582 SECTIONAL TRANSACTIONS.— G. 



According to the general scheme of the Zuyderzee works, a heavy bank will enclose 

 the southern part of the gulf ; of the enclosed area (915,000 acres) four parts (total 

 area 550,000 acres) are to be reclaimed separately. In the centre a fresh-water lake 

 (Yssellake) of 270,000 acres will remain as a storage basin to receive the water of the 

 River Yssel and other tributaries. The lake will discharge into the Waddenzee 

 by twenty-five sluices in two groups ; each sluice is 40 feet wide. 



V/hen the influence of the enclosing upon the tides in the Waddenzee was investi- 

 gated it was found that the tidal range would increase in those parts, and that especially 

 storm tides would rise to a higher level than at present (maximum 4'5 inches at 

 Den Oever, Isle of Wieringen). 



Consequently the enclosing dam has to be constructed with a higher crown than 

 was deemed sufficient previouslj', and the sea banks around the Waddenzee have to 

 be heightened. 



The enclosing dam will consist of a boulder clay core with a body of sand covered 

 with clay behind it ; the slopes are faced with stone pitching, and the toes are 

 protected from scour by mattresses of brushwork. The height of the crest varies 

 from 20 feet 4 inches to 24 feet 8 inches above Normal Amsterdam Level ; on a high 

 berm on the inner side a railway and a road are projected. The dam is being built 

 upon the sea bottom, which has a depth of about 10 feet below L.W., excepting 

 the deeper channels. 



The dam, with a total length of 18J miles, is to be built in such a way that the 

 tidal currents around the head of the work will cause the least possible impediment. 

 The enclosing will be effected gradually in eight years ; the final closing will be 

 executed in two places simultaneously, where the deepest channels have to be crossed. 

 To that end artificial bars or sill dams will be constructed in the channels beforehand, 

 to serve as a base for the superstructure of the dam. 



The mean velocity of the flow over the sills will increase during the operation. 

 The extent of the increase has been calculated, and the distribution of the velocities 

 over the crown of the sill dams was investigated by experiments on small-scale models. 

 It was found that by taking adequate measures it will be possible to control the velocity 

 and to keep it beneath a dangerous limit. 



The banks of the areas to be reclaimed will be constructed on the same principle 

 as the enclosing dam : a core of boulder clay and a main body of sand. 



After these banks will have been constructed the water is to be pumped ofE the 

 embanked areas, and the canals, drains and roads are to be laid out on the dry sea 

 bottom before the soil can be cultivated. 



The capacity of the pumpmg plants will be sufficient to drain off a rainfall of 

 ^ inch per twenty-four hours in the same period. 



In the N.W. polder (which at present is being embanked) two pumping stations 

 will be erected, with a total capacity of 835 cubic yards per minute. 



If no serious contrariety is encountered the enclosure of the Zuyderzee will be 

 accomplished in 1934. The N.W. polder will be embanked in 1929 and the soil will 

 be cultivated in 1934. 



The whole of the Zuyderzee works, if progressing favourably, can be finished in 1952. 



Joint Discussion witli Section L on School, University, and Practical 

 Training in the Education of the Engineer. (Sir William Ellis, 

 G.B.E. ; Col. Ivor Curtis, C.B.E. ; Sir Henry Fowler, K.B.E. ; 

 Mr. W. W. Vaughan ; Prof. A. L. Mellanby ; Prof. Sir James 

 Henderson ; Prof. W. Kerr.) 



Col. Ivor Cuetis. — (1) Modern developments make an increasing call on the 

 engineer of to-day — for wider practical knowledge, more thorough scientific training 

 and better general education. This is not confined to the professionally qualified 

 engineer, but extends down the whole chain of responsible workers. 



(2) As an aftermath of the war the country is fighting for its existence as an 

 industrial nation. To live it must design better, produce more cheaply, give better 

 value and sell better than its rivals. Training for production and management has 

 become a vital issue. 



(3) With the spread of modern ideas and the development of education a greater 

 flow is to be expected from the bench to positions of professional responsibility and 

 management. 



