Options for opening/closing Te Waihora
Many options have been proposed to open/close Te Waihora. Summaries of over 27 options are presented here categorized into:
- Mechanical
- Structural general
- Structural - channels
- Structural - culverts/siphon/weirs
- Combined options
- Other options
Opening options are desired because if left in its natural state, the water level would rise to ~4m before naturally breaching the Kaitorete Barrier. The corresponding water surface area would be very large, causing widespread flooding in the Canterbury plains.
Some of challenges to opening/closing the Lake are:
- Tides, Swells, and Wave action
- Hydraulic Gradients between Lake and Sea
- High winds affecting lake water levels
- Unstable, poorly graded gravels and eroding coastline
Te Waihora is an extremely complex system with many stakeholders and interested parties.