Harbour Improvements.

Wanganui Herald, Volume XXXVIII, Issue 11252, 10 May 1904, Page 6

Harbour I mprovements.

TO THE EDITOR.

, Sir,;— Since I last wrote to you, a letter appeared from Mir Baynes, apparently advocating the purchase and use of a suction dredge. Such dredges have been invented since I left Efngland, and I never saw one 4it^^rork. k . ( lt seems, .to jne^Jipweyej, that though they irfay do very well for the removal%of mud or fine sand, they could have ■ little*effect- ©n---gravel — eyen-euci fioe-igravel-as is on our flats. I have seen the Priesti^an£s dredge at work in Wellington repeatedly, and.^was, much surprised at the small quantity^ it lifted at each haul, and at all the finer stuff escaping; so that I do nottnink that type 'of dredge would suit our river. I noticed, too, that Mr Baynes simply proposed to tip the spoil "over the training wall and allow it to be washed aW"ay by-the tide, instead" of retaining it by means of cross cradges or otherwise. Mr ii.' Sarjeant also 'wrote, admitting that the question is one between the town and' freezing works,- and 'asserting- that the ! latter are the mainstafy.of the district. No doubt they 'benefit' the .'glazier"* 'by -keeping' up the price of stock, and also those who «re fortunate enough- to have % sharbs in- the freezing works; but they are opposed to the general interest,- -as they tend to-keep-up the price of bxitchers' meat to the whole population,- of whom only «• small proportion are benefited by the works. It is monstrous to try to" be'ntefit those works at the cost of injuring the public generally, by lessening the navigability of : tJie river be--low the town-. The shallowness of the flats ;fcaise> life -freights' of- all gdbd imported" fromjWellington and prevents large vessels from •Teaching- the" town.' Tf -we -had twenty feet of water right down to the sea we could import goods direct from England-, and the whole public would benefit by the lowered •■prices. " Many people" Kere'Ttiave" pools on their properties formed by damming up water courses, and anyone who will take the trouble to look will see that the velocity of the current is checked directly the .water enters ' fife" pool;' atict that there is scarcely any current at all,' and what there' is, is confined to the surface. There is not6nly 4 no 'scour "in" the "pool,- but the silt .brought down >by the.wa.ier' is" deposited in the bottom. And this is exactly what is t happening below the tojyri. to the in : ..creased width. *of the' , river -there' is little "velocity, and instead of scour .there" is constant deposit of silt:" It 'would "be- one everlasting job to keep on dredging the silt as it is deposited; and the deposit would be -greatest in , the very channel.- formed by the i dredges." '■'Mr f Bafr's idea inf! designing the training walls evidently was to maintain a deep channel by restricting the. flow of the water to the space between .' them;-, bat -to do this they would need to have been carried up to above high-water mark of spring tides, and as this would have required at least five times as much- stone, it^as quite beyond our means. I notice 1 -' that -there is one great difference between old marine engineers and ,tte new seKool. Tlie latter have had experience of better appliances for moving heavy blocks of stone' and of ' new kinds of- dredges; • but tJ^r wliole s ,idea | is to fight against nature, a contest in j whic,h they are bound to get the worst, as she will always be damaging their works arid occasionally sweeping them away altogether,;,as has. actually,, Jjap^ened in, the case of outside sea walls in England, wh'iclT i had cost vast sums of money. We old engi- ■ neor« went. to work scientifically. 'We as- j sistcd nature, merely guiding' her in her operations, so as to get her to do our work for us: and I am sure this was the wiser course. ' We also preferred constructing harbaurs within the coast-line, rather ,,than in the open sea, where they would be exposed to the action of the winds during storms. — I am, etc., ."„;,■•,, •'. -A; #../•*€. iFJELD. .