Darling Range Rural Land Capability Study
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Research Library Land resources series Natural resources research 1990 Darling Range rural land capability study Peter Donald King M R. Wells Follow this and additional works at: https://researchlibrary.agric.wa.gov.au/land_res Part of the Agriculture Commons, Natural Resources Management and Policy Commons, and the Soil Science Commons Recommended Citation King, P D, and Wells, M R. (1990), Darling Range rural land capability study. Department of Primary Industries and Regional Development, Western Australia, Perth. Report 3. This report is brought to you for free and open access by the Natural resources research at Research Library. It has been accepted for inclusion in Land resources series by an authorized administrator of Research Library. For more information, please contact [email protected]. ISSN 1033-1670 AGDEX 526 LAND RESOURCES SERIES No. 3 DARLING RANGE CAPABILITY STUDY ft P. D. King and M.R. Wells WESTERN AUSTRALIAN DEPARTMENT OF AGRICULTURE Preface The Division of Resource Management, Western Australian Department of Agriculture, undertakes land resource surveys and land capability assessments to assist land use planning in Western Australia. These projects are in particular demand for rural land within the greater Perth metropolitan area, an area under significant subdivision or rezoning pressures for more intensive and largely non-agricultural land uses. Cover: The perspective shown was produced by combining a Digital Terrain Model with geometrically corrected Thematic Mapper satellite data over the study area. The work was undertaken by the Remote Sensing Applications Centre, Department of Land Administration and the Division of Resource Management, Department of Agriculture. A NATIONAL SOIL CONSERVATION PROGRAM FUNDED PROJECT DARLING RANGE RURAL LAND CAPABILITY STUDY By: P. D. King and M.R. Wells Editors : D.A.W. Johnston and L.J. Snell Design by: L.T. Webb LAND RESOURCES SERIES No. 3 April, 1990 DEPARTMENT OF AGRICULTURE Baron-Hay Court South Perth 6151 WESTERN AUSTRALIA ISSN 1033-1670 AGDEX 526 1 LAND RESOURCES SERIES No. 3 The authors P.D. King and M.R. Wells, Research Officers, Soil Conservation Service Branch, Division of Resource Management, Department of Agriculture, Western Australia National Library of Australia Cataloguing-in-Publication entry King, P.D. (Peter Donald), 1959- Darling Range rural land capability study. Bibliography. ISBN 0 7309 2700 8. 1. Land use — Western Australia — Darling Range — Planning. Land Rural 2. use, — Western Australia Darling — Range — Planning. 3. Land capability for agriculture Western Australia Darling — — Range. I. Wells, M.R. II. Western Australia. Dept. of Agriculture. III. Title. (Series : Land Re- sources Series ; No. 3). 333.7317099412 0 Chief Executive Officer of the Western Australian Department of Agriculture 1990. LAND RESOURCES SERIES No. 3 2 This report contains the results of the land resource survey and land capability assessments for rural-residential and associated agricultural Use and application land uses in the eastern part of the Perth metropolitan area. The assessment methodology developed as part of this project is reported by Wells and King (1989). Users will need to refer to this publication for definitions and assessment of some of the terms and methods used herein. The results of the Darling Range project are presented in a tabular format to allow ready access to information relating to each land unit shown on the accompanying maps. Three types of information may be accessed for any land unit or group of units. These are: • land characteristics (soils and landforms) • land qualities • land capability assessments. Land characteristics provide factual information about the physical attributes of land included within a land unit. Examples are depth of soil to rock and the slope gradient of the land surface. Land qualities provide assessed values of properties which directly influence land use, such as erosion risk and foundation soundness. Land capability assessments, expressed as capability classes, provide a ranking of the ability of land within a map unit to support a particular type of use without causing land degradation. This ranking is based on a consideration of the values of those qualities which are likely to affect, or be affected by, the particular type of use. The capability class is usually followed by a subclass notation indicating the quality, or qualities which are limiting to the land use being considered. The three levels of information associated with the map units provide the user with a data base to assist land use planning at various scales. Using either manual or computer aided selection and display techniques, areas of land with a low capability to support a particular land use activity, such as housing or effluent disposal, can be shown on a map. At a regional planning scale, this information would be useful for indicating areas best avoided for future residential development. For catchment based land use planning, the values of certain land qualities and the way results are presented would, for example, identify areas of land with a high risk of causing water pollution by subsurface drainage after the application of fertilizer. At a more detailed scale, the mapping and data base can assist farm planning, the evaluation of land subdivision, and development proposals on individual properties. This is facilitated by maps presented on a cadastral base, although accuracy limitations imposed by the mapping scale will require on-site inspection and perhaps more detailed mapping. The data provide an important starting point with a descriptive framework for the land, highlighting limitations likely to affect new forms of management or changes in the type of land use. A knowledge of relevant land qualities and the extent to which they might limit a proposed form of land use will, in many cases, enable management strategies to be formulated to overcome the limitations. Land zoning categories such as 'special rural' or 'special residential' currently (1990) allow planning authorities to apply specific land use and management controls in rural-residential situations, These controls are aimed at minimizing the potential for land degradation and retaining, as far as possible, the rural character or visual amenity value of an area. By identifying the particular qualities and characteristics of land which could result in land degradation, the results of land capability assessments provide the basis of design for relevant land use and management inputs. Stocking limits, clearing controls or soil conservation measures could be conditions of subdivision or land use provisions attached to zoning amendments. In certain areas however, the capability of land to support a particular use may be so low that it should be avoided and an alternative use sought. 3 LAND RESOURCES SERIES No. 3 Whatever level of planning land capability information is used, it must be recognized that it is only one input into the land use decision making process. Capability analysis is based on biophysical data and does not take into consideration socio-economic or political factors, which must be included in the planning process to ultimately decide the most suitable use for any piece of land. LAND RESOURCES SERIES No. 3 4 Page Contents Use and application 3 Abstract 7 Introduction 9 Purpose and scope of report 9 Regional setting 9 Existing land use 9 Agriculture 9 Extractive industries 9 Water catchments 11 Rural residential 11 Climate 11 Geology 15 Geomorphology 16 Vegetation 17 Water resources 18 Surface drainage systems 18 Groundwater 19 Regulations on groundwater use 19 Methodology 21 Land resource survey 21 Land capability assessment 22 Results 29 Land resource survey 29 Explanation of mapping units 29 Soils of the study area 29 Soils of the Darling Plateau surface 30 Soils of the dissected valleys, spurs and Darling Scarp 30 Soils of the Dandaragan Plateau and scarp 30 Soils of the Ridge Hill Shelf 30 Soils of the Pinjarra Plain 30 Land characteristics and land qualities 39 Land capability assessment 39 Land use considerations and recommendations 108 Considerations and recommendations 108 Darling Plateau 108 Lateritic uplands 108 Minor valleys within upland surface 108 Incised valleys and the Darling Scarp 109 Upland spurs 109 Dandaragan Plateau 109 Lateritic uplands 109 Scarp below plateau surface 109 Swan Coastal Plain 110 Ridge Hill Shelf 110 Pinjarra Plain 110 Acknowledgements 116 References and bibliography (includes references in Appendices 2, 3, 4 and 6) 117 LAND RESOURCES SERIES No. 3 Appendices Page 1. Legend to land resource maps 122 2. Soil type descriptions 127 3. Land use rating tables 140 4. Engineering properties of major geological units 146 5. Values for factors used in erosion risk assessments 152 6. Methods used for soil analysis 161 7. Development guidelines for small rural lots 163 8. Laboratory results microfiche (attached) 165 9. Land capability maps (microfiche) 165 10. Land resource maps (3 sheets) 165 List of tables Table Page 1 Agricultural land use statistics 1985-86 season 10 2 Gross value of agricultural commodities 1985-86 season 10 3 Correlation of geological compared with geomorphological nomenclature 17 4 Summary — surface water resources 19 5 Groundwater availability — proclaimed groundwater areas 21 6a Land capability classes 23 6b Land capability subclasses 23 7 Land qualities assessed for each land use activity 24 8a Characteristics used to assess qualities related to conservation 25 8b Characteristics used