Shoreline Changes Along the Outer Shore of Cape Cod from Long Point to Monomoy Point,
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 thq 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 cu yd (based on 2 cu yd/ft of recession or accretion); maximum eroded was 914 cu yd. 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1978
- Accession Number
- ADA060297
Entities
People
- Lawrence W. Gatto
Organizations
- Cold Regions Research and Engineering Laboratory