This is a monumental, atlas-type case-book of changes in the shorelines of the United States, including Alaska and Hawaii. (FOOTNOTE 1) It has a dual role: (i) to give, in non-technical terms, basic data for environmental management, and (ii) also to describe for earth scientists and engineers some of the controlling conditions of coastal change.
Changes at one locality for each 25 to 30 miles of the coast south of Canada are analyzed and their changeability described. The book ranks with the classical coastal development treatises of Johnson (1919), King (1959) and Zenkovitch (1967).
One specialist usually wishes that other specialists had expanded their major writings along the lines in which he himself is working. In this case, it would have been helpful if the authors, time and space permitting, had pointed ont the particular kinds of coastal units that are typically changeable and what other types have been most nearly stable during the record period.
In the sand-and-clay coastal environment, the most stable coastal sectors that I have studied are on barrier island chains which are smooth and well aligned. Such coasts have relatively strong wave energy, large sand supply, and lie back of broad, not too gently sloping continental shelves (Price, 1954, figs. 1-5). Along the main central reach of the 3-mile-long Galveston Island, Texas, where the shelf beyond the foot of the barrier slopes 2 to 3 feet per mile offshore, and where the shelf is not covered by high submerged ridges, or "banks," the barrier shoreline had advanced and retreated through a range of 50 feet between about 1930 and 1960. During the same period, along the northern part of Padre Island, where the shelf slopes 6 feet per mile, the shoreline had advanced and retreated through a range of about 100 to 150 feet between 1930 and 1967. An exception occurred where a bulge of a migrating tidal delta was smoothed out. The Shepard and Wanless treatise gives negative evidence of such stability in its not discussing the more stable barrier stretches.
The flow through a tidal inlet is a jet (Price, 1963), both on the flood and the ebb tide. Thus, the tidal delta, with its bars, shoals, spits, and islets, lies in the area of maximum display of hydrodynamic energy for a barrier-bordered coast (Price, 1968, a and b). The data of the treatise are in harmony with these observations, and many of its examples of shoreline change are within the range of influence of the tidal jet.
Migration of a tidal inlet along a barrier is fairly common and lengthens the area of frequent change. In the native state, such migrations tend to be cyclic, with a period measured, perhaps, in centuries, as in the case of Aransas Pass, Texas. Between 1720 and 1900, this inlet was twice halted when it encountered a large down-current tidal delta.
River deltas are progradational forms of sand-and-clay coasts. These are treated by Shepard and Wanless and need no comment here.
A fairly common coastal type subject to shoreline change is the ridged cuspate foreland. While the large examples, as Cape Canaveral and Cape San Blas of Florida, are few, there are many smaller ones. Spits are numerous and characteristically changeable. A single dominant longshore sediment drift direction prolongs a spit and the hook is the result of the wrapping of wave patterns around the spit end. Cuspate forelands are a result of alternating drift directions.
Another highly changeable type of barrier coast, typified by the 65-mile Mississippi Sound chain, has relatively short, poorly aligned islands which are being eroded on one end and extended on the other. Such chains have insufficient sand-supply in relation to longshore current strength to maintain a smooth oceanic shoreline with a minimum of inlets and tidal deltas. A still more
irregular stretch of barrier chain is the 225-mile line of short island segments of the Georgia and South Carolina coasts, a central sector of the 645-mile barrier that stretches from Cape Hatteras to Palm Beach. The numerous vigorous tidal deltas cut the shallow shelf into a series of hydrodynamic cells with varying and highly variable directions of sediment drift. The strengths of the jets of these inlets are increased by the out-flow of the numerous rivers of this humid region.
Two-thirds of the Atlantic and Gulf of Mexico coasts of the United States from Long Island, New York, southward and westward are bordered by barrier chains with the longest being 645 miles long from Virginia Beach to Palm Beach. Although barriers are relatively few and widely scattered along the coasts of the Pacific Ocean, there are several on that coast of the United States that range in length upward to 10 miles or a little longer. The book shows that, in spite of the short season of ice-free waters, the arctic coast of Alaska has several barrier chains ranging from 25 to 150 miles in length. Barriers, while mutable in general, are not the only types of coasts for which the book gives records of shoreline changes.
Readers of the treatise will join his personal friends in regretting Harold Wanless' death, especially as it came before this notable book had been put in print.
New York: Mcgraw-hill Book Co., 1971, 579 Pages, $39.50.
References
JOHNSON, D. W., 1919, Shore Processes and Shoreline Development. John Wiley and Sons, New York, 584 pp. Reprinted 1965.
KING, C. A. M., 1959, Beaches and Coasts. Edward Arnold, London, 403 pages.
PRICE, W. A., 1954, Dynamic environments: reconnaissance mapping, geologic and geomorphic, of continantal shelf of Gulf of Mexico: Gulf Coast Assoc. Geol Socs., Trans., v. 4, p. 75-107.
PRICE, W. A., 1963, Patterns of flow and channeling in tidal inlets: Jour. Sedimentary Petrology, v. 33, p. 279-290.
PRICE, W. A., 1968a, Tidal deltas, in Fairbridge, R. W., (ed.) Encyclopedia of Geomorphology, Reinhold, New York, 1151, 1152.
PRICE, W. A., 1968b, Tidal inlets, in Fairbridge, R. W. (ed.), Encyclopedia of Geomorphology, Reinhold, New York, 1152-1155.
PRICE, W. A., 1971, Environmental impact of Padre Isles development: Shore and Beach, v. 39. p. 4-10.
ZENKOVITCH, V. P., 1967, in Steers, J. A. (ed.) Processes of coastal development, Oliver and Boyd, Edinburgh, 738 p.
Acknowledgements
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Footnotes
FOOTNOTE 1. A review of this book by J. V. Byrne (Science, Jan. 1972, p. 158) well describes its nature and coverage.
Source
http://archives.datapages.com/data/sepm/journals/v42-46/data/042/042002/0488.htm