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Dams

 

What is a Dam

The Building Act 2004 defines a Dam as artificial barrier and its appurtenant structures that:

  1. Is constructed to hold back water or other fluid under constant pressure so as to form a reservoir.
  2. Is used for the storage, control, or diversion of water or other fluid.
  3. Retains 3 or more metres depth and holds 20,000 or more cubic meters volume, or water or other fluid.
A dam includes:
  1. a flood control dam
  2. a natural feature that has been significantly modified to function as a dam
  3. a canal.

A dam does not include a stop bank designed to control floodwaters. All dams that meet this criterion are required to obtain a building consent from the relevant regional council.

What is an Appurtenant Structure?

The pump house, power source, conduits, penstocks, spillways, sluice gates, intake tower, etc are all appurtenant structures.

What if my proposal does-not meet the definition of a dam?

If your structure holds more than 35,000 litres of water but does not meet the definition of a dam, it will still need a building consent. In this situation, a building consent is required to be issued by the territorial authority.

What is required for a Dam?

Two project information memoranda are also required. One is issued by the territorial authority and the other by the regional authority; this is because each authority holds different information in relation to properties.

Inspections are required and will be advised on a case-by-case basis. Most inspections will be undertaken by the design engineer at various hold-points in accordance with the design engineer’s recommendations.

What information do I need for Building Consent?

In addition to an application form, you will need to supply 3 copies of the following information:

  • Design report identifying the loading parameters, flood and freeboard, seismic loads, geotechnical issues, reservoir capacity and hazards considerations. Structural plans, calculations and a producer statement design review will also be required.
  • Site plan.
  • Aerial photographs.
  • Information on any specified systems.
  • Cross-sections showing the height and depth of the dam and the capacity or volume of the reservoir.
  • Long-section through the dam axis showing spillways, basin and drainage, etc.
  • Information on any appurtenant structures.