National Assessment of Shoreline Change— Historical Shoreline Change Along the North Coast of Alaska, U.S.-Canadian Border to Icy Cape Open-File Report 2015–1048 U.S. Department of the Interior U.S. Geological Survey Cover: Oblique aerial photograph at Flaxman Island showing tapped and untapped thermokarst lakes, caribou tracks, narrow beaches, and bluff failures along the coast. Image taken August 9, 2006. National Assessment of Shoreline Change— Historical Shoreline Change along the North Coast of Alaska, U.S.–Canadian Border to Icy Cape By Ann E. Gibbs and Bruce M. Richmond Open–File Report 2015–1048 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2015 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit http://www.usgs.gov or call 1–888–ASK–USGS (1–888–275–8747). For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Gibbs, A.E., and Richmond, B.M., 2015, National assessment of shoreline change—Historical shoreline change along the north coast of Alaska, U.S.–Canadian border to Icy Cape: U.S. Geological Survey Open-File Report 2015–1048, 96 p., http://dx.doi.org/10.3133/ofr20151048. ISSN 2331-1258 (online) iii Contents Executive Summary .......................................................................................................................................1 Introduction.....................................................................................................................................................3 U.S. Geological Survey National Assessment of Shoreline Change ............................................3 The Role of State and Federal Governments ...................................................................................4 Previous National and Northern Alaska Shoreline Assessments .........................................................5 Geology and Geomorphology of the North Coast of Alaska ...................................................................6 Lands of Unique Importance ...............................................................................................................6 Geologic and Tectonic Setting ............................................................................................................7 The Late Quaternary ....................................................................................................................7 Surficial Geology and Geomorphology .............................................................................................8 Coastal Environments .................................................................................................................8 Coastal Bluffs ......................................................................................................................8 Beaches and Barrier Spits ................................................................................................9 Barrier Islands .....................................................................................................................9 Coastal Lagoons ..................................................................................................................9 Wetlands ............................................................................................................................10 Deltas ................................................................................................................................10 Permafrost .........................................................................................................................10 Thermokarst .......................................................................................................................10 Dunes ................................................................................................................................10 Methods of Analyzing Shoreline Change ................................................................................................11 Compilation of Historical Shorelines ...............................................................................................11 1940s-Era Shorelines .................................................................................................................12 2000s-Era Shorelines .................................................................................................................13 Estimation of Shoreline Position Uncertainty ................................................................................14 Calculation of Shoreline Change Rates ..........................................................................................16 Estimation of Shoreline Change Rate Uncertainty at Individual Transects .....................16 Estimation of Regionally Averaged Shoreline Change Rate Uncertainty .........................16 Historical Shoreline Change Analysis ......................................................................................................17 (1) U.S.-Canadian Border to Jago River ..........................................................................................25 Introduction.................................................................................................................................25 Sheltered Mainland-Lagoon Shoreline Change ...................................................................26 Exposed Open-Ocean Shoreline Change ..............................................................................26 (2) Jago River to Staines River .........................................................................................................31 Introduction.................................................................................................................................31 Sheltered Mainland-Lagoon Shoreline Change ...................................................................33 Jago River Delta to Okpilak-Hulahula River Delta .......................................................33 Okpilak-Hulahula River Delta to Sadlerochit River .....................................................33 Sadlerochit River to Konganevik Point ..........................................................................34 Konganevik Point to Staines River .................................................................................34 Exposed Open-Ocean Shoreline Change ..............................................................................35 Jago River Delta to Okpilak-Hulahula River Delta .......................................................35 iv Contents—Continued Okpilak-Hulahula River Delta to Sadlerochit River .....................................................35 Sadlerochit River to Konganevik Point ..........................................................................35 Konganevik Point to the Staines River ..........................................................................36 (3) Staines River to Sagavanirktok River .........................................................................................38 Introduction.................................................................................................................................38 Sheltered Mainland-Lagoon Shoreline Change ...................................................................41 Exposed Open-Ocean Shoreline Change ..............................................................................41 Flaxman Island ..................................................................................................................44 Maguire Islands ................................................................................................................45 Stockton Islands ...............................................................................................................45 McClure Islands ................................................................................................................45 Tigvariak Islands ...............................................................................................................45 (4) Sagavanirktok River to Colville River .........................................................................................47 Introduction.................................................................................................................................47 Sheltered Mainland-Lagoon Shoreline Change ...................................................................49 Heald Point to Point McIntyre (Prudhoe Bay) ..............................................................49 Point McIntyre to Kuparuk River Delta .........................................................................49 Kuparuk River Delta to Milne Point ................................................................................49 Milne Point to Oliktok Point .............................................................................................51