MR. BLACKETT'S REPORT ON TIMARU BREAKWATER.

Akaroa Mail and Banks Peninsula Advertiser, Volume 4, Issue 401, 8 June 1880, Page 2

MR. BLACKETT'S REPORT ON TIMARU BREAKWATER.

[By Telegraph.] (from the lyttelton times.) Wellington, June 1. Mr Blackett, in his report on the Timaru breakwater, says: — "My last report on the Timaru Harbor Board works was on July 3, 1879, and was intended to reply to ce'tain questions asked by tbe Minister for Public Works, viz.:—What amount of damage was inflicted on the railway, and how much of this waß due to the Harbor Board's operations ; what action is necessary, and its probable cost, in order to prevent further encroachments, and to arrange that the Harbor Board, if thought responsible, should undertake the repairs? The reply to the above questions was unqualified, namely, that there could be no doubt that the damage to the railway line north of Timaru harbor works was due largely to the erection of the breakwater, but until further evidence wa3 obtained it was difficult to state bow much of the damage was due to the works, and how much to the violence of storms. Since this the action of tbe sea has been closely watched by Mr W. H. Lowe, the Resident Engineer for Railways, who has twice reported on the subject, A perusal of these reports shows the prejudicial action of the breakwater in so clear and strong a light that there need now be no uncertainty in the mind of anj one who is capable of justly estimating the importance oE the effects therein recorded. The facts are briefly these—Before any breakwater was erected tie sea beach was covered with a coating of shingle of such depth and quantity as to act as a protection to the softer parts, of which the beach on which it lay was composed. This shingle, or the upper layer of it, was in an almost constant state of motion along the beach northwards, due to the action of the sea. When the breakwater was erected, it acted as a stop to the flow of. shingle, which became banked up on its so.ithern face, while the shingle which had already passed the line ot breakwater still continued its motion gradually ; as it moved, laying bare, and deprived ot its natural protection or clo.hing of shingle, its denudation and destruction by the sea became rapid, as described m Mr Lowe's report. This action, if the building of the breakwater is proceeded with, will-go on; tho shingle will be moved northwards and no further supply following, the spits or beaches across the mouths of the lagoons will disappear, and the railway embankment across these lagoons will be laid open to the attacks of the sea. This action, will not be confined to the locality of Timaru. It will be felt in duo course of time (shorter or longer according to circnmsiance.) along the whole stretch of coast line to Lake Eilesmere, working changes the nature, but not the full extent, of which can readily be foreseen." Mr Blackett then proceeds to quote Mr Carruthers' report to the Timaru and Gladstone Board of Works in 1871. His words were :—"The shingle being thus stopped it would collect on tbe south side of the breakwater, until in the course of time it had pitched; out to the end of the latter, when the northerly motion would begin again. In the meantime the shingle to the north, beyond the protecting influence of''the- breakwaler would have been still moving northwards, and as no new shingle could come to supply the place of that which had'moved, the coast would soon be bare, and the sea would begin to cut it dsvn. The first effect of the above works wb>ild be the degradation of the coast to the.north. 'The detached shingle beach across Washdyke lagoon would next begin to disappear. . I strongly recommend the Board not to undertake the work, notwitharan ,V,n<r thg nywit hoiwfit a harbor at cou^^^^^^^^^^^^^^^^^^^H This be!__mm^^^^^^^^| round the end of the ing the so-called harbor in its passage, and eventually gain the north-east beach, where, after a while, the normal state of affairs would again be restored. The beach would be again clothed with its natural protection, and further damage would be arrested. This desirable result would be hastened if the breakwater were wholly.or partially removed or broken up. My recommendation, therefore, is this : To stop the building of the breakwater at once, add afterwards to remove or break it up so as to lessen its prejudical effects on the beach, the adjoining lands, and railway works to the north."