term rate measured in the state.

Open-File Report 2006-1219  55
56% of the coast and the average long-term rate was –0.2 m/

yr (Table 6B). Long-term accretion rates averaged 0.2 m/yr.

The short-term net average shoreline change rate was 

–0.6 m/yr, , as averaged over 113.3 km of coastline. The 

short-term average accretion rate of 0.9 m/yr was the highest 

in Central California and occurred along 20% of the coast. 

The short-term average erosion rate of –1.0 m/yr, was the 

same as the rate observed in the Morro Bay region. 

The long-term and short-term shoreline change rates 

were significantly different. The net average shoreline 

change shifted to a more erosional trend from the long-term

(0.0 m/yr) to the short-term (-0.6 m/yr). There were distinct 

changes in the patterns and magnitudes of shoreline change 

from north of Point Arguello to the southern limit of this 

region. To the north, the magnitudes of change, especially 

in the short-term, were highly variable and oscillated from 

erosion to accretion (Figure 33). North of Point Sal, longterm accretion shifted to high rates of short-term erosion, 

with rates increasing dramatically from north to south. 

The highly (spatially) variable change rates also occurred 

in the central portion of this region between Point Sal and 

Point Arguello. South of Point Arguello, the coastline was 

stable during the long-term period, however, the short-term

trend is strongly erosional along this undeveloped coast. 

In the northern part of this region, short-term erosion rates 

were high along the central part of Pismo State Beach and 

exceeded -2.0 m/yr in some areas. In general, along the 

Pismo State Beach coast the long-term trend was stable 

with the exception of the southern segment where long-term

change went from dominantly accretion to the most rapid 

erosion in this section, which was at Guadalupe Dunes 

(Figure 33; Table 9B). This dominant trend of erosion, just 

south of the Santa Maria River, is likely related to flood 

control projects on the Santa Maria River. The highest 

short-term erosion rates (-6.7 m/yr) were the highest in the 

state for a non-nourished system. The highest accretion 

rates both in the long- and short-term were within Vandenberg Air Force Base, approximately 10 km north of Purisima Point.

Southern California

The Southern California section extends from El 

Capitan State Beach north of Santa Barbara to the Mexico 

border (Figure 1), approximately 420 km of coastline. The 

shoreline change data for this section of the California coast 

is divided into five regions: Santa Barbara South, Santa 

Monica, San Pedro, Oceanside and San Diego (Figure 14C). 

This section of coastline has the longest stretches of 

continuous, linear beaches in the state, although there are 

many areas where the beaches are narrow and are backed 

by coastal cliffs or bluffs. This is also the most engineered 

coastline in the state, consisting of numerous harbors, ports, 

breakwaters, jetties and groins. There are only a few small 

Figure 34. Photographs from January 1989 shows the well-developed dune field at Guadalupe Dunes; the beach 

in this area has the highest short-term erosion rates in the State (photo: Copyright © 2002-2005 Kenneth & Gabrielle Adelman, California Coastal Records Project, www.californiacoastline.org).

Open-File Report 2006-1219  56
data gaps for Southern California: in the Point Fermin area, 

and in the San Clemente - Laguna Beach region. Both of 

these gaps are due to lack of 1800s-era t-sheets. 

 A total of 280.7 km of coastline was included in our 

long-term Southern California analysis, whereas the shortterm analysis covered 315.0 km of coast. The net long-term

shoreline change rate for the section was accretional, with 

an average rate of 0.3 m/yr and the net average short-term

rate was –0.1 m/yr.

Santa Barbara South Region

The Santa Barbara South region begins within the 

Santa Barbara littoral cell, at El Capitan Beach State Park, 

approximately 15 km north of Goleta Point and the University of California Santa Barbara campus (Figures 14C 

and 35). This region includes the beach communities of 

Santa Barbara, Ventura and Oxnard among others. With 

the exception of the coast north of Santa Barbara, this 

is a highly developed to urbanized coastline and numerous engineering structures and nourishment projects have 

greatly altered the natural patterns of shoreline change. The 

beaches along this stretch of coast are narrow, and undergo 

large seasonal fluctuations in beach volume (Norris, 1964; 

Thompson, 1987; Flick, 1993).

Long-term shoreline change trends were measured 

along 84.6 km of the Santa Barbara South region. The 

net average long-term shoreline change rate was 0.1 m/yr 

(Table 6C), and of the measured coast, 44% accreted and 

56% eroded. The average long-term accretion rate was 

higher than the erosion rate, 0.5 m/yr versus –0.2 m/yr. The 

maximum long-term accretion rate (2.0 m/yr) was located 

at West Beach, Santa Barbara, immediately adjacent to the 

harbor breakwater.

Between the 1970s and 1990s the net average shoreline change rate was -0.5 m/yr, measured along 88.0 km 

of the coast. The short-term erosion rate, which averaged 

–1.2 m/yr, occurred along 72% of the coast. The short-term 

average accretion rate, 1.1 m/yr, was the highest in Southern California, and was observed along 28% percent of the 

region.

North of Santa Barbara, most of the coastline had little 

measurable change in the long-term (Figure 35). In the 

short-term, however, the area at and just north of Isla Vista 

experienced high short-term erosion rates, exceeding –2.0 

m/yr. In Santa Barbara, shoreline change was strongly influenced by the breakwater construction and subsequent extensive sand-bypassing (Figure 36) at Santa Barbara Harbor 

(Clayton, 1991; Wiegel, 1994). Relatively high long-term

erosion south of Santa Barbara at Sandyland and Carpinteria beaches (-0.2 to –0.4 m/yr) changed to a strong trend of 

accretion in the short-term (Figure 35). Recent anecdotal 

evidence suggests this area is currently undergoing rapid 

erosion; the short-term accretion likely was an artifact 

of disrupted or reversed transport directions during the 

1997-98 El Niño. This analysis only utilizes data through 

1998, and shoreline change trends may have become more 

erosional since then. 

South of Rincon Point, there is an increase in the 

spatial density of harbors, marinas and ports, such as 

at Ventura, Channel Islands and Port Hueneme. These 

structures substantially affect the shoreline change rates. 

Emplacement of groin fields along Buenaventura Beach in 

the 1960s produced a long-term accretion rate of 2.0 m/yr; 

however, the wide beaches that developed on the north side 

of the groins eroded rapidly from the 1970s to the 1990s, 

when erosion rates exceeded -2.0 m/yr. The highest erosion 

rates in both the long-term (-0.7 m/yr) and short-term (-5.5 

m/yr) were located at Ormond Beach, approximately 6 km 

south of Port Hueneme Harbor. The maximum short-term 

accretion rate of 6.0 m/yr was measured at South Beach in 

Ventura (Table 9C). Overall, the net shoreline change rate 

changed from slightly accretional to strongly erosional from 

the long-term to the short-term.

Santa Monica Region 

The Santa Monica region is approximately 85 km long 

and extends from Point Dume to Point Vincente (Palos 

Verdes) (Figures 14C and 37). This region is within the 

Santa Monica littoral cell and the Point Dume subcell 

(Inman and Frautschy, 1966). The coastline, which is extensively developed, includes the well-known beach communities of Los Angeles County (including Malibu, Manhattan 

Beach, Redondo Beach and Santa Monica). The coast 

has been highly engineered, including beach nourishment 

projects, shoreline armoring, construction of jetties, groin 

fields and offshore breakwaters (California Dept. of Navigation and Ocean Development, 1977; Clayton, 1991; Flick, 

1993; Wiegel, 1994). Prior to the 1920s, the beaches within 

Santa Monica Bay were relatively narrow. The first beach 

nourishment began in 1938 and continued into the 1990s, 

although the volumes decreased substantially in the more 

recent time period (Clayton, 1991; Flick, 1993; Leidersdorf 

and others, 1994).

The net average long-term shoreline change rate, 

measured along 66.0 km of coast, was 0.4 m/yr. The average long-term erosion rate was –0.1 m/yr (Table 6C) and 

occurred along 31% of the coast. The average long-term 

accretion rate was 0.7 m/yr. 

During the more recent time period, the net short-term 

shoreline change rate, averaged over 75.2 km of coast, was 

-0.1 m/yr. Where the short-term rate was erosional, the 

average rate was –0.5 m/yr; this occurred along 60% of 

the beaches. The average accretion rate, 0.9 m/yr, occurred 

along 40% of the beach.

The highest short-term erosion rates (-2.2m/yr) in the 

Santa Monica region were observed at Trancas Beach north 

of Point Dume, within the Dume subcell. Additionally the 

highest short-term accretion rates (4.0 m/yr) were also measured in the northern portion of the region, at Amarillo State 

Beach north of Malibu Point (Figure 37; Table 9C).

Open-File Report 2006-1219  57
Shoreline Change Rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance Along Coast (km)

10

20

30

40

60

70

80

90

110

0

50

100

Isla Vista

West Beach, Santa Barbara

Santa Barbara Harbor

East Beach, Santa Barbara

Carpinteria

Rincon Point

Buenaventura State Beach

Oxnard Beach

Port Hueneme

Point Magu

Ventura Marina

Sandyland

El Capitan Beach State Park

Shoreline Change: Santa Barbara South Region

Accretion Erosion

Santa Barbara Cell

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Ormond

Beach

Figure 35. Shoreline change rates for the Santa Barbara South region. The analysis begins at El Capitan 

Beach State Park in the north, and extends 110 km southeast to Point Magu. The maximum long-term erosion rate was –0.7 m/yr at Ormond Beach and the maximum short-term erosion rates was –5.5 m/yr, also at 

Ormond Beach.

Open-File Report 2006-1219  58
The average erosion rate in this region increased 

five-fold from the long-term to the short-term (Table 6C). 

Accretion rates remained nearly consistent from one time 

period to the next. Widespread accretion was related to the 

construction of coastal facilities. According to Flick (1993) 

an average of 800,000 m3/yr of sand was placed on Santa 

Monica beaches between the 1940s and the 1960s. This 

material was primarily from two projects, construction of 

the Hyperion sewage facility and dredging of Marina del 

Rey.

In the long-term, much of the northern Santa Monica 

littoral cell was stable with little or no measurable change 

(Figure 37). The short-term trends along the northern 

portion of the littoral cell are more variable. Beginning at 

Figure 36. Dredging of spit at Santa Barbara Harbor. Dredged material is placed down-drift of the harbor where 

it replenishes East Beach, which accreted more than 6.0 m/yr from the 1970s to 1990s. (photo: Copyright © 2002-

2005 Kenneth & Gabrielle Adelman, California Coastal Records Project, www.californiacoastline.org).

Region Long-term

(m/yr) Location Short-term(m/yr) Location

Santa Barbara S

 Max. erosion -0.7 Ormond Beach, 6 km south of Port 

Hueneme Harbor -5.5 Ormond Beach, 1.7 km south of Port Hueneme Harbor

 Max. accretion 2.0 West Beach, Santa Barbara, 

north of harbor 6.0 Ventura South Beach, at Santa Clara River flood control channel

Santa Monica

 Max. erosion -0.3 Leo Carillo State Beach -2.2 Trancas Beach, 6 km north of Pt Dume

 Max. accretion 0.3 Trancas Beach, 4.5 km north of Pt Dume 4.0 Amarillo State Beach, 2 km north of Malibu 

Pt

San Pedro

 Max. erosion -2.4 1.5 km south of Newport Bay Harbor -2.2 Newport Beach Max. accretion 2.0 Huntington State Beach, north of jetty 2.8 Huntington State Beach, 0.6 km north of jetty 

Oceanside

 Max. erosion -0.3 Cardiff State Beach -3.5 Del Mar Beach

 Max. accretion 1.9 Oceanside Harbor (north side) 6.8 Doheny State Beach, south of Dana 

Point Harbor

San Diego

 Max. erosion 0.0 --- -3.6 Mission Beach Park, north of jetty Max. accretion 3.3 Silver Strand State Beach 1.6 Silver Strand State Beach

Table 9C. Maximum and minimum shoreline change rates: Southern California

Open-File Report 2006-1219  59
Figure 37. Shoreline change rates for the Santa Monica region. The analysis begins within the 

Dume subcell to the north near Solromar and extends to Vincente Point. The maximum long-term 

erosion rate was –0.3 m/yr at Leo Carillo State Beach and the maximum short-term erosion was 

–2.2 m/yr at Trancas Beach.

Shoreline Change: Santa Monica Region

Solromar

Malibu Point

Marina del Ray Harbor

Vincente Point

Trancas Beach

Amarillo Beach

Malibu Lagoon

State Beach

Santa Monica

 State Beach Santa Monica breakwater

Dockweiler State Beach

Hermosa Beach

King Harbor

Accretion Erosion

Shoreline change rate (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km)

0

10

20

30

40

50

60

70

80

Santa Monica Cell

Figure 37

Point Dume

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Open-File Report 2006-1219 60
the interior of Santa Monica Bay, where groin fields exist 

along Santa Monica State Beach, the long-term change 

trend became predominantly accretional to Hermosa Beach 

(Figure 37). According to Coastal Frontiers (1992), as of 

the early 1990s, this approximately 32-km section of coast 

had 5 breakwaters, 3 jetties, 19 groins, 5 revetments and 6 

piers (Figure 38).

The short-term trend showed primarily erosion 

throughout the northern half of the region except north and 

south of Malibu. From the interior beaches of Santa Monica 

Bay to the southern end of the region, the short-term change 

trend, while highly variable, shifts to erosional (Figure 38).

From the 1970s to the 1990s, the 2.5 km stretch of beach at 

Dockweiler State Beach eroded at a maximum rates of over 

1.9 m/yr (Figure 37), despite the extensive groin fields and 

nourishment projects. The long-term change at Dockweiler State Beach was accretional, due primarily to massive 

nourishment projects. The distinct shift to erosion began 

sometime after 1970, when artificial material was no longer 

placed on these beaches (Flick, 1993; Wiegel, 1994). 

San Pedro Region

This region includes both the San Pedro littoral cell and 

the Laguna subcells to the south (Figure 9). The small 

(~14 km long) Palos Verdes subcell to the north of Point 

Fermin was not covered by this report because the coastline 

here is rocky with occasional narrow pocket beaches, and 

thus has little sandy shoreline. The San Pedro region extends 

approximately 67 km from Point Fermin to Dana Point 

(Figures 14C and 39). The massive Los Angeles Harbor 

complex and breakwater west of Long Beach (Figure 40) 

occupy the northern 14 km of the region. The communities 

of Long Beach, Huntington Beach and Newport Beach (Figure 14C) are all located within the San Pedro region. The 

Laguna littoral subcells begin at Newport Bay and extend 

south approximately 22 km to Dana Point. Due to a data 

gap in the 1800s-era t-sheets we were not able to calculate 

long-term shoreline change rates along a large potion of the 

southern half of this region, although we do have more data 

for the short-term analysis.

Net long-term shoreline change rates in the San Pedro 

region averaged 0.5 m/yr. The average long-term erosion 

rate, which was –0.3 m/yr, was the highest in Southern 

California. However, long-term erosion was observed along 

Figure 38. Oblique aerial photograph of a breakwater along the highly engineered Santa Monica coastline (Copyright © 2002-2005

Kenneth & Gabrielle Adelman, California Coastal Records Project, www.californiacoastline.org).

Open-File Report 2006-1219 61
Shoreline Change: San Pedro Region

Shoreline change (m/yr)

Distance along shore (km)

Long Beach

Seal Beach

Bolsa Chica State Beach

Huntington

State Beach

West Newport Beach

Laguna Subcells San Pedro Cell

Salt Creek Beach Dana Point

Los Angeles Harbor

Laguna Beach

Accretion Erosion

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

8 6 4 2 0 -2 -4 -6 -8

20

30

40

50

60

70

Figure 39. Shoreline change rates for the San Pedro region. The analysis extends from Los 

Angeles Harbor to Dana Point. The maximum long-term erosion rate was –2.4 m/yr south of 

Newport Bay Harbor and the maximum short-term erosion was –2.2 m/yr at Newport Beach.

Open-File Report 2006-1219 62
only 12% of the 30.3 km of shoreline analyzed. The average rate of long-term accretion was 0.6 m/yr (Table 6C). 

The net short-term change rate, averaged along 46.3 

km of coastline, is 0.5 m/yr, the highest rate in of all California regions, and the only net accretional short-term trend 

in Southern California. For the short-term period, erosion in 

the San Pedro region was observed along 35% of the coast 

and averaged –0.5 m/yr. The average accretion rate was 

1.0 m/yr. 

Beach nourishment and coastal construction projects 

greatly influenced the shoreline change patterns within 

the San Pedro region (Herron, 1987; Clayton, 1991; Flick, 

1993; Wiegel, 1994). There was a dominantly accretional 

trend throughout the northern half of the San Pedro region 

(Figure 39) . The accretion is a result of ongoing nourishment programs that were designed to counteract a loss in 

natural sediment input from the Los Angeles, San Gabriel 

and Santa Ana Rivers where major flood control structures 

trap natural sediment (Clayton, 1991; Flick, 1993; Wiegel, 

1994). Accretion rates from Seal Beach to Huntington State 

Beach (Figure 39) were substantially higher in the shortterm than the long-term. Low rates of long-term erosion at 

Bolsa Chica State Beach make this the only section of coast 

in the San Pedro littoral cell to have measurable long-term

erosion, with a maximum of -0.4 m/yr. The area of maximum short-term erosion was on Newport Beach where the 

short-term rates reached -2.2 m/yr (Table 9C). There were 

very few areas of measurable long-term erosion throughout the southern portion of the San Pedro region, with the 

exception of a small stretch of beach south of Newport Bay 

Harbor where the long-term erosion rate was –2.4 m/yr. The 

pattern of short-term rates in the southern half of the San 

Pedro region indicated that this section of coast was stable 

(Figure 39). 

Oceanside Region

The Oceanside region is within the Oceanside littoral 

cell, which is the second largest of the Southern California 

cells (Figure 9). This region extends approximately 90 

km from Dana Point to Point La Jolla in the south (Figures 

14C and 41). The many beach communities in this region 

include Carlsbad, Solana Beach, Encinitas, San Clemente, 

Oceanside and Del Mar. Nearly 15 km of shoreline north of 

the Oceanside Harbor is within the Camp Pendelton Marine 

Corps Base. Much of the shoreline consists of narrow 

beaches backed by cliffs and many of the beaches have been 

nourished (Flick, 1993). According to the U.S. Army Corps 

of Engineers (1991), nearly 26 million m3 of sand were 

placed on beaches in the Oceanside littoral cell from 1954 to 

1988, and the earliest nourishment began in the late 1920s 

on Doheny State Beach (Clayton, 1991).

The net long-term shoreline change rate for the 

Oceanside region, averaged over 78.0 km, was 0.2 m/yr. 

Average long-term erosion was –0.1 m/yr, and occurred 

along 31% of the coast. Average long-term accretion was 

0.3 m/yr, the lowest average long-term accretion rate of the 

Southern California regions (Table 6C). 

The net short-term average shoreline change rate for 

the Oceanside region was -0.1 m/yr and was assessed over 

79.3 km of coastline. The average short-term erosion rate, 

–0.6 m/yr, occurred along 67% of the coast. The average short-term accretion rate was 0.9 m/yr, and the highest 

short-term accretion rate, 6.8 m/yr, was measured at Doheny 

State Beach (Table 9C), where sand-fill was placed north 

Figure 40. Oblique aerial photograph of the Los Angeles Harbor (photo: Cheryl Hapke, USGS).

Open-File Report 2006-1219 63
Shoreline Change: Oceanside Region

Shoreline change (m/yr)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km) 

0

10

20

30

40

50

60

70

80

Doheny State Beach

San Onofre 

Beach

Santa Margarita

River Mouth

Oceanside

Harbor

Del Mar City Beach

Torrey Pines

City Beach

Point La Jolla

Dana Point

Accretion Erosion

Oceanside Cell

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 41. Shoreline change rates for the Oceanside region. The analysis extends from 

Dana Point to Point La Jolla. The maximum long-term erosion rate was –0.3 m/yr at Cardiff 

State Beach and the maximum short-term erosion rate was –3.5 m/yr at Del Mar Beach.

Open-File Report 2006-1219 64
of the San Juan Creek jetty in 1964 (Price, 1966; Wiegel, 

1994). 

There is a clear differentiation in shoreline change 

trends between the northern and southern parts of the 

Oceanside region. Most of the beach north of Oceanside 

Harbor (Figure 41) was stable or accreting, except immediately adjacent to the Harbor where the maximum long-term

accretion rate of 1.9 m/yr was recorded. This accretion 

was related to the construction of the harbor jetties which, 

when completed in 1968, began to trap vast amounts of 

sand moving downcoast (Flick 1993). The short-term

change north of the harbor was predominantly accretion, 

except for the areas around San Onofre State Beach and 

the Santa Margarita River mouth. South of the Oceanside 

Harbor, the shoreline was relatively stable in the long-term; 

however, the short-term trend was dominantly erosion, and 

erosion rates increased to the south. The maximum shortterm erosion rates, which were measured at Del Mar City 

Beach (-3.5 m/yr), also were high at Torrey Pines Beach 

(-2.2 m/yr) (Figure 42) as well. According to Flick (1993), 

the north jetty at Oceanside Harbor either has trapped sand 

or deflected it offshore (or both), leading to an increasingly 

starved system in the southern part of the region.

San Diego Region

The San Diego region includes both the Mission Bay 

and Silver Strand littoral cells that together extend for 

approximately 45 km from Point La Jolla to the Mexico 

border (Figures 14C and 43). The coastline in this region 

consists of rocky coast with small pocket beaches, low-relief 

linear beaches, and narrow beaches backed by cliffs. The 

shoreline is highly engineered, with large coastal facilities such as the flood control jetties at Mission Bay and the 

2300-m-long Zuniga Jetty at the entrance to San Diego Bay 

(Figure 44). In addition, many beaches have been nourished, principally the result of coastal construction projects, 

beginning as early as the 1930s (Clayton, 1991). As a result 

of data gaps in the 1800s-era t-sheets in this area, our longterm analysis within the San Diego region is limited to the 

linear beaches of Pacific Beach and Mission Beach Parks in 

the northern half of the region.

Long-term shoreline change rates for the San Diego 

region were measured along 21.9 km of sandy shoreline. 

The net average long-term rate was 0.9 m/yr, the highest net 

change rate in the state. Average long-term erosion is 

–0.1 m/yr, and occurred along 21% (Table 6C) of the shoreline. The average long-term accretion rate was 1.2 m/yr, the 

highest average long-term accretion rate in the state.

The net average short-term shoreline change rate, 

measured along 26.2 km of coastline, was –0.8 m/yr and 

occurred along 90% of the measured shoreline. Both the 

net shoreline change and the percent of eroding beaches 

changed substantially from the long- to the short-term

(Table 6C). This suggests that the region became increasingly unstable in the latter part of the 20th century.

Although the long-term shoreline change trend was 

accretional in the San Diego region, both the rate of erosion 

and the percentage of eroding coast increased significantly 

in the short-term period (Figure 43; Table 6C). Short-term

erosion was measured over large stretches of coastline, 

such as along Mission Beach Park just north of the northern 

Mission Bay jetty, as well as along the southern portion of 

Silver Strand State Beach. The highest short-term erosion 

Figure 42. Narrow beach fronting tall coastal bluffs at Torrey Pines City Beach. The 

short-term beach erosion rates are high in this area (photo: Gary Griggs, UCSC).

Open-File Report 2006-1219 65
Shoreline Change: San Diego Region

Shoreline change (m)

8 6 4 2 0 -2 -4 -6 -8

Distance along shore (km)

0

10

20

30

40

Point La Jolla

Silver Strand Cell Mission Bay Cell

Mission Bay

Mission Beach Park

Pacific Beach Park

Zuniga Jetty

Mexico border

San Diego Bay entrance

Silver Strand

State Beach

Accretion Erosion

Short-term rate

Long-term rate

* * Max. erosion 

and accretion

*

*

Figure 43. Shoreline change rates for the San Diego region. The analysis extends from 

Dana Point to the Mexico border. There is no measurable long-term erosion rate in this 

region; the maximum short-term rate was –3.6 m/y at Mission Beach Park.

Open-File Report 2006-1219 66
rate (-3.6 m/yr) was observed at Mission Beach Park 

(Table 9C). Other than just north of the Mission Bay jetty, 

the Mission Bay littoral cell showed little long-term change. 

In the southern half of the San Diego region, there was rapid 

long-term accretion (3.3 m/yr) adjacent to Zuniga Point and 

breakwater (Figure 44) on Coronado Island. The effect of 

this structure diminished to the south. The highest long-term

accretion rates were directly related to the entrapment of 

sand against an along-shore barrier (USACE, 1986; Wiegel, 

1994). Short-term shoreline change in the southern half 

of the region shifted from accretion in the north (with the 

exception of immediately adjacent to the breakwater) to 

erosion in the south. The highest erosion rates along this 

section of coast were over -2.0 m/yr.

DISCUSSION AND FURTHER 

CONSIDERATIONS

Summary of Shoreline Changes

According to a recent study by the California Department of Boating and Waterways and the California State 

Coastal Conservancy (2002) the state of California has 

1,860 km of open ocean coastline. Of this, 1,188 km has 

some type of fronting beach. In many cases, especially in 

Northern and Central California, the beaches are narrow 

strips of sand fronting coastal cliffs or bluffs and may only 

be exposed during lower tides. Shoreline change analyses 

were not conducted for the approximately 36% of the total 

length of the California coastline that is characterized as 

rocky. In this report, long-term rates of shoreline change 

are provided for 728.1 km of the total length of sandy shore, 

and short-term rates are provided for 807.1 km. Of the 

sandy shorelines, gaps in either the lidar data or T-sheets 

resulted in a lack of four shorelines along 27% of the coast 

characterized as beach. Therefore, in this report we present 

long-term shoreline change rates for 40% of the total California coast and short-term rates for 44% of the total length 

of coastline.

Of the California shoreline where long-term rates 

of change were quantified 40% were eroding; the highest regionally-averaged long-term erosion rate, -0.2 m/yr, 

occurred in the Monterey Bay and San Francisco South 

regions. This rate is high due to the artificially high erosion in the southern portion of the Monterey Bay caused by 

long-term sand mining operations (Griggs and others 2005; 

Thornton and others, 2006). Average long-term erosion 

rates for California were highest in the San Pedro region in 

Southern California (-0.3 m/yr), the Monterey Bay region 

in Central California (-0.6 m/yr) and the Klamath region in 

Northern California (-0.4 m/yr). The San Francisco South 

region experienced erosion along the most coastline (76%). 

One of the highest specific areas of long-term erosion in the 

state (-1.8 m/yr) was on the north side of Point Año Nuevo 

in the San Francisco South region (Table 9B) where a spit 

was breached in the late 1800s and large volumes of sand 

where mobilized and transported down coast. In Southern 

California, the highest measured long-term erosion rate, 

-2.4 m/yr, was south of Newport Bay Harbor. In Northern 

California, the maximum long-term erosion rate (-1.2 m/yr) 

Figure 44. Oblique aerial photograph of Zuniga Point and breakwater at the entrance to the 

San Diego Harbor (photo: Cheryl Hapke, USGS).

Open-File Report 2006-1219 67
was adjacent to the Klamath River mouth where a dynamic 

spit shifts spatially through time.

Overall the highest long-term accretion rates were 

associated with coastal engineering structures and beach 

nourishment sites (Southern and Central California) and 

where there is high sediment supply from large rivers 

(Northern California). The highest rate of long-term accretion (4.8 m/yr) occurred 10 km south of the Klamath River 

mouth, and appeared to be a natural rate, likely associated 

with sediment influx from the soft bluff and gullies that are 

incised in the bluffs.

In general, there was a statewide increase in the percent 

of sandy shoreline that eroded from the long-term (40%) 

to the short-term (66%). This trend implies that erosion 

hazards have increased in California, especially from the 

1950s-70s to the late 1990s. This may be related to the 

climatic shift that began in the mid-1970s when California’s 

climate entered a period of more frequent and stronger 

storms, including two of the most intense, and damaging El 

Niño winters of the last century. It must also be remembered 

that our analysis only extends up to 1998 (or 2002 in some 

areas) and does not include trends that may have developed 

since.

Planned Updates and Related Research

The USGS plans to revise and report on rates of 

shoreline change for California every 5 to 10 years, and 

thus this report and associated data should be considered 

a work in progress. The revision interval will depend on 

new information and technological advances that will allow 

relatively rapid shoreline position acquisition, processing, 

and dissemination. Future revisions will also incorporate 

the results of ongoing shoreline research. For example, we 

plan to continue to refine the methodology that we applied 

to quantify the effects of using different shoreline proxies 

on the shoreline change rates. We will also explore other 

approaches to reduce shoreline positioning uncertainty 

(spatial errors) and shoreline sampling uncertainty (temporal 

variability). GPS technology has greatly reduced positioning 

errors so that they are no longer a significant component of 

the uncertainty analysis. GPS and lidar also eliminate the 

need for digitization and introduction of associated positioning errors. The dynamics of sandy beaches ensure that shortterm shoreline fluctuations will not be eliminated entirely 

from future shoreline positions, but data being collected in 

various coastal regions as part of the USGS regional studies 

will provide quantitative assessments of seasonal and interannual changes in shoreline position. These assessments 

will provide a means to determine if the detected shoreline 

change is within the expected range of movement and allow 

us to further constrain the uncertainties.

Influence of Human Activities

As coastal communities continue to grow along the 

California Coast, potential conflicts may arise between 

preservation of property (typically privately owned) and 

conservation of the beach (typically publicly owned). Past 

social responses indicate that these conflicts most likely will 

be resolved through a combination of beach nourishment 

projects and shoreline protection structures. Both of these 

engineering responses to erosion alter the natural beach processes and eventually lead to artificial shoreline positions. 

Adding sand to eroding beaches is a common method 

to mitigate storm damage and to maintain a recreational 

beach. Beach nourishment alters the rates of retreat by 

causing rapid artificial accretion of the shoreline. In those 

areas where nourishment is frequent, the trends of shoreline change will be biased toward accretion or stability. 

Additionally, the proposed removal of dams in some of the 

watersheds in California may alter the shoreline change 

trends, as previously impounded sediment begins to make 

its way into the littoral system. Passive erosion of the beach 

by emplacement of seawalls or revetments may initially lead 

to an increase in the rate of erosion, but the rate will slow 

to zero if the beach erodes away in front of the structure. 

Because many beaches are already altered by shoreline 

protection projects and more will be altered in the future, 

the methods of analyzing shoreline movement have to 

take shoreline stabilization activities into account so that 

the documented trends and derived rates of change can be 

expressed in their proper context. 

Distinguishing between natural rates of shoreline 

movement and those influenced directly by human activities is crucial when historical rates of change are used for 

planning and to project future shoreline positions. Improved 

methods of analyzing shoreline movement will be needed to 

document the natural rates of shoreline change.

REFERENCES

Anders, F.J., and Byrnes, M.R., 1991, Accuracy of shoreline 

change rates as determined from maps and aerial photographs: Shore and Beach, v. 59, p. 17-26.

Anderson, R.S., Densmore, A.L., and Ellis, M.A., 1999, 

The generation and degradation of marine terraces: Basin 

Research, v. 11, p. 7-19.

Barnard, P.L. and Hanes, D.M., 2006, Coastal monitoring of 

the May 2005 dredge disposal offshore of Ocean Beach, 

San Francisco, California: U.S. Geological Survey, OpenFile Report, Report Series 2006-1140, 27 pp., http://pubs.

usgs.gov/of/2006/1140/

Barton, C.C., Dismukes, J.S., and Morton, R.A., 2003, 

Complexity analysis of the change in shoreline position at 

Duck, NC: Proceedings Coastal Sediments ‘03, 7p.

Open-File Report 2006-1219 68
Bascom, W., 1954, Characteristics of natural beaches: 

Proceedings of the 4th Coastal Engineering Conference, 

1953, in Johnson, J.W. (ed.), Council on Wave Research, 

The Engineering Foundation, p. 163-180.

Benumof, B.T., Storlazzi, C.D., Seymour, R.J., and Griggs, 

G.B. 2000, The relationship between incident wave 

energy and seacliff erosion rates: San Diego County, 

California: Journal of Coastal Research, v. 16, n. 4, p. 

1162-1178.

Brown, K.M., Richmond, B.M., and Scholar, D.C., 1998, 

Oceanographic influence on beach morphology during an 

El Niño winter along the Santa Cruz County Coast: EOS 

Transactions, AGU Fall Mtg., San Francisco CA., v. 79, 

n. 45, p. F486.

California Coastal Commission, 1997, California Coastal 

Access Guide (5th Edition), Berkeley, University of California Press, 304 pp.

California Department of Boating and Waterways and California State Coastal Conservancy, 2002, California Beach 

Restoration Study, Sacramento, CA, 280 pp.

California Dept. of Navigation and Ocean Development, 

1977, Study of beach nourishment along the southern 

California coastline: State of California, the Resources 

Agency.

California Geological Survey, 2002a, California Geomorphic Provinces: CGS Note #36, 4 pp.

California Geological Survey, 2002b, Generalized Geologic 

Map of California: CGS Note #17, 4 pp.

Chin, J.L., Wong, F.L., and Carlson, P.R., 2004, Shifting 

shoals and shattered rocks – how man has transformed the 

floor of west-central San Francisco Bay: U.S. Geological 

Survey Circular 1259, 30 pp.

Clayton, T.D., 1991, Beach replenishment activities on 

the U.S. Continental Pacific Coast: Journal of Coastal 

Research, v. 7, n. 4, p. 1195-1210.

Cooper, W.S. 1967, Coastal Dunes of California: Geological Society of America Memoir 104, 131 pp.

Coastal Frontiers, 1992, Historical changes in the beaches of 

Los Angeles County, Malaga Cove to Topanga Canyon, 

1935-1990: County of Los Angeles, Dept. of Beaches and 

Harbors, 105 pp.

Crowell, M., and Leatherman, S.P., eds., 1999, Coastal 

erosion mapping and management: Journal of Coastal 

Research, Special Issue 28, 196 pp.

Crowell, M., Douglas, B.C., and Leatherman, S.P., 1997, 

On forecasting future U.S. shoreline positions: A test of 

algorithms: Journal of Coastal Research, v. 13, p. 1245-

1255.

Crowell, M., Leatherman, S.P., and Buckley, M.K., 1993, 

Shoreline change rate analysis: Long-term versus shortterm: Shore and Beach, v. 61, n. 2, p. 13-20.

Crowell, M., Leatherman, S.P., and Buckley, M.K., 1991, 

Historical shoreline change; Error analysis and mapping 

accuracy: Journal of Coastal Research, v. 7, p. 839-852.

Dingler, J.R. and Reiss, T.E., 2002, Changes to Monterey 

Bay beaches from the end of the 1982-83 El Niño through 

the 1997-98 El Niño, In Eittreim S.L. and Noble, M. 

(eds.), Marine Geology Special Issue: Seafloor Geology 

and Natural Environment of the Monterey Bay National 

Marine Sanctuary, v. 181, p. 249-264.

Dolan, R., Anders, F. and Kimball, S., 1985, Coastal erosion 

and accretion, In National Atlas of the United States of 

America, U.S. Geological Survey, Reston, VA. 

Douglas, B.C., and Crowell, M., 2000, Long-term shoreline position prediction and error propagation: Journal of 

Coastal Research, v. 16, p. 145-152.

Flick, R.E., 1993, The myth and reality of Southern California beaches: Shore and Beach, v. 61, no. 3, p.3-13.

Flick, R.E., 1998, Comparison of California tides, storm 

surges, and mean sea level during the El Nino winters of 

1982 –83 and 1997-1998: Shore and Beach, v. 66, n. 3, p. 

7-11. 

Flick, R.E., Murray, J.F., and Ewing, L.C., 2003, Trends in 

the United States Tidal Datum Statistics and Tide Range: 

Journal of Waterway, Port and Coastal Engineering, v. 

129, n. 4, p. 155-164.

Griggs, G.B., 1994, California’s Coastal Hazards: Journal of 

Coastal Research Special Issue No. 12, p. 1-15.

Griggs, G.B. and Fulton-Bennett, K., 1988, Rip-rap revetments and seawalls and their effectiveness along the 

Central California coast: Shore and Beach, v. 56, n. 2, p. 

3-11.

Griggs, G. B., and Johnson, R. E., 1976, Effects of the Santa 

Cruz Harbor on coastal processes of Northern Monterey 

Bay, California: Environmental Geology, v. 1, n. 5, p. 

299 312.

Griggs, G.B. and Johnson, R. E., 1979, Coastline Erosion: 

Santa Cruz County, California: California Geology, v. 32, 

n. 4, p. 67 76.

Open-File Report 2006-1219 69
Griggs, G.B. and Patsch, K., 2004, California’s coastal cliffs 

and bluffs, In M.A. Hampton and G.B. Griggs (eds.), Formation, Evolution, and Stability of Coastal Cliffs – Status 

and Trends: U.S. Geological Survey Professional Paper 

1693, p. 53-64.

Griggs, G.B. and Patsch, K., 2005, Año Nuevo to the Monterey Peninsula: In Living with the Changing California 

Coast, Griggs, Patsch and Savoy (eds.), University of 

California Press, p. 228-269.

Griggs G.B., Patsch, K., and Savoy, L., 2005a, Living with 

the Changing California Coast, University of California 

Press, 540 pp.

Griggs G.B., Patsch, K., and Savoy, L., 2005b, The evolution of the California Coast: In Living with the Changing California Coast, Griggs , Patsch and Savoy (eds.), 

University of California Press, Berkeley, p. 8-17.

Griggs G.B., Patsch, K., and Savoy, L., 2005c, Understanding the shoreline: In Living with the Changing California 

Coast, Griggs , Patsch and Savoy (eds.), University of 

California Press, Berkeley, p. 38-74.

Griggs, G.B. and Savoy, L.E., 1985, Living With the 

California Coast: Duke University Press, Durham, North 

Carolina, 393 pp.

Griggs, G., Weber, J., Lajoie, K. and Mathieson, S., 2005, 

San Francisco to Año Nuevo: In Living with the Changing California Coast, Griggs, Patsch and Savoy (eds.), 

University of California Press, p. 270-310.

Guza, R. and O’Reilly, W, 2001, Wave prediction in the 

Santa Barbara Channel: MMS OCS Study 2001-005, 

Coastal Research Center, Marine Science Institute, 

University of California, Santa Barbara, California, MMS 

Cooperative Agreement Number 14-35-0001-30758, 8 

pp. 

Habel, J.S. and Armstrong, G.A., 1978, Assessment and 

atlas of shoreline erosion along the California coast: 

State of California Department of Boating and Ocean 

Development, Sacramento, CA, 277 pp.

Hapke, C.J., 2005, Estimated material yield from coastal 

landslides based on historical digital terrain modeling, 

Big Sur, California: Earth Surface Landforms and Processes, v. 30, p. 679-697.

Hapke, C., 2005, Monterey Peninsula to Morro Bay: In Living with the Changing California Coast, G. Griggs and K. 

Patsch (eds.), University of California Press, Berkeley, p. 

311-333.

Harden, D.R., 1998, California Geology, Prentice-Hall, New 

Jersey, 477 pp.

Hare, S.R. and Mantua, N.J., 2002, Empirical evidence for 

North Pacific regime shifts in 1977 and 1989: Progress in 

Oceanography, v. 24, p. 6-14.

Hearon, G and Willis, C., 2002, Chapter 2: California Beach 

Setting, In M. Coyne and K. Sterrett (eds), California 

Beach Restoration Study, California Department of 

Boating and Waterways and State Coastal Conservancy, 

Sacramento, California, p. 2-1 to 2-6. Available on-line 

at: http://www.dbw.ca.gov/beachreport.asp

The Heinz Center, 2000, Evaluation of erosion hazards: The 

H. John Heinz III Center for Science, Economics and the 

Environment, Washington, D.C., 203 pp.

Herron, W.J., 1980, Artificial beaches in Southern California: Shore and Beach, v. 48, n. 1, p. 3-12.

Herron, W.J., 1987, Sand Replenishment in Southern California: Shore and Beach, v. 55, n. 3⁄4, p. 87-91.

Hickey, B.M., 1979, The California Current SystemHypotheses and Facts: Progress in Oceanography, v. 8, n. 

4, p. 191-279. 

Inman, D.L., and Chamberlain, T.K., 1960, Littoral sand 

budget along the southern California coast, In Volume 

of Abstracts, Report of the 21st International Geological 

Congress, Copenhagen, Denmark, p. 245-6.

Inman, D.L. and Frautschy, J. D., 1966, Littoral processes 

and the development of shorelines: Coastal Engineering—Santa Barbara Specialty Conference, October 1966, 

American Society of Civil Engineers, p. 511-536.

Inman, D.L. and Jenkins, S.A., 1999, Climate change and 

the episodicity of sediment flux of small California rivers: 

Journal of Geology, V. 107, p. 251-270.

Inman, D.L. and Masters, P.M., 1991, Budget of sediment 

and prediction of the future state of the coast: State of 

the Coast Report, San Diego Region, Coast of California Storm and Tidal Waves Study, U.S. Army Corps of 

Engineers, Los Angeles District, Ch 9, 105 pp. Available 

online: http://repositories.cdlib.org/sio/cmg/10/

Inman, D.L. and Nordstrom, C.E., 1971, On the tectonic and 

morphologic classifications of coasts: Journal of Geology, 

v. 79, p. 1-21.

Johnson, J.W., 1971, The significance of seasonal beach 

changes in tidal boundaries: Shore and Beach, v. 39, n. 1, 

p. 26-31.

Krabill, W., Wright, C., Swift, R., Frederick, E., Manizade, S., Yungel, J., Martin, C., Sonntag, J., Duffy, M., 

Hulslander, W., and Brock, J., 2000. Airborne laser mapping of Assateague National Seashore Beach. Photogrammetric Engineering & Remote Sensing, v. 66, p. 65-71.

Open-File Report 2006-1219 70
Leidersdorf, C.B., Hollar, R.C., and Woodell, G., 1994, 

Human Invervention with the Beaches of Santa Monica 

Bay, California: Shore and Beach, v. 62, n. 3, p. 29-38.

Maloney, N. and Chan, K. M., 1974, A summary of knowledge of the Southern California Coastal Zone and Offshore Areas (SOK, SC): v. 1, Sept. 1974, The Southern 

California Ocean Studies Consortium of the California 

State Universities and Colleges, Report to Bureau of Land 

Management, Department of Interior, Washington, D.C.

Merritts, D., Savoy, L., Griggs, G. and Walker, R., 2005, 

Point Delgada to Point Arena: In Living with the Changing California Coast, Griggs , Patsch and Savoy (eds.), 

University of California Press, p. 192-203.

Moore, L. J., 2000, Shoreline mapping techniques: Journal 

of Coastal Research, v. 16, p. 111-124.

Moore, L., Ruggiero, P., and List. J., 2006, Comparing 

mean high water and high water line shorelines: Should 

proxy-datum offsets be incorporated in shoreline change 

analysis?: Journal of Coastal Research, v. 22, n. 4, p. 

894-905.

Morton, R.A., 1991, Accurate shoreline mapping: past, 

present, and future: American Society of Civil Engineers, 

Coastal Sediments ‘91, v. 1, p. 997-1010.

Morton, R.A., 1996, Geoindicators of coastal wetlands and 

shorelines, in Berger, A.R., and Iams, W.J., eds., Geoindicators: Assessing rapid environmental changes in earth 

systems: A.A. Balkema, Rotterdam, p. 207-230.

Morton, R.A., Miller T.L, and Moore, L.J., 2004, National 

Assessment of shoreline change: Part 1, Historical shoreline changes and associated coastal land loss along the 

U.S. Gulf of Mexico, U.S. Geological Survey Open File 

Report 2004-1043, 44 pp.

Nelson, C.S. 1977, Wind stress and wind stress curl over the 

California Current: NOAA Tech. Rep. NMFS SSRF-714, 

U.S. Dept. of Commerce, NOAA, NMFS, 87 pp.

Newberger, P., 1982, Physical oceanography and meteorology of the California Outer Continental Shelf: POCS 

Technical Paper No. 82-2, Prepared by Minerals Management Service, Pacific OCS Region for U.S. Department 

of the Interior.

Norris, R.M., 1964, Dams and beach sand supply in Southern California: Papers in Marine Geology, R. L. Miller 

(ed.), New York: Macmillan, pp. 154 71.

Orme, A.R., 1992, Late Quaternary deposits near Point Sal, 

South-Central California: A time frame for coastal-dune 

emplacement: In Fletcher, C.H. and Wehmiller, J.F. 

(eds.), Quaternary Coasts of the United States: Marine 

and Lacustrine Systems, SEPM Special Publication No. 

48, p. 309-315.

Pajak, M.J., and Leatherman, S.P., 2002, The high water 

line as a shoreline indicator: Journal of Coastal Research, 

v. 18, p. 329-337.

Peterson, C.D. and Phipps, J.B., 1992, Holocene sedimentary framework of Grays Harbor basin, Washington, 

USA: In Fletcher, C.H. and Wehmiller, J.F. (eds.), 

Quaternary Coasts of the United States: Marine and 

Lacustrine Systems, SEPM Special Publication No. 48, p. 

273-286.

Pincetl, S.S., 2004, Transforming California: A Political 

History of Land Use and Development: John Hopkins 

University Press, Baltimore, MD, 400 pp.

Price, R.C., 1966, Statement of the California Department of 

Water Resources: Shore and Beach, v. 34, n. 1, p. 22-32.

Richmond, B.M., 1988, Ephemeral delta development at the 

mouth of Aptos Creek, Northern Monterey Bay, In Ellen, 

S.D., and Wieczorek, G.F. (eds.), Landslides, floods, and 

marine effects of the storm of January 3-5, 1982, in the 

San Francisco Bay region, California: U.S. Geological 

Survey Professional Paper 1434, p. 265-281.

Ruggiero, P., Kaminsky, G.M., and Gelfenbaum, G., 2003, 

Linking proxy-based and datum-based shorelines on a 

high-energy coastline: Implications for shoreline change 

analyses: Journal of Coastal Research Special Issue 38, p. 

57-82.

Ruggiero, P., Komar, P.D., McDougal, W.G., Marra, J.J. 

and Beach, R.A., 2001, Wave runup, extreme water levels 

and the erosion of properties backing beaches: Journal of 

Coastal Research, v. 17, n. 2, p. 407-419. 

Ruggiero, P., Komar, P.D., McDougal, W.G. and Beach, 

R.A., 1996, Extreme water levels, wave runup, and 

coastal erosion, Proceedings 25th Coastal Engineering 

Conference, ASCE, 2793-2805.

Runyan, K. B., and Griggs, G. B., 2002, Contributions from 

Coastal Cliff Erosion to the Littoral Budget, In M. Coyne 

and K. Sterrett (eds.), California Beach Restoration 

Study, California Department of Boating and Waterways 

and State Coastal Conservancy, Sacramento, California, 

51pp. Available on-line: http://www.dbw.ca.gov

/beachreport.asp

Sallenger, A.H., Krabill, W., Swift, R., Brock, J., List, J., 

Hansen, M., Holman, R.A., Manizade, S., Sontag, J., 

Meredith, A., Morgan, K., Yunkel, J.K., Frederick, E. 

and Stockdon, H., 2003. Evaluation of airborne scanning 

lidar for coastal change applications: Journal of Coastal 

Research, v.19, p. 125-133.

Open-File Report 2006-1219 71
Savoy, L., Merritts, D. Griggs, G., and Rust, D., 2005, The 

Northern California Coast: The Oregon Border to Shelter 

Cove: In Living with the Changing California Coast, 

Griggs, Patsch and Savoy (eds.), University of California 

Press, p. 163-191.

Seymour, R.J., 1998, Effects of El Niño’s on the West 

Coast wave climate: Shore and Beach, v. 66, n. 3, p. 3-6.

Shalowitz, A.L., 1964, Shore and sea boundaries. Publication 10-1, U.S. Department of Commerce, Washington, 

DC, 749 pp.

Shepard, F.P., 1950, Beach Cycles in Southern California: 

USACE Beach Erosion Board, Technical Memorandum 

No. 20, 26 pp.

Stauble, D.K., and Brumbaugh, R.W., 2003, An assessment 

of the nation’s shorelines, USA: Shore and Beach, v. 71, 

p. 11-18.

Stockdon, H.F., Holman, R.A., Howd, P.A. and Sallenger, 

A.H. Jr., 2006, Empirical parameterization of setup, 

swash, and runup: Coastal Engineering, v. 53, p.573-588.

Stockdon, H.F., Sallenger, A.H., List, J.H. and Holman, 

R.A., 2002, Estimation of shoreline position and change 

from airborne topographic lidar data. Journal of Coastal 

Research, v. 18, p. 502-513.

Storlazzi, C.D. and Griggs, G.B., 1998, The 1997-98 El 

Niño and erosion processes along the central coast of 

California: Shore and Beach, v. 66, n. 3, p. 12-17.

Storlazzi, C. and Griggs, G.B., 2000, The influence of El 

Niño-Southern Oscillation (ENSO) events on the evolution of central California’s shoreline: Geol. Soc. Am. 

Bull., v. 112, n. 2, p. 236-249.

Storlazzi, C.D., Willis, C.M, and Griggs, G.B. 2000, Comparative impacts of the 1982-83 and 1997-98 El Niño 

winters on the central California coast: Journal of Coastal 

Research, v. 16, n. 4, p. 1022-1036.

Storlazzi,C.D. and Wingfield,D.K, 2005, Spatial and temporal variations in oceanographic and meteorologic forcing along Central California:1980-2002: U.S. Geological 

Survey Scientific Investigations Report 2005-5085, 30 

pp.

Taylor, J.R., 1997, An Introduction to Error Analysis: The 

Study of Uncertainties in Physical Measurement, University Science Books, Sausalito, CA, 327 pp.

Thieler, E.R., and Danforth, W.W., 1994, Historical shoreline mapping (1). Improving techniques and reducing 

positioning errors: Journal of Coastal Research, v. 10, p. 

549-563.

Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Miller, 

T.L., 2005, Digital Shoreline Analysis System (DSAS) 

version 3.0; An ArcGIS© extension for calculating shoreline change: U.S. Geological Survey Open-File Report 

2005-1304.

Thompson, Warren C., 1987, Seasonal orientation of California beaches: Shore and Beach, v. 55, n. 3⁄4, p. 67-70.

Thornton, E.B., Sallenger, A.H., Conforto Sesto, J., Egley, 

L. A. , McGee, T., and. Parsons, A.R., 2006, Sand Mining 

Impacts on Long-Term Dune Erosion in Southern Monterey Bay, Marine Geology, v. 229, n. 1-2, p. 45-58.

U.S. Army Corps of Engineers, 1971, National Shoreline 

Study, California Regional Inventory, 106 pp.

U.S. Army Corps of Engineers, 1986, Southern California 

coastal processes data summary: Coast of California 

Storm and Tidal Wave Study, CCSTWS 86-1, 572 pp.

U.S. Army Corps of Engineers, 1991, State of the Coast 

Report, San Diego Region: Coast of California Storm and 

Tidal Wave Study, Los Angeles District.

U.S. Army Corps of Engineers, 2003, California costal 

sediment master plan, 905(b) reconnaissance report, Los 

Angeles District, 34 pp.

USGS/UCSC/NASA/NOAA Collaborative Research Group, 

1998, A collaborative program to investigate the impacts 

of the 1997-98 El Niño winter along the California coast: 

Shore and Beach, v. 66, n. 3, p. 24-32.

Weber, K.M., List J.H., and Morgan, K.M., 2005, An operational mean high water datum for determination of shoreline position from topographic lidar data: U.S. Geological 

Survey Open-File Report 2005-1027.

Wiegel, R.L., 1994, Ocean beach nourishment on the USA 

Pacific Coast: Shore and Beach, v. 62, n. 1, p. 11-36.

Wiegel, R.L., 2002, Large quantity of sand blown inland 

over top of seawall: Shore and Beach Observation, v. 70, 

n. 2, p. 11-12.

Willis, C.M., 2002a, Impediments to fluvial delivery of 

sediment to the shoreline, In M. Coyne and K. Sterrett 

(eds.), California Beach Restoration Study: California 

Department of Boating and Waterways and State Coastal 

Conservancy, Sacramento, California, p. 130-177. 

Available on-line at: http://www.dbw.ca.gov

/beachreport.asp

Willis, C.M., 2002b, Assessing natural and human alterations to coastal sediment supply in California and the 

impacts on regional beach sustainability, Ph.D. Dissertation, University of California Santa Cruz, Santa Cruz, 

CA, 142 pp.

Open-File Report 2006-1219 72