Permanent opening - 120m southern pier/60m northern pier (Mr Bray's plan)

Year proposed

  1875

Status

  Not implemented

Location description

  Taumutu

Description of option

  A permanent opening with a 400 foot long pier run out at Taumutu from south spit was proposed. This structure would intercept gravels with its head inclined well to the north so as to protect the mouth from SW seas. It was proposed that gravels would be carried past the mouth in deep water and thrown on the northern 200 foot long pier/spit. To prevent this gravel being washed from the north spit into the mouth, and to strengthen the north spit, a short jetty would most likely need to be constructed to the north of the mouth, inclined towards the former so as to contract the mouth to 2 to 2.5 chains.

Opening, closing, and lake level control description

  Permanent opening.

Maximum discharge

 

Maintenance/Management description

  Dredging likely to be required. Later report by Langbein (1932) states "opinion large majority (of engineers) have is that the mouth would be silted up with shingle in a very short space of time".

Cost description

  1875: Jetties (9,900 pounds), scour protection for south spit in form of sheet piling or wharfing (4,500 pounds), provision for extension of jetties by a third of length (4,800 pounds) = 14,400 pounds

Fish passage benefit rating

  Low

Potential running impacts or benefits

  Scouring of the natural river waters and "tidal water flowing in at high water will keep a clear outfall for drainage and if the mouth is not too wide sufficient depth may be had for coasters and coasting steamers which may find a safe harbour here ..."