PORT OF WANGANUI.

Wanganui Chronicle, Volume LXXVI, Issue 18256, 15 August 1921, Page 5

PORT OF WANGANUI.

MR BLAIR MASON’S REPORT. THE LOCAL PROBLEM DISCUSS?!) Tho report which tho Wanganflf Harbour Board have received from their consulting engineer, Mr Blair Mason, contains several points of exceptional interest, and indicates that the possibility of a harbour for the accommodation of deep draught vessel? is closer at hand than is generally an. ticipated, provided, however, that th* Board proceeds on certain and definite linos which he clearly indicates. Tho report stresses the fact that it is by scouring influence that present and prospective depths will be maintained. In other words, the river will practice ally its own work, provided that the flowing waters are directed in a proper way. MISDIRECTED SCOUR. Mr Blair Mason’s investigations show that although there is ample depth at the Castlecliff wharf the same satisfactory conditions do not continue in a {seaward direction, as in consequence of shoaling caused through filtration of sand through the north mole, the trend of the deep channel is towards the eMj of a south mole, thence in a southerly direction and practically parallel with the coast. By making the north mole impervious to the littoral sand drift and training the current to follow the concavity of the north mole. Mr Blair Mason. contends that the now of the river can bo directed straight to the sea, the volume being su/fftcient to maintain, by scour alone a deep water channel to tho Castlecliff wharf (and later on to the basin) which will enable the berthage of vessels up to 24 feet in draught. SUGGESTED GROYNE. The most interesting point in regard to the improvement of the lower harbour is a suggested low-water training wall out into the channel from the shore fend of the south mole,* tho object being to concentrate the flow alongside the north mole, and which, in Mr Blair Mason’s opinion, would neither impede the inflow of sea water on the flood tide nor offer any difficulties to vessels working the port. THE RIVER CHANNEL. As far as the river channel between Castlecliff and Wanganui is concerned Mr Blair Mason is definitely of the opinion that a minimum depth of ten feet of water at low spring tides can be maintained by scour, but he is equally insistent that the fairway must bo kept clear of snags and inijxKlinienti to the flow in the way of wharves or jetties stretching out into the river. T/his latter contention indicates that the Board blundered badly in consenting to the erection of the present Imlay wharf, when a structure of a different nature might easily have served the same purpose. On that occasion, however, the Board were advised by their then resident engineer (Mr C. H. Howarth) that the Imlay wharf, as planned, would have no deleterious effect, and the Board’s members, being laymen and inexperienced in designing harbours, can at least offer tho excuse that they followed the advice of an engineer. VALUE OF DREDGES. Tn the face of Mr Blair Mason’s advice that the scour of the river will provide sufficient depth for big steamers drawing up to 24 feet to lierth inside. and that in future dredging will play an unimportant part in maintaining the river channel, tho Board must seriously consider the practical value of the dredges Rubi Seddon and Kaione, and it remains to be seen whether either of those vessels will be necessary for the amount of excavation necessary to complete the interior of the proposed basin at Castlecliff. It is to be hoped that the Harbour Board will concentrate its efforts on the lines as indicated by Mr Blair Mason, so that at' the earliest possible moment Wanganui will be abl<> to offer shipping facilities for oversea vessels.