SEWERAGE.

Evening Star, Issue 3125, 24 February 1873, Page 2

SEWERAGE.

To the Editor.

Sir —As in all schemes for draining this city, there seems to be a great want felt by not knowing bow to obtain sufficient fall to carry off all matter likely to collect in the harbor, in consequence of it being only au ann of the sea, and not having any large ffe-h water str am, which, when flooded, would tend to keep the harbor clean and free ; and also on account of the rise and fa'l of tide being so small that its effects is hardly felt, I beg to offer a suggestion which,‘to to my mind, would remove the difficulty. We all know that when water is confi ied and suddenly released it acquires an im* potus in proporti *u to the amount of pressure brought to bear upon it. To get this pres, sure, I propose to erect flood gates from island to island, across the harbor, near Port Chalmers. At high tide once in twenty* four hours—as near to midnight as possible, so as not to interrupt navigation—l would have the gates closed until one hour before low water, then remove them, when there would be sufficient pressure to cause a fifteen knot current. This, L believe, would completely empty the harbor above the gates, and take all collected matter with it. Another result would be, that the channel below the gates, all the way to the sea, would be deepened by thd force of water, which might be helped by the steam dredge, while the current was running. L have not seen anything of the kind, and should like to real the comments cf yourself or any of your readers upon the idea,— X am, &c., Progress. Dunedin, 22nd Feb., 1873.