Managing Earthworks under the Resource Management Act
Abstract
Earthworks can generate a variety of adverse effects on land, air and water bodies, with the significance of these effects varying depending on their scale and the environment within which they occur.
Regional councils and territorial authorities are jointly responsible for managing the effects of earthworks under the Resource Management Act (RMA) and this arrangement can result in jurisdictional confusion.
To help practitioners understand the effects of earthworks and to better equip them to address the challenge of managing these effects, this guidance note aims to:
- outline the issues and effects arising from earthworks
- clarify the functions of regional councils and territorial local authorities in managing earthworks, including managing the potential overlap of jurisdictional responsibilities
- identify methods to manage the effects of earthworks
- provide best practice examples of managing the effects of earthworks, including reference to existing plan provisions, definitions and non-regulatory methods
- direct practitioners to further information sources and examples of techniques to manage the effects of earthworks.
Guidance Note
Earthworks: Issues and Effects
Functions of Regional and District Councils in Managing Effects of Earthworks
Definition of 'Earthworks ' in Regional and District Plans
Methods for Managing the Effects of Earthworks in RMA Plans
Introduction
Earthworks are undertaken to create the areas of level land used for living, business and recreation, and the required gradients for paths and roads that enable people to get from place to place. They are integral to the construction of foundations and of buildings. For all of these reasons, and more, earthworks are part of most development projects undertaken at the small and large scale including by individuals.
Managing earthworks is a complex issue. This is due in part to the wide range of activities covered by the term 'earthworks ', as well as the wide range of effects generated. It is also further complicated by:
- the overlap in jurisdictional responsibility between regional and city/district councils under sections 30 and 31 of the RMA (refer functions section).
- the role of the Building Act through the issue of building consents in controlling site works (including sedimentation) and stability of earthworks and structures
- the considerable technical/engineering component in determining the effects of proposed earthwork activities and appropriate management methods.
Earthworks: Issues and Effects
Earthworks involve revealing, disturbing, removing or depositing soil / earth which results in the creation of exposed surfaces. These surfaces are created by activities such as land contouring for urban development and roading, quarrying, filling operations (including cleanfills), clearing vegetation, forestry, agriculture and horticulture.
If not managed well, earthworks have the potential to cause significant adverse effects on the environment such as:
- increased loadings of sediment in surface water bodies resulting in reduced water quality and potential damage to aquatic ecosystems
- effects on local amenity, such as visual changes and construction effects, including traffic movements, noise and dust
- effects on natural hazards, such as induced or accelerated erosion or slope instability, and altered drainage patterns and flood risk
- loss or damage to natural landforms, vegetation and habitats
- loss or damage to natural features, cultural and archaeological sites
- discharge or disposal of material from contaminated sites.
Functions of regional and district councils in managing effects of earthworks
Resource Management Act 1991
Regional council responsibilities
Section 30 of the RMA sets out the statutory responsibilities of regional councils. These include controlling the use of land for soil conservation purposes, maintenance and enhancement of water quality and ecosystems, and controlling discharges of contaminants.
Definition of Contaminant
Under Section 2 of the RMA "contaminant" is defined as
"includes any substance (including gases [odourous compounds,] liquids, solids, and micro-organisms) or energy (excluding noise) or heat, that either by itself or in combination with the same, similar or other substances, energy or heat -
(a) When discharged into water, changes or it likely to change the physical, chemical, or biological condition of water; […]"
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Accelerated loads of sediment have the ability to change the physical, chemical, or biological condition of water and, therefore, fall within the definition of 'contaminant ' under the RMA.
The two primary approaches available to regional councils to manage the effects of earthworks are:
- control of the use of land
- control of the discharge of contaminants.
Territorial local authority responsibilities
Section 31(1) of the RMA sets out the statutory responsibilities for territorial local authorities. Controlling the use, development or subdivision of land covers a wide range of issues, including vegetation cover, amenity values, infrastructure, roading, and natural hazards. As earthworks can have adverse effects on all these matters, territorial local authorities will need to evaluate how these matters are to be appropriately managed.
Section 106 of the RMA amongst other things requires territorial authorities to consider land stability issues (erosion, falling debris, subsidence, slippage and inundation) and access when determining subdivision applications.
Managing potential overlap between regional and city/district councils
Regional and city/district councils are responsible for controlling different aspects of earthwork activities. Consequently, councils need to direct specific attention towards the mechanisms they use to manage areas of potential overlap and to ensure that unnecessary duplication of consent processes is avoided.
Typically regional councils focus on the effects of earthworks on water quality and ecosystems, and city/district councils tend to focus on land-use effects such as amenity. However, blurring of these functions does occur and can result in duplication, particularly in relation to consents.
Auckland Regional Council Water Quality Research
Until recently the effects of land generated sediment on the habitat values of waterbodies was not well understood. Over the last 10 years a considerable amount of research has been undertaken in the Auckland region on the effects of accelerated loads of sediment entering water bodies (refer "ARC Technical Publication 264 - Effects of sedimentation on macrofaunal communities: a synthesis of research studies for ARC).
However, it is important to recognise that Auckland soils, particularly clay soils, have particular characteristics, including the ability to remain in suspension for extended periods of time. This is due to their very fine texture and their ability to be readily conveyed to lower receiving environments vulnerable to elevated sediment loading and sediment deposition. Consequently, this research may not be readily applicable in all parts of New Zealand as the effects of sediment discharge on water quality will depend on the type of soil and land use of the contributing catchment, together with the characteristics of the receiving environment.
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To address this situation, more effective reliance on regional policy statements could be made by regional councils to help clarify respective functional responsibilities. In particular, policies and methods should be included that clearly identify how the effects of earthworks activities are to be managed across the region and by whom. This is particularly relevant now that district plans are required to give effect to regional policy statements under s75(3) of the RMA.
Particular steps that local authority practitioners should consider concerning overlapping functional responsibilities include:
- clear allocation of responsibility: clear identification in regional policy statements and/or regional and district plans of relevant issues and effects concerning earthworks, including the particular issues and effects that each council will assume responsibility for. Consideration should also be given to applying a single consent process to minor earthwork activities
- local authority collaboration - policy development: Active collaboration between regional and city/district councils in preparing and developing plan provisions to manage the effects of earthworks, particularly prior to notification.
- Referencing: Inclusion of references in district and regional plans to respective earthworks management regimes
- local authority liaison - earthwork management and monitoring: Regular liaison group meetings between regional and city/district council staff involved in managing and monitoring earthworks
- joint hearings: convening joint hearings where regional and city/district council consents are required (s102 of the RMA).
Definition of 'earthworks ' in regional and district plans
The term 'earthworks ' is used in a wide range of situations. It is not exclusively referred to in plans as other related terms such as 'soil disturbance ', 'land modification ' and 'excavations ' are also commonly used.
As a variety of definitions apply to these terms a range of differing interpretations of 'earthworks ' can result. Some definitions also include a range of exclusions, such as cleanfilling, quarrying, normal household gardening practices, and horticultural and pastoral farming activities.
The Environment Court has been asked to determine the meaning of 'earthworks ' on a number of occasions (refer Case Law). Based on these determinations, a definition of earthworks can include details on what physical activities constitute earthworks, such as:
- blading
- contouring
- ripping
- moving
- removing
- placing
- replacing
- excavation
- cutting
- filling.
Any list which forms part of a definition should describe the common physical works and methods of earthwork activities. The definition should not include minimum/maximum thresholds (eg, excavations in excess of 1.0m in depth), as these should form part of the associated rules (performance standards and terms). Two examples of a working definition for earthworks are:
- the Auckland Regional Plan: Sediment Control - the definition describes the general activity and provides clear examples as follows:
'the disturbance of land surfaces by blading, contouring, ripping, moving, removing, placing or replacing soil or earth, or by excavation, or by cutting or filling operations'.
- the Proposed Rodney District Plan - the definition describes the general activity and also highlights activities which are specifically excluded from the general definition:
'Earthworks means modification of land surfaces by blading, contouring, ripping, moving, removing, placing or replacing soil or earth, or by excavation, or by cutting or filling operations, including the importation of fill (see definition of clean fill), provided that within the Special 16 (Omaha South Development) Zone, earthworks exclude the cultivation of land and the digging of holes for the erection of posts or the planting of trees, landscaped area and gardens.'
Methods for managing the effects of earthworks in RMA plans
Research and background investigations
The following should be used as a guide when preparing plan provisions to manage earthworks:
- environmental outcomes (optional): Identify the measurable outcomes which you are aiming to achieve; this will help define the objectives, policies and methods required to achieve these outcomes.
- Building Act: overlap with the role of the Building Act should be minimised when considering land stability issues. The Building Act controls stability issues (including slippage and inundation) in respect of new buildings and structures. Any structure 1.5 metres in height or more, that supports any load including soil (such as a retaining wall) requires building consent
- consultation: should be based on commissioned technical reports and focus on parties directly associated with earthwork activities, such as contractors, engineers, forestry companies and developers. Where appropriate, it may be beneficial to involve the Earthquakes Commission as well as professional organisations like IPENZ and NZIS (refer Consultation Guidance Note for more information on consultation).
Definitions: To avoid confusion and misunderstanding include clear definitions of terms in plans (See Definitions section above).
Technical expertise
It is important to obtain technical engineering advice to determine both the effects of earthwork activities and appropriate methods to manage their effects. This might include geotechnical, structural engineering, landscape and ecological advice.
Rules and methods to manage the effects of earthworks for resource consent or policy/plan purposes should consider issues such as soil type / characteristics, topography, faults and sensitivity of the receiving waters to any sediment run-off. Technical expertise should be used to assist in understanding different interactions and natural processes.
Experts with an understanding of earthwork processes, operations and environmental impacts will help identify methods to manage the effects of earthworks in a manner that is effective, efficient and workable.
Translating the science around the effects of earthworks into specific policy guidance can be challenging and development of a process to reconcile conflicting advice should be considered.
Evaluation and assessment
An assessment of the region/district and the risks posed by earthworks is a first step in any evaluation. The costs and benefits of the methods selected to manage earthwork activities will also need to be carefully considered (refer to the Examples of costs and benefits for earthworks and the Section 32 Guidance Note).
A number of the effects from earthworks are interrelated. Methods should be evaluated and adapted to reflect the local environmental conditions (ie, soil characteristics, topography, climate, and sensitivity of receiving waters to sediment run-off). Successful methods used in other regions/districts should be evaluated based on local environmental conditions before being applied in other areas.
Avoiding earthworks: it may be appropriate to avoid subdivision and development in certain locations due to the sensitivity of the receiving environment (refer to Okura Catchment in North Shore City, Relevant Case Law) or to require provision of specific mitigation for subdivision applications in order to overcome s106 land stability concerns (eg, Henry v Kapiti Coast DC W024/03).
Objectives and policies in regional/district plans
(Also refer Plan Framework Guidance Note)
Objectives establish the overall aim concerning resource management issues identified. The Manukau Operative District Plan (PDF 1MB) has overarching objectives that relate to earthworks. The Waikato Regional Plan includes region-wide objectives as well as area-specific examples.
Policies provide guidance as to how earthworks will be managed in the area. The policies need to specifically identify which particular effects are being managed, and who is responsible for their management. The policy should direct the broad actions to be taken to achieve the objectives, and will assist in determining any resource consent applications (refer Manukau Operative District Plan - Rural 4 Zone (Policy 12.8.4) (PDF1.9MB) and North Shore City District Plan Proposed Variation 66 and Plan Change 6 - Long Bay Structure Plan (Section 9A.3.2).
Regulatory methods
Rules in regional/district plans
(Also refer Rule Writing Guidance Note)
Rules are the primary method used by councils to manage the effects of earthworks. Regional councils generally have a "Sediment Control" or "Land Disturbance" regional plan to regulate earthworks and sediment discharges (refer ARC Best Practice Example). The ARC Sediment Control Plan is an example of an effects-based approach to sediment control, including rules relating to sensitive environments (in riparian areas), soil types and topography. Rules can be developed where they apply to a whole region/city/district or on a catchment basis, and can establish varying activity status and thresholds.
Region/city/district wide versus catchment wide
There are two broad regulatory approaches used to manage earthworks:
- general rules: apply to all earthwork activities throughout the whole region/city/district. This approach is commonly used in district plans
- catchment or defined area rules: apply on a catchment or area level. The catchment or area approach is normally based on identifying the underlying environmental or heritage-related characteristics of these areas and managing the potential impact that earthworks may have on them (ie, stricter thresholds in outstanding landscapes, areas where a known or probable concentration of archaeological or wahi tapu sites exists, sensitive coastal receiving environments, steeply sloping land, and areas adjacent to waterbodies). Refer to the Wellington Regional Soil Plan.
In some situations, both approaches might be used with general rules applying to the region/city/district complemented with targeted provisions applying to more sensitive areas.
Activity status and thresholds
Activity status and associated thresholds are a common method used by regional and territorial authorities to manage earthworks. Thresholds can be based on such factors as the area, volume, height/depth of a cut/fill or slope of an earthwork (refer Regional and District Plan Best Practice Examples).
- Territorial authority rules typically focus on effects from earthworks on amenity values (e.g. dust, sediment, visual qualities and hazards) and on land stability issues associated with both subdivision and land use. Minor earthworks are generally permitted provided they meet performance standards relating to volume, area, gradient and heights of cut/fill. If these minimum standards are exceeded, a resource consent is generally required (for example refer Rule 4A.1E – Maintenance and Condition of Land and Buildings of the Auckland City District Plan – Isthmus Section (272KB). Also refer to Wellington City Plan Change 70) for examples of minimum standards and resource consent provisions. Note: these examples relate to an urban environment and may not suit a rural area.
- Volume versus area versus cut depth/fill height: Historically, earthworks ' standards have been based on volume as there is a direct correlation with effects such as traffic movements and construction noise. In addition, the height and / or legnth of cut/fill has been commonly used to manage effects on natural hazards and the landscape, with area controls used for sediment run-off management. Regardless of the choice of control, it is important that the standard specifically relates to the effects being managed.
Resource consent applications
Resource consent applications should include erosion and sediment control plans when associated earthworks are likely to cause significant adverse effects. This will ensure there is sufficient information available to assess the effects of the proposal, and the ability to avoid, remedy or mitigate these effects.
- Sediment control methods are those measures that capture sediment after it has been entrained in run-off. These include silt fences, decanting earth bunds and sediment retention ponds (refer Auckland Regional Council, Technical Publication 90). There are also chemical sediment control measures available, such as flocculation. Flocculation dosing needs to be managed in order to maximise its effectiveness and to minimise (unused) chemical flocculants entering watercourses. Note research on the effects of flocculants of marine ecology has been undertaken by ARC (‘TP 226 Overview of the Effects of Residual Flocculants on Aquatic Receiving Environments’ and ‘TP227 The Use of Flocculants and Coagulants to Aid the Settlement of Suspended Sediment in Earthworks Run-off : Trials, Methodology and Design [draft]’).
Resource consent conditions
Resource consent conditions are the primary means by which the effects of earthwork activities are controlled and managed. Conditions can cover:
- review conditions relating to earthworks, and erosion and sediment control
Refer to Conditions of Resource Consents for examples of generic conditions.
In imposing conditions on resource consents, it is important to recognise that no sediment control techniques are 100 percent effective. These techniques minimise, but do not avoid, the sediment load discharged to the receiving environment (refer to an example of sediment catchment yield under different sediment control scenarios relating to the northern motorway extension of State Highway 1 (ALPURT B2)).
To ensure compliance, a combination of active monitoring of consent conditions and consent holder self-monitoring is required. In addition, integrated monitoring between regional and territorial local authorities can help manage the effects of earthworks.
Bylaws
Under ss145 and 146 of the LGA 2002, territorial authorities can make bylaws for the purposes of protecting the public from nuisance, for public health and safety and to protect infrastructure. Consequently, bylaws can be prepared to control and manage the effects of earthworks and the discharge of sediment for these purposes.
Bylaws provide territorial authorities with a mechanism to control any effects of earthworks which are not related to "effects on the environment" (eg, the potentially damaging effects of earthworks and associated sediment run-off on council stormwater drainage, wastewater and water supply infrastructure). The management of effects on local amenity including noise, traffic movements, and soil and sediment run-off deposited as nuisance can be controlled by both bylaws and the RMA.
Codes of practice/standards
Codes of practice/standards have been developed at both national and local levels. Some codes are directly referenced in plans, while others are administered outside of RMA processes (refer Guidance Note on Writing provisions for regional and district plans). Prior to adopting any nationally based standards, local authorities should assess their suitability relative to their own individual circumstances.
- NZS 4404: 2010 `Land Development and Subdivision Infrastructure’This standard includes requirements for earthworks and geotechnical needs and supersedes the eairler version NZS 4404:2004.
- A large number of city/district councils have also developed their own codes of practice for land development or engineering. These codes commonly have a chapter that relates to the management of earthworks (eg, Tasman District Council Code of Practice, PDF 28KB).
Non-regulatory methods
Guidelines/ practice notes
Erosion and sediment control guidelines are a common method used by regional councils to outline accepted/recommended principles and practices. For example, the ARC Erosion and Sediment Control Guidelines (TP No. 90) are used as a 'good practice ' document by many councils around the country.
Councils also place emphasis on minimum earthworks strategies, through guidelines such as ARC Low Impact Design Manual for the Auckland Region (TP No. 124).
Subdivision/development guidelines produced by district/city councils often incorporate design principles and practices relating to roading and built development and advise how these should influence earthworks (eg SNZ HB 44:2001 "Subdivision for People and the Environment"). Most guidelines encourage developers to limit earthworks in the first instance, but where they are necessary the guidelines provide practical advice on methods to manage their effects.
Education
Education programmes can be developed to advise landowners, developers, engineers, planners and surveyors about managing earthworks, including erosion and sediment control measures. Depending on the target audience, such programmes can be implemented through seminars, on-site meetings, field demonstrations, information booklets and guidelines. Examples of education programmes include two courses which the Auckland Regional Council (ARC) has developed - one involved in implementing erosion and sediment control plans (aimed at contractors) and another for practitioners involved in plan preparation (aimed at consultants). In addition, the ARC holds an annual erosion and sediment control field day.
Material can be prepared to inform landowners, developers, engineers, planners, surveyors and builders about managing earthworks, including erosion and sediment control measures (eg, refer Environment Waikato Erosion and Sediment Control: Guidelines for Soil Disturbing Activities). This could include information about the techniques available and the different environments and circumstances where they are best suited. Aside from making this material available from council offices it can also be distributed at field days and training seminars, through contractors ' associations and direct mail-outs to interested parties.
Integrated management techniques
Greater use of an integrated suite of management techniques has the potential to improve the administration and enforcement of regulatory methods. For example, land-use provisions in district plans can give effect to objectives and policies contained in regional plans and the management of small-scale earthworks in district plans may achieve regional council outcomes for water quality. However, achievement of effective integrated management also depends on such factors as educated contractors, good engineering standards and competent monitoring.
A further option is the transfer of powers between regional and district councils under s33 of the RMA. A clear mandate would need to be established for the basis of this transfer and how it is to be implemented.
Other legislative requirements
Other legislation also indirectly manages activities associated with earthworks.
- Historic Places Act 1993: Earthworks can result in the disturbance or destruction of archaeological or waahi tapu sites. Section 10 of the Historic Places Act requires an authorisation to be obtained from the Historic Places Trust before any known or probable archaeological site can be destroyed, damaged or modified (refer to Heritage Management Guidelines for Resource Management Practitioners). Earthworks ' consents can include an advice note to this effect. It may also be appropriate to ensure the discretion specified in the relevant rules of the district or regional plan allows these matters to be directly dealt with through the consent process, including the imposition of associated conditions.
Best practice examples
Regional plans
Two approaches are available to manage the effects of earthworks in regional plans: controlling land-use activity and controlling discharge of sediment. Some regional councils use a combination of both these approaches. The choice of approach will depend on regional characteristics.
Controlling land-use activities of earthworks
This approach relies on s9 of the RMA to control earthwork activities. Where land-use activities are regulated by a plan, the discharge of associated sediment can be permitted under s15 of the RMA provided the land-use activity is either permitted or granted consent under s9 of the RMA.
Regional councils that have adopted this approach include:
Controlling discharge of sediment from earthworks
This approach relies on s15 of the RMA to control the discharge of sediment from earthwork activities by developing policies and methods based on water quality standards. In determining standards for permitted activities, regard is had to the provisions in s70 of the RMA.
Regional councils that have adopted this approach include:
- Proposed Waikato Regional Plan (Rule 4.2.21) - concentrations of suspended solids
- Wairau and Awatere Resource Management Plan – rule 27.1.10.1.3 uses the black disc test of visual clarity.
Permitted activities
The range of permitted activity thresholds specified in regional plans is quite broad and can cover:
- discharge standards such as visual clarity.
Further controls may be used in circumstances where earthworks have the potential to cause significant adverse effects.
Additional Regional Plan Regulatory Methods
- Restrictions on the time of year/ season, in which earthwork activities can occur;
- Limits on concentrations of sediment in site run-off;
- Avoidance of earthworks in overland flow paths (flooding);
- Avoidance of earthworks in areas prone to instability and erosion;
- Avoidance of areas in close proximity to water courses, wetlands, lakes and the coastal marine area;
- Requirement for re-vegetation, reinstatement and stabilisation of the site;
- Implementation of erosion and sediment control measures to minimise sediment entering receiving waterbodies in a catchment. Reference is often made to guidelines developed by regional councils.
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District plans
Permitted activities
District plan rules can rely on a range of factors to determine thresholds for permitted activities. These can include a combination or all of the following:
- maximum volume (m3)
- maximum area (m2)
- minimum distance to perennial watercourses, lakes and wetlands (metres)
- minimum distance to Mean High Waters Springs (metres)
- average slope
- maximum slope (see for example Wellington City Council’s District Plan (Plan Change 70) for an example of how to handle slope within a site where gradients vary)
- minimum distance from a site boundary
- dust effects (where, for example, consent is not required if no off-site effects occur)
- maximum depth of cut (normally altered ground level measured vertically (metres)).
Any thresholds specified in plans should be based on the effects of the earthworks' activities. Technical/engineering advice should be sought in determining the threshold level for permitted activities. Further controls can also be specified where there is potential for significant adverse effects.
Additional District Plan Regulatory Methods
- Avoidance of earthworks in overland flow paths (flooding);
- Avoidance of earthworks in areas prone to instability and erosion;
- Avoidance of areas in close proximity to water courses, wetlands, lakes and the coastal marine area;
- Thresholds limiting excavations and unretained filling;
- Avoidance of material deposited on public roads and accessways;
- Requirement for re-vegetation and stabilisation of the site;
- Dust control measures to avoid nuisance effects beyond the boundary of the site;
- Protocols for earthworks where archaeological features are exposed or found; and
- Implementation of erosion and sediment control measures to minimise sediment entering receiving waterbodies in a catchment. Reference is often made to guidelines developed by city/district councils and / or regional councils
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Provisions in district plans for earthworks in sensitive receiving environments
Some plans include standards and terms for earthwork activities. These apply at the subdivision and development stage when earthworks and the associated sediment discharge can significantly affect the receiving environment. Examples include:
Guidelines
Guidelines are useful tools to help applicants comply with district plan requirements.
Examples of guidelines prepared by city/district councils include:
Other references
Other useful references to consider in the development of district plan provisions for earthworks include:
Conditions on resource consents
Use of management plans
Management plans (which commonly include "erosion and sediment control plans") are often required by councils under s108(3) RMA to manage the effects of earthworks. The purpose of a management plan is to provide information about the way in which the consent holder intends to comply with the more specific controls imposed by consent conditions (refer Relevant Case Law).
Some regional councils are now requiring erosion and sediment control plans to be provided as part of a consent application. Not only do these plans assist with assessing the effects of a proposal they can also help inform the development of appropriate conditions of consent (Refer Generic Example of Sediment Control Plan).
Effects on archaeological sites and sites of significance to Māori
When assessing the effects of earthworks on cultural heritage features, archaeological sites and sites of significance to Māori it is important to consider what, if any, conditions should be applied.
Areas for consideration include, for example, requiring sites or features not affected by earthworks to be fenced or marked off or requiring an Accidental Discovery Protocol to be prepared in the event that a site is unintentionally uncovered. Refer Historic Heritage Guidance Note , Heritage Management Guidelines for Resource Management Practitioners and Example Archaeological Site Resource Consent Conditions for further details.
Effects of dust
Dust can create a nuisance by reducing visibility and is an effect on amenity values that can be considered by city and district councils. Refer Example of Dust Management Resource Consent Condition.
RMA provisions
Section 2 - Interpretation includes definition of 'contaminant', 'discharge', 'discharge permit' and 'land-use consent'
Sections 5, 6, 7 and 8 Purpose and Principles
Section 9 - Restrictions on the use of land
Section 11 - Restrictions on the subdivision of land
Section 13 - Restrictions on the use of Beds of Lakes and Rivers
Section 15 - Discharge of contaminants into environment
Section 17 - Duty to avoid, remedy or mitigate adverse effects
Section 30 - Functions of regional councils under this Act
Section 31 - Functions of territorial authorities under this Act
Section 65 - Preparation and change of other regional plans
Section 68 - Regional rules
Section 69 - Rules relating to water quality
Section 70 - Rules about discharges (provides direction on minimum receiving water quality standards)
Section 73 - Preparation and change of district plans
Section 76 - District rules
Section 104 - Consideration of applications
Section 105 - Matters relevant to certain applications
Section 106 - Consent authority may refuse subdivision consent in certain circumstances including where land is likely to be subject to erosion, subsidence and slippage
Section 107 - Restriction of grant of certain discharge permits (unless minimum receiving water quality standards are met)
Section 108 - Conditions of resource consent
Section 108A - Bonds
Relevant case law
A volume of case law is available on individual resource consent applications to undertake earthworks as part of comprehensive site developments. Much less case law is available on policy and plan provisions for earthworks management.
North Shore City Council v Auckland Regional Council [1997] NZRMA59 / Green and McCahill Holdings Limited v Auckland Regional Council [1997] NZRMA519 / Keep Okura Green Society and Okura Ratepayers and Residents Association Inc and Okura Land Group and Auckland Regional Council v North Shore City Council [2003] NZRMA A095. These cases concern the risks of ecological damage arising from sediment run-off events from earthworks and the extent to which subdivision and associated development should be provided for in the Okura catchment, including limiting development to avoid adverse effects. The Court accepted the findings of modelling predictions and research by NIWA. This assessed the risks of ecologically damaging sediment events on the Okura estuary resulting from earthworks associated with rural intensification.
Landco Mt Wellington Limited v Auckland City Council (Decision A010/2005). The definition of earthworks in the Auckland City District Plan: Isthmus Section was examined in this case. An examination was made of the type of works related to quarrying and earthworks. The Court found a proposal to excavate rock and gravel from a disused quarry at Mt Wellington, Auckland City was declared to be "earthworks" not quarrying. The term earthworks was considered a broad term which included drilling and blasting of scoria and basalt for development purposes.
Wood v West Coast RC C127/99 [2000] NZRMA 193 4 NZED 734. The Court found that a management plan can be required as a condition of consent but its purpose should be to provide information about the way in which the consent holder intends to comply with more specific controls set out in other conditions of consent. Furthermore, as technology may change, the consent holder should have the ability to change the management plan without having to change the conditions of the consent.
Ravensdown Growing Media v Southland RC C194/00, 6 NZED 95. This case concerns review conditions that can be imposed when using a standards/management plan approach.
Related guidance notes
- Air quality
- Historic heritage
- Landscapes
- Subdivision
- Surface water quality
- Plan development
- Resource consents
- Development of the policy framework
- Writing provisions for regional and district plans
Relevant publications
Technical guidelines
Technical Publication No.69: Environmental Impacts of Accelerated Erosion and Sedimentation
Published by Auckland Regional Council - 1996
This publication outlines the physical effects of accelerated erosion and sediment on the environment and includes information from a wide variety of sources.
Technical Publication No.90: Erosion and Sediment Control Guidelines for Land Disturbing Activities in the Auckland Region
Published by Auckland Regional Council - 2008
These guidelines provide a comprehensive overview of the principles of erosion and sediment control and the adverse effects associated with land disturbing activities. Practical management guidance is offered on erosion control, sediment control, works within a watercourse, quarries and vegetation removal.
Technical Publication No.124: Low Impact Design Manual for the Auckland Region
Published 2010
This manual outlines a range of measures for promoting low impact site development, such as buildings, stormwater management, and erosion and sediment control. Case studies are used to highlight the application of low impact site development in different environments.
Soil Conservation Technical Handbook
Published 2001
This handbook provides detailed information on the forms and processes of erosion that occur throughout New Zealand, and outlines techniques for managing these and associated land disturbance activities.
Erosion and Sediment Control: Guidelines for Soil Disturbing Activities – Technical Publication TR2002/01
Published 2003
These guidelines are similar in nature to the Auckland Regional Council guidelines (TP90) but with a particular focus on the different soils and environmental characteristics in the Waikato region.
Guidelines for Assessing Planning Policy and Consent Requirements for Landslide Prone Land (PDF 6 MB)
Published by GNS Science Limited - 2007
The guidelines primarily aim to assist planners in determining whether planning documents and consent applications incorporate appropriate information on landslide and slope instability hazards.
Heritage guidelines
Heritage Management Guidelines for Resource Management Practitioners
Published by New Zealand Historic Places Trust - August 2004
Guidelines to assist local authorities, owners and developers to identify and manage historic heritage under the RMA, and information on archaeological site obligations under the Historic Places Act.
International literature
Managing Urban Stormwater: Soil and Construction (4th Edition)
Published April 2004
This document offers a practical guide to erosion and sediment control on urban building sites. It includes a series of fact sheets highlight a range of approaches which can be used, from overall site management to specific management practices.
Soil and Erosion and Sediment Control Guidelines for Queensland Construction Sites
Published 1996
These guidelines provide an overview of the principles of erosion and sediment control management. Different management techniques are discussed, including the particular circumstances where they can be applied.
Urban Erosion and Sediment Control
Published by NSW Department of Conservation and Land Management - 1992
This document describes the effects of land disturbing activities and provides practical advice on a range of management techniques applicable to urban areas. Many NSW local authorities refer to this document in their own guidelines.
Current challenges
Integrated management
Achieving integrated management of earthworks between regional and district plan provisions, as the management issues are closely interrelated. RMA plans need to be clear about the respective responsibilities of each council, including who will assume responsibility for administering the different effects and how monitoring will be carried out and by whom.
There is potential for the RMA and the Building Act to overlap where the latter is able to consider stability issues that might be caused by some earthworks. However, the Building Act is, for small-scale structures, reactive (ie, where there is no need for a building consent) and hence some councils may decide that the Act does not provide sufficient control over potential creation of hazard or on consequential off-site effects from earthworks. Therefore, complementary provisions that deal with site stability may need to be prepared, bearing in mind the need to minimise overlaps with Building Act provisions.
Plan rules - Performance standards and thresholds
Defining the volume of sediment to be discharged per volume of total run-off discharged from a site is a challenge in developing performance standards for sediment discharge in regional plans.
Equally, developing performance standards for earthworks based on determinants such as defining the surface area exposed, slope, and distance from the receiving environment poses a similar challenge for district plans. It is difficult to set thresholds for a district or region-wide rule when there is a lot of variation in the local environment.
Resource consent conditions
Common practice is to impose a condition on a resource consent requiring preparation of an Erosion and Sediment Control Plan to manage earthworks. However, this can lead to a generic plan being developed that may not fully address particular site/development related effects. The non-specific nature of this approach may also create consequential enforcement difficulties.
Alternatively, inclusion of an Erosion and Sediment Control Plan as part of a resource consent application ensures the plan specifically relates to the individual circumstances of the proposal and that potential effects are understood at the time an application is considered. However as these plans are generally not developed until the detailed design stage of a project there may be information critical to the assessment of the application that is unavailable at the time of lodgement.
Managing non-point source discharges
Non-point source discharges are discharges that are diffuse and do not have a single point of origin. Discharges from small scale earthworks (often allowed as permitted activities in regional and district plans) can pose difficulties in monitoring compliance with consent conditions and plan rules, especially with temporary discharge events.
Managing the effects from large-scale earthworks is also problematic. The monitoring and maintenance of erosion and sediment control measures is difficult to enforce. In particular, regular monitoring to ensure these measures are operating effectively is crucial to managing the adverse effects.
Acknowledgements
This guidance note was prepared by Catherine Clarke and Hamish Wesney of Boffa Miskell Limited, and Brian Handyside of Erosion Management Ltd. The note was further shaped and reviewed by Greg Vossler and Gina Sweetman of the Ministry for the Environment. The Ministry for the Environment would also like to thank the following people for their input into the preparation of this material:
- Jan Crawford, Planning Consultants Ltd
- Matt Trlin, Porirua City Council
- Michael Parsonson, Southern Skies Environmental Ltd.
This guidance note was prepared in March 2007 and was revised to reflect the changes introduced by the Resource Management Amendment (Streamlining and Simplifying) Act 2009 by Greg Lee of Beca.
