January 2012 Noise Impact Assessment Report for Proposed Cable Tow System For Wakeboarding & Water-skiing Grand Canal Dock, Dublin 4

Transcription

1 January 2012 Noise Impact Assessment Report for Proposed Cable Tow System For Wakeboarding & Water-skiing Grand Canal Dock, Dublin 4 MALONE O REGAN 2B Richview Office Park, Clonskeagh, Dublin 14. Tel: Fax: enviro@morce.ie St. Catherine s House, Catherine Street, Waterford. Tel: Fax : info@waterford.morce.ie 13, Mill Street, Galway. Tel: Fax : info@morce.ie

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3 Noise Impact Assessment Report December 2011 Grand Canal Dock Dublin 4 Table of Contents Executive Summary Page No. 1.0 Introduction Assessment Methodology Results Assessment Conclusions and Recommendations References... 7 Figures Figure 1 Site, Noise Monitoring and Noise Sensitive Receptor Locations Malone O Regan Contents

4 Executive Summary Malone O Regan was commissioned by John Spain Associates to prepare a detailed noise impact assessment report for a proposed cable-tow system for wakeboarding and water skiing at. The proposed development consists of a cable-tow two pylon system of approx. 13.8m in height and with a cable length of 170 metres supported by anchor ties. A floating launch jetty will be located on the eastern side of the cable-tow system and the system will be powered by a quiet electric motor. The system will only be operated during day time hours and it is envisaged that 4-8 users will utilise it per hour. In order to assess the impact on the existing ambient noise environment and the nearest noise sensitive receptors (NSRs), a site visit and baseline noise survey in the area was conducted to characterise the receiving environment. In order to identify potential noise sources and associated levels, a desk-based study of noise assessment reports prepared for similar operations in the UK and US was conducted. The site visit and noise survey was conducted on the 1 st December The existing ambient daytime noise environment of the site and immediate surrounding areas is typically urban in nature and is dominated by traffic noise and by different activities taking place in premises adjacent to the dock. The daytime L Aeq,t values measured ranged 55 to 61dB. There will be no construction phase as such for the proposed development. Instead, there will be an installation phase where key pieces of equipment will be put in place over a one day period. It is not envisaged that the installation will have any significant impact on the nearest noise sensitive receptors which include the Grand Canal Wharf, Waterfront and Waterside apartment schemes. In the absence of similar developments in Ireland and in order to predict the noise impact on the nearest noise sensitive receptors noise levels recorded at a large water ski centre with two cable tows in UK were utilised. It is envisaged that the main noise source generated by the cable tow system when in operation will be customers squealing on the skier jetty area. Acoustic reports completed for two similar sites in the UK (Jarman, 2007) and US (ABC Acoustics, 2006) state that the noise generated from the cable tow itself, including the electric motor, is insignificant. Using standard methodologies, the noise levels from the skier jetty area, the cable tow motor and skiers on the water are not predicted to exceed existing ambient noise levels and will not exceed the typical criterium set for day time (08:00hrs 22:00hrs) of 55 db(a) L eq, 1 hour. Furthermore, the cumulative noise impact is not anticipated to be significant and is likely to be negligible. It is concluded that the operational phase of the proposed development will have a negligible impact on the existing ambient noise environment at the nearest NSRs. It is recommended however that maintenance of the system in accordance with the manufacturer s instructions be carried out in order to avoid any potential noise issues arising in the future. Malone O Regan Executive Summary

5 1.0 Introduction Malone O Regan was commissioned by John Spain Associates to prepare a detailed noise impact assessment report for a proposed cable-tow system for wakeboarding and water skiing proposed by Surfdock at. Refer to Figure 1 for proposed location. This report addresses the noise impact associated with both the installation stage and the operational phase of the proposed development. 1.1 Proposed Development Location and Noise Sensitive Receptors The proposed cable-tow system will be located along the northern side of the outer basin of Grand Canal Dock adjacent to Hanover Quay. Grand Canal Dock is surrounded by a variety of uses including residential, industrial, commercial and recreational. The area is typically urban in nature with the waterbody currently used for a number of existing recreational activities. There are a number of apartment buildings surrounding the dock and these include the Grand Canal Wharf, the Waterfront and Waterside Apartment schemes as illustrated on Figure 1. These blocks represent the noise sensitive receptors (NSRs 1-3) potentially affected by the proposal. 1.2 Proposed Development Description The proposed development consists of a cable-tow two pylon system approx. 13.8m in height with a cable length of 170 metres supported by anchor ties. The wakeboard and waterski users will operate in the water adjoining the cable-tow system. Cable-tows work by replacing a ski boat normally used to pull the skier. The system is similar to the drag-lift used in snow skiing, but in water skiing it pulls the skier on a circuit around the water body. The cable-tow system proposed in this application has 1-2 carriers on the cable system, allowing a maximum of 2 people to ski simultaneously. The running cable goes back and forth between 2 pylons. A floating launch jetty will be located on the eastern side of the cable-tow system. The cable-tow system will be powered by an electric motor similar in power, operation and size to the engine found, for example, in a Toyota Prius car. This motor is located on the Floating Skier area. The majority of the proposed system is submerged and not visible. The existing jetty on the south dock is to be used as a berth for a boat taxi which will be used to transport customers to and from the cable-tow area. The existing Surf Dock premises on Charlotte Quay or the South Dock, which consists of the Naomh Eanna boat and three portacabins, will be used as a reception area, changing room and toilet facility for the customers. The existing public car parking on Charlotte Quay/South Dock will be made available for use by customers. The facility will be accessed via the existing 2 way entrance from South Dock Road. There is a possibility that the proposed wakeboard and water-ski system could stage events from time to time where additional number of users, i.e. over and above the projected 4-8 users per hour, could be catered for. These events however would be Malone O Regan 1

6 subject to separate licensing and approval and are therefore outside the scope of this assessment. 2.0 Assessment Methodology The methodology used in completing this assessment is presented below. 2.1 Measurement Methodology Baseline noise monitoring was undertaken on the 1 st December 2011 at three locations (NM1-3) in order to characterise the existing receiving noise environment at the proposed development site (Refer to Figure 1). Monitoring was conducted during the day time period only as the cable tow will not be operated during the night time period. The methodology followed was in accordance with the recommendation of the International Standards Organisation Document: ISO 1996 Parts 1, 2 and 3 (1982), the EPA Guidance Note on Noise in Relation to Scheduled Activities, 2006 and the EPA Environmental Noise Survey Guidance Document, Noise measurement was carried out using a BRUEL & KJAER 2250 Hand Held Analyser Sound Level Meter (Type I) equipped with 2250 Logging Software BZ7224 and Frequency Analysis Software BZ7223. The monitoring equipment was calibrated before use using a BRUEL & KJAER acoustical calibrator (Type 4231). The noise levels were measured using the A-weighted network, and a fast sampling interval. At all sample locations the noise meter was positioned on a tripod 1.5 meters above ground level and at least 2m from any reflecting surfaces. Weather conditions were ideal for noise assessment on the days of monitoring. The parameters measured were as follows: L AEQ is the A weighted equivalent continuous sound level the sound level of a steady sound having the same energy as a fluctuating sound over a specified measurement period. L A10 is the A weighted noise level which is exceeded for 10% of the specified measurement period. This gives an indication of the upper limit of fluctuating noise such as that from road traffic. L A90 is the A weighted noise level exceeded for 90% of the measurement period and is useful in providing an indication of the background noise level experienced over the measurement period. All measurements were as dba; i.e. decibels measured using the A-Weighted network, which corresponds to the frequency at which humans perceive noise. 2.2 Deskbased Study of Similar Operations It is understood that the proposal is the first of its kind in Ireland and therefore research on similar proposals in the UK and US was undertaken in order to identify typical noise levels associated with the operation. In particular, a noise impact assessment (Jarman, 2007) for a water ski facility with two cable-tows at Datchet, Berkshire, UK, provided measured noise levels at known distances. These have been used to predict the noise levels likely to arise at the nearest NSRs to the proposal at Grand Canal Dock. Malone O Regan 2

7 2.3 Prediction Methodology Noise levels at the nearest noise sensitive receptors as a result of the above described operations were predicted to the nearest noise sensitive receptors in accordance with the requirements of ISO Acoustics Attenuation of sound during propagation outdoors Part 2: General method of calculation where appropriate. 3.0 Results 3.1 Ambient Noise Environment The results of day time noise measurements for the monitoring conducted in December 2011 are shown in Table 1. Table 2 outlines a description of the predominant noise sources noted during this monitoring event. In general, and as expected, the sound pressure levels recorded are typical of an urban noise environment. Overall the dominant noise source affecting the site is traffic on the road network and different activities in the Grand Canal and premises nearby. Noise monitoring points NM1 and NM3 are the most representative of the existing external ambient noise levels at the nearest NSRs during the daytime period. Table 1 Day and Night-time Noise Monitoring Results Location Time Day time L Aeq15min L A10, 15min L A90, 15min NM1 14: NM2 16: NM3 16: Table 2 Location NM1 NM2 NM3 Description of Day time Noise Sources Description of Day time Noise Sources The main noise sources recorded at this location were the humming constant noise from the outlet vent of nearby premises located approx 50m to the west of NM1, intermittent drilling activities at sheds located approx 50m to the north and wires from sailing boats clanging against the poles. Other noise sources were seagulls and the Viking splash tour boat entering the water. The main noise sources recorded at this location were background traffic noise, a constant humming noise from the outlet vent of nearby premises and intermittent bells noise from a nearby church. Other noise sources were seagulls and the Viking splash tour boat and people talking as they walked past the meter. The main noise source recorded at this location was background traffic noise. Other noise sources included reverse beepers, seagulls, the Viking splash tour boat and people talking as they walked past the meter. Malone O Regan 3

8 4.0 Assessment 4.1 Construction/Installation Noise The proposed cable-tow system will require very little in terms of what would typically be considered construction works. Four pre-cast underwater concrete anchors and two underwater concrete mast bases will be installed on the canal floor. Mast-to-anchor tie lines will extend from the concrete anchors to anchor the masts from which the 170 metre Rixen cable-tow will operate. It is anticipated that the installation works will take only one day (approx 8hrs) to be completed. It is envisaged that 1-2 HGVs, a flat bed and a hoist crane will be used during the day. Overall, it is considered that the installation works will not have a significant impact on existing ambient noise levels at the nearest NSRs given the duration of the works, the low numbers of plant equipment involved and existing background noise levels that prevail in the area. 4.2 Operational Noise Operational Noise Criteria Prior to carrying out the assessment of the noise impact of the operational phase of the proposed development, it is appropriate to set external criteria to ensure that existing and future noise sensitive receptors are not affected by nuisance noise arising from the proposed development. Appropriate guidance in relation to noise intrusion from continuous sources in residential and other buildings is contained within BS8233:1999 Sound Insulation and Noise Reduction for Buildings Code of Practice. This British standard sets out recommended noise limits for indoor ambient noise levels. A selection of the internal criteria taken from the standard is presented in Table 3 below. Table 3 Recommended Indoor Ambient Noise Levels Criterion Typical Situation Design Range L Aeq, T Good Reasonable Reasonable resting/ Living Room sleeping conditions (residential) Bedroom Reasonable speech or telephone communications (offices) Reasonable conditions for study or work requiring concentration (offices) Reasonable listening conditions Source: BS8233:1999 Department store Restaurant Corridor Museum Meeting room, executive office Staff Room Classroom Cinema, church Concert hall, theatre The existing external ambient noise environment is urban in nature therefore the design range set for reasonable conditions are applicable. Allowing for an open window, a Malone O Regan 4

9 daytime ( hrs) external criterium of 55 db(a) L eq, T has been determined at the facade of the NSRs Potential Operational Noise Sources The following potential noise sources will arise as a result of the operation of the proposed development: 1. Cable-tow system, including the potential noise arising from vibration of the cable and the electric motor. 2. People talking/ squealing at the proposed skier launch jetty and when wakeboarding/ water skiing. 3. Wave spray from skiers passing. 4. Taxi boat transporting customers from the existing jetty on the south dock to the cable area and vice versa. 5. Cars arriving, departing and manoeuvring on the south dock. It is expected that the proposal will operate 7 days a week, 12 months of the year. The projected opening hours are as follows: November-April hrs May-October hrs As stated earlier, it is estimated that approximately 4-8 people will use the system per hour. Persons using the facility will congregate at the Surfdock classroom and changing facilities on the south dock. It is expected that two staff would be required to operate the facility at all times Predicted Noise Levels Noise Generated as a Result of the Cable Tow System It is envisaged that the main noise source generated by the cable tow system in operation will be people squealing. Acoustic reports completed for two similar sites in the UK (Jarman, 2007) and US (ABC Acoustics Inc., 2007) state that the noise generated from the cable tow itself, including the electric motor and the cables running between the two pylons, is insignificant. The survey completed in the UK is summarised below: Noise levels at 20 m from the cable tow launch area ranged 63-67dB L Aeq 5min and averaged 66dB L Aeq 5min. The main noise source recorded by the survey was people squealing as people were going onto the tow. Noise levels away from the cable tow launch area (200m from the launch area and 25m from the cable ties) where the noise from cable and passing skiers were the predominant noise source ranged 55-57dB L Aeq 5min. Noise from the proposed development will attenuate with distance in accordance with the following equation: Equation 1: 20log(R1/R2) Malone O Regan 5

10 Where R1 is the distance to the receptor and R2 is the distance at which the sound pressure level (SPL) is measured. Using the equation above and taking into account the distance between each NSR and the skier launch jetty and the cable ties, the noise levels at each NSR have been calculated and are set out in Tables 4 and 5 below. Table 4 Predicted Noise Levels at the NSRs as a result of the operation of the skier launch jetty Receptor Name and Number Resultant level Approx distance to the L skier launch jetty (m) Aeq 1hr (db) Daytime NSR1 Grand Canal Wharf, South Dock NSR2 Waterfront Apartments, Hanover Quay NSR3 Waterside Apartments, Charlotte Quay Table 5 Predicted Noise Levels at the NSRs as a result of the cable ties and passing skiers Receptor Number Resultant level Approx distance to the L cable ties (m) Aeq 1hr (db) Day time NSR NSR NSR Based on the above predicted values, the criterium set in Section will not be exceeded and the levels are not predicted to be in excess of the existing ambient noise levels including the background noise represented by the L A90 values recorded. The cumulative noise impact is not anticipated to be significant and is likely to be negligible. Noise Generated as a Result of Car-Parking and the Taxi Boat Car-parking associated with the proposal will be low and will have an imperceptible impact as the area along the South Dock which is currently used for parking in any case. Similarly the taxi use will be low and the impact will be imperceptible as the dock is currently used for other water based activities. Malone O Regan 6

11 5.0 Conclusions and Recommendations It is concluded that the operational phase of the proposed development will have a negligible impact on the existing ambient noise environment at the nearest NSRs. It is recommended that maintenance of the system in accordance with the manufacturer s instructions be carried out in order to avoid any potential noise issues arising in the future. 6.0 References 1. Jarman, N., 2007, Datchet Waterski Noise Impact Assessment, Report Ref. 2007/18901/R1, Cole Jarman Associates, UK. 2. ABC Acoustics Inc., 2006, Draft Acoustical Analysis Report, Santee Lakes Water Sports project, Report ref.: 2012D Malone O Regan 7

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