Dams - Building Consents

Dams - Building Consents and Safety Requirements

The Building Act 2004 has made Regional Councils responsible for all activities in regards to dams. These requirements are additional to any requirements for dams under the Resource Management Act 1991 which are also administered by Regional Councils.

If you own a dam or canal or are planning to construct, modify or remove a dam, canal or structure associated with a dam then you will be affected by at least one, if not both of the above Acts.

The Building Act requires that works involving a Large Dam will need a Building Consent.

If your dam does not fit within the definition of a Large Dam it still must be constructed in accordance with the Building Code and may be subject to the Dam Safety Scheme.

To improve efficiency Horizons Regional Council (Horizons) along with all other North Island Regional Councils has transferred its powers to process all Dam Building Consent applications to Waikato Regional Council.

 Definition of a Dam

Section 7 of the Building Act defines a dam as:

(a) an artificial barrier, and its appurtenant structures, that -

(i) is constructed to hold back water or other fluid under constant pressure so as to form a reservoir; and

(ii) is used for the storage, control, or diversion of water or other fluid; and

(b) includes -

(i) a flood control dam; and

(ii) a natural feature that has been significantly modified to function as a dam; and

(iii) a canal; but

(c) does not include a stopbank designed to control flood waters

Appurtenant Structure means a structure that is integral to the safe functioning of the dam as a structure for retaining water or other fluid.

 Large Dam

Section 7 of the Building Amendment Act 2013 defines a Large Dam as a dam that has a height of 4 or more metres and holds 20,000 or more cubic metres volume, of water or other fluid.

New Section 133B sets out the method for measuring the height of a dam as follows:

The height of a dam is the vertical distance from the crest of the dam and must be measured,-

a)     In the case of a dam across a stream, from the natural bed of a stream at the lowest downstream outside limit of the dam; and

b)     In the case of a dam not across a stream, from the lowest elevation at the outside limit of the dam; and

c)     In the case of a canal, from the invert of the canal.

The Building Amendment Act 2013 defines the crest of the dam as “the uppermost surface of a dam, not taking into account any camber allowed for settlement, or any curbs, parapets, guard rails, or other structures that are not part of the water-retaining structure; and for the avoidance of doubt, any freeboard is part of the water-retaining structure for the purposes of this definition.”

 Application Forms, Brochures and Checklists

A series of brochures about the requirements for building and maintaining dams and the relevant application forms are available to download directly from Waikato Regional Council.

 Dams Safety Scheme

As part of the Dam Safety Scheme Horizons Regional Council and all other Regional Councils are required to maintain a register of all classifiable and referable dams within their respective regions.

The register enables Councils to record the potential impact classification of classifiable and referable dams as required under the Dam Safety Scheme and enables Councils to maintain contact with dam owners to provide them with information on matters of importance, such as new regulations and guidance material on dam safety.

Please contact freephone 0508 800 800 or email for further information.

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