be determined, whether the gain or loss of land in a coastal region is 
due to: 
a. natural, cyclical and local fluctuation from a basic 
average position, 
b. natural long-term trends, or 
c. human interference. 
It is therefore quite understandable that opinions in professional circles 
on the effect of sea groins havealways been controversial and even at 
present are widely disputed, 
In view of the considerable cost of coastal construction it was found 
necesSary to examine the German literature on the subject to determine 
which publications on the effect of sea groins are of importance and also 
which results can be accepted without reservation. The survey is limited 
to papers which are generally easy to obtain and can be perused, examined 
and evaluated. Unpublished papers in official or private arehives are 
not considered, The very extensive foreign literature such as Abecasis 
(Portugal), Bruun (U.S.A. and Denmark), Minikin (England), De Rouville 
(France), Schijf (Holland), Zenkovich (U.S.S.R.) is not used and only 
occasionally referred to. Even in foreign countries opinions vary con- 
siderably on this subject. 
II - COLLECTION AND EVALUATION OF GERMAN DOCUMENTATION ON GROINS 
The first sea groins in Germany were constructed in the period 1818 
to 1821. The first publications dealing with them are about one hundred 
years old. They may be found in manuals and in approximately forty dif- 
ferent periodicals. In addition to engineering papers, there are numerous 
publications by geographers, geologists, oceanographers and local his- 
torians, in which are described certain conditions and events useful for 
the groin investigation, or in which pertinent relationships and develop- 
ments are revealed, 
All of these papers, together with the treatises of those German 
engineers engaged in coastal research, offer material for a new science of 
coastal morphology. Coastal engineering and coastal morphology are there- 
fore in close relationship. Remarkable surveys on morphological studies 
are given in the book by Valentin (1952) "The Coasts of the Earth''. How- 
ever, only a few of the essays in that book deal with coastal engineering 
problems and groins. 
Petersen's classification of German documentation on groins is divided 
according to coastal subjects, regions involved, and also chronologically. 
39 
