CO129-373 - Public Offices - 1910 — Page 405

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M. de Rijke's quarterly report, dated the 20th April, 1907, is also then quoted, as follows:-

"A resounding of Gough Island Reach shows that the depth all along Ship Channel has increased, while Junk Channel has shallowed."

The memorandum further states that at that date-

"the so-called Inner Bar has almost disappeared, and there is to-day, from the arsenal to the mouth of the river, a uniform depth of at least 18 feet at lowest low-water level; in other words, the works which the River Conservancy tries to achieve are already almost in existence."

113. The memorandum, in summarising the conclusions arrived at, contains the following:-

K

According to M. de Rijke's own words, the forcing over of the main stream of a river like this, without causing new impediments and without much interrupting navigation, is often found to be a most difficult task, even when using numbers of men skilled in such work." The Kajow Bar, which should facilitate this 'forcing over,' has entirely disappeared, and there must now be a certain danger if it is tried. Is it, under these circumstances, advisable to run such an incalculable and enormous risk ? Or what security does M. de Rijke's scheme give that, in the course of its execution, shipping will not be seriously hampered or even interrupted ?

"The expense of the Ship Channel's closing up under the present conditions will be--as admitted by the quarterly reports-much higher than at first estimated. Will this There are at the disposal twenty annual votes of 460,000 taels each. amount, under all circumstances, suffice for the complete execution of M. de Rijke's scheme?

"If these two questions cannot be answered with certainty, might it not be taken into serious consideration to make use of the natural tendency of the river, choosing the present fair-way (Ship Channel) by improving and straightening it ?

It is quite obvious that thereby the shipping can in no way be hampered, and, moreover, the expenses will be considerably smaller.

"We would like to mention that our misgivings are shared by experts."

114. We have made these quotations from the memorandum of the "Deutsche Vereinigung," for the purpose of focussing attention on the main points where difference of opinion existed between the advocates of the Ship Channel route and those who favoured the scheme for the development of Junk Channel,

Captain Schellhoss's further Criticisms.

115. Captain Schellhoss also explained, at an interview, that in his opinion the Jetty Works at Woosung were of a much heavier section than required, and pointed out that owing to the large expenditure upon them and on the great works, previously described, which were required to divert the river from its normal course at Gough Island, it had been necessary to raise a large loan, with the consequence that there had to be paid away in interest a sum amounting to one-third of the total available work fund. He considered that all the improvements required might have been effected at the rate of 460,000 Haikwan taels per annum, in which case almost 3 000,000 Haikwan taels more would have been available for productive expenditure.

116. Captain Schellhoss also questioned the necessity for the series of six cross dams behind the main longitudinal dam at Upper Gough, and the introduction in nearly every case of two cribs, connecting the shore with the various parallel works, instead of relying on one only.

117. Criticisms were also expressed by Captain Schellhoss and some others with regard to the administration of the works. This matter does not, however, appear to us to have a direct bearing upon the main question which we are called upon to investigate, viz., whether or not in the scheme, as carried out, is the best which could have been adopted, and also whether there is a probability of its being permanently successful.

XII.-M. DE RIJKE'S VIEWS GENERALLY ON THE FOREGOING CRITICISMS. 118. Taking first the points raised in the memorandum of the "Deutsche Vereinigung," it will now be conceded that the fears formally expressed with regard to cutting off Shanghai for a time from the sea, or of increased difficulties in the navigation during the construction of the works, have been proved to be unfounded.

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Reasons for the Selection of Junk Channel.

119. M. de Rijke answered the foregoing criticisms in writing, and also explained his views to Mr. Wilson and Mr. Matthews; his replies on the question of the selection of the Junk Channel for improvement rather than the Ship Channel may be summarised as follows:--

(a.) That a much straighter and better course is thereby obtained, both for tidal development and for navigation.

(b.) That owing to the sharp concave bend in the Ship Channel and the action of the tidal currents thereon, the defence works on the right bank would require to be almost continuous, and, having to be constructed in deep water, would, of necessity, prove very costly to carry out in the first instances, and would entail heavy maintenance charges in the future.

(c.) That in consequence of the insufficiency of the cross sectional area of the Ship Channel branch of the river, either very heavy dredging work would have been necessary along Gough Island shore, or else a portion of the Junk Channel must have been left open, which might have resulted in the continuation of the Inner Bar, and would have defeated the whole object of training the river and the creation of a single waterway for the flux of the tides.

(d.) That the training works extending from the left bank, below Gough Island, which would be required to divert the flood currents into the Ship Channel would have to be carried across deep water, and be of exceptional strength on account of the abrupt angle around which the stream would have to be turned."

At the same time the development of the flood tide would have been seriously injured by being forced around so sharp a curve.

(e.) That works of a similar description, though of a loss substantial character, would have been required from the left bank, above Gough Island, in order to divert the ebb currents into the Ship Canal.

(f) That a channel of the full section required, and with good curves, could be more readily obtained through Junk Channel, and, moreover, the training works necessary, apart from the main parallel dam at Upper Gough, could be constructed almost entirely in shallow water.

Cross Dams at Upper Gough.

120. With reference to the series of cross dams behind the main parallel dam at Upper Gough, and the system of double or treble cribs, connecting the shore with the various parallel works, M. de Rijke considered a provision of this kind essential, on so soft a bottom as is here experienced, in order to subdivide the fall of the stream over the works in such a manner as to reduce scour at the foot of the dam, and to facilitate the deposit of silt between the cribs. Although he had allowed for the six upper dams in his estimate of April 1909, in case they might all be required, he proposed only to construct such of them as experience might find to be necessary as the works proceeded.

XIII.-OUR OPINION WITH REGARD TO THE WORKS EXECUTED BY M. DE RIJKE.

121. We have thought it desirable to describe fully the works which have been proposed and those which have been executed, and have referred at length to the reasons which led to the adoption of the design of the works which have been carried out, and also to the views which are entertained generally at Shanghai with regard thereto. It now becomes necessary that we should express our opinion, which we do after most careful consideration, with reference to these important matters.

Preference for Junk Channel Route.

122. Dealing first with the principal controversial point, viz., as to whether the Ship Channel or the Junk Channel should have been selected for improvement; we are strongly of opinion, after mature reflection, that the right course was adopted in the decision to improve and develop the Junk Channel.

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[2958 kh-1]

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