The Evening Star WEDNESDAY, MARCH 27, 1929. FLOOD PREVENTION.

Evening Star, Issue 20135, 27 March 1929, Page 8

The Evening Star WEDNESDAY, MARCH 27, 1929. FLOOD PREVENTION.

Rni’GHi.v the public cost of the drainage of Dunedin stands at about a million sterling. At the close of last financial year the debenture-holders of the Drainage Board's loans were owed over £900,000, and when the current year ends in a few days it will probably be found that most of the £90,000 balance of the last quarter of a million pounds loan authorised in 192.5 has been issued. When the board was inaugurated early this century, and the estimated cost of the propped works was announced, the ratepayers were so alarmed by the figure that it was speedily revised, and announced at under £200,000, excluding the cost of reticulation-—without which, oL course, the system would have been largely- ineffective. Without resort to some such subterfuge there appeared a grave danger of matters being left in their then most unsatisfactory position, of the new Drainage Board being stillborn, and its proposals scrapped. In view of tho present system it is instructive to recall how tiic Drainage Board came into being. Towards the dose of last century friction between the Otago Harbour Hoard and the Dunedin City Council over the discharge of sewage into the harbour came to a head. Tho Government appointed Air C. Napier Bell, a 'Wellington engineer, to arbitrate. His award, dated Alarch, 1899, was of such a nature that tho City Council became convinced of the necessity for the creation of a thoroughly effective system of drainage, not only for the city,.but lor the surrounding boroughs, at that time separate municipalities. The result was legislation defining a drainage area and providing for the establishment ot n drainage board. The first works undertaken were the Forhury road storm water channel and the main intercepting sewer, both having outlets in the ocean.

Tins change brought about far more harmonious gelations between the Harbour ami Drainage Boards, and later (since the council’s absorption of the Drainage Board) between the council and the Harbour Board. There have been minor differences of opinion, chiefly over the* liability for providing drainage for the areas continually added by the Harbour Board’s reclamation works. But assurance was given in public yesterday that the two bodies and their respective engineers arc coordinating, and doing idieir utmost in the matter of putting right Hood damage. Furthermore, both engineers are to report on the best means of flood prevention. Necessarily these must deal chiefly with the Leith, the principal flood agent. Here there enters the usually unsatisfactory situation of dual control. The position is all the more unsatisfactory because in the case of one of the parties control is disavowed. One of the first measures for Hood prevention must be cleaning the bed of the Leith from the almost incredible amount of detritus left by the* flood. Yesterday the deputy-mayor informed a deputation that '' the City Conned wjs not responsible as far as the cleaning of the bed of the Loith was concerned. It* was the responsibility of the, people on the banks of the river. The Drainage Board solicitors had made it clear that the woik must bo done by the residents ” At a public meeting tho previous evening it had been stated that legislation last year had vested control of the bed of the Leith in the City Council. That, unfortunately, is pure invention. There is reason to believe that in this matter Hie council’s hark is worse than its bite. The task of dealing with boulder banks of the nature and extent that now occupy parts of the Leith tied is plainly not one for individual residents. But is it not timo that this extraordinary legal position was ended? The longer it is allowed to persist the longer is the Hood danger likely to be temporised with, instead of being tackled In earnest. It should bo a matter of duty and not of charity on tho part of one public body to devise and construct some permanent work that will at least greatly minimise the Leith Hood menace. Necessarily it must involve heavy expense. Among the multitude of opinions expressed publicly and privately in the last week may bo noticed tho revival of a Leith diversion project. This dates back to about 1880, and was revived in these columns after the 1923 floods. Since the latter date, however, conditions have been entirely changed by the creation of Logan Park. The idea was to intercept the Leith just above the Dundas street bridge, and lead it by a tunnel through the hill into Lake Logan (as it then was). The length of tunnel

would perhaps be rather over a quarter of a mile, iu which distance the same fall would be given as iu the present route of about a mile. There seems to bo a consensus of opinio,i that tho Leith Canal’s cross-section is far too small in area, and that it should be enlarged or ■duplicated. As against.tho cost of a supplementary outlet by the suggested tunnel there would bo the heavy decrease of risk to the extensive low-lying locality from Dundas street southward, now regularly threatened by a swollen Leith.