Practice Guideline 1: Interpreting ‘Natural Ground Level’
The new ‘Practice Guideline 1 – Natural Ground Level’ (Practice Guideline) seeks to provide a consistent guide for interpreting the meaning of ‘natural ground level’ as it is used in the Planning & Design Code (Code).
This is the first practice guideline to be published pursuant to section 43 of the Planning, Development and Infrastructure Act 2016 (Act). It is therefore worth exploring the role of practice guidelines under the Act, and how this Practice Guideline clarifies or modifies the interpretation of the Code.
Background – Practice Guidelines generally
Section 43 of the Act enables the State Planning Commission to make practice guidelines that may assist in the interpretation, use, or application of the Planning Rules (including the Code) or Building Rules.
Pursuant to section 43(2), practice guidelines may:
- make declarations as to the effect of provisions in the Planning or Building Rules; and
- specify variations that will constitute minor variations in deemed-to-satisfy development.
This first Practice Guideline is in the nature of a practice guideline under section 43(2)(a) of the Act to assist in the interpretation of provisions under the Code.
If a relevant authority acts in accordance with this Practice Guideline, it will be taken to be acting consistently with the relevant provision(s) of the Code (see section 43(3) of the Act).
Effect of the Practice Guideline – interpreting ‘natural ground level’
Despite the term ‘natural ground level’ being variously used in the Code – particularly in relation to maximum wall and post heights – it is not defined within the Act or Code, nor did it appear within the former Development Act 1993. Case law has been relied upon to interpret the meaning of ‘natural ground level’ where variously used in the Code, particularly in instances where the ‘natural’ level cannot be easily identified.
The intent of the Practice Guideline is a codification of the principles established by the existing case law in order to assist in interpreting the Code.
The common meaning of ‘natural ground level’ is taken to be the ‘natural surface level of the ground’. The term ‘natural’ is further understood to be the level which has been formed or created by nature, with no artificial involvement. As such, ‘natural ground level’ refers to a pre-modified ground level, before any alteration by cutting, benching, or filling.
This level must be ascertainable (i.e. by observing obvious groundworks or historical cross-sections). However, in practice what is truly ‘natural’ often is not readily discernible, or may be impossible to determine, and the Courts have therefore imbued the interpretation of ‘natural ground level’ with considerable flexibility (see, for instance, Paior v The Corporation of The City of Marion [2017] SAERDC 4; Evans v City of Victor Harbor [2010] SAERDC 64; and Mila Enterprises Pty Ltd v City of Holdfast Bay [2005] SAERDC 34).
As such, if the ‘natural’ ground level is not easily ascertained, the Courts have held that the existing ground level may, in some circumstances, be taken as the point of measurement for the ‘natural ground level’ (see Mila Enterprises Pty Ltd v City of Holdfast Bay [2005] SAERDC 34 at [29] and [30]). This may occur if there is no obvious cut, bench, or fill to the land to ascertain the original level, or if the modifications to the ground have occurred over time such that there is minimal data to identify the ‘natural ground level’.
Clause 9 of the Practice Guideline identifies several instances where this flexible approach should be applied, and further, where it should not be applied. These are provided as a set of four contextual examples of varying difficulty, being:
- dwelling proposals on unmodified sites;
- dwelling proposals on modified sites (excavation and filling);
- dwelling proposals on longstanding sites where the ‘natural’ ground level is ambiguous or unknown; and
- dwelling proposals in instances where the ‘natural’ ground level is known, but not relevant (e.g. greenfield developments where site modifications have already occurred).
Interpreting ‘finished ground level’
The Practice Guideline describes a general understanding of the terms ‘finished ground level’ or ‘finished site level’ (the terms being interchangeable).
Pursuant to clause 7 of the Practice Guideline, the ‘finished ground level’ of a site is taken to be the surface level after all modifications have been completed. As such, it represents the future finished surface level of the ground once all works have been performed to artificially modify the ground level.
Earthworks or retaining walls are taken to be included within the height of the ‘finished ground level’.
Applying the Practice Guideline
Interpreting the meaning of ‘natural ground level’ in relation to particular development applications can be fraught with difficulty. This first Practice Guideline outlines how the term ‘natural ground level’ is to be understood and applied in various contexts, and codifies instances where the interpretation is less straightforward. It should be used as an interpretive aid where the determination of ‘natural ground level’ is necessary.
As the first Practice Guideline to be published, councils and relevant authorities should be alert to any future development of these instruments as interpretative aids to other concepts in the Code.
For more specific information on any of the material contained in this article please contact Nicholas Munday on +61 8 8217 1381 or nmunday@normans.com.au.
