Design guides and engineering codes of practice are often used as a method of providing additional guidance and certainty for assessing subdivision applications.
1) Engineering requirements
Most councils have a set or code of engineering standards covering such matters as servicing and infrastructure standards, road widths, earthworks, New Zealand Standards, etc. Some district plans will include engineering standards as part of the plan, and others will have a code of practice that stands outside the district plan. (See reference to external documents for more information).
While having engineering standards as part of a district plan provides certainty this approach does have some disadvantages. These include:
- Engineering standards can increase the size and complexity of the plan.
- The prescribed standards can often address health and safety issues which do not achieve the purpose of the RMA in managing environmental effects.
- Engineering codes are not always the best way for providing for innovative planning approaches.
- Time delays associated with updating the engineering standards in the plan to reflect changes in practice.
- Engineering standards once in the plan can only be changed by variation or plan change. It is doubtful whether technical standards of this nature should be set through a public process.
Issues of asset transfer from a developer to a council may be best managed outside of the plan. This is to be contrasted to the fundamental health and safety requirements being met in subdivision design and the role of the district plan in setting out these expectations. The approach taken to engineering design can be influential in the design outcome of a subdivision.
It is important that careful consideration is given to how engineering standards will impact on the outcome, and it may be possible for effects to be managed in a way different to prescribed standards. To help manage this issue:
- A district plan should outline what the effect is that needs to be managed, leaving open some discretion in the way that effect can be addressed (this should be as part of a resource consent) - engineering codes could be used simply as a guide to "acceptable solutions".
- Permitted or controlled activity status could apply where provisions in a code of standards are met.
This will leave it open for the developer and the council to agree on an alternative standard, perhaps through a controlled or restricted discretionary activity process, which may better manage effects than the prescribed standards.
Changing technologies, for instance in the area of stormwater management are able to be more easily considered when the engineering code is not part of the plan. It is helpful for the district plan to contain criteria against which alternative standards can be assessed. It is also important to ensure that the engineering standards are appropriate and do not create outcomes that conflict with the land use objectives and policies. For example, there may be situations where it is appropriate to provide for a lesser width of road to achieve better urban design.
2) Codes and standards
Published New Zealand Standards that can be referred to within the district plan are:
- The New Zealand Handbook - Subdivision for People and the Environment (SNZ HB 44:2201) published by Standards New Zealand provides alternative environmental approaches and encourages creativity in the design process.
- New Zealand Standard NZS 4404:2010 land development and subdivision infrastructure encourages sustainable development and design that emphasises liveability and environmental quality. It incorporates up to date design principles such as low impact design solutions to stormwater management and urban design principles as well as covering requirements for earthworks, geotechnical needs, roads, and other infrastructure needs.
3) Design guides
Subdivision design guides provide assistance to applicants in interpreting assessment criteria. They are non-prescriptive and may form part of, or sit alongside, the district plan.
A design guide could include:
- Illustrations and guidance of recommended site and road layout and ways in which effects, for instance on landscape or character, can be avoided or mitigated.
- Illustrations and guidance of recommended planting, earthworks, infrastructure and maintaining ecological values.
- References to provisions in the district plan such as objectives, policies or rules relevant to a particular area.
4) Information requirements
In accordance with s75(2)(g), the district plan may state the information to be submitted with an application for a resource consent. Further information may be required under s92.
The district plan should clearly outline the extent to which engineering detail will be required at subdivision consent application stage. It may be appropriate for a district plan to require only that level of detail at consent application stage that is required to give confidence that the effects of subdivision can be adequately avoided, mitigated or remedied. This could be in the form of concept drawings that enable an assessment of effects to obtain the resource consent.