Discussion. A Model Study of the Behaviour of Beaches and Groynes.

Abstract

Research.lo It would be interesting to know whether similar models were used in each case and how the conclusions of the Author compared with those of the D.S.I.R.85. The coastline hydraulic model could be an unreliable instrument for the study of the coastline unless it was based upon reliable information. It was dependent therefore upon a study of the coast and the natural laws which operated there, as described in a series of Papers by MC Hoyle and Mr King."."No account appeared to have been taken of these Papers in the conduct of the experiments described by Mr Kemp, and in the view of Mr Hoyle and Mr King the results are therefore invalid and should be regarded as academic exercises upon a purely fictitious coastline, having no applications in practice.86. The validity of the experiments, in so far as they were intended to represent conditions in nature, was in doubt for the following reasons:(a) The coastal hydraulic model could only reproduce some, and not all, natural phenomena; therefore limitations were imposed upon it. (Provided these limitations were understood and stated, however, certain natural phenomena could be demonstrated and this should not be regarded as wholesale condemnation of the hydraulic model.) (b) The coastal hydraulic model was a machine comparable with a computer, into which information was fed. If the basic information was wrong then faulty conclusions would emerge. In the present case the information fed into the model was not consistent with nature.(c) When an experiment had been concluded the results had still to be interpreted, which might be done in different ways by different people according to the attitude which was taken towards the coastline itself.