Signatur:
ZSP-201-78/17
In:
CRREL Report, 78-17
Beschreibung / Inhaltsverzeichnis:
Abstract: This investigation utilized historical and recent aerial photographs and satellite imagery in 1) estimating changes in positions of the high-water line and sea cliff break and base, in rates of accretion and/or erosion, and in volumes of transported sediment, and 2) providing a preliminary evaluation of the direction of littoral transport along the outer Cape Cod coast. Using aerial photographs acquired in 1938, 1952, 1971 and 1974 with manual photointerpretation techniques, changes in the distances from selected reference points to the cliff break, cliff base and the high-water line were measured. LANDSAT-1 and -2 imagery acquired from 1 September 1972 to 28 May 1975 was evaluated for use in determining the directions of littoral transport that are active the predominant amount of time. Although the imagery has been very useful for this purpose at other locations, it proved to be useless along the outer shore of Cape Cod. Largest net migrations of the high water line from 1938 to 1974 occurred in the northern and southern portions of this coast. The northern maximum high water line was 321.4 ft, the southern was 1794.6 ft. The central portion of the coast was generally more stable with changes varying from 6.8 to 157.6 ft. Cliff-base recession rates varied from 0.4 to 7.3 ft/yr. Maximum estimated net volume of sediment deposited per linear foot of beach from 1938 to 1974 was 334 yd^3 (based on 2 yd^3/ft of recession or accretion); maximum eroded was 914 yd^3. Changes in the configuration of spits were used to evaluate directions of littoral transport since suspended sediment concentrations were generally not sufficient to act as natural tracers of surface currents. Based on the literature and a determination of the portion of the coast perpendicular to the direction of dominant wave approach, the location of the nodal zone for predominant littoral directions of drift probably shifts between the area near Spectacle Pond and North Truro Air Force Station. This investigation has illustrated a photo interpretation technique that is useful in performing a reconnaissance of coastal change. The data obtained from this method can be used to supplement those acquired by ground surveys and are valid as first approximations for planning subsequent, more detailed surveys.
Materialart:
Schriftenreihen ausleihbar
Seiten:
vi, 49 Seiten
,
Illustrationen
Serie:
CRREL Report 78-17
URL:
https://hdl.handle.net/11681/9394
Sprache:
Englisch
Anmerkung:
CONTENTS
Abstract
Preface
Conversion factors: U.S. customary to metric units of measurement
Introduction
Background
Previous investigations
Analytical procedures
Results and discussion
Shoreline changes: High-water line
Shoreline changes: Cliff recession
Volumetric changes
Nodal zone location and direction of littoral transport
Error evaluation
Summary and conclusions
Future research
Selected bibliography
Appendix A: Maps of shoreline with overlays for 1938, 1952, 1971 and 1974
Appendix B: Supplementary data for estimating shoreline change
Standort:
AWI Archiv
Zweigbibliothek:
AWI Bibliothek
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