9 LANDSCAPE and VISUAL IMPACT ASSESSMENT 9.1 Introduction 9.1
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Civil Engineering and Development Department Trunk Road T4, Sha Tin EIA Report 9 LANDSCAPE AND VISUAL IMPACT ASSESSMENT 9.1 Introduction 9.1.1 This section of the report presents the Landscape and Visual Impact Assessment (LVIA) of the proposed Trunk Road T4, Sha Tin. Figure 9.1 shows the preliminary layout of Trunk Road T4 within the context of the Sha Tin valley. The report outlines the landscape baseline conditions, planning and development control framework, and the visually sensitive receivers (VSRs), and identifies the landscape and visual impacts which will occur during the construction and operation phases of the proposed development. The report then goes on to recommend mitigation measures and identifies residual impacts apparent after mitigation. The assessment also outlines any cumulative impacts that will be attributed to the proposed scheme. 9.1.2 The Landscape and Visual Impacts are considered as follows: • Landscape impact assessment shall assess the source and magnitude of developmental effects on the existing landscape elements, character and quality within the context of the site and its environs; and, • Visual impact assessment shall assess the source and magnitude of effects caused by the proposed development on the existing views, visual amenity, character perceived by the visually sensitive receivers within the context of the site and its environs. 9.2 Legislation and Guidelines 9.2.1 The Environmental Impact Assessment Ordinance (EIAO) was introduced in 1997 and came into effect in April 1998. The methodology for undertaking the landscape and visual impact assessment is in general accordance with the assessment criteria and guidelines in Annexes 10 and 18 of the Technical Memorandum on Environmental Impact Assessment Process (EIA-TM). The list of legislation, standards and guidelines applicable to this assessment is as follows: • Environmental Impact Assessment Ordinance (Cap. 499.S.16) and the Technical Memorandum on EIA Process (EIA-TM), particularly Annexes 10 and 18 • Hong Kong Planning Standards and Guidelines (HKPSG) • Sha Tin Outline Zoning Plan (No. S/ST/20) dated 18 June 2004 • WBTC No. 25/92 – Allocation of Urban Street Trees • WBTC No. 25/93 – Control of Visual Impact of Slopes • WBTC No. 19/98 – Advisory Committee on the Appearance of Bridges and Associated Structures • WBTC No. 17/2000 – Improvement of the Appearance of Slopes • WBTC No. 14/2002 – Management and Maintenance of Natural Vegetation and Landscape Works, and Tree Preservation • GEO Publication No. 1/2000 – Technical Guidelines on Landscape Treatment and Bio- engineering for Manmade Slopes and Retaining Walls • ETWB TCW No.2/2004 - Maintenance of Vegetation and Hard Landscape Features • HyDTC 6/98 on Visibility of Directional Signs • EIAO Guidance Note No. 8/2002 – Preparation of Landscape and Visual Impact Assessment F:\Projects\IA3008 - Trunk Road T4\Report\EIA.doc 9 - 1 Arup-Cinotech Civil Engineering and Development Department Trunk Road T4, Sha Tin EIA Report 9.3 Landscape Impact Assessment Methodology 9.3.1 The assessment of the potential impacts of a proposed development on the existing landscape involves the following procedures: • Definition of Study Area; • Baseline survey including landscape resources and landscape character; • Assessment of level of sensitivity to change of the landscape resources; • Identification of magnitude of change associated with the construction and operation of the proposed development (quantification included where appropriate); • Assessment of potential landscape impacts; • Identification of the significance thresholds of landscape impact. 9.3.2 The Study Area for the landscape assessment is defined as the area within 500m of the project boundary. The baseline survey of the existing landscape resources and character is carried out using a combination of site inspection and desktop survey. A detailed tree survey will be undertaken (refer to Appendix M). The landscape elements considered include: • Local topography • Woodland extent and type • Other vegetation types • Built form • Patterns of settlement • Land use (including confirmed or planned developments) • Scenic spots • Details of local materials, styles, streetscapes, etc. • Prominent watercourses • Cultural or religious significance • Heritage value 9.3.2.1 The baseline survey sets out the landscape context of the site by describing the landscape resources and the associated landscape character. Landscape character is derived from the pattern or combination of landscape resources. The Study Area is subdivided into broadly homogenous units of similar character for the purposes of assessment. 9.3.3 The impact is derived from the degree or magnitude of change which the proposed development will cause to the existing landscape context (resources and character) and its ability to tolerate that change, i.e. its sensitivity. The sensitivity of the landscape resources within the Study Area is based on baseline survey information and protective designations, in the absence of a territory wide landscape assessment. Degree of sensitivity is classified in accordance with the following: • High: a landscape resources or character type that is rare, protected or considered to be of high value within the local area, or in Hong Kong, based on existing legislation and baseline survey; • Moderate: a landscape resources or character type that is of moderate importance locally based on the baseline survey; • Low: a landscape resources or character type that is considered to be of low value due to widespread occurrence, ease of replacement or eroded state for example, based on the baseline study. 9.3.4 The magnitude of change for landscape resources or character is similarly graded, as follows; • High: high quantitative loss or addition of a landscape resources or notable permanent change to a character area; • Moderate: moderate quantitative loss or addition to a landscape resources or partial erosion/reinforcement of landscape character resulting in a moderate change; F:\Projects\IA3008 - Trunk Road T4\Report\EIA.doc 9 - 2 Arup-Cinotech Civil Engineering and Development Department Trunk Road T4, Sha Tin EIA Report • Low: minor quantitative loss or addition to a landscape resources or slight alteration to landscape character that may be temporary; • Negligible: effect on landscape resources or character is barely noticeable or of very limited duration. 9.3.5 The degree of impact is derived from the following matrix. The majority of impacts are defined as either adverse or beneficial. In some instances an identified impact may be neither adverse nor beneficial and is described as negligible. Where no impact is predicted, the magnitude of change stated as no change. Table 9.1 Significance Threshold for Landscape Impacts High Moderate Impact Moderate / Significant Significant Impact Impact Moderate Slight / Moderate Moderate Impact Moderate / Impact Significant Impact Low Slight Impact Slight / Moderate Moderate Impact Impact Proposals No change/ Negligible Negligible Negligible Negligible Low Medium High Magnitude of ChangeCaused by Sensitivity / Quality of Landscape 9.3.6 The identification and assessment of the potential landscape impacts is a product of the sensitivity of the landscape or landscape resource, and the magnitude of change arising from the proposed development. The assessment will be undertaken during the construction phase, the opening year and the design year. The above matrix will apply in the assessment of the majority of situations, however, in certain cases a deviation from this may occur, e.g. the impact may be so major that a significant impact may occur to landscape resources or character rated as low sensitivity. 9.3.7 The degree of impact is considered as follows: Table 9.2 Definition of significance of Landscape Impact Adverse / Beneficial Impacts Significant: Moderate: Slight: Negligible: adverse/beneficial adverse/beneficial adverse/beneficial change is impact where the impact where the impact where the noticeable but proposal would cause proposal would cause proposal would cause deemed to be significant a noticeable a barely perceptible neither adverse deterioration or deterioration or deterioration or nor beneficial. improvement in improvement in improvement in the existing landscape existing landscape existing landscape quality quality quality 9.4 Tree Survey Methodology 9.4.1 To minimize conflicts with existing vegetation a full tree survey in accordance with WBTC 24/94 F:\Projects\IA3008 - Trunk Road T4\Report\EIA.doc 9 - 3 Arup-Cinotech Civil Engineering and Development Department Trunk Road T4, Sha Tin EIA Report has been undertaken for the whole development site. This will facilitate the fine-tuning of the proposed detail design for the landscape and ensure that any significant trees, will where possible, be protected during both the design and construction periods. Trees within the site boundary will be surveyed individually as the existing site conditions allow. 9.5 Visual Impact Assessment Methodology 9.5.1 The assessment of the potential visual impact of the scheme comprises two distinct parts: • Baseline survey to describe existing visual context − Identification of visual envelope − Identification of visually sensitive receivers (VSRs) • Visual impact assessment based on relative sensitivity of receiver and magnitude of change predicted as a result of the proposal. 9.5.2 The baseline survey of all views towards the proposals is undertaken by identifying: • The visual envelope (or visual zone): area representing