Elevated Lock with Sluice gate

Year proposed

  1932

Status

  Not implemented

Location description

  Taumutu, Harts Creek

Description of option

  An elevated lock and sluice gate near the current opening site was proposed to reduce the amount of mechanical work required by the machinery, and to enable an opening to be created in a shorter time. Langbein proposed closing off the small arm of Lake Ellesmere at Taumutu - diverting Harts Creek into this part of the lake. This inflow could be supplemented by pumping water from the lake proper if required. This smaller lake would be managed by the control of sluice gates which would be opened into a channel leading into the pilot cut and out to the opening.

Opening, closing, and lake level control description

  Could significantly reduce machinery hours per opening and hence decrease costs. The final cut can be made using the water from the lock to open the lake in bad weather, and once open, help maintain an opening in less ideal circumstances.

Maximum discharge

  above 300 cumecs

Maintenance/Management description

  Seepage of water through shingle bank may make it impossible to raise water in lock sufficiently.

Cost description

  A large diversion such as this would be uneconomic.

Fish passage benefit rating

  Low

Potential running impacts or benefits

  Environmentally & culturally incompatible.