Wellington Shire Council Implementation of Coastal Strategy Land Capability Assessment

Wellington Shire Council Implementation of Coastal Strategy Land Capability Assessment March 2008 Contents 1. Background 1 1.1 Recent Strategy and Policy Decisions 1 1.2 Current Implementation Process 1 2. Methodology 2 2.1 Initial Methodology 2 2.2 Data Availability 2 2.3 Revised Methodology 3 3. Data 4 3.1 Data Sorting 4 3.2 Critical Data Sets 4 4. Analysis 12 4.1 Stage 1: Areas Inappropriate for Additional Dwellings 12 4.2 Stage 2: Capability Assessment for Dwelling Densities 12 4.3 Assigning Capability Scores for Dwelling Densities 13 5. Findings 18 5.1 Key Constraints to Development of Dwellings 18 5.2 Implications for Current Adopted Settlement Structure 21 5.3 Implications of Land Capability Assessment 23 5.4 Utilising the Outcomes of the Land Capability Assessment 23 Appendices A Flora and Fauna Report B Landscape Assessment Report C Table of Capability Scores for Dwelling Density Scenarios D Land Capability Mapping Implementation of Coastal Strategy i Land Capability Assessment 31/20287/138968 1. Background 1.1 Recent Strategy and Policy Decisions The Wellington Shire Council adopted the Wellington Coast Subdivision Strategy Option 4 – Nodal Urban settlement pattern at its meeting of 20th September, 2005 and the preparation of the Wellington Coast Subdivision Strategy: The Honeysuckles to Paradise Beach was finalised in February 2007. The Strategy was developed in accordance with the relevant coastal planning and management principles of the Victorian Coastal Strategy, 2002 prepared by the Victorian Coastal Council, and the Gippsland Coastal Board’s Coastal Action Plans. This strategy provides a preferred settlement structure for the Wellington Coast between Paradise Beach and The Honeysuckles, as a way to encourage development that responds appropriately to environmental values and community needs, and is consistent with established policy in the Victorian Coastal Strategy. 1.2 Current Implementation Process In February 2007 the Victorian Government convened two committees to provide recommendations to government relating to the preferred approach to dealing with the long• term issues surrounding old and inappropriate subdivisions along the Ninety Mile Beach in Gippsland. These include the Project Control Group (PCG) and the Interdepartmental Working Group (IWG). The PCG is due to deliver its recommendations to Government at the end of 2007. In May 2007, GHD was requested to undertake a land capability and suitability assessment to provide additional supporting information for the deliberations of the PCG and IWG in relation to the Strategy. The objective of the assessment is to provide a rational and structured basis for measuring the capability and suitability of land to accommodate residential development. This aims to test the variations in physical conditions that determine capability and the supplementary socio•economic conditions that determine suitability. This may result in some areas presenting as incapable or unsuitable to accommodate residential development, and for the remaining areas may suggest a spectrum of capability and suitability according to dwelling density thresholds. Implementation of Coastal Strategy 1 Land Capability Assessment 31/20287/138968 2. Methodology 2.1 Initial Methodology The initial methodology proposed for the land capability and suitability assessment was discussed in a Methodology Workshop held on 23rd May, 2007 with the IWG. The suggested process was to involve an integrated approach to measuring capability for dwelling densities. This is based on a series of land qualities, evaluated for established land resource units, to measure how they may limit certain dwelling density opportunities by resulting in greater land degradation risk and more costly management inputs. Rating tables would then be prepared for each dwelling density. The table describes the variations in land qualities that contribute to a land resource mapping unit having a capability ranking I – V. Each land resource mapping unit would have a pre•assessed series of land qualities and could be interpreted to have a level of capability for the relevant dwelling densities. A multi•criteria assessment based on multiple and separate spatial datasets would be integrated by attributing multiple data items using a common weighting scale. Weightings would be assigned based on separate objectives, rationale, criteria and measurements for each data item. Finally, weighted spatial polygons would be merged by intersection and amalgamation using GIS queries. It was acknowledged at the workshop that no land resource unit mapping is available for the project area. Indeed, various members of the IWG agreed that the land resources of the project are relatively homogeneous. The IWG also resolved that there is insufficient spatial variation in the socio•economic considerations, which may inform dwelling density alternatives within the project area, to render continuing with the land suitability elements (or human values) of the assessment process. Finally the IWG agreed to proceed with acquiring the remaining relevant data required for the land capability assessment; interrogate the data obtained for quality, accuracy and applicability, and verify any data gaps. 2.2 Data Availability The workshop held on the 23rd May, 2007 included discussions on each possible dataset available for use in the project. For each dataset the likely agency or data custodian was identified, as well as a list of possible contacts to assist in obtaining the data for the project. Following the workshop, the relevant contacts and agencies were contacted and a number of important spatial datasets were obtained. These investigations also confirmed that other seemingly useful datasets would or could not be obtained due to their limited applicability or coverage. Various key datasets, however, were successfully acquired and these will be discussed in greater detail in Section 3.2 of this report. The datasets successfully obtained were discussed and reviewed for relevance to the project in a second workshop held on 2nd August, 2007 with the Interdepartmental Working 2 Implementation of Coastal Strategy Land Capability Assessment 31/20287/138968 Group (IWG). At this workshop the IWG confirmed that the land capability assessment should be finalised. Discussions at the workshop emphasised the need for an updated methodology for the land capability assessment to accommodate a two•stage approach as outlined below. 2.3 Revised Methodology The need for a two•stage process resulted from the IWG review of available datasets and the understanding that some datasets indicate that land is completely inappropriate for dwellings, and other datasets suggest possible variations in capability for different dwelling densities. The revised two•stage process was agreed to include: Stage 1: Determine appropriate and inappropriate (Go – No Go) areas for dwellings. Stage 2: Determine dwelling density capabilities for the remaining areas. The IWG also suggested that additional key datasets should be integrated into the land capability assessment, including: » Mapping which reflects the observations from the Landscape Values Assessment regarding the variations in landscape qualities in the project area; » The mapped outcomes from an on•site assessment of flora and fauna characteristics to be undertaken as soon as possible; and » The mapped outcomes from an assessment of climate change and sea level rise implications for the project area to be undertaken by Ethos NRM, and that in this regard a meaningful assessment may be reliant on more detailed topographic data for the coast, from the Victorian Government purchase of new LIDAR contour information. Implementation of Coastal Strategy Land Capability Assessment 3 31/20287/138968 3. Data 3.1 Data Sorting The GIS datasets acquired for the assessment were sorted and stored electronically, and various elements of the data were recorded in a comprehensive spreadsheet. 3.2 Critical Data Sets 3.2.1 Flood Data It was agreed by the IWG that areas within the 1 in 100 year flood extent be considered inappropriate for development and excluded from the Land Capability Assessment. The Gippsland Lakes Flood Level Modelling Project of 2004 developed new estimates for the 1 in 100 year flood levels for the Gippsland Lakes. The results are based on methods that use available meteorological and river flow records to account for physical influences such as streamflows, wind and ocean levels. Recommended 1% (1:100yr) annual exceedence levels are summarised in the report for various locations around the Gippsland Lakes area, although a value was not recommended for Lake Reeve. A recommended 1 in 100 year flood AHD level for the project area, however, was discussed by GHD with Professor Rodger Grayson of the Science Team that undertook the flood modelling for the project, who advised that the flood level value recommended for Loch Sport should be adopted for the project area. This coincides with 1.9 m AHD. Grayson stated that observations made from the more recent floods that occurred in the Gippsland Lakes area confirms the appropriateness of the adoption of this value for the land surrounding Lake Reeve. These 1 in 100 year flood levels do not include consideration of additional increases in flood levels that may result from climate change induced sea level rise. It was agreed at the IWG workshop that the extent of this increase, generally being discussed as relevant to Victoria is 0.7 m. Since this workshop the Victorian Coastal Council has adopted

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