Civil Engineering and Development Department Trunk Road T4, Sha Tin EIA – Executive Summary EXECUTIVE SUMMARY (Environmental Impact Assessment) 1. Introduction 1.1 The existing Tai Po Road (Sha Tin Section) is suffering from traffic congestion during peak hours. The Sha Tin and Ma On Shan District Traffic Study (STMOS) completed in 1995 concluded that provision of Trunk Road T4 would alleviate the congestion. This was further confirmed by a review study undertaken by Transport Department (TD) in 2001 based on the latest estimate of traffic growth. The STMOS also predicted that there would be congestion at critical junctions of the urban road network within the Sha Tin Town Centre during peak hours. Provision of Trunk Road T4 on elevated structures as a direct route would alleviate the congestion at the town centre. 1.2 According to the Preliminary Project Feasibility Study (PPFS) completed by Territory Development Department in February 1997 and the Commissioner for Transport’s Review Report for Trunk Road T4 completed in 2001, completion of Trunk Road T4 by 2009 is recommended. The Strategic Highway Project Review Report No. 9/02-03 in May 2003 stated that T4 has an important role in relieving the local road network and the need for the project is well established. The Final Traffic Impact Assessment Report completed on the current Trunk Road T4 Investigation (Agreement No. CE 1/2002 (HY)) also concludes that Trunk Road T4 would help relieve the congestion of Tai Po Road (Sha Tin Section) and several junctions within the Shatin area and is therefore needed by 2009. 2. Description of the Project “Trunk Road T4” Main Description 2.1 The proposed Trunk Road T4 will connect the southern Sha Tin Road with the northern Shing Mun Tunnel Road and Trunk Road T3 in Tai Wai. It will provide a direct traffic connection between Ma On Shan and Tai Wai / Kwai Chung by-passing the busy Sha Tin Town Centre area. The preliminary layout of the proposed Trunk Road T4 is attached in Figure 1 of this summary. 2.2 The scope of the current Trunk Road T4 Investigation study comprises: (a) The construction of about 1.6km of dual 2-lane elevated carriageway of trunk road standard connecting the proposed Trunk Road T3 and Sha Tin Road. (b) The provision of connections to Trunk Road T3, Shing Mun Tunnel Road and Sha Tin Road. 2.3 This scope is slightly different from the original one in the Project Brief and the EIA Study Brief. Upon the completion of the Value Management Workshop, the connections to Che Kung Miu Road (CKMR) were proposed to be deleted. It was noted that Transport Department confirmed their F:\Projects\IA3008 - Trunk Road T4\Report\EIAO Process\ES\EIA ES ES - 1 Arup-Cinotech v2_0.doc Civil Engineering and Development Department Trunk Road T4, Sha Tin EIA – Executive Summary endorsement of the deletion of the CKMR connection in a letter dated 23 December 2003. Justification for the Project 2.4 Based on survey results and the link capacity analyses of the latest traffic impact assessment (TIA) study conducted under Agreement No. CE 1/2002 (HY), Tai Po Road (Sha Tin Section) is already experiencing close to capacity conditions during peak hours. This link, which serves as the direct access to T3 if T4 is not in place, would degrade further in performance and experience a V/C ratio of 1.11 by 2009. It is anticipated that this link would continue to get worse in later years unless mitigation measures are applied. The performance pattern of Tai Po Road (Sha Tin Section) indicates that T4 could relieve this link in 2009 and 2016, indicating that T4 is already needed by 2009. 2.5 The need for T4 by 2009 becomes more apparent when comparing the performances of junctions in the Shatin area in the “without T4” and the “with T4” scenarios. The effect of T4 in alleviating traffic conditions within the Sha Tin Town Centre will be most felt along Sha Tin Rural Committee Road/ Sha Tin Wai Road and Lion Rock Tunnel Road, the key corridors running parallel to T4. The performance of junctions along these key corridors will improve considerably with T4 in place. In particular, the junctions of Yuen Wo Road/ Sha Tin Rural Committee Road, Tai Chung Kiu Road/ Sha Tin Rural Committee Road/ Sha Tin Wai Road and Sha Tin Road Slip Road/ Sha Tin Wai Road will be over-loaded without T4 in design years 2009 and 2016, but will operate within capacity if T4 is implemented. Considering the number of problematic junctions which could be relieved by T4, as well as T4’s overall positive impact on Tai Po Road (Sha Tin Section) and other local junctions, it is clear that T4 is needed by 2009 and more so by 2016. 3. Environmental Impact Assessments 3.1 Noise Construction Phase 3.1.1 The construction noise impacts without any mitigation measures on the identified noise sensitive receivers (NSRs) would be adverse. With implementation of appropriate noise mitigation measures such as use of quiet equipment, rescheduling of noisy construction activities and erection of temporary barriers and enclosures, the cumulative construction noise levels with consideration of the concurrent project of Trunk Road T3 at all the representative NSRs except for Christ College (CC) would be reduced to the planning limits. 3.1.2 It was estimated that the construction period for such activities in front of CC would last for about F:\Projects\IA3008 - Trunk Road T4\Report\EIAO Process\ES\EIA ES ES - 2 Arup-Cinotech v2_0.doc Civil Engineering and Development Department Trunk Road T4, Sha Tin EIA – Executive Summary one month. It was recommended to carry out the construction of the retaining wall during the non-examination period or the long school holidays. In addition, CC was already installed with air conditioners under the school insulation programme. Therefore, the short-term residual construction noise impact would be minimized as far as possible. Operational Phase 3.1.3 Traffic noise impacts are considered as the major issue in this project, for the proposed T4 would run through the well developed areas with high-rise residential buildings and villages on both sides of the road. The unmitigated traffic noise levels at the identified NSRs are predicted to exceed the noise limits owing to the high traffic volume and the close proximity to the nearby NSRs. 3.1.4 Noise mitigation measures including enclosures, cantilevered barriers and vertical barriers on the road segments have been thoroughly examined. With implementation of the purpose-built noise mitigation measures, the traffic noise levels arising from new Trunk Road T4 at all the NSRs will be reduced to meet the noise criteria but some of the NSRs would still exceed the noise criteria due to the noise contribution from the existing roads and T3. 3.1.5 Figures 2a-c shows the proposed noise mitigation scheme on the Trunk Road T4 for the existing noise sensitive receivers while Figure 3 depicts the recommended noise mitigation measures for the planned Che Kung Temple Station Development. 3.1.6 For those NSRs still having high traffic noise exposure, an eligibility test for noise insulation programme was examined under ExCo directive but no NSR fulfilled all three eligibility criteria. Therefore, there will be no insurmountable traffic noise impact during the operational phase. 3.2 Air Quality Construction Phase 3.2.1 Exceedances of 1-hour construction dust guideline at some identified air sensitive receivers (ASRs) are predicted during construction without any mitigation measures. With implementation of the dust suppression measures such as regular water-spraying and good site practice, the mitigated construction dust levels at all ASRs would comply the relevant air quality objectives (AQOs) and the construction dust guideline. No residual dust impact is anticipated. Operational Phase 3.2.2 With installation of the noise mitigation measures on the road segments, the secondary air quality impacts arsing from vehicles have been investigated by using the CALINE4 model. According to the modelling results, the predicted pollutant concentrations are below the relevant AQOs. No F:\Projects\IA3008 - Trunk Road T4\Report\EIAO Process\ES\EIA ES ES - 3 Arup-Cinotech v2_0.doc Civil Engineering and Development Department Trunk Road T4, Sha Tin EIA – Executive Summary residual air quality impact during operational phase is expected and no mitigation measures are required. 3.3 Water Quality Construction Phase 3.3.1 The potential impacts on water quality have been identified in this assessment. These potential sources of impact comprise construction runoff and drainage; debris, refuse and liquid spillages from general construction activities; and sewage effluents from the construction workforce. Minimization of water quality deterioration would be achieved through implementing adequate mitigation measures such as control measures on drainage from the site to minimize construction run-off. Proper site management and good housekeeping practices are also be required to ensure that construction wastes would not enter the nearby open drainage channels. Sewage effluent arising from the construction workforce also require appropriate treatment measures, such as through provision of portable chemical toilets. As such, with implementation of these recommended mitigation measures, no insurmountable impact on the water quality is anticipated during the construction phase. Operational Phase 3.3.2 With adoption and incorporation of appropriate drainage collection and treatment systems, no detrimental operational water quality impact is expected. Provided that appropriate drainage facilities and regularly cleaning and maintenance practices are implemented, the water quality impact during the operational phase is not expected. 3.4 Waste Management 3.4.1 The quantities of wastes, which would be generated for the Project, have been estimated in the EIA Report.