Shoreline retreat of the Corte Madera marshes, 1853 to 2016, Marin County, California

Open-File Report 2020-1074
By: , and 



The greater San Francisco Bay estuary, prior to human intervention, encompassed about 2,200 km2 of tidal and salt marshes. Over time, these areas became increasingly diked, developed, and altered from their natural state. In addition, natural forces are always driving a continually shifting equilibrium.

This study area, the Corte Madera marshes, is a tidal marsh or wetland located in southeastern Marin County, and it borders an embayment of central San Francisco Bay along about 2.8 km of shoreline. Most of this shoreline is located within the Corte Madera Marsh Ecological Reserve, managed by the California Department of Fish and Wildlife. Other areas within the marsh include (1) unincorporated Greenbrae (at the boardwalk), (2) diked land (that is, isolated from tidal action) owned by the Golden Gate Bridge Highway and Transportation District, and (3) urbanized areas such as in the Mariner Cove subdivision of Corte Madera. The present tidal marsh area was historically subdivided into the following informally named tracts, listed from north to south: Heerdt marsh, north Muzzi marsh, inner and outer Muzzi marshes, Marta’s marsh, and Triangle marsh.

The purpose of this study is to derive the magnitudes and rates of shoreline change (both erosion and accretion) for the Corte Madera shoreline, with particular emphasis on the time period from 1931 to 2016. The rates of change are then related to different shoreline types (that is, natural or diked) and (or) locations on the shoreline.

Suggested Citation

Carkin, Bradley A., Kayen, Robert E., and Wong, Florence L., 2020, Shoreline retreat of the Corte Madera marshes, 1853 to 2016, Marin County, California: U.S. Geological Survey Open-File Report 2020–1074, 36 p., 6 appendixes,

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Introduction
  • Purpose
  • Previous Work
  • Modifications Affecting the Corte Madera Shoreline
  • Delineation of the Shoreline
  • Methods
  • Rate Uncertainties
  • Results
  • Discussion
  • Acknowledgments
  • References Cited
  • Appendix 1. End Point Rates for Corte Madera Creek (CC) and Heerdt Marsh (HM-1 through HM-7) Rate-Calculation Zones, Corte Madera Shoreline
  • Appendix 2. End Point Rates for North Muzzi Marsh (North) Rate-Calculation Zone NM-N, Corte Madera Shoreline
  • Appendix 3. End Point Rates for North Muzzi Marsh (South) Rate-Calculation Zone NM-S, Corte Madera Shoreline
  • Appendix 4. End Point Rates for Outer Muzzi Marsh Rate-Calculation Zone OM, Corte Madera Shoreline
  • Appendix 5. End Point Rates for Marta’s Marsh Rate-Calculation Zone MM, Corte Madera Shoreline
  • Appendix 6. End Point Rates for Triangle Marsh Rate-Calculation Zone TM, Corte Madera Shoreline

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Shoreline retreat of the Corte Madera marshes, 1853 to 2016, Marin County, California
Series title Open-File Report
Series number 2020-1074
DOI 10.3133/ofr20201074
Year Published 2020
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Pacific Coastal and Marine Science Center
Description vi, 36 p.
Country United States
State California
County Marin County
Other Geospatial Corte Madera Marshes
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional metadata about this publication, not found in other parts of the page is in this table