National Assessment of Shoreline Change: a gis compilation of Vector Shorelines and Associated Shoreline Change Data for the Sandy Shorelines of Kauai, Oahu, and Maui; Hawaii
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- Introduction
- Methods
- Calculation of Shoreline Change Rates
- Geospatial Data
- References Cited
Conversion Factors and Datum
All positional measurements were made in the Universal Transverse Mercator (UTM) coordinate system on the North American datum of 1983 (NAD 83) or World Geodetic System datum of 1984 (WGS 84; north and west Maui regions, only). Data provided with this report was reprojected to the Geographic Coordinate System (GCS, latitude and longitude) on the WGS 84 datum. AbstractSandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline changes. Working with researchers from the University of Hawaii, the U.S. Geological Survey's National Assessment of Shoreline Change Project has compiled a comprehensive database of digital vector shorelines and shoreline-change rates for the islands of Kauai, Oahu, and Maui; Hawaii. There is currently no widely accepted standard for analyzing shoreline change. Existing measurement and rate-calculation methods vary from study to study and preclude combining results into statewide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method that is consistent from coast to coast for measuring changes in shoreline position. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner. Please refer to our full report on shoreline change for Kauai, Maui, and Oahu (Fletcher and others, 2011) for additional information regarding shoreline compilation, rate calculation methods, measurement uncertainties, and a summary of the results. IntroductionThis compilation of open-ocean, sandy shorelines for three of the eight main Hawaiian islands (Kauai, Oahu, and Maui) is part of a series that already includes published shoreline data for the Gulf of Mexico, Southeast Atlantic, California, New England, and Mid-Atlantic coasts (Morton and others, 2004; Morton and Miller, 2005; Hapke and others, 2006; Hapke and others, 2010) and will eventually include reports for the Pacific Northwest and Alaska. The Hawaii shoreline data differ from previously published U. S. Geological Survey (USGS) reports in the series in that shorelines derived from lidar (Light Detection and Ranging) data were not utilized. Attempts were made to use all available historical shoreline data from aerial photographs and topographic survey sheets that meet minimum quality standards for resolution and positional accuracy. The Hawaii shoreline data provided with this report incorporate all available shorelines that were used in calculating shoreline change rates. Typically, one historical shoreline is available for each decade from the early 1900s through the 2000s. The Kauai, Oahu, and Maui coasts were subdivided into a total of eleven analysis regions for the purposes of reporting regional trends in shoreline change rates. Long-term rates were calculated from all shorelines (from the early 1900s to the most recent), whereas short-term rates were calculated from post-World War II shorelines only. MethodsThis section describes the methods used to compile shoreline data and calculate rates-of-change for the Kauai, Oahu, and Maui coasts. Shoreline DataHistorical shoreline data were acquired from multiple sources and have been documented in the shoreline metadata files made available in this report. Shoreline data were digitized from National Oceanographic and Atmospheric Administration (NOAA) Topographic Sheets (T-sheets) and aerial photographs. The dates of historical shorelines range from the early-1900s to 2000s. The historical shorelines are based on an interpreted low water mark (LWM) that was digitized from topographic maps and aerial photographs following the methods of Fletcher and others (2003) and Romine and others (2009). Previously published U. S. Geological Survey (USGS) reports in the series used the high water line (HWL). In Hawaii, the high reflectivity of Hawaiian white carbonate beaches reduces the visibility of the HWL on historical aerial photographs. Excellent water clarity relative to most continental beaches allows the delineation of the LWM on historical aerial photomosaics, which is distinguished by a black and white or color tonal change at the base of the foreshore. The shorelines extracted from T-sheets are referenced to a HWL. To include T-sheet shorelines in the time series of historical shorelines, the HWL is migrated to a LWM in our study using an offset calculated from measurements in beach profile surveys at the study beach or a similar nearby location. Uncertainty resulting from positional and mapping errors is calculated for each shoreline segment and is included in an ‘Accuracy’ attribute field in the shoreline data. Calculation of Shoreline Change RatesRates of shoreline change were generated within ArcMap version 9.3 using the Digital Shoreline Analysis System (DSAS) version 4.2, an ArcGIS tool developed by the USGS (Thieler and others, 2009). The tool is a freely available application designed to work within the ESRI ArcGIS software. DSAS is used to generate orthogonal transects starting from a reference baseline and intersecting the shoreline positions at 20-m intervals. The distance measurements between the transect/shoreline intersections and the baseline are then used to calculate the rate-of-change statistics. Shoreline change rates were calculated using weighted least squares regression (WLS), which accounts for uncertainty in each shoreline position when calculating a trend line. The weight for each shoreline position is the inverse of the positional uncertainty squared, so that shorelines with higher uncertainty have less influence on the trend line than data points with smaller uncertainty. Rates of change and ± uncertainty values (at the 95-percent confidence interval) were calculated in meters per year over the long-term (all available years), and short-term (post- World War II) to capture potential changes in trends or rates. The linear regression method of determining shoreline-change rates was based on an assumed linear trend of change between the earliest and latest shoreline dates. Data for shoreline areas where such a linear trend did not exist and shoreline-change rates have not remained constant through time would produce a poor linear fit to the data with a higher reported uncertainty. The long- and short-term transect metadata files provide descriptions of the two fields associated with the linear regression rate calculation, and additional information can be found in Section 7 of the DSAS user guide. Geospatial DataData in this report are available as downloadable files based on the eleven geomorphic regions within the Kauai, Oahu, and Maui study areas. The index maps show the extent of each region. All vector data are delivered as ESRI shapefiles in the geographic coordinate system (WGS84) and distributed with Federal Geographic Data Committee (FGDC) compliant metadata in Extensible Markup Language (*.xml) format. Tabular data are delivered as dBase IV (*.dbf) structured files which can be read with ESRI ArcGIS software as well as many other available spreadsheet programs. Metadata are also provided for all spatial and tabular data in text (*.txt) and FGDC Classic (*.html) format. ESRI ArcCatalog 9.x can also be used to examine the metadata in a variety of additional formats. This report includes all of the files necessary to perform shoreline change analyses using the Digital Shoreline Analysis System (DSAS) software. Please refer to (Thieler and others, 2009) for information about the DSAS software application that was used to perform the rate calculation methods, which are discussed at length in the full report on the National Assessment of Shoreline Change: Historical Shoreline Change in the Hawaiian Islands (Fletcher and others, 2011). The following files are available for download for each geomorphic region (see index maps): Compiled shorelines from T-sheets and aerial photographs, which are attributed within each dataset and included in the metadata Offshore baseline used for generating shore-normal transects in DSAS Long-term transect file with rates Short-term transect file with rates Data layers can be downloaded individually using the table below. Individual layers are provided as WinZip files. If WinZip® is not currently installed on the local system, go to WinZip® (http://www.winzip.com) to download the latest version. (data catalog, Hawaii_OFR_GIS_data_catalog_R2.xls goes here) 
References CitedFletcher, C.H., Romine, B.M., Genz, A.S., Barbee, M.M., Dyer, M.M., Anderson, T.R., Lim, S.C., Vitousek, S., Bochicchio, C., and Richmond, B.M., 2011, National Assessment of Shoreline Change: Historical Shoreline Changes in the Hawaiian Islands, U.S. Geological Survey, no. U.S. Geological Survey Open-File Report 2011-1051, p. xx p. Fletcher, C.H., Rooney, J.J.B., Barbee, M., Lim, S.-C., and Richmond, B.M., 2003, Mapping Shoreline Change Using Digital Orthophotogrammetry on Maui, Hawaii: Journal of Coastal Research, v. Special Issue 38, p. 106-124. Hapke, C.J., Himmelstoss, E.A., Kratzmann, M.G., List, J.H., and Thieler, E.R., 2010, National assessment of shoreline change: historical shoreline changes along the New England and Mid-Atlantic coasts, no. U.S. Geological Survey Open-file Report 2010-1118, p. 57. Hapke, C.J., Reid, D., Richmond, B.M., Ruggiero, P., and List, J., 2006, National assessment of shoreline change: Part 3: Historical shoreline change and associated coastal land loss along sandy shorelines of the California Coast, U.S. Geological Survey Open File Report 2006-1219 (http://pubs.usgs.gov/of/2006/1219/), p. 79. Morton, R.A., and Miller, T.A., 2005, National assessment of shoreline change: Part 2: Historical shoreline changes and associated coastal land loss along the U.S. Southeast Atlantic Coast, U.S. Geological Survey Open File Report 2005-1401 (http://pubs.usgs.gov/of/2005/1401/), p. 40. Morton, R.A., Miller, T.A., 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 (http://pubs.usgs.gov/of/2004/1043), p. 44. Romine, B.M., Fletcher, C.H., Frazer, L.N., Genz, A.S., Barbee, M.M., and Lim, S.-C., 2009, Historical shoreline change, Southeast Oahu, Hawaii: Applying polynimoial models to calculate shoreline change rates: Journal of Coastal Research, v. 25, no. 6, p. 1236-1253. Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Ergul, A., 2009, Digital Shoreline Analysis System (DSAS) version 4.0 - An ArcGIS extension for calculating shoreline change: U.S. Geological Survey Open-File Report 2008-1278. Directory: coastal -> USGS OFR HI shorelinechange USGS OFR HI shorelinechange -> National Assessment of Shoreline Change: Historical Shoreline Changes in the Hawaiian Islands USGS OFR HI shorelinechange -> National Assessment of Shoreline Change: Historical Shoreline Changes in the Hawaiian Islands USGS OFR HI shorelinechange -> National Assessment of Shoreline Change: Historical Shoreline Changes in the Hawaiian Islands USGS OFR HI shorelinechange -> National Assessment of Shoreline Change: Historical Shoreline Changes in the Hawaiian Islands coastal -> Subject: Science Length: 15 minutes Location coastal -> Plants for Rain Gardens Recommended for Southeastern North Carolina coastal -> Bait, Bluefins, and Light Leaders By Captain Ralph Wilkins coastal -> U. S. Citizens or permanent residents of the U. S. or its possessions coastal -> **exclusive media invite coastal Home Care Announces Official Sponsorship and Cohosting of the Delmarva Shorebirds’ Silver Sluggers Program Opening Day Event bethesda, md– April 14, 2015 Download 0.63 Mb. Share with your friends:
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