Draft Executive Summary for C2008

Table 3.1a Summary of Environmental Assessments

	Construction	Operation	Residual Impact
Project Description	· Construction 10km of trunk sewers/rising mains and 7 sewage pumping stations	· Operations of 7 SPSs · The expansion of sewers/rising mains networks under the Stage 1 works of this Project to deliver domestic sewage for treatment at Yuen Long Sewage Treatment Works will extend coverage area of sewage collection and thus will allow 33% more sewage flow to be treated. Untreated sewage would otherwise be discharged to inland waters.	n/a
Air Quality	With the implementation of mitigation measures, no adverse construction dust impacts are envisaged.	With the installation of odour removal systems at the sewage pumping stations, no adverse odour nuisance is envisaged.	No adverse residual impact is expected.
Noise	The construction noise assessment indicated that unmitigated sources of construction noise associated with the proposed development and projects in the vicinity (ie the non designated elements of this project and Kam Tin Bypass; Yuen Long Bypass Floodway; Yuen Long, Kam Tin, Ngau Tam Mei and Tin Shui Wan Drainage Improvement Works Stage 1) would cause exceedances of the daytime construction noise criteria at the majority of the nearby NSRs. Mitigation measures such as quiet plant, limiting the use of PME and movable noise barriers/enclosures have been recommended where appropriate. In view of the close proximity of some NSRs to the sewer laying works, exceedances are still predicted even allowing for all practical mitigation measures being implemented.	Noise impacts due to the proposed sewage pumping stations would not be insurmountable provided that the planning recommendations described in this report are followed.	Exceedances of the daytime construction noise criteria are predicted at the following NSRs: · Scattered House near Kam Tin Shi (D1) · Yuk Yat Garden Phases II (D4) · Scattered House in Nam Sang Wai (D12) · Kam Tin Shi North (D22) · Scattered House beside Kam Sheung Life Lutheran Church (D30) · Ng Ka Tsuen (D33) · Planned Residential Development beside Kam Tsin Wai (A-YL-KTS-174) (D36) · Kam Tsin Wai (D38) · Kam Kong Villa (D39) · Planned Residential Development near Shui Tsan Tin (DPA/YL-KTS/-YL-KTS-82) (D40)
Water Quality	With the implementation of mitigation measures, no adverse water quality impacts are envisaged.	Reductions in pollutant loads to the streams and watercourses adjacent to the areas to be connected to the new sewerage system are estimated as follows: · Suspended solids – 320 kg day^-1; · BOD – 340 kg day^-1; · COD – 730 kg day^-1; · TKN – 70 kg day^-1; · Ammonia – 40 kg day^-1; and · E. coli – 3.5x1014 cfu day^-1. These loads represent approximately 10% of the total pollutant loads to the inland waterways.	No residual impact is expected.
Waste	With the implementation of good waste management practices, no adverse waste management impact is envisaged.	With the implementation of good waste management practices, no adverse waste management impact is envisaged.	No residual impact is expected.
Land Contamination	Based on the available information and the findings of the site inspections, there is no evidence to suggest that the potentially contaminated sites identified in this study will be the source of significant off-site migration of contaminants to the proposed alignment of the sewer and locations of the pumping stations.	No operational impact is expected.	No residual impact is expected.
Ecology	Direct habitat loss of approximately 0.26 ha cultivated lands of moderate ecological value, including the proposed location of pumping stations P4 (0.09 ha), P6 (0.07 ha) and P7 (0.10 ha), approximately 0.15 ha of abandoned fishpond (P2) and approximately 1.02 ha of urbanised/developed areas as a result of landtake for the construction and related temporary storage areas.	No operational impact is expected.	There will be the loss of 0.15 ha of abandoned and partially filled fishpond with low impact and other low quality habitats including 0.26 ha of cultivated land and 1.02 ha of urbanised/disturbed area. No adverse residual impact (direct or indirect) is expected due to the construction and operation of the sewerage system and pumping stations after the implementation of the proposed mitigation measures.
	Indirect impact to the associated fauna, in the sections that the sewer crosses over the MDC.
	Indirect impact to the birds inside WCA and WBA due to the increased noise impact, human activities and disturbance such as storage or dumping of construction material and construction site runoff.
	Indirect impact to the surrounding habitats and associated wildlife arising from increased noise impact, human activities and disturbance such as storage or dumping of construction material and construction site runoff.
Fisheries	It is estimated that approximately 0.15 ha of the abandoned fish pond will be lost through construction of pumping station P2. This impact is not expected to be of concern as the fish pond is inactive and currently abandoned.	No operational impact is expected.	There are no residual impacts expected to occur to aquaculture fisheries resources and operations as a result of the construction and operation of the proposed sewerage system and pumping stations.

Cultural Heritage	No direct impact to the identified historical buildings or features is expected.	No operational impact is expected.	No residual impact is expected.
	Set back of construction works to avoid encroachment of safe margins, attention of site works to remove underlying obstructions, careful selection of construction plant and construction method, structure survey of Ng Ka Tsuen historic compound and vibration monitoring have been recommended to ensure that the structural integrity of the historic compound at Ng Ka Tsuen would not be affected by the construction of the Ng Ka Tsuen Sewage Pumping Station. Precaution on start up and stopping of pumps and noise radiation is also recommended to ensure any operational vibration impact is kept to a minimum.
	No significant archaeological deposits would be impacted by most of the proposed sewerage facilities, except Shui Tsan Tin, Ng Ka Tsuen and Pang Ka Tsuen Sewage Pumping Stations. A six month period has been recommended to allow for an archaeological field investigation to be undertaken at each of these proposed pumping station sites and once the land is resumed and access is gained, but before any construction takes place. Mitigation measures agreed with the AMO, should be implemented to mitigate any potential impacts. Before undertaking any fieldwork, a qualified archaeologist should obtain a Licence from the Authority under the Antiquities and Monuments Ordinance (Cap. 53).
Landscape and Visual	“Significant” visual impact is predicted at the historic house at Ng Ka Tsuen (1C). “Moderate adverse” landscape impact is predicted to the Village Development LCU during construction. “Slight/Moderate Adverse” visual impacts to viewer groups at Sensitive Visual Receivers (SVR) during construction, at the following locations. · Sha Po Tsuen Residential Development (1A); · Kam Tin Shi Residential Development (1B); · Residential Developments near Shui Tsan Tin SPS (1D); · Residential Developments near Pang Ka Tsuen SPS (1E); · Residential Development near Leung Uk Tsuen SPS (2A); and · Residential Developments west of Pang Ka Tsuen (3D).	“Significant” visual impact is predicted at the historic house at Ng Ka Tsuen (SVR-1C) due to the close proximity to Ng Ka Tsuen SPS. “Slight/Moderate Adverse” visual impacts are predicted to those viewer groups at SVRs identified for the construction phase. The source of the visual impact is SPSs in proximity to residents during the operation phase of these SPSs.	The incorporation of mitigation measures into the Project will be effective in reducing “Moderate/Significant Adverse” construction impacts in the Village Development LCU to “Slight Adverse”. The incorporation of mitigation measures into the Project will be effective in reducing “Significant” to “Moderate” visual impacts to SVR-1C during construction and from “Significant” to “Moderate” and “Negligible” visual impacts at “Day 1” and “Year 10”, respectively during operations. The incorporation of mitigation measures into the Project will be effective in reducing “Slight/Moderate Adverse” to “Slight Adverse” visual impacts to SVRs-1A, 1B and 3D and to “Negligible” to SVRs- 1D, 1E and 2A during construction and from “Slight/Moderate Adverse” to “Slight adverse” and “Negligible” visual impacts at “Day 1” and “Year 10”, respectively during operations.

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3 Summary of Environmental Assessments