Abstract

Key Words

Land resource assessment (LRA), geomorphological framework, Corangamite region, soil-landform mapping.

Introduction

Soil is critical to the provision of fundamental ecosystem services, especially where land use and land management choices rely on this versatility of soil but may also compromise these services if land is inappropriately managed. Land Resource Assessment (LRA), which provides the understanding of the variety of soils and their relationships in the landscape, is an essential tool for any land use activity, from agriculture to waste disposal.

Land resource assessment activities had been carried out in Victoria since the early 1940's, principally commencing with large-scale irrigation region surveys. Farm planning, crop productivity issues and water allocation were key drivers behind this initiation. Regional surveys aimed at determining the most appropriate forms of land use in regions commenced in the 1950's and eventually covered much of the state, producing maps based on Land Systems. Regional soil-landform surveys along with a range of smaller surveys targeted to specific areas of rural development (e.g. wine industry) and assessment of areas proposed for urban development were undertaken during the 1970's. Land capability surveys for local government and larger regional surveys followed in the 1980's and 1990's (Imhof et al 2000).

This paper describes recent advances in LRA product development along with the inventory process and the integration of national approaches with the adoption of the revised 'Geomorphic Framework for Victoria' in regional land resource assessment.

Methods

The inventory of soils across landscapes of the CCMA region was defined from pre-existing surveys, in particular those of Maher and Martin (1987) and Pitt (1981). Industry-specific site investigations for dairying and cropping, an opportunistic survey along a gas pipeline (MacEwan, Imhof and Newman 2002), and regional extension activities have provided other soil profile data. Soil-landform units were identified from the coupling of enhanced resource assessment techniques including remote sensing (e.g. radiometrics) with existing geology and soil/landscape mapping and additional field investigations. This resulted in the development of topographical, soils, climate, vegetation, land use and land characteristic information for over 200 soil-landform units across the Corangamite region. In derivation of a 'consistent' LRA product, important facets of the process described here include the LRA inventory process and distribution formats used in disseminating this information to users.

LRA inventory process

Across the CCMA region a number of previous land and soil surveys existed (carried out by government organisations over the last 30 years). Importantly, these studies were developed at different scales for specific purposes including land capability assessment and land systems mapping. While at different scales, these surveys often observed the underlying principle that aims to provide the reader with base information to ‘examine the nature and interactions of features of the natural environment’ while focusing on ‘sustained productivity of the land, its use and management’ (Pitt 1981). As a result, information presented in these studies is varied and is reflected in the style and contents of the survey reports and mapping (as documented in Robinson et al. 2003).

Map creation

In generating a soil-landform map for the Corangamite region, a number of factors were considered in the editing and compilation phases – including an assessment of the utility and quality of existing information and mapping boundaries. The functional role of previous soil surveys in creation of the revised soil-landform map for the CCMA region are documented in Robinson et al (2003) and provide a basic yet fundamental role as 'soil surveyor metadata' that underpins principles used in integration of data. An example of this is provided for two existing surveys in Table 1.

Table 1 Example of functional role of soil surveys in creation of the soil-landform map for the CCMA region

Survey title	Functional role in map creation
An interim report on the land in the Heytesbury settlement Scheme (Pitt et al 1977)	This report is a natural extension of the Otway Range Land Systems report (Pitt 1981) into the neighbouring Heytesbury area. Mapping and descriptions from this survey were accommodated in the revised compilation of map units and their descriptions.
Terrain Classification for Engineering Purposes of the Queenscliffe area, Victoria. (Grant 1973)	Terrain units created using the PUCE (Pattern-Unit-Component-Evaluation) program provided a map basis for field investigation of the Bellarine Peninsula in the current survey. Being the only existing comprehensive survey to cover this area, the mapping was incorporated into the generated soil-landform map after critical assessment in the field. Soils information was limited, however, so additional soil pits were characterised for the current survey.

A summary of the steps involved in derivation of soil-landform units for the CCMA region is outlined and summarised below.

1. Collation of soil-landscape data (review/digitise existing linework/point data). Existing soil and land survey mapping (polygon data) was reviewed and the overlap between soil-landform survey defined (including comparison of contextual data contained within reports) and edited with consideration of survey scale, quality and detail. This involved digitising, scanning and capture of data from a variety of sources.

2. Examination against spatial datasets - initial soil-landform map outputs being compared against spatial datasets including Digital Elevation Models (DEM), Airborne Gamma Ray Spectrometry (AGRS), geological datasets and existing soil point data (varied intensity and currency). Relationships between soil-landscapes and spatial datasets were defined for geomorphic provinces across the region.

3. Reconnaissance field survey – whereby soil-landform units were compared against topography and known landscape features. Relationships were further refined to account for spatial variability and 'knowledge gaps' in existing soil and land survey.

4. Field survey (soil pits). Late in 2002, fifteen soil pits were characterised to complement the nearly 800 historical sites and fill important gaps in the regional soil inventory. Pits were located to provide ‘representative’ examples of major soil types (focussed in the south of the catchment where knowledge gaps were considered greatest). Soil pits were fully characterised, including site and morphological features, chemical and physical properties, and photos were taken of the soil profile and associated landscape.

5. Using available digital datasets, existing mapping and soils information derived from field survey and existing terrain information; soil-landform units were defined and assigned relevant soil/landscape contextual information (topographical, soils, climate, vegetation, land use and land characteristics) in compilation of the LRA product.

Soil-landform units and the geomorphic framework

Soil-landform relationships, their frequency, but also the role and understanding of geomorphic landscapes, evolution and processes is essential in undertaking land resource assessment. The geomorphological framework adopted for this LRA project reflects a new approach to soil-landform mapping in Victoria. This approach provides context for analysis of landscapes at a range of scales and degree of complexity. Geomorphology provides the main mapping framework in this study, and the basis for ‘nesting’ the soil-landform units (which approximate to detailed Land Systems level mapping, but without some of the ecological connotations). This enables the description at the soil-landform level (1:100 000 scale) to be relatively scale-free as many of the contextual issues are dealt with by the geomorphology at a number of smaller (broader) scales (or ‘tiers’) (Robinson et al 2003). The soil-landform unit is the principal mapping unit and has been integrated within this geomorphological framework, at or below the geomorphological sub-regional level (‘tier 3’). An example of this framework and its application in this land resource assessment is provided below in Figure 1.

Figure 1. Geomorphic Framework example for subset area of the Corangamite region – showing tier 1, 2 and 3 mapping

Distribution format and LRA data structure

The distribution format chosen for this LRA project was CD-ROM. Numerous LRA products are CD-ROM based with examples for Victoria and Australia provided below in Table 2. This format was chosen for this LRA project due to the ability to dynamically link mapping and report outputs and the economic expense of hardcopy report production. The number of documents (reports, maps and various other supporting material) captured as part of the LRA project and volume of information (number of pages) is presented in Table 3.

Soil-landform maps are linked to contextual data that can be interrogated by the user. This contextual data includes soil-landform unit descriptions, soil point descriptions, geomorphological descriptions and framework along with soil group information. Data collected on each soil-landform unit is presented in tabular form with accompanying background unit information (photographs, topographic section, three-dimensional representation and location of where the unit occurs within the catchment).

Links have been formulated from the full report to appendices that include previous reports (especially soil surveys and documents used in compilation of the base mapping products). All maps and contextual data is provided in Adobe® Portable Document Format (PDF). A simplified version of the dynamic link structure for the CD-ROM is presented in figure 2 and an example soil-landform unit description in Figure 3.

Table 2. Example of recent LRA CD-ROM products from state government organisations across Australia.

State	Year of publication	Title
Victoria	2000	Goulburn Broken dryland regional development project
	2001	A land resource assessment of the Glenelg-Hopkins region
South Australia	2003	Murraylands Land Resource Information
New South Wales	2003	Soil landscapes of the Narooma 1:100 000 Sheet (Narooma, Tuross Head, Tilba, Bermagui)
Western Australia	2003	AGMAPS LAND PROFILER - Shires of Capel, Busselton & Augusta-Margaret River

Figure 2. Data (dynamic) link structure used in the CCMA LRA CD-ROM product.

Table 3 Documents included and produced as part of the LRA project.

Product group	No. of Adobe® Portable Document Format files	Total pages (size may vary from A4 to A1)
Soil-landform unit descriptions	203	609
Soil-landform maps	13	13
Land degradation maps	79	79
Final report (includes geomorphological units and soil groups)	1	131
Soil profile descriptions	165	330
Appendices - past reports	22	793
Appendices - past maps	28	28
	Total	1983

Figure 3. Example of soil-landform unit description.

Results & Discussion

Land Resource Assessment procedure and incorporation of the Geomorphic Framework

The approach used in derivation of soil-landform maps for this project represents a revision of methods used by soil surveyors in historic LRA products of the 1970's and early 1980's. This revision, however, represents an ideal opportunity for users and producers of LRA products to ‘drill down’ through information products in a logical and conceptually simple process (Figure 4). Use of the geomorphic framework provides this 'missing' structure that has been sought by many LRA products over the last decade. Additionally this LRA provides a classic example of a LRA process, but also may be used as a model for LRA across the country through the strong integration of geomorphology into the process and the national needs for consistent geomorphology products at this stage in numerous environmental modelling procedures.

Figure 4 Structural setting for documents of the LRA using a 'top-down' approach for obtaining information.

A benefit also to be considered is the ability to integrate new data into this LRA approach. The geomorphic framework provides a basis from which new soils and landscape data can be readily integrated. There is the potential to revise and update soil-landform descriptions while increasing levels of understanding on landscape processes and affects of land management practices. It is expected that the new geomorphic framework will be readily integrated into current national mapping frameworks such as the Australian Soil Resources Information System (ASRIS) - being generated as part of the National Land and Water Resources Audit (NLWRA).

The procedure used in this LRA represents a process for integration of various soil and land surveys of different scales while highlighting strengths and weaknesses of the products. Through use of metadata and presentation of all steps in the mapping process, issues regarding quality assurance and control have been addressed and documented - providing somewhat of a transparent method that is easily repeatable for other landscape surveys.

Distribution format and data structure

Advantages and disadvantages exist when using CD-ROM as a distribution format. The main disadvantage is data currency where a product that is delivered is out-of-date due to the fact that the data can’t be constantly updated. The CD-ROM captures a fixed moment in time. For some data layers this is satisfactory as their update rate may be yearly or less frequent, while other layers (e.g. cadastral datasets - including land parcels and roads) may have the potential to be updated daily or weekly. The CD-ROM product is also generally developed as a standard product where ‘one size fits all’ (all audiences receive the same product). Tailoring of products for different user groups involves considerable work and therefore expense.

Data access is another disadvantage where 'corporate' spatial data requires data supply agreements for use by user groups. This issue has been addressed through the use of static maps produced as PDF files, avoiding use of data supply agreements. Adobe® Portable Document Format (PDF) is becoming the open de facto standard for electronic document distribution. This universal file format preserves fonts, formatting, graphics, and colour of any source document, regardless of the application and platform used to create the primary material. The files are compact and can be shared, viewed, navigated, and printed as intended by a user with freely available reader software. As well as being used to publish report style information, they are also very good for publishing traditional style maps in an electronic form.

The advantages of the CD-ROM product are their speed, storage capacity, inexpensive along with reliability. Adequate access to internet by regional users is still varied and often find that having a CD-ROM product is much faster to use than accessing the web. Another advantage is that clients often like to have a ‘physical product’ for their investment. They often like to ‘see’ what their money has been spent on and prefer a physical product rather than being given a web site address.

The report has also been made available on DPIs Victorian Resources Online website¹. This website also provides maps from the Corangamite LRA report which are delivered as Adobe® Portable Document Format (PDF) files with links to soil-landscape descriptions and soil profile information. The website also provides additional information on the natural resources (e.g. climate, soil, landform, soil, biodiversity, water) in the Corangamite region. Complementary information on this website (e.g. overview soil maps of the region, downloadable versions of previous reports etc) adds value to the current document.

There are many potential future distribution means for the LRA products. One method is via the Internet using the Victorian Department of Primary Industries (DPI) corporate spatial service delivery tool ‘MapShare²’. As an Internet Mapping Framework (IMF), MapShare provides a corporate infrastructure that facilitates the publishing of interactive maps on both the Internet and Intranet where users aren't required to have specialist software to view and interrogate the spatial data. This enables users to have GIS functionality (e.g. zoom-in and zoom-out, pan around the map, identify features in the map, do queries on databases with included metadata), as well as link (hyperlink) to other websites and print out maps based on specific themes of interest (also known as map views). Also the ability to customise the map services to suit different audiences (e.g. more detailed or technical for advanced users and simpler for the general public) is an advantage of this distribution format. Data currency can also be maintained as data custodians have the ability to continually update spatial data as new data and information becomes available.

The disadvantages of using ‘MapShare’ as a future distribution means for LRA is speed and access. Users need to have an internet connection to be able to view the product, and the speed of their connection will affect the quality of their experience with the product. Logistically an issue is the time and skills required in development of the interface, along with time in updating spatial dataset currency.

Conclusion

The adoption of the geomorphic framework in the LRA process provides a means of creating a consistent and reviewable approach to soils and landscape analysis. This simple hierarchal framework presents a transparent and easily understood structure for numerous user groups including scientists, natural resource extension staff and land managers. The LRA process used for this project has dealt with soil and land surveys of various scales, intensity and therefore detail. Appropriate documentation of these steps and issues towards integration into a complete soil-landform coverage for a region should be fundamental as a method of conveying quality issues and the rationale taken to vindicate this approach.

New means and formats for distribution of spatial and related data have resulted in many changes in LRA product information sharing over the last decade. Currently, both CD-ROM and internet provide means of data distribution, and therefore knowledge generation. In practical terms, CD-ROM products have a user group that is dominated by scientists and natural resource extension staff, whilst internet-based information is also accessed land managers and other spectrums of the community (e.g. local government). Ultimately with time and improved telecommunications, the internet is a likely means by which LRA information will be distributed while accommodating vast quantities of historic and current spatial and textural data.

References

Grant K (1973) Terrain Classification for Engineering Purposes of the Queenscliffe Area, Victoria. Technical Paper 12. CSIRO.

Imhof M, Rampant P, Bluml M (2000) The future of land resource assessment in Victoria. Australian Collaborative Land Evaluation Program (ACLEP) Newsletter 9/2. 6-16.

MacEwan RJ, Imhof M, Newman A (2002) Opportunistic soil survey along a pipeline trench – adding value and dimensions to knowledge of regional landscapes. FUTURESoils conference proceedings. Australian Society of Soil Science National Conference, Perth Western Australia, 2-6 December 2002. 102-3

Maher JM, Martin JJ (1987) Soil and landforms of south-western Victoria, Part 1 - Inventory of soils and their associated landscapes. Department of Agriculture and Rural Affairs. Research Report Series #40.

Pitt AJ (1981) A Study of the Land in the Catchments of the Otway Ranges and Adjacent Plains Report No. TC-14. Soil Conservation Authority.

Pitt AJ, Jakimoff AW and Evans BJ (1977) An interim report on the land in the Heytesbury settlement scheme. Soil Conservation Authority.

Robinson N, Rees D, Reynard K, MacEwan R, Dahlhaus P, Imhof M, Boyle G and Baxter N (2003) A land resource assessment of the Corangamite region. Department of Primary Industries, Victoria.

Web Links

¹http://www.dpi.vic.gov.au/dpi/vro/coranregn.nsf/pages/soil_landform_map

²http://www.dse.vic.gov.au/DSE/dsencor.nsf/LinkView/836EE128E54D861FCA256DA200208B945FD09CE028D6AA58CA256DAC0029FA1A