8.                                    NOISE IMPACT

8.1                                Background

8.1.1.1                    The study area for the potential noise impacts from the construction and operation of the proposed STF is 300m from the boundary of the facilities.  After carrying out detailed desktop review and site survey, no noise sensitive receiver (NSR) was identified within the study area.  Hence no assessment was carried out for the potential noise impacts from the construction and operation of the proposed facilities.

8.1.1.2                    However, during the operation phase of the STF, extra traffic generated from trucks delivering dewatered sludge to the proposed STF is anticipated.  Assessment for the potential off-site traffic noise impact at NSRs along Lung Kwu Tan Road is deemed necessary.

8.1.1.3                    This section presents the assessment for the potential off-site traffic noise impact at the NSRs and compares the traffic noise impact for scenarios with and without the operation of the STF.

8.2                                Traffic Noise Criteria under Environmental Impact Assessment Ordinance

8.2.1.1                    The potential noise impact from the off-site traffic generated from the STF was assessed in accordance with Annex 5 “Criteria for Evaluating Noise Impact” and Annex 13 “Guidelines for Noise Assessment” of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM). Annex 5 of the EIAO-TM defines the criteria L10 (1 hour) for road traffic noise at various NSRs:

l        70 dB(A) at the façades of dwellings, hotels, offices;

l        65 dB(A) at the façades of schools, places of public worship, courts of law, place where unaided voice communication is required; and

l        55 dB(A) at the façades of hospital.

8.2.1.2                    In the case of any façades of NSRs are exposed to predicted noise levels exceeding the relevant noise criteria and noise induced by the proposed STF contribute significantly to the overall traffic noise level by 1.0 dB(A) or more, direct mitigation measures shall be proposed.

8.3                                Assessment Area

8.3.1.1                    The assessment area for the off-site traffic noise is the area within 300m from the curb side of the Lung Kwu Tan Road from Castle Peak Power Station A to Lung Kwu Sheung Tan.  Other than the small portion of the area close to the Power Station zoned as Open Space and Green Belt, the remaining portion of the assessment area is currently with no zoning in the Outline Zoning Plan.  The location of the assessment area is shown in Figure 8.3.

8.4                                Existing and Planned Sensitive Receivers

8.4.1.1                    In accordance with Annex 13 of the EIAO-TM, 4 numbers of representative NSRs were identified along Lung Kwu Tan Road for this traffic noise impact assessment. All of these representative NSRs are located in the area with no zoning.

8.4.1.2                    No statutory planned use in the area is known currently.  Many land lots within the assessment area are privately owned.  Some land lots are with existing buildings and some are vacant lands. Should a land owner wish to construct a building within his/her land lots, he/she has to apply for a building licence from the Lands Department.  The permission of the application is subject to the decision of the Lands Department.

8.4.1.3                    In view of this situation, there is a potential that new sensitive receivers would exist in the assessment area at any time.  However, as the existing NSRs are already located in close proximity along Lung Kwu Tan Road, future NSR, if any, should be in a similar condition of traffic noise exposure.

8.4.1.4                    Representative NSRs were selected for the assessment and agreement with the authority was sought.  The details of the NSRs are given in Table 8.1.

Table 8.1         Summary of Representative Noise Sensitive Receivers

NSR ID

Description

Use

No. of  Floors

N1

Village house No.314 at Lung Tsai

Residential

3

N2

Village house No.177 at Sha Po Kong

Residential

3

N3

Village house No.23 at Pak Long 

Residential

3

N4

Tin Hau Temple at Pak Long

Place of public worship

1

 

8.4.1.5                    The relative locations of the STF and the NSRs are shown in Figure 8.1.  The photos of the representative NSRs are provided in Appendix 8.1.  The approximate horizontal distances between the proposed STF and Lung Kwu Tang Road to the representative NSRs are given in Table 8.2.  Detailed locations of the NSRs are shown in Figure 8.2a and 8.2b.

Table 8.2         Horizontal Distance from STF and Lung Kwu Tang Road to Representative Noise Sensitive Receivers

NSR ID

Distance from Proposed STF, km

Distance from Lung Kwu Tang Road (near kerb), m

N1

4.0

21

N2

3.8

20

N3

3.5

11

N4

3.5

27

 

8.5                                Assessment Methodology

8.5.1.1                    The peak hour traffic flow of the maximum traffic projection within a 15 year period upon commencement of the Project was adopted for the traffic noise prediction.  The projected year of the maximum flow was determined to be 2027. Two scenarios i.e. with and without the operation of the proposed STF in 2027 were studied.

8.5.1.2                    In order to have a better understanding of the potential off-site traffic noise impact, the prevailing scenario i.e. 2012 before commencement of the proposed STF was studied.  The predicted peak hour traffic flows of the three scenarios are summarized in Table 8.3.  The traffic flows adopted has been endorsed by the Transport Department.

Table 8.3         Projected Peak Hour Off-site Traffic Flow

Road section

Prevailing 2012 Without STF (veh/hr)

Year 2027

Without STF

(veh/hr)

With

STF (veh/hr)

Lung Kwu Tan Road (section from Lung Fai Street to Public Bus terminal at Pak Long)

400 (59%)

650 (60%)

680 (62%)

Lung Kwu Tan Road (section from Public Bus terminal at Pak Long to Yung Long Road)

240 (74%)

420 (72%)

440 (73%)

Note: The figures in brackets represent the percentage heavy vehicle.

 

8.5.1.3                    As there is no noise screening structure along Lung Kwu Tan Road in front of the NSRs, the first floor (the most affected level) of the NSRs is used for carrying out the prediction.  Traffic noise levels at representative NSRs were predicted and evaluated against the assessment criterion.  The noise prediction was carried out using the in-house computer noise model, which is based on the UK Department of Transport’s Calculation of Road Traffic Noise (CRTN) procedures.

8.6                                Evaluation of Potential Traffic Noise Impact

8.6.1.1                    The potential traffic noise impact at representative NSRs was assessed based on the three traffic scenarios.  Table 8.4 summarized the predicted road traffic noise levels at the representative NSRs for the 2012 prevailing scenario and the 2027 without STF operation scenario.

Table 8.4         Predicted Noise Levels at Representative NSRs

NSR ID

Assessment level

Assessment Criteria, dB(A)

Predicted noise levels, dB(A)

2012

Prevailing

2027

Without STF

N1

1/F

70

72.5

74.7

N2

1/F

70

73.0

75.2

N3

1/F

70

73.7

76.0

N4

1/F

65

70.4

72.7

 

8.6.1.2                    As revealed from the assessment results shown in Table 8.4, the predicted traffic noise levels at all representative NSRs for both the 2012 prevailing scenario and the 2027 without STF operation scenario would exceed the noise criteria stipulated in the EIAO-TM.

8.6.1.3                    Table 8.5 summarized the predicted road traffic noise levels at the representative NSRs for the 2027 with and without STF operation scenarios.

Table 8.5           Predicted Noise Levels at Representative NSRs in 2027

NSR ID

Assessment level

Predicted Noise Levels, dB(A)

Difference, dB(A)

Without STF (1)

With STF (2)

(2) – (1)

N1

1/F

74.7

75.0

0.3

N2

1/F

75.2

75.5

0.3

N3

1/F

76.0

76.3

0.3

N4

1/F

72.7

73.0

0.3

 

8.6.1.4                    For the 2027 with STF operation scenario, as shown in the assessment results, the changes in noise levels due to the induced traffic would be +0.3 dB(A).  Since the changes in predicted noise levels are all well below 1 dB(A), the potential off-site traffic noise impact on the identified NSRs due to the operation of the proposed STF would be considered insignificant.

8.7                                Conclusions

8.7.1.1                    The assessment focused on the traffic noise impact due to the off-site traffic generated from the operation of the proposed STF.  A traffic noise impact assessment was carried out for the prevailing scenario (Year 2012 before commencement of the proposed STF) and scenarios with and without the operation of the STF in 2027.

8.7.1.2                    Assessment results indicated that the predicted traffic noise due to the off-site traffic generated from the proposed STF would not result in significant increase in traffic noise impact on the NSRs along Lung Kwu Tan Road.