Environmental Factor Guideline: Landforms

Purpose

The purpose of this guideline is to communicate how the factor Landforms is considered by the Environmental Protection Authority (EPA) in the environmental impact assessment (EIA).

Specifically, the guideline:

• describes the factor Landforms and explains the associated objective
• discusses the environmental values of landforms, and how this links with other factors
• describes the criteria that may be used to determine whether a landform is significant
• describes EIA considerations for this factor
• provides a summary for the type of information that may be required by the EPA to undertake EIA related to this factor
• describes issues commonly encountered by the EPA during EIA of this factor

What are landforms?

For the purposes of EIA, the EPA defines Landforms as:

The distinctive, recognisable physical features of the earth's having a characteristic shape produced by natural processes. A landform is defined by the combination of its geology (composition) and morphology (form). 

During EIA, the EPA focusses on the impacts to potentially significant landforms 

Landforms are a component of the landscape. The EPA considers a landscape to be:

All the features of an area that can be seen in a single view, which distinguish one part   of the earth’s surface from another part. Landscapes can be either natural (largely unaffected by human activity) or anthropogenic (created or largely modified by human activity).

How this factor links with other environmental factors

The EPA recognises that there are inherent links between the factor Landforms and other environmental factors as landforms may support numerous and varied environmental values. Potential impacts on an environmental value which may be supported by a landform, for example a threatened species, benthic community, heritage or amenity, are addressed in the relevant guidelines for other environmental factors, including but not limited to Flora and Vegetation, Terrestrial Fauna, Subterranean Fauna, Coastal Processes and Social Surroundings.

While impacts to these environmental values will be considered under the relevant environmental factor, the EPA will consider the impacts to Landforms in concert with these other factors in order to assess impacts on environmental values and an ecosystem’s integrity as a whole.

The environmental objective for the factor Landform 

The EPA’s environmental objective for the factor Landforms is: “To maintain the variety and integrity of significant physical landforms so that environmental values are protected.”

This objective recognises that the geology and morphology of a landform can have value in their own right, as well as the important role significant landforms often have in supporting environmental values.

Landforms can support numerous and varied environmental values which can include being a foundation for particular ecosystems, being sites of special scientific interest related to geology and geomorphology, and representing examples of important physical landscape processes. Landforms can also embody social and cultural values. They can have strong historical and cultural associations and provide enjoyment through aesthetics or active use (e.g. tourism, climbing, hiking, etc.).

Consistent with this objective, the EPA will firstly determine whether the landform to be impacted is a significant landform. If the EPA determines that the landform is significant, further assessment regarding the impacts of the proposal or scheme may be required to demonstrate whether the environmental objective for Landforms can be met.

Determining if a landform is significant

The following criteria may be used in determining whether a landform is significant:

• Variety
  The landform is a particularly good or important example of its type. The landform is not well represented over the local, regional or national scale or differs from other examples at these scales, either naturally or as a result of cumulative impacts from existing and reasonably foreseeable activities, developments and land uses.
   
• Integrity
  The landform is intact, being largely complete or whole and in good condition.
   
• Ecological importance
  The landform has a distinctive or exclusive role in maintaining existing ecological and physical processes; for example, by providing a unique microclimate, source of water flow, or shade. The landform supports endemic or highly restricted plants or animals.
   
• Scientific importance
  The landform provides evidence of past ecological processes or is an important geomorphological or geological site. The landform is of recognised scientific interest as a reference site or an example of where important natural processes are operating.
   
• Rarity
  The landform is rare or relatively rare, being one of the few of its type at a national, regional or local level.
   
• Social importance
  The landform supports significant amenity, cultural or heritage values linked to its defining physical features.

The landform does not have to meet all criteria, and may only meet one, to be considered a significant landform.

Consideration for environmental impact assessment

• the current state of knowledge of the environmental values supported by the landform
• the significance of potential impacts of the proposal or scheme to the landform's environmental values and defining features
• the scale of potential impacts of the proposal or scheme to the landform and its environmental values
• the extent of impacts on the landform from previous and reasonably forseeable activities, development or land uses
• the impact of the proposal or scheme on the stability and integrity of the landform
• application of the migration hierarchy to avoid and minimise impacts to significant landforms, where possible.

When considering the significance of potential impacts to significant Landforms, the EPA may have regard to the various matters as outlined in Section 5 of the Statement of Environmental Principles, Factors and Objectives.

Impacts

The focus of this factor and its environmental objective is on the significance of impacts to a significant landform and its defining features. In considering these impacts, the EPA will focus on the impact of the removal or alteration of the landform’s defining geology, morphology or abiotic processes and the level of dependent environmental values.

The areas which may be used to determine whether a landform is significant and to consider the impacts to landforms, including calculation of cumulative losses, in a local context are termed the Local Assessment Unit (LAU). LAUs are location specific and need to be defined on a case-by-case basis. They should be configured to allow for aspects of the local environment such as, but not limited to geology, morphology, sedimentary or cave systems, and the position of landforms within the broader landscape.

Information required for EIA

Where Landforms has been identified as a preliminary key environmental factor, the EPA may require the proponent to provide information or studies including, but not limited to the following:

• identification of the spatial extent of the landform in the local and regional context
• a description of the geology and morphology and associated processes of the landform
• analysis of whether the landform is significant in a local (or LAU, if relevant), regional and national context having regard to the criteria for determining if a landform is significant
• identification of the environmental values supported by the landform, and a discussion of the interrelationships between the values including how the proposal or scheme will affect the role of the landform in maintaining these values (e.g. through changes in surface water or groundwater flows, wind movement, precipitation, temperature, stability, landscape connectivity, and soil composition / chemistry)
• prediction of the direct, indirect and cumulative impacts from the proposal or scheme (including extent, severity and duration) on the landform and each key criteria
• an analysis of whether the landform is robust and therefore less sensitive to damage or degradation from development activities, or whether it is easily disturbed or degraded
• evaluation of the significance of the direct, indirect and cumulative impacts on the landform/s in a local (or LAU, if relevant), regional and national context
• description of how the mitigation hierarchy (avoid, minimise, rehabilitate) has been applied
• discussion on whether there is likely to be a significant residual impact
• identification of mitigation, management measures and contingency plans to demonstrate and ensure that residual impacts are not greater than predicted.

Issues

The following issues are matters that are commonly encountered by the EPA due to the nature of proposals and schemes that are referred to it. Background on these issues is provided here to help proponents and the community engage with EIA. This issues section will be updated from time to time to reflect new issues as they arise in referrals and EIA.

Banded Iron Formations

Banded iron formation (BIF) ranges in Western Australia form part of the Yilgarn Craton geological formation that covers the Midwest and Goldfields regions, and the Pilbara Craton that covers the Pilbara region. These ranges are amongst the oldest landforms on earth, deposited as chemical sediments at the bottom of the sea over two billion years ago, and later uplifted by tectonic processes. The hard, iron-rich rock is erosion resistant, leaving craggy hills and ridges isolated in predominately flat landscape.

BIF ranges are high points in the landscape, with their cooler, wetter conditions forming island-like refuges for plants and animals not found in the surrounding flat, dry plains. This includes species and communities that have highly restricted distribution and range endemics (species which only occur on one range). Being distinct features in an otherwise flat landscape, they also support social and economic values including tourism. 

The EPA recognises that there may be significant biodiversity and mineral resource values in the BIF ranges and it is not possible to reconstruct the structure of BIF ranges, once removed.

Mesas

Mesas are landforms characterised by flat top hills bounded on at least one side by a steep slope or cliff and can vary in size. Mesas are erosional remnants that persist because of
a protective layer of more resistant sedimentary rock, often over more easily weathered materials. Mesas can be separated into two main types, being (1) discrete mesa landforms or (2) partial mesas merging with an adjacent landform.

Mesa landforms can support important environmental values for example, providing
habitat for subterranean fauna.

Mesa formations are common in the Pilbara region and are associated with several geology types. These tend to be large scale when compared to smaller mesas found in the Midwest. There has been an increased interest in mining mesa landforms in the Pilbara for their mineral resource values, and consideration of cumulative impacts to these landforms may become an issue in future assessments.

Dunes and dune fields

A dune is a mound or ridge of sedimentary particles, usually sand, formed by the action of either wind or water. Aeolian dunes may be found in coastal regions where sand accumulates at the back of a beach and in inland sand ‘seas’ of desert regions. Parabolic dunes are crescent-shaped isolated dunes which close downwind. Desert dunes range from less than a metre to 10m in height and occur in a variety of forms.

The Alkimos dune system north of Perth is considered to have national and world significance as an excellent example of parabolic dunes belonging to the Quindalup dune system, which developed around 10,000 years ago during the Holocene. The dunes are approximately two kilometres wide and extend four kilometres inland and provide amenity and geo-heritage values as well as supporting coastal vegetation, which provides stability for the dunes. Other important dunes occur along the coast of Western Australia.

Activities which can impact on dunes include coastal development and sand mining. These activities may bisect or remove important dune systems or cause disruption of sediment flow, and result in loss of environmental values supported by dune systems. These impacts are potentially significant in the context of increasing development pressure in coastal areas.

Caves and dune systems

Caves are natural cavities or systems of chambers beneath the surface of the earth. A cave system occurs where a group of caves is connected, or the same underground river or stream flows through the cave group. The largest caves and caverns in WA are formed mostly in limestone.

The Leeuwin Naturaliste Ridge in the South West Region contains over 150 limestone caves which have scientific and social value, as well as providing habitat for fauna and flora. A number of caves on the Leeuwin Naturaliste Ridge and in Yanchep National Park support dense growths of aquatic root mats in cave streams and pools which are recognised as Threatened Ecological Communities. Caves in the Pilbara region form habitat for the Pilbara Leaf Nosed Bat.

Surface activities such as changes to hydrology, removal of vegetation, pollution and land development can impact on caves, and are potentially significant if they will result in the loss of environmental values supported by caves or cave systems.

 

Version	Change	Date
1.0	(Initial version)	13 December 2016
2.0	Update environmental objective and restructure document to clarify the focus for EIA Update information required for EIA and the use of Local Assessment Units Add new Issue: Mesas Editorial changes for consistency across the framework	29 June 2018

EPA publications are updated from time to time. Please consult the EPA website to ensure you have the most recent version.

Copyright
EPA 2018, Environmental Factor Guideline: Landforms, Environmental Protection Authority, Western Australia.
© June 2018, Environmental Protection Authority

This work is copyright. You may download, display, print and reproduce this material in unaltered form only (retaining this notice) for your personal, non-commercial use or use within your organisation. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. Requests and inquiries concerning reproduction and rights should be addressed to the Chair, Environmental Protection Authority.

Disclaimer
This document has been published by the Environmental Protection Authority. Any representation, statement, opinion or advice expressed or implied in this publication is made in good faith and on the basis that the Authority and staff of the Department of Water and Environmental Regulation are not liable for any damage or loss whatsoever which may occur as a result of action taken or not taken, as the case may be in respect of any representation, statement, opinion or advice referred to herein. Professional advice should be obtained before applying the information contained in this document to particular circumstances.

EPA 2018, Environmental Factor Guideline: Landforms, Environmental Protection Authority, Western Australia.
© June 2018, Environmental Protection Authority