3 CONSIDERATION OF ALTERNATIVES

3.1 Scenarios with and without the Project

Without the Project

3.1.1 According to the traffic impact assessment for future year taking into account the planned and committed developments including ARQ, capacity problems are anticipated to be experienced at the following key road links and junctions:

· The junction of Sau Mau Ping Road / Lin Tak Road is currently overloaded (Reserve Capacity < 0%) and queuing is observed at Sau Mau Ping Road (SMPR) eastbound approach during AM peak hour, which is mainly due to the heavy traffic flows and the delay caused by the existing signalized junction. With the existing junction layout, it is anticipated that the problem of insufficient junction capacity and vehicle queuing at Sau Mau Ping Road will be worsened upon the intake of ARQ.

· Frequent on-street pick-up/drop-off activities are observed along the existing Lin Tak Road during the peak hour periods. The traffic at Lin Tak Road is blocked by the stopping vehicles carrying out the pick-up/drop-off activities on the carriageway, and the road capacity of Lin Tak Road is greatly reduced by the stopping vehicles. In future, only limited trips from ARQ would travel via Lin Tak Road, and the road capacity problem would be slightly worsened based on the current road layout.

· The junction of Clear Water Bay Road / On Sau Road would operate with insufficient junction capacity, i.e. reserve capacity < 0%, upon the intake of ARQ population.

· Clear Water Bay Road westbound prior to the merging point with Shun Lee Tsuen Road currently has 1 traffic lane only, this section would be overloaded (traffic volume / capacity ratio > 1.2) upon the intake of ARQ population.

With the Project/Benefits of the Project

3.1.2 After the construction of the road improvement works, the abovementioned junction capacity and road capacity would be improved as follows:

Ÿ In general, the road improvement works enhance the junction capacity and road capacity and hence the queuing and idling time of vehicles would be reduced. This would reduce the air emissions from idling. With the implementation of the noise mitigation measures, the noise sensitive receivers in the vicinity would benefit from a less noisy environment.

Ÿ The signalized junction of Lin Tak Road / Sau Mau Ping Road would be modified into a free-flow junction. This would significantly improve the queuing issue due to the delay of signalized junction. The lay-bys on both sides of Lin Tak Road would be lengthened for frequent pick-up/drop-off activities such that the blockage issue would be eliminated. In addition, the existing sensitive receivers (e.g. Po Tat Estate and Hong Wah Court) would benefit from a less noisy environment after the erection of noise barriers at Sau Mau Ping Road and the cantilever noise barrier on the newly constructed flyover.

Ÿ The Method-of-Control (MOC) of the signalized junction at Clear Water Bay Road / On Sau Road would be modified to improve the junction performance. In addition, the existing sensitive receivers (e.g. Sienna Garden and Tai Pan Court) would benefit from a less noisy environment after the erection of noise enclosure at the junction of Clear Water Bay Road / On Sau Road. Furthermore, the proposed scheme with U-turn facility on the west side of On Sau Road would reduce woodland loss and require fewer trees to be felled.

Ÿ The road capacity would be enhanced at the widened section of New Clear Water Bay Road westbound and the new merging lane of Shun Lee Tsuen Road. In addition, the existing sensitive receivers (e.g. Shun Lee Estate) would benefit from a less noisy environment after the erection of noise enclosure at New Clear Water Bay Road.

3.1.3 In conclusion, the implementation of the Project would not only cope with the additional traffic generated from the ARQ Development and but also improve the existing traffic condition. The residents could benefit from the Project by spending less time in congestion, exposing to fewer emissions from idling vehicles and enjoying a less noisy environment with the implementation of the proposed noise mitigation measures.

3.2 Consideration of Alternative Development Options

General

3.2.1 To assess the suitability of the alternative options, considerations were based on environmental impacts, engineering issues and disturbance to the community.

3.2.2 For each RIW, options of the alignment and structural configurations were developed and reviewed. The review has taken into account engineering feasibility, site constraints, construction programme and environmental considerations.

RIW at J/O Lin Tak Road and Sau Mau Ping Road

3.2.3 To assess the suitability of the alternative options of this RIW, considerations were made on environmental, engineering, planning and public nuisance during the decision making process.

3.2.4 For this RIW, two options of the alignment and structural configurations were developed and reviewed. The review has taken into account engineering feasibility, site constraints, construction programme and environmental considerations.

Option A

3.2.5 Option A (Figure 3.1) is the layout recommended in the FS stage mainly comprises of the following works:

· A new flyover overpassing the junction of Sau Mau Ping Road, Lin Tak Road and Tseung Kwan O Road. The alignment of the proposed flyover is partly encroached to the western footpath of the existing Sau Mau Ping Road viaduct and the existing viaduct is required to be modified to facilitate the proposed viaduct construction.

· To accommodate the western abutment of the proposed flyover at Sau Mau Ping Road, the Sau Mau Ping Road eastbound is shifted northwards encroaching into Po Tak Estate’s slope (Slope No. SMPR-A), and land resumption at Po Tak Estate will be required.

· To realign Tseung Kwan O Road slip road to Sau Mau Ping Road southward involving reform of the existing slope on the southern side of Tseung Kwan O Road slip road (Slope No. SMPR-B) and construction of bored pile retaining wall on top of such reformed slope will be required.

· To construct 2 long lay-bys at both bounds of Lin Tak Road and local widening of Lin Tak Road southbound from 1 lane to 2 lanes opposite Hing Tin Estate. The works involve rock excavation on the existing slopes along Lin Tak Road (Slope No. LTR-A).

· To modify the junction of Lin Tak Road and Sau Mau Ping Road providing a free-flow lane from Sau Mau Ping Road eastbound to Tseung Kwan O Road slip road. The modification works involve modifying the existing traffic signalization system and the provision of a retaining wall along the northern edge of Tseung Kwan O Road slip road.

Option B

3.2.6 Option B (Figure 3.1) is also developed includes the following major works:

· A new flyover is also proposed under this option overpassing the junction of Sau Mau Ping Road, Lin Tak Road and Tseung Kwan O Road but the alignment of the proposed flyover is skewed to avoid encroaching to the footprint of the existing Sau Mau Ping Road viaduct. No modification works to the existing viaduct are required.

· Sau Mau Ping Road eastbound is shifted southwards to accommodate the western abutment of the proposed flyover at Sau Mau Ping Road. This would avoid encroaching into Po Tak Estate’s slope and no land resumption is required. The existing Slope No. SMPR-A will not be affected.

· Under this option, Tseung Kwan O Road slip road to Sau Mau Ping Road should be realigned further southwards. Reforming of the existing slope (Slope No. SMPR-B) is still required and construction of bored pile retaining wall on top of the reformed slope is proposed.

· Under this option, the proposed 2 long lay-bys at each bound of Lin Tak Road are realigned following the alignment of the existing Lin Tak Road as far as possible. The extent of rock excavation on the existing slopes along Lin Tak Road (Slope No. LTR-A) is minimized. Besides, the upstream of Lin Tak Road southbound only has one traffic lane; this option omits the local widening of Lin Tak Road southbound opposite Hing Tin Estate, which could minimize the corresponding rock excavation at the existing slope i.e. southern end of Slope No. LTR-A.

Option Evaluation

3.2.7 The comparison of the engineering works involved between Option A and Option B is shown below Table 3.1:

Table 3.1 Comparison of the Engineering Works Involved between Option A and Option B

Criteria	Alignment Option
Criteria	Option A	Option B
Impact to Existing Slopes	Rock excavation on the existing slope, Slope No. LTR-A, at Lin Tak Road. Resume the existing slope, Slope No. SMPR-A, of Po Tak Estate. Reform the existing slope, Slope No. SMPR-B, at Tseung Kwan O Road slip road.	Rock excavation on the existing slope, Slope No. LTR-A, at Lin Tak Road is still required but minimized. Avoid encroaching to the existing slope, Slope No. SMPR-A, of Po Tak Estate. Reform the existing slope, Slope No. SMPR-B, at Tseung Kwan O Road slip road.
Land Issue	Land resumption is required for the proposed existing slope, Slope No. SMPR-A, of Po Tak Estate.	Land resumption is not required under this option.
Transport and Operation Planning	Alignment design will satisfy the design requirements in general.	Alignment design will satisfy the design requirements in general.
Engineering Issues	The proposed road layout requires diversion of the existing utilities at Sau Mau Ping Road and Lin Tak Road. The proposed flyover and free flow lane will improve the capacity of the J/O Lin Tak Road and Sau Mau Ping Road. The works involve modification of the existing Sau Mau Ping Road viaduct.	The proposed road layout requires diversion of the existing utilities at Sau Mau Ping Road and Lin Tak Road. The proposed flyover and free flow lane will improve the capacity of the J/O Lin Tak Road and Sau Mau Ping Road. The alignment of flyover is slightly skewed to avoid the modification works of the existing Sau Mau Ping Road viaduct. The alignment design of the proposed flyover is complying with the relevant design requirements.
Construction Duration	Similar to both options.	Similar to both options.
Disturbance to the Community	Due to larger dust and noise impact, a greater disturbance to the community would be expected.	A less disturbance to the community would be expected.

3.2.8 The comparison of potential environmental benefits and disbenefits are shown below Table 3.2.

Table 3.2 Comparison of Potential Environmental Benefits and Disbenefits Involved between Option A and Option B

Criteria	Alignment Option
Criteria	Option A	Option B
Construction Dust	Extensive slope cutting would be required at the slopes outside Po Tat Estate (Slope No. SMPR-A) and along Lin Tak Road (Slope No. LTR-A). Removal of the flange of the existing Sau Mau Ping Road viaduct’s abutment would also be a source of dust generation. The potential for dust impact is higher comparing to Option B.	Extent of slope cutting at the slopes outside Po Tat Estate (Slope No. SMPR-A) and along Lin Tak Road (Slope No. LTR-A) is avoided and minimized. Removal of the flange of the existing Sau Mau Ping Road viaduct’s abutment is no longer required. The dust impact is reduced comparing to Option A.
Construction Noise	Noise sensitive receivers in Po Tat Estate are likely to be affected due to the large scale of slope cutting. Noise impact is envisaged during the rock excavation along Lin Tak Road.	Since no slope cutting is required at Po Tak Estate, noise sensitive receivers in the vicinity of Po Tak Estate would be less affected. Noise impact is envisaged during the rock excavation along Lin Tak Road but the extent of cut slope is minimized. Noise impact is less comparing to Option A.
Waste Management	Large amount of C&D material is expected due to slope cutting.	Less C&D material will be generated under this option.
Water Quality	Wastewater is likely to be generated from slope works.	Similar amount of wastewater is likely to be generated from slope works.
Ecological Impact	The vegetation on the existing slope, Slope No. SMPR-A, outside Po Tat Estate would be directly impacted.	The affected vegetation on the Slope No. SMPR-A, outside Po Tat Estate would not be directly impacted.
Landscape Impact	The vegetation on the existing slope, Slope No. SMPR-A, outside Po Tat Estate would be greatly affected. These trees would be felled or transplant.	As the road alignment is shifted away from the slope of Po Tak Estate, Slope No. SMPR-A, the extent of affected trees is minimized.
Visual	Temporary stage during construction The existing rock slope at Lin Tak Road (Slope No. LTR-A) will be set back and then reformed to another rock cut slope. The surface of the existing Slope LTR-A is natural rock with minimal trees. During the construction stage, the concerned slope will be excavated in stages and the surface can still be visualised as far as possible. Therefore, low adverse visual impact is anticipated. Permanent stage upon completion The affected slopes at Sau Mau Ping Road, Slope Nos. SMPR-A and SMPR-B, will be reformed to similar conditions as the existing. Low adverse visual impact is anticipated.	Temporary stage during construction Similar to Option A, the excavation on Slope No. LTR-A will be carried out in stages and the surface can still be visualised as far as possible during construction stage. Therefore, low adverse visual impact is anticipated. Permanent stage upon completion The affected Slope No. SMPR-B will be reformed to similar conditions as the existing. Low adverse visual impact is anticipated.

3.2.9 According to the comparison in Tables 3.1 and 3.2, the evaluation is summarised in Table 3.3 as below:

Table 3.3 Summary of Options Evaluation for RIW at J/O Lin Tak Road and Sau Mau Ping Road

	Option A		Option B
Traffic Engineering	Desirable	Alignment design complied with the design standard but require modification of the existing Sau Mau Ping Road viaduct.	Desirable	Alignment design complied with the design standard but modification of the existing Sau Mau Ping Road viaduct is avoided.
Require land Resumption of Private Land	Yes	Proposed layout has been encroached into Slope No. SMPR-A that fall within Po Tak Estate.	No ✓
Volume of Excavation	More	Excavation of Slope No. LTR-A at Lin Tak Road is expected to be large.	Less ✓	Excavation volume of Slope No. LTR-A is minimized.
Construction Dust	More	Modification of the existing Sau Mau Ping Road is a dust generation source.	Less ✓	Avoid modification of the existing Sau Mau Ping Road can eliminate a dust generation source.
Construction Noise	More	More excavation of Slope No. LTR-A at Lin Tak Road, higher construction noise impact.	Less ✓	Less excavation of Slope No. LTR-A at Lin Tak Road, lower construction noise impact.
Ecological Impact	More	Greater impact due to vegetation removal at Slope No. SMPR-A.	Less ✓	Less impact as Slope No. SMPR-A will not be affected.
Landscape Impact	More	More excavation of the existing slopes along Sau Mau Ping Road and Lin Tak Road, more existing greening on these slopes is affected.	Less ✓	Less excavation of the existing slopes along Sau Mau Ping Road and Lin Tak Road, less existing greening on these slopes is affected.
Visual Impact	Slight during construction and slight during operation	During construction, the existing rock face can still be visualised. Upon completion, all the affected slopes will be reformed to similar conditions as the existing.	Slight during construction and slight during operation	During construction, the existing rock face can still be visualised. Upon completion, all the affected slopes will be reformed to similar conditions as the existing.
			More Desirable

3.2.10 Option B has been determined having less environmental impacts and it provides overall environmental benefits over the other option, and presents the optimum scheme from an operational and environmental perspective.

RIW at J/O Clear Water Bay Road and On Sau Road and J/O Clear Water Bay Road and New Clear Water Bay Road

3.2.11 To assess the suitability of the alternative options of this RIW, considerations were made on environmental, engineering, planning and public nuisance during the decision making process. For this RIW, four options of the alignment and structural configurations were developed and reviewed. The review has taken into account engineering feasibility, site constraints, construction programme and environmental considerations.

Option C

3.2.12 Option C (Figure 3.2) is the layout recommended in the FS stage mainly comprises of the following works:

· To add a new U-turn facility, at approx. 200m from the eastern side of the junction of Clear Water Bay Road / On Sau Road, for the traffic at Clear Water Bay Road eastbound turning into the westbound carriageway of Clear Water Bay Road. An additional traffic lane is proposed at the westbound carriageway of Clear Water Bay Road for traffic turning into On Sau Road.

· The existing slope along the Clear Water Bay Road westbound, Slope No. CWBR-A, will be cut to facilitate the proposed U-turn facility.

· Modify the signalization of junctions of Clear Water Bay Road / On Sau Road and New Clear Water Bay Road / Clear Water Bay Road.

Option D

3.2.13 Option D (Figure 3.2) is also developed including the following major works:

· Alternative location for the U-turn facility is proposed, at approx. 150m from the western side of the junction of Clear Water Bay Road / On Sau Road, for the traffic from On Sau Road heading to Sai Kung travelling via Clear Water Bay Road westbound turning into Clear Way Bay Road eastbound. Under this option, traffic from Clear Water Bay Road eastbound can have a direct right turn to On Sau Road.

· The existing slopes between Clear Water Bay Road eastbound and Fei Ha Road, Slope No. CWBR-B, will be cut to facilitate the proposed U-turn facility.

· Modify the signalization of junctions of Clear Water Bay Road / On Sau Road and New Clear Water Bay Road / Clear Water Bay Road.

Option E

3.2.14 Option E (Figure 3.2) is developed based on Option D shifting the U-turn facility southward including the following major works:

· The proposed U-turn facility is similar to Option D, at approx. 150m from the western side of the junction of Clear Water Bay Road / On Sau Road. This U-turn facility allows the traffic from On Sau Road heading to Sai Kung travelling via Clear Water Bay Road westbound turning into Clear Way Bay Road eastbound. Again, this option allows traffic from Clear Water Bay Road eastbound turning directly to On Sau Road.

· It is found that the maximum level difference between Clear Water Bay Road and New Clear Water Bay Road is over 12m and bored piles should be constructed along Clear Water Bay Road to retain such high level difference. Furthermore, the existing Slope No. CWBR-C is stabilized by soil nails and these soil nails will obstruct the construction of bored piles. Hence, shifting the proposed U-turn facility southward is not a wise design.

Option F

3.2.15 Option F (Figure 3.2) is proposed using a roundabout at the J/O Clear Water Bay Road and On Sau Road and this option mainly comprises of the following works:

· To add a roundabout at the junction of Clear Water Bay Road / On Sau Road. This can facilitate traffic at Clear Water Bay Road eastbound turning into On Sau Road directly and from On Sau Road turning into Clear Water Bay Road westbound.

· The signalized junction of Clear Water Bay Road / On Sau Road will be removed.

· However, there are high traffic volumes at the junction approaches and the proposed roundabout option will not be able to handle the traffic flows, long queue would be found at Clear Water Bay Road westbound approach. Also, discharge of vehicles could not be controlled at roundabout, and it could not be link up with the adjacent signalized junction (downstream junction of Clear Water Bay Road / New Clear Water Bay Road), vehicles stacking in between two junctions would likely tail back to the roundabout and the operation of roundabout would be adversely affected. As this option can’t serve the function requirements satisfactorily, this option is considered to be technically not favourable.

Option evaluation

3.2.16 As Options E and F are technically not favourable as described in Para. 3.2.13 and 3.2.14, only Options C and D are evaluated in details and the comparison of the engineering works involved between Option C and Option D is shown below in Table 3.4:

Table 3.4 Comparison of the Engineering Works Involved between Option C and Option D

Criteria	Alignment Option
Criteria	Option C	Option D
Impact to Existing slopes	The existing slopes along Clear Water Bay Road westbound, Slope No. CWBR-A, will be cut to facilitate the proposed U-turn facility.	The existing slopes between Clear Water Bay Road eastbound and Fei Ha Road, Slope No. CWBR-B, will be cut to facilitate the proposed U-turn facility.
Land Issue	Land resumption is not required under this option.	Land resumption is not required under this option.
Transport and Operation Planning	Alignment design will satisfy the design requirements in general.	Alignment design will satisfy the design requirements in general.
Engineering Issues	The proposed road layout requires diversion of the existing utilities at the Clear Water Bay Road eastbound footpath. After entering into the U-turn facility, weaving at Clear Water Bay Road westbound is required for traffic heading to On Sau Road.	The proposed road layout requires diversion of the existing utilities at the Clear Water Bay Road eastbound footpath. Traffic from Clear Water Bay Road eastbound can have a direct right turn to On Sau Road. It is more convenient for road users heading back to the development of ARQ.
Construction Duration	Similar to both options.	Similar to both options.
Disturbance to the Community	Proposed U-turn facility is more far away from Sienna Garden but closer to Taipan Court. Hence, it is expected that less disturbance to the residents in Sienna Garden but more disturbance to those in Taipan Court.	Proposed U-turn facility is more far away from Taipan Court but closer to Sienna Garden. Hence, it is expected that less disturbance to the residents in Taipan Court but more disturbance to those in Sienna Garden.

3.2.17 The comparison of potential environmental benefits and disbenefits are shown below in Table 3.5.

Table 3.5 Comparison of Potential Environmental Benefits and Disbenefits Involved Between Option C and Option D

Criteria	Alignment Option
Criteria	Option C	Option D
Construction Dust	Dust will be generated from the slope excavation works along Clear Water Bay Road westbound, Slope No. CWBR-A.	Dust will be generated from the slope excavation works between Clear Water Bay Road eastbound and Fei Ha Road, Slope No. CWBR-B.
Construction Noise	Noise sensitive receivers in Sienna Garden will be affected due to the slope excavation works.	Noise sensitive receivers in Sienna Garden will be affected due to the slope excavation works.
Waste Management	More C&D material is expected as the extent of slope excavation is larger than the other option.	Less C&D material will be generated under this option.
Water Quality	Wastewater is likely to be generated from slope works.	Similar amount of wastewater is likely to be generated from slope works.
Ecological Impact	Woodland habitat of moderate to high ecological value, including five flora species of conservation importance, on Slope No. CWBR-A would be directly impacted.	Woodland habitat of low ecological value, including two flora species of conservation importance, on Slope No. CWBR-B would be directly impacted.
Landscape Impact	The vegetation on slope features along Clear Water Bay Road westbound, Slope No. CWBR-A, would be affected.	The vegetation on slope features between Clear Water Bay Road eastbound and Fei Ha Road, Slope No. CWBR-B, would be affected. Less vegetation is affected under this option.
Visual	Temporary stage during construction The existing greening on Slope No. CWBR-A will be removed for the construction of the proposed U-turn facility. Permanent stage upon completion The affected slope will be reformed and compensatory planting can be proposed to mitigate the visual impact.	Temporary stage during construction The existing greening on Slope No. CWBR-B will be removed for the construction of the proposed U-turn facility. The extent of the affected slope is smaller in comparing to Option C. Hence, visual impact is lower under this option. Permanent stage upon completion The affected slope will be reformed and compensatory planting can be proposed to mitigate the visual impact.

3.2.18 According to the comparison in Tables 3.4 and 3.5, the evaluation is summarised in Table 3.6 as below:

Table 3.6 Summary of Options Evaluation for RIW at J/O Clear Water Bay Road (CWBR) and On Sau Road and J/O Clear Water Bay Road (CWBR) and New Clear Water Bay Road (NCWBR)

	Option C		Option D
Traffic Engineering	Less Desirable	Road users on CWBR eastbound heading back to On Sau Road need to take longer route i.e. using the U-turn facility. Weaving at Clear Water Bay Road will happen.	More Desirable ✓	More direct route for road users on CWBR eastbound heading back to On Sau Road. No weaving problem. Traffic from On Sau Road to CWBR eastbound, of which the traffic volume is small, will make use the proposed U-turn facility under this option.
Require Land Resumption of Private Land	No	No resumption of private land is anticipated.	No	No resumption of private land is anticipated.
Volume of Excavation	More	Excavation of Slope No. CWBR-A will be required.	Less ✓	Excavation of Slope No. CWBR-B will be required and this option involves less excavation.
Construction Dust	More	Dust will be generated from the slope excavation works along Clear Water Bay Road westbound, Slope No. CWBR-A.	Less ✓	Less dust will be generated under this option as the extent of affected slope is less.
Construction Noise	Similar to both options and can be mitigated	Construction noises due to the construction of roadwork, slope works, noise mitigation, etc can be mitigated by restricted working hours and provision of suitable silencer.	Similar to both options and can be mitigated	Construction noises due to the construction of roadwork, slope works, noise mitigation, etc can be mitigated by restricted working hours and provision of suitable silencer.
Ecological Impact	More	Woodland of higher ecological value including five species of conservation importance would be directly impacted.	Less ✓	Woodland of lower ecological value including only two species of conservation importance would be directly impacted.
Landscape Impact	More	More excavation of the existing slope, Slope No. CWBR-A, more existing greening on these slopes is affected.	Less ✓	Less excavation of the existing slopes along Sau Mau Ping Road and Lin Tak Road, less existing greening on these slopes is affected.
Visual Impact	Moderate during construction and slight during operation	During the construction stage, the existing greening on Slope No. CWBR-A will be removed for the construction of U-turn facility. Medium visual impact is anticipated. Upon completion, the affected slope, Slope CWBR-A will be reformed to similar conditions as the existing.	Moderate during construction and slight during operation	During the construction stage, the existing greening on Slope No. CWBR-B will be removed for the construction of U-turn facility. Medium visual impact is anticipated. Upon completion, the affected slope, Slope CWBR-B will be reformed to similar conditions as the existing.
			More Desirable

3.2.19 Option D has been determined having less environmental impacts and it provides overall environmental benefits over the other option, and presents the optimum scheme from an operational and environmental perspective.

RIW at J/O New Clear Water Bay Road near Shun Lee Tsuen Road

3.2.20 For this RIW, two options of the alignment and structural configurations were developed and reviewed. The review has taken into account engineering feasibility, site constraints, construction programme and environmental considerations.

Option G

3.2.21 Option G (Figure 3.3) is the layout recommended in the FS stage mainly comprises of the following works:

· Widening a section of 130m length of the existing New Clear Water Bay Road westbound carriageway opposite to Shun Lee Estate from one lane to two lanes.

· Construct a new Shun Lee Tsuen Road slip road within the area of an existing slope to increase the merging length and to improve the sight line for traffic from Shun Lee Tsuen Road.

· Excavation works to the existing slope, Slope No. NCWBR-A, along the existing Shun Lee Tsuen Road slip road.

Option H

3.2.22 Alternative Option H (Figure 3.3) is developed, which is similar to Option G but the widening works is carried out by shifting New Clear Water Bay Road eastbound towards north. It includes the following major works:

· By shifting the New Clear Water Bay Road eastbound northward, approx. 130m length of the existing New Clear Water Bay Road westbound carriageway opposite to Shun Lee Estate can be widened from one lane to two lanes.

· Construct a new Shun Lee Tsuen Road slip road within the area of an existing slope to increase the merging length and to improve the sight line for traffic from Shun Lee Tsuen Road.

· Excavation works to the existing slope, Slope No. NCWBR-B, along the existing New Clear Water Bay Road eastbound.

Option evaluation

3.2.23 The comparison of the engineering works involved between Option G and Option H is shown below in Table 3.7:

Table 3.7 Comparison of the Engineering Works Involved between Option G and Option H

Criteria	Alignment Option
Criteria	Option G	Option H
Impact to Existing Slopes	The existing slope, Slope No. NCWBR-A, along the existing Shun Lee Tsuen Road slip road will be excavated.	The existing slope, Slope No. NCWBR-B, along the existing New Clear Water Bay Road eastbound will be excavated. Most of these existing slopes are having soil nails.
Land Issue	Land resumption is not required under this option.	Land resumption is not required under this option.
Transport and Operation Planning	Alignment design will satisfy the design requirements in general.	Alignment design will satisfy the design requirements in general.
Engineering Issues	The proposed road layout requires minor diversion of the existing utilities at Shun Lee Tsuen Road slip road. This option requires extension of an existing pedestrian subway connecting Shun Lee Street and Shun Lee Tsuen Road.	The proposed road layout requires diversion of many existing utilities at the verge and slow lane of the New Clear Water Bay Road eastbound. This option requires demolition of an existing staircase of Lee On Road viaduct and associated re-provisioning works. This option requires relocate of the existing bus stop at New Clear Water Bay Road eastbound outside Shun Lee Estate. The road alignment of this option will encroach into the planter area of Shun Lee Estate. Modification to both soft and hard landscaping works will be required.
Construction Duration	Duration will be shorter than Option H because the slope excavation works involved less soil nails slopes.	Duration will be longer than Option G because the slope excavation works involved many slopes with soil nails.
Disturbance to the Community	Slope excavation at Slope No. NCWBR-A is closer to Shun Lee Disciplined Services Quarters thus Option G will have more disturbance to the community at Shun Lee Disciplined Services Quarters than Option H.	Slope excavation at Slope No. NCWBR-B is closer to Shun Lee Estate thus Option H will have more disturbance to the community at Shun Lee Estate than Option G.

3.2.24 The comparison of potential environmental benefits and disbenefits are shown below in Table 3.8.

Table 3.8 Comparison of Potential Environmental Benefits and Disbenefits Involved between Option G and Option H

Criteria	Alignment Option
Criteria	Option G	Option H
Construction Dust	Dust will be generated from the slope excavation works along the existing Shun Lee Tsuen Road slip road.	Dust will be generated from the slope excavation works along the New Clear Water Bay Road eastbound.
Construction Noise	Impact to surrounding noise sensitive receivers is similar in both options.	Impact to surrounding noise sensitive receivers is similar in both options.
Waste Management	Similar to both options.	Similar to both options.
Water Quality	Wastewater is likely to be generated from slope works.	Similar amount of wastewater is likely to be generated from slope works.
Ecological Impact	Plantation of low ecological value, including one, planted flora species of conservation importance at the toe of Slope No. NCWBR-A, will be directly impacted.	Plantation of low ecological value at the toe of Slope No. NCWBR-B will be directly impacted.
Landscape Impact	The vegetation at the toe of the slope feature along Shun Lee Tsuen Road slip road, Slope No. NCWBR-A, will be affected. Compensatory planting will be required.	The vegetation at the toe of the slope feature along New Clear Water Bay Road eastbound, Slope No. NCWBR-B, will be affected. Compensatory planting will be required.
Visual	The proposed road improvement under this option is located at the trough of slopes, which is not visually sensitive. The visual impact during construction shouldn’t be significant. Upon completion, the affected slope, Slope NCWBR-A, will be reformed to similar conditions as the existing.	Similarly, the proposed road improvement under this option is located at the trough of slopes, which is not visually sensitive. The visual impact during construction shouldn’t be significant. Upon completion, the affected slope, Slope NCWBR-B, will be reformed to similar conditions as the existing.

3.2.25 According to the comparison in Tables 3.7 and 3.8, the evaluation is summarised in Table 3.9 as below:

Table 3.9 Summary of Options Evaluation for RIW at J/O New Clear Water Bay Road near Shun Lee Tsuen Road

	Option G		Option H
Traffic Engineering	Desirable	Alignment design can satisfy the design requirements in general.	Desirable	Alignment design can satisfy the design requirements in general.
Require Land Resumption of Private Land	No	No resumption of private land is anticipated.	No	No resumption of private land is anticipated.
Volume of Excavation	More desirable ✓	Excavation volume of Slope No. NCWBR-A will be similar to Option H. Requires excavation for subway extension.	Less desirable	Excavation volume of Slope No. NCWBR-B will be similar to Option H but this option involves larger extent of slope with soil nails. Requires demolition of an existing staircase of Lee On Road viaduct, relocation of the existing bus stop, and reprovisioning of the hard and soft landscape works at Shun Lee Estate.
Construction Dust	Similar to both options and mitigable	Dust generated from the Slope No. NCWBR-A, which is similar to Option H.	Similar to both options and mitigable	Dust generated from the Slope No. NCWBR-B, which is similar to Option G.
Construction Noise	Less ✓	Construction noises due to the construction of roadwork, slope works, noise mitigation, etc can be mitigated by restricted working hours and provision of suitable silencer.	More	Construction noises due to the construction of roadwork, slope works, noise mitigation, etc can be mitigated by restricted working hours and provision of suitable silencer. Demolition of the existing staircase of Lee On Road viaduct, relocation of the existing bus stop, and reprovisioning of the hard and soft landscape works at Shun Lee Estate will induce additional construction noise but can be mitigated.
Ecological Impact	Similar to both options	The extent of affected vegetation is similar for both options. The only flora species of conservation importance is artificially introduced (planted) to the environment.	Similar to both options	The extent of affected vegetation is similar for both options.
Landscape Impact	Similar to both options	The extent of affected greening is similar for both options.	Similar to both options	The extent of affected greening is similar for both options.
Visual Impact	Slight during construction and slight during operation	The proposed road improvement under this option is located at the trough of slopes, which is not visually sensitive. The visual impact during construction shouldn’t be significant. The affected slope, Slope NCWBR-A, will be reformed to similar conditions as the existing.	Slight during construction and slight during operation	The proposed road improvement under this option is located at the trough of slopes, which is not visually sensitive. The visual impact during construction shouldn’t be significant. The affected slope, Slope NCWBR-B, will be reformed to similar conditions as the existing.
	More Desirable

3.2.26 Option G has been determined having less environmental impacts and it provides overall environmental benefits over the other option, and presents the optimum scheme from an operational and environmental perspective.

3.3 Consideration of Alternative Construction Methods and Sequences of Works

RIW at J/O Lin Tak Road and Sau Mau Ping Road (Option B)

3.3.1 The main construction activities at the J/O Lin Tak Road and Sau Mau Ping Road as follows:

· Retaining wall along Tseung Kwan O Road slip road to Sau Mau Ping Road;

· Rock slope cutting at Lin Tak Road; and

· A single flyover overpassing the junction of Sau Mau Ping Road, Lin Tak Road and Tseung Kwan O Road.

Retaining wall along Tseung Kwan O Road slip road to Sau Mau Ping Road

3.3.2 L-shape retaining wall and piled retaining wall have been considered. Using L-shape retaining wall requires large amount of deep excavation on the existing slope, Slope No. SMPR-B, in order to achieve sufficient soil mass for the retaining mean. More construction vehicles will be required for exporting the excavated materials in early construction stage as well as to importing the backfilling materials. The size of the L-shape retaining wall is envisaged to be massive. Piled retaining wall was therefore proposed, which could minimize the excavation works as well as to streamline the structural form of the retaining structure that could be visualised by the public. The comparison of the benefits and dis-benefits between L-shape retaining wall and piled retaining wall is illustrated in Tables 3.10 as below:

Table 3.10 Comparison of Benefits and Disbenefits between Different Construction Methods for Retaining Wall along Tseung Kwan O Road Slip Road to Sau Mau Ping Road

	L-shape Retaining Wall		Piled Retaining Wall
Volume of Excavation	More	Large and deep excavation are required to achieve sufficient soil mass.	Less ✓	Only shallow excavation is required for cap construction.
Construction Duration	Longer	Deep excavation requires substantial temporary works erection. Long construction duration is anticipated.	Shorter ✓	Piling works can be commenced at the crest of slope that could be commenced once the works site is available.
Construction Noise	More	Construction noise is mainly induced by the excavation works. More excavation requires longer duration of the construction. Hence, more construction noise impact.	Less ✓	Less excavation would have less construction noise impact. Piles will be sunken by down the hole drilling rig, which will not induce excessive noise.
Construction Dust	Similar to both options	Dust will be generated during excavation works but it can be mitigated.	Similar to both options	Dust will be generated during excavation works and pile installation works but it can be mitigated.
Construction Traffic	More frequent	More excavation would induce more frequent construction traffic	Less frequent ✓	Less excavation would induce less frequent construction traffic

Rock slopes cutting at Lin Tak Road

3.3.3 Cutting the existing rock slopes at Lin Tak Road can be carried out by blasting or drill-and-break methods. However, the rock slopes at Lin Tak Road is very close to Hong Wah Court, Hing Tin Estate as well as Lam Tin High Level Water Service Reservoir and it is not desirable to use blasting method. Drill-and-break method is therefore anticipated.

Sequence of Works

3.3.4 It is envisaged that the rock excavation will be started from the northern end of Lin Tak Road toward the southern end. This could provide more flexibility for the contractor to schedule their works outside the examination period of the nearby school, St. Edward’s Catholic Primary School. The comparison of the benefits and dis-benefits between rock slopes cutting at Lin Tak Road is illustrated in Tables 3.11 as below:

Table 3.11 Comparison of Benefits and Disbenefits between Different Construction Methods for Rock Slopes Cutting at Lin Tak Road

	Blasting		Drill-and-break
Engineering Consideration	Not desirable	The existing rock slope at Lin Tak Road is very close to residential area, i.e. Hong Wah Court and Hing Tin Estate, as well as Lam Tin High Level Water Service Reservoir. Blasting at such location is risky and not permitted.	More desirable ✓	Drill-and-break is a reliable and permitted construction method.
Environmental Consideration	The selection of rock excavation method is determined by engineering consideration. As blasting is not permitted, environmental benefits and dis-benefits will not be further elaborated.

	Sequence of Rock Excavation at Lin Tak Road starts from South to North		Sequence of Rock Excavation at Lin Tak Road starts from North to South
Construction Duration	Volume of excavation remains unchanged. Hence, construction duration will be similar to both options.
Construction Noise	Similar to both options but with less flexibility on the construction planning	Overall construction noise impact will be similar to both sequences of works. However, the construction noise should be further controlled during some critical academic schedules of St. Edward’s Catholic Primary School. Commencement of the excavation works at the southern end of Lin Tak Road would have less flexibility on construction planning.	Similar to both options but with more flexibility on the construction planning ✓	Overall construction noise impact will be similar to both sequences of works. However, excavation works starting from the northern end of Lin Tak Road would allow more flexibility for the contractor to schedule their works outside the critical academic activities of St. Edward’s Catholic Primary School. Hence, the construction noise impact to the academic activities of the school can be less significant.

Flyover overpassing the J/O Sau Mau Ping Road, Lin Tak Road and Tseung Kwan O Road

3.3.5 The proposed flyover can be erected by precast and in-situ method. Having considered that the length of the proposed viaduct is only 200m and only one new viaduct is proposed, it is not an effective and environmental friendly approach to adopt precast construction method. The construction of the proposed flyover is by in-situ method.

3.3.6 The comparison of the benefits and dis-benefits between precast and in-situ construction method for the flyover overpassing the junction of Sau Mau Ping Road, Lin Tak Road and Tseung Kwan O Road is shown in Tables 3.12 as below:

Table 3.12 Comparison of Benefits and Disbenefits between Different Construction Methods for Viaduct Overpassing J/O Sau Mau, Lin Tak Road and Tseung Kwan O Road

	In-situ Method		Precast Method
Construction Duration	Faster ✓	The proposed viaduct is relatively short, only 200m. Erection of falseworks for in-situ method will be fast and conventional process.	Fast	The proposed viaduct is relatively short. It takes longer time to set up launching girder for precast method rather than flaseworks erection.
Cost	Effective ✓	In-situ method for short viaduct is cost effective.	Not effective	It is not cost effective to mould the steel formworks for the precast segments for such short viaduct.
Environmental Friendliness	Less ✓	As the viaduct is short, in-situ method won’t use too much falseworks and formworks. However, all the falseworks and formworks can be sold for reuse.	More	The precast formworks only can be used once and can’t be reused for other project.
Construction Noise	Higher during normal working hours	More on-site activities during normal working hours are envisaged. Hence, higher construction noise is expected during normal working hours.	Higher outside normal working hours	More night works are required for segments erection. Hence, higher construction noise is expected outside normal working hours.

RIW at J/O Clear Water Bay Road and On Sau Road and J/O Clear Water Bay Road and New Clear Water Bay Road (Option D)

3.3.7 The main construction activities at the J/O Clear Water Bay Road and On Sau Road and J/O Clear Water Bay Road and New Clear Water Bay Road comprise:

· The existing slopes between Clear Water Bay Road eastbound and Fei Ha Road will be cut to facilitate the proposed U-turn facility; and

· Roadwork and associated works

Slope works between Clear Water Bay Road eastbound and Fei Ha Road

3.3.8 There are not many available options of construction methods for the slope excavation works. It is anticipated that the excavation works at slope between Clear Water Bay Road eastbound and Fei Ha Road will be carried out by backhoe, which is a conventional excavation method. The excavation works will be carried out at roadside area and the existing carriageway of Clear Water Bay Road, Fei Ha Road and Fei Ngo Shan Road can be maintained. The roadside excavation works will create space for the construction of the proposed U-turn facility. This is a simple and efficient construction sequence. Hence, less construction materials will be used.

Roadwork and associated works

3.3.9 Construction method of roadwork and associated works is well established in Hong Kong following the requirements as stipulated in the general specification published by the government of HKSAR. For the road drain construction, trenchless method was considered but such method is not applicable because the proposed drainage pipes are not deep, only approx. 1.5m below the proposed carriageway level. Hence, stage-by-stage open trench method is envisaged.

Sequence of Works

3.3.10 It is anticipated to cut back the slope between Clear Water Bay Road and Fei Ha Road in early stage. The newly formed area for the U-turn facility can be use as temporary stockpile area for the excavated material so that the mount of disposal can be minimized.

3.3.11 The environmental benefits of the construction method and sequence as discussed in Para. 3.3.7 to 3.3.10 are summarized in Table 3.13 as below.

Table 3.13 Summary of Environmental Benefits for the Construction Method and Sequence for the RIW at J/O Clear Water Bay Road and On Sau Road and J/O Clear Water Bay Road and New Clear Water Bay Road

	Environmental Benefits
Construction Duration	Fast ✓	The slope excavation is a conventional and well adopted method. Many available plant and workers are available in the market. Hence, speedy construction is anticipated.
Use of Construction Materials	Less ✓	It is anticipated to start the roadside exaction works to create space for the construction of the proposed U-turn facility. This is a simple and efficient construction sequence. Hence, less construction materials will be used.
Environmental friendliness	Good ✓	The proposed road drain system is at shallow depth and small amount of excavated materials will be resulted. Open trench method laying the pipes stage-by-stage can allow maximum reuse of the excavated materials and generated waste will be minimal. The early completion of the excavation works at the slope between Clear Water Bay Road and Fei Ha Road can act as temporary stockpile area, which can maximize the re-use of the excavated materials.
Construction noise	Mitigable	Construction noise impact to the nearby residential area near On Sau Road is less but impact to the nearby residential area near Fei Ngo Shan Road is more and suitable mitigation measures to be provided.

RIW at J/O New Clear Water Bay Road near Shun Lee Tsuen Road (Option G)

3.3.12 The main construction activities at the J/O New Clear Water Bay Road near Shun Lee Tsuen Road include:

· Cut back the slope toe of Slope No. NCWBR-A for widening of New Clear Water Bay Road westbound and construction of a new Shun Lee Tsuen Road slip road

· Roadwork and associated works

Slope works at Slope No. NCWBR-A

3.3.13 The slope excavation works can be carried out by backhoe, which is a conventional excavation method. The excavation works will be carried out in stages and the excavated materials reused as backfilling works as far as possible. The slope works will be carried out at roadside area and the existing carriageway of New Clear Water Bay Road can be maintained. The roadside excavation works will create space for the construction of the proposed slip road. This is a simple and efficient construction sequence. Hence, less construction materials will be used.

Roadwork and associated works

3.3.14 Construction method of roadwork and associated works is well established in Hong Kong following the requirements as stipulated in the general specification published by the government of HKSAR. Alternative construction method is not anticipated.

Sequence of Works

3.3.15 The sequence of works can be divided into three works fronts such as: widening of New Clear Water Bay Road westbound, excavation of soil slope and excavation of soil nail slope. The early completion of the widening of New Clear Water Bay Road can be used as temporary stockpile area for the excavated material from the soil slope works front. The excavated material at the soil nail slope works front can be used as the backfilling materials for the proposed slope features at the soil slope works front. Ultimately, all the stockpile excavated materials can be reused as the backfilling.

3.3.16 The environmental benefits of the construction method and sequence as discussed in Para. 3.3.12 and 3.3.15 are summarised in Table 3.14 as below.

Table 3.14 Summary of Environmental Benefits for the Construction Method and Sequence for the RIW at J/O New Clear Water Bay Road near Shun Lee Tsuen Road

	Environmental Benefits
Construction Duration	Fast ✓	The slope excavation is a conventional and well adopted method. Many available plant and workers are available in the market. Hence, speedy construction is anticipated.
Use of Construction Materials	Less ✓	It is anticipated to start the roadside exaction works to create space for the construction of the proposed slip road. This is a simple and efficient construction sequence. Hence, less construction materials will be used.
Environmental friendliness	Good ✓	The early completion of the road widening works of New Clear Water Bay Road westbound can act as temporary stockpile area, which can maximize the re-use of the excavated materials. Besides, the excavated materials from soil nail slope can be used as the backfilling materials of the proposed slope features, which also can maximize the re-use of the excavated materials.
Construction noise	Mitigable	Construction noise impact to the nearby residential area along the New Clear Water Bay Road eastbound is less but impact to the nearby residential area along the New Clear Water Bay Road westbound is more and suitable mitigation measures to be provided.

3.4 Selection of Preferred Scenario

3.4.1 As discussed in above Section 3.2 and 3.3, it is recommended to adopt the following road schemes:

RIW at J/O Lin Tak Road and Sau Mau Ping Road

3.4.2 Option B is adopted for RIW at J/O Lin Tak Road and Sau Mau Ping Road with consideration as summarized below:

· The proposed layout has fulfilled all the functional requirements and not involved resumption of private land.

· This recommended option involves less rock excavation at slope along Lin Tak Road. This can minimize the generation of construction dust as well as construction noise due to the excavation works.

· The extent of the affected slope at Sau Mau Ping Road is minimised, of which, impact to the existing greening on the slope is also minimised. The affected slope will be reformed and greening will be provided to the similar condition as the existing condition. The visual impact is kept to minimum.

· Less ecological impact is anticipated compared to Option A as Slope No. SMPR-A would not be affected.

· Due to the geographic constraint, the proposed rock slope excavation works is close to the residential area i.e. Hong Wah Court and Hing Tin Estate, as well as Lam Tin High Level Water Service Reservoir. Such excavation works will be carried out by drill-and-break method.

· The proposed road layout also provides opportunity for starting from north to south. This can allow more flexibility for the contractor to schedule their works outside the critical academic activities, e.g. examination periods of St. Edward’s Catholic Primary School. Hence, the construction noise impact to the academic activities of the school can be less significant.

· Under the recommended option, the proposed viaduct will be constructed by in-situ method taking into account of the relatively short span. Falseworks can be erected immediately once the site is available, which is a fast method and will avoid the possibility of prolonged adverse environmental impact. Furthermore, all the falseworks and formworks can be sold for reuse, which can minimize the waste generation.

RIW at J/O Clear Water Bay Road and On Sau Road and J/O Clear Water Bay Road and New Clear Water Bay Road

3.4.3 Option D is adopted for RIW at Clear Water Bay Road and On Sau Road and J/O Clear Water Bay Road and New Clear Water Bay Road with consideration as summarized below:

· The proposed layout is more desirable in avoiding the weaving problem at Clear Water Bay Road westbound and no private land is affected.

· This recommended option involves less excavation at slope along Clear Water Bay Road comparing to Option C. This can minimize the generation of construction dust due to the excavation works.

· The construction noise induced from the works can be mitigated by providing suitable measure. For example tight control of the restricted working hours or using suitable silencer for plant.

· The extent of the affected slope under the recommended option is smaller than Option C. Therefore, impact to the existing greening on the slope is minimized. The affected slope will be reformed and greening will be provided to achieve similar condition as the existing condition. Hence, the visual impact is kept to minimum.

· The ecological impacts are reduced compared to Option C as woodland of lower ecological value including only two species of conservation importance would be directly impacted.

· The excavation works on slope is conventional and well adopted method, sufficient supply of construction plant and workers will be available. Familiarisation of the works nature can speed up the progress and the construction programme is more certain. Hence, it can avoid the possibility of prolonged adverse environmental impact.

· The proposed layout under the recommended option mainly involved roadside works to create space for the construction of the proposed U-turn facility. This is a simple and efficient construction sequence. Hence, less construction materials will be used.

· The proposed road layout also provides opportunity for early completion of the excavation works so that the newly formed area can be act as temporary stockpile area. Hence, maximize the re-use of excavated materials.

· The proposed road drain system will be kept at shallow level as far as possible in accordance with the relevant design standard and this can minimize the excavated materials.

RIW at J/O New Clear Water Bay Road near Shun Lee Tsuen Road (Option G)

3.4.4 Option G is adopted for RIW at New Clear Water Bay Road near Shun Lee Tsuen Road with consideration as summarized below:

· The proposed layout has fulfilled all the functional requirements and does not involve the resumption of private land.

· This recommended option involves excavation at Slope No. NCWBR-A and the proposed road improvement works has less impact to the surrounding structures comparing to Option H. This can minimize the generation of construction dust as well as construction noise due to the excavation works.

· The extent of the affected slope is similar to both options. The affected slope will be reformed and greening will be provided to achieve similar condition as the existing condition. Hence, the visual impact is kept to minimum.

· The proposed layout under the recommended option mainly involved roadside works to create space for the construction of the proposed slip road. This is a simple and efficient construction sequence. Hence, less construction materials will be used.