PORT AND CITY.

Press, Volume LXIII, Issue 19180, 10 December 1927, Page 17

PORT AND CITY.

10 IHI EDITO* 0» THS P»IS§. Sir,—According to the report on dredging of Lyttelton Harbour by the acting-engineer or* the Hoard in your issue of Thursday last, £II,OOO a year can be 6aved by making the dredge Canterbury us© its four engines coupled tor steaming and dumping through hopper doors. "'•Ye may well ask what has the Board been doing to allow this waste of £II.OOO to go on for so many \-ears past? But the act-ing-engineer's good work in the right direction does not clinch the matter by any means. The report stated: "The pumping of dredgings into the reclamation area by the suction dredge Canterbury ceased in April, 1935, and since then the spoil has been deposited at sea.'" The acting-engineer has now come half-way back to Little Port Cooper to dump the dredgings and save £II,OOO. Why not come the whole way back and make vastly greater savings by pumping into reclamation areas nearby P As we said in one of our letters of last year, ''lf on the engineer's own figures it pays to reclaim, whv not do so? Why dump the dredgings into the harbour?''

We are glad that our suggestions of last year in regard to the disposal of dredgings have at last borne a little fruit as represented by the actingengineer's constructive proposals being adopted by the Board. Let the Board now frame a comprehensive policy in regard to disposal of dredgings and future reclamations and make the escape of those dredgings impossible, foolproof. The public are now aware how some rj,000,000 tons of dredgings were pumped into the 72-acre reclamation and liow some 8,000,000 tons escaped into the harbour again. To this fact we believe that the Head of the Bay, Charteris Bay, and Governor's Bay bear silent testimony, and now the acting-engineer says, '"lt is not surprising to find that soundings recently taken show that the depths in the entrance channel are not only not increasing as is of course desirable, but have not been maintained. Consequently it is imperative that the amount of spoil lifted and carried away should bo considerably increased." Nor are wo of course surprised. His remedy is to speed up the dredge and dump in Little Port Cooper, save £II,OOO per annum, have the possibility that some of tho dumpings escape sooner or later, and provide no future area of use to the port in any shape or form. On the other hand our remedy is to also speed up the dredge, but dump behind reclamation walls, save amounts varying from £117,000 in the case of Diamond Harbour to £300,000 in the case of Charteris Bay, have the certainty that the dumpings will not escape, and provide areas which will bo a source of revenue to the port. Wo have already quoted definite figures which haive never been questioned to show- that it pays to reclaim simply because it reduces dredging cast to a minimum. It is unquestionable, in our* opinion, that if the mud behind the reclamation wall in Lyttelton had stayed where put, the harbour depths in the inner and 'outer entrance channel would have been maintained, nay increased. We disagree with the acting-engineer that "large quantities of mud are obviously still being carried into the harbour from the hills." Therein does not lie trie .problem of dredging in Lyttelton Harbour. Little Port Cooper is a compromise—a good one—the half-way rest house between vagrant dredgings and dredgings hi close confinement and between maximum cost in dredging and j minimum cost in dredging, but no engi- j neer in the world can say that they { will not escape sooner or later. On the other hand every engineer in the world, including the Board's actingengineer, will say that once dredgings are placed behind a modem harbour retaining wall, similar to that in Wellington, they cannot escape, and they will provide land which will be a source of revenue for all time.

The present action 011 the part of the acting-engineer is no doubt a step in the rig-lit direction with which we are heartily in*agreement. It now remains for the Board to go further .and place before the public a definite policy and programme of development.— Yours, etc., THE PORT AND CITY COMMITTEE. Christchurch, December 9th, 1927.