Description: Reduced Transect Counts for Regional Averaging. Attempt to numerically reduce the number of transects used to calculate regional uncertainty. Pedicated on the assumption that each transect uncertainty is partially independent of the others. Therefore these represent an indicator of how many unique areas my exist that control/drive change in a given area (e.g., pocket beaches, sections of a peninsula, etc.) The spatial location of the points is generalized - there is no inherent significance other than to reprensent a theoretical aggregation of transects for a certain area.
Copyright Text: Hapke, C.J., Himmelstoss, E.A., Kratzmann, M., List, J.H., and Thieler, E.R., 2010, National Assessment of Shoreline Change; historical shoreline change along the New England and Mid-Atlantic coasts: U.S. Geological Survey Open-File Report 2010-1118, pp16-17
Description: A compiliation of historic data for CT from the late 1800s to the late 2000s from several sources: US Coast & Geodetic Survey/NOAA Topographic Survey Sheets, or T-Sheets (1870s, 1880s, 1900s, 1910s, 1930s, 1940s, 1950s, 1960s, 1980s & 2000s); USGS Topgraphic Maps (1950s, 1960s, 1970s, 1980s) & NOAA Environment Sensitivity Index (ESI) data (1990). Only data from the late 1800s, 1990, and the late 2000s provides complete coverage for the entire coast over a reasonably set period of time. All other data sources address sections of the coast, but not the entire state. As such, there are varying amounts of time-series data at any location along the coast. All data has been combined to utilize a uniform system of attributes - since the NOAA T-Sheet data was the most voluminous source of information their schema was used as the default; other data sources transferred similar data into the NOAA schema. There were various ways different source materiall defined and classified the shoreline; this descriptive information was retained in the field called "ATTRIBUTE" and to a lesser extent "INFORM." The "SOURCE_ID" field is used to track the varying source data types. Several temporally related fields exist: "SRCE_DATE" in YYYYMMDD format is the best representation of the source material date and is suitable for sorting chronologically; "DSAS_DATE" uses a format predifined for the DSAS software package and replicates the information from "SRC_DATE." The field "DECADE" allows for aggregation/sorting by decade. The field "UNCERT_M" is required by the DSAS software and represents a cummulative positional uncertainty estimate (in meters) for eaxh shoreline segment. The value combines best estimates for common sources of error - source survey/compilation, map georeferencing, map digitizing, and water level interpretation/location. The estimates are derived from serveral published papers from USGS when conducting similar studines witnin the northeast, and the total value represents the square root of the sum of squares. The field "CONCERN" identifies sections of shoreline that, under professional review, are deemd to be incorrectly located or eroneously depict shoreline. The review process entailed creating buffers based on the uncertainty values and comparing shorelines to assorted aerial photography. While the photo vintages and the shorelines were not complimentary in all cases, there are enough areas of immobility (e.g., rocky shorelines, exposed bedrock, certain manmade structures, etc.) that persist in stable enough positions to enable a general determination of goodness of fit. Shorelines that matched these features within the appropriate uncertainty buffers were identified as "N" for no concern: shorelines that exceeded the uncertainty bounds due to spatial misalignment issues (e.g., out of reference) or were likely misinterpreting the best location of shoreline (i.e., tidal flats instead of a higher water line) were identified as "Y." In cases were uncertainty bounds were exceeded, but there was no conclusive way to determine the reason, or if they were in an areas of high shoreline variability, they were assumed to be correct and coded as "N." Rather than being removed, they were coded as such to either (a) easily be omitted from any analysis, or (b) subject to a reassessment of uncertainty in order to be more appropriately used. The data is preconfiguered to be compatible with the USGS Digital Shoreline Analysis System (DSAS) and is suitable for both cartographic displays and more rigorus shoreline change analysis studies.
Copyright Text: NOAA,
USGS,
CT DEEP
National Assessment of Shoreline Change: Historical Shoreline Change along the New England and Mid-Atlantic Coasts, by Cheryl J. Hapke, Emily A. Himmelstoss, Meredith G. Kratzmann, Jeffrey H. List, and E. Robert Thieler, Open-File Report 2010-1118.
National Assessment of Shoreline Change Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast, by Cheryl J. Hapke, David Reid, Bruce M. Richmond, Peter Ruggiero and Jeff List, Open-File Report 2006-1219.
The Predictive Accuracy of Shoreline Change Rate Methods and Alongshore Beach Variation on Maui, Hawaii
Ayesha S. Genz†, Charles H. Fletcher†, Robert A. Dunn†, L. Neil Frazer†, and John J. Rooney‡
Journal of Coastal Research 23 1 87–105 West Palm Beach, Florida January 2007
†Department of Geology and Geophysics
School of Ocean and Earth Science and Technology
University of Hawaii
‡Joint Institute of Marine and Atmospheric Research
University of Hawaii Pacific Islands Fisheries Science Center
Improving Accuracy and Statistical Reliability of Shoreline Position and Change Rate Estimates
Journal of Coastal Research 25 5 1069–1081 West Palm Beach, Florida September 2009
Peter Ruggiero† and Jeffrey H. List‡
†Department of Geosciences Oregon State University
‡Coastal and Marine Geology Program U.S. Geological Survey