environmental issues Figure 15 and Figure 16 show the road network in and around the Project area. A description follows.

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1 7 assessment of key environmental issues 7 Assessment of key environmental issues 7.1 Traffic and transport Traffic and transport issues associated with the Project relate almost entirely to the construction phase. This chapter provides an outline and review of the likely traffic operations, analysis of traffic volumes and proposed traffic arrangements including spoil routes. A copy of the full report can be found in Volume Two of the Environmental Assessment Existing traffic conditions Road networks Figure 15 and Figure 16 show the road network in and around the Project area. A description follows. Bunnerong In the vicinity of Bunnerong STS, Military Road is a local road with a carriageway width of about 11 metres. Bunnerong Road south of Botany Road is a regional road but becomes an arterial road north of Botany Road. The southern section of Anzac Parade is also a regional road and has a carriageway width of about seven metres. At La Perouse point, Anzac Parade terminates in a loop around the Botany Bay National Park. The width of the loop road is about 18.5 metres including shoulder and 90 degree angled parking. All intersections along Anzac Parade and Bunnerong Road south of Botany Road are controlled by regulatory signs. There are no traffic signals or roundabouts along the proposed Bunnerong route. Kurnell Prince Charles Parade is a local road with a carriageway width of about 8.5 metres. Silver Beach Road is a local road with a carriageway of about 7.5 metres. Captain Cook Drive between Silver Beach Road and the Kurnell STS is a regional road with a carriageway width of between 11 and 13 metres. Captain Cook Drive between Silver Beach Road and Torres Street has a carriageway width of about 12 metres. All intersections along the route are controlled by regulatory signs with the exception of the intersection of Captain Cook Drive and Torres Street which is controlled by a roundabout. There are no signalised intersections along the proposed Kurnell route. Traffic volumes Overall, the highest traffic volumes in the Project area are experienced along Anzac Parade on weekends, where daily traffic volumes can approach 7,400 per average weekend day or 834 vehicles per hour. Traffic volumes along the affected roads within Bunnerong are also significant along Military Road, west of Bunnerong Road which carries about 440 vehicles in the weekday afternoon peak hour. Traffic volumes along the affected roads within the Kurnell side of the Bay are greatest along Captain Cook Drive, west of Silver Beach Road which carries about 300 vehicles in the weekday afternoon peak hour. 68 EnergyAustralia

2 Figure 15: Road network around Bunnerong STS (Source: UBD, reproduced with permission) Botany Bay Cable Project Environmental Assessment 69

3 7 assessment of key environmental issues Figure 16: Kurnell road network (Source: UBD, reproduced with permission) Bus services Bunnerong Sydney Buses operates a total of seven bus services in the Project area, comprising: route service 391 that is a daily daytime service between the city and La Perouse via Anzac Parade, Bunnerong Road and Military Road route services L94/ /X94 that operate between Little Bay and La Perouse via Anzac Parade route services 309 and L09 that operate between Bunnerong Road and Bumborah Point Road via Military Road. On weekdays there are a total of 170 bus services operating in and out of La Perouse via Anzac Parade (south of Bunnerong Road). On Saturdays and Sundays there are about 130 and 90 services respectively. Along Bunnerong Road between Anzac Parade in the south and Military Road in the north, there are about 16 weekday bus trips split equally between in bound and outbound trips. The services operating along Military Road (391, L09 and 309) generate about 100 bus trips on a weekday, 57 Saturday services and 49 Sunday services. Kurnell Crowthers Bus Company operates one (weekdays and weekends) bus service within the assessment area, comprising of route service 987. There are about 24 weekday bus movements in and out of Kurnell via Captain Cook Drive, Prince Charles Parade and other roads in the area. 70 EnergyAustralia

4 Pedestrians Bunnerong La Perouse Museum, open from Wednesday to Sunday, generates the greatest pedestrian movements within the Bunnerong assessment area, with an average visitation rate of between 15 and 20 persons on weekdays (50 students on a school trip) and up to 40 persons on weekends. The La Perouse shopping area located on the western side of the Anzac Parade loop road also generates pedestrian activity, particularly on weekends. Kurnell There is minimal pedestrian activity in the Kurnell assessment area, other than that generated by the pre-school centre off Captain Crook Drive, retail facilities and residential land uses. Some pedestrian activity is generated by visitation to Silver Beach and the Botany Bay National Park although this is minimal and largely restricted to weekends during the summer months Spoil disposal Chapter 2, Section Proposed Works, provides an outline of the proposed construction activities that would impact traffic flow within the Project areas. It is anticipated that spoil generation and transportation would generate the greatest disruption to local traffic flow within the Bunnerong and Kurnell Project areas. Spoil generation and transportation The total spoil volumes and truck loads/trips for the Bunnerong and Kurnell sites are shown in Table 9. Table 9: Estimated spoil truck loads and trips Site Spoil volume Truck type Bogie 1 Truck & dog 2 Semi trailer 3 Load Trips Load Trips Load Trips Bunnerong 5, , Kurnell 2, Total 8, , Bogie has 12 tonne capacity or about 9 cubic metres of spoil 2. Truck & Dog has 33 tonne capacity or about 24 cubic metres of spoil 3. Semi Trailer has 30 tonne capacity or about 21 cubic metres of spoil Spoil generated from trench excavation would be transported from the site by truck. The truck load and trip volumes assume that one cubic metre of spoil equates to about 1.4 tonnes of material. The total number of truck loads and trips could be reduced by the use of higher capacity trucks such as Truck and Dogs (truck and trailer) and Semi Trailer vehicles. Bunnerong cable trenching works and HDD operation Spoil extracted from the Bunnerong site would most likely be deposited at a local landfill site. In a worst case scenario, all spoil removed from the trench would need to be trucked to a more remote location. A total of between 500 and 1,176 truck trips would be required to transport the spoil from the Bunnerong site. It is estimated that excavation would take place at a rate of about 200 metres per day such that the maximum daily truck trip generation would be about 75 truck Botany Bay Cable Project Environmental Assessment 71

5 7 assessment of key environmental issues trips. It is estimated that less than 10% (eight truck trips) would be generated during the morning and afternoon peak periods, assuming a worst case scenario where all spoil is removed by bogies. This rate of hourly and daily truck trip generation is well within the capacity of lower and higher order roads within the area. The impact of 75 daily and 8 hourly truck trips upon intersection operation would be negligible. Spoil from the horizontal directional drilling works at La Perouse would be removed via the aforementioned route. Kurnell cable trenching works and substation works Spoil would most likely be transported to a nearby landfill facility on Captain Cook Drive. Spoil transportation from the Kurnell site would require between 234 and 626 truck trips. If these trips are spread over two weeks, total daily trip generation could be as low as 40 trips per day or four peak hour trips. If, however, the rate of excavation is similar to that assumed for the Bunnerong site, the maximum truck trip generation would also be about 75 truck trips per day or about eight truck trips per peak hour. Trucks would access the work site via Taren Point Road and Captain Cook Drive. On the assumption that excavation takes place at a rate of about 200 metres per day, the maximum daily truck trip generation would be about 75 truck trips or between six and eight truck trips per hour Traffic arrangements during construction Traffic Management Plans (TMPs) for Bunnerong and Kurnell are based on the maintenance of traffic flow by keeping one traffic lane open during trench excavation and refilling. However, there may be locations where temporary road closures are required for safety and constructability reasons. Indicative TMPs have been generated for the proposed works, a sample of which is shown in Figure 17. Before construction, a Construction Traffic Management Plan (CTMP) would be developed. A copy of the CTMP would be sent to the RTA, Randwick City Council and Sutherland Shire Council prior to construction. During construction, the proponent would ensure that vehicles associated with the Project do not transport hazardous materials along affected roads. This would be incorporated into the conditions of contract for trucking companies engaged on the Project. The following section provides a detailed overview of traffic arrangements during the construction period. 72 EnergyAustralia

6 Figure 17: Sample traffic management plan Bunnerong Road and Military Road intersection Bunnerong side Figure 18 shows the construction stages for the land based trenching and cable laying component of the Project that were used for traffic assessment purposes. Stage A Stage A extends from Bunnerong STS to Bunnerong Road via Military Road (300 metres). The trench would be constructed along the western side of the 10 metres wide road carriageway with the eastern side kept open to accommodate two way traffic flows under manual traffic control, either by manned Stop/Go signs or portable traffic signals. Vehicular access to and from the properties along both sides of the road would be maintained during construction. Pedestrian access during excavation/refilling would be Botany Bay Cable Project Environmental Assessment 73

7 7 assessment of key environmental issues provided along the eastern side of Military Road. The intersection of Military Road and Bunnerong Road is a give way controlled intersection and would be maintained during construction as it provides access to Prince of Wales Drive and Bumborah Point Road. Stage B Stage B extends from Military Road to the northernmost access way to Botany Cemetery via Bunnerong Road (630 metres). This section of Bunnerong Road comprises a total road width of 12 metres (an eight metre carriageway and two metre wide shoulders). The trench would be constructed along the western side of Bunnerong Road with the eastern side of the carriageway kept open to accommodate two way traffic flows under manual traffic control. The shoulders are partially sealed and adequate to accommodate traffic flow during construction if necessary. The nature strip along the western side of Bunnerong Road is about 10 metres in width. Power poles are located along this western side about one metre back from the edge of the road shoulder. Bus stops are located in this section of Bunnerong Road just south of Military Road. Stage C Stage C extends from the northernmost access way to Botany Cemetery to Yarra/Woomera Roads via Bunnerong Road (730 metres). This section of Bunnerong Road comprises a total road width of 10 metres (six metre carriageway and two metre wide shoulders). The trench would be constructed along both the western and eastern sides of Bunnerong Road (to minimise the impact on surrounding residences) with the opposite side of the carriageway kept open to accommodate two way traffic flows under manual traffic control. The shoulders are partially sealed and adequate to accommodate traffic flow during construction if necessary. At some locations, trenching would be necessary across the road carriageway. A culvert is located across Bunnerong Road near Woomera Reserve and the La Perouse Primary School. At the culvert the width of Bunnerong Road narrows to 10 metres with a narrow one metre wide shoulder on the eastern side. There is almost no shoulder on the western side crossing the culvert. The 10 metres width is nevertheless wide enough to accommodate trenching/refilling and two way traffic flow along the eastern carriageway under manual traffic control. Bunnerong Road is restricted to 40kph during school days between the hours of 8am to 9.30am and 2.30pm to 4pm. Within Stage C there are a few properties with direct vehicular access to Bunnerong Road. Stage D Stage D extends from Yarra Road to the Anzac Parade loop intersection at the bus turning area via Bunnerong Road and Anzac Parade (900 metres). In Stage D, Bunnerong Road comprises a total road width of 10 metres (six metre carriageway and two metre wide shoulders along both sides of the road). The trench would be constructed along both the western and eastern sides of Bunnerong Road at different locations with the opposite side of the eight metre carriageway kept open to accommodate two way traffic flows under manual traffic control. The shoulders are partially sealed and adequate to accommodate traffic flow during construction if necessary. At some locations, trenching would occur across the road carriageway. In particular, at the intersection of Bunnerong Road and Mirrabooka Crescent where the cables would traverse to the western side of the road just north of Mirrabooka Crescent. There is minimal direct vehicular access onto this section of Bunnerong Road. Bus stops are located on both sides of Bunnerong Road near Grose Street. A bus turning area and shelter is located on the western side of Bunnerong Road to the north of the intersection of Anzac Parade and the Anzac Parade loop. It includes the eastern section of the loop road from the point at which the trench meets the submarine cable interface. The interface location at the southern end of the Bunnerong site is immediately south of the La Perouse Bus Turnaround and immediately north of the 74 EnergyAustralia

8 junction of the Anzac Parade Loop and Anzac Parade. The cables would emerge from the bore into the jointing bay and then travel via the trench up Anzac Parade. This would require the temporary relocation of the La Perouse bus terminus. Figure 18: Construction stages on each side of the Bay Botany Bay Cable Project Environmental Assessment 75

9 7 assessment of key environmental issues Kurnell side Stage A Stage A extends from the submarine cable interface point to the junction of Prince Charles Parade and Silver Beach Road. The trench would be constructed along the northern side of the road carriageway with the southern side of the carriageway kept open to accommodate two way traffic flows under manual traffic control. Vehicular access to and from the properties along the southern side of Prince Charles Parade would be maintained during construction as well as pedestrian access along the southern footpath of Prince Charles Parade. Stage B Stage B extends from Prince Charles Parade to Captain Cook Drive via Silver Beach Road (260 metres). Silver Beach Road has a carriageway width of eight metres. Trench excavation would occur along the western side of the carriageway with the eastern side being maintained for two way traffic flow under manual traffic control. The road is too narrow to trench down the middle and provide for adequate traffic flows. Therefore, in the alternative, the road could be closed to through traffic for the duration of excavation (about six hours). Under such an arrangement traffic destined for Prince Charles Parade would be detoured via Torres Street or Captain Cook Drive. Access to properties will be maintained throughout the works, although there may be short delays experienced by drivers while work is underway outside their properties. Pedestrian access would be maintained to properties at all times. Stage C Stage C extends along Captain Cook Drive to the intersection with Bridge Street. Trench excavation could occur along the western side of Captain Cook Drive requiring both removal and reconstruction of the roundabout and the threshold located about 28 metres south of the roundabout in Captain Cook Drive. The Torres Street/Captain Cook Drive roundabout has the following dimensions: central island diameter 4.1 metres (not mountable) outer island diameter 8.2 metres (mountable) circulating carriageway width 5.5 metres to 6.8 metres wide. Removal, trenching and refilling at the roundabout would necessitate partial closure of Torres Street at its intersection with Captain Cook Drive. Traffic would be maintained along the eastern carriageway. At this point, the road has a carriageway width of 12 metres which is adequate to enable maintenance of two way traffic flow under manual traffic control during trenching and refilling. Stage D Stage D comprises Captain Cook Drive from its intersection with Bridge Street south to Kurnell STS. The road has a 12 metre carriageway width comprising two traffic lanes and kerbside parking lanes. Trenching and refilling would continue along the western side of the carriageway. Trenching and refilling across the Bridge Street intersection would require temporary road closure during which time access to properties in Bridges Street would be possible via Tasman and Dampier Streets. Trenching and refilling across the Tasman Street intersection may require a temporary road closure during which time access to properties in Tasman Street would be possible via Bridges and Dampier Streets. A culvert is located across Captain Cook Drive just north of the vehicular access way to the STS. To avoid trenching across or near this culvert it may be necessary to commence diversion of the trench into the STS site at a point north of the culvert. 76 EnergyAustralia

10 7.1.4 Traffic impacts peak hour capacity Measuring intersection and road capacity performance The Traffic Management Plans have been developed on the basis of a manual assessment of peak hour traffic capacity changes in regards to the following performance indicators: degree of saturation a measure of the ratio between traffic volumes and the capacity of the intersection average delay in seconds per vehicle level of service a measure of the overall performance of the intersection (summarised in Table 10 below). Table 10: Levels of service Level of service Average delay/vehicle (secs/vehicle) Traffic signals, roundabouts Give way & stop signs A Less than 14 Good operation Good operation B 15 to 28 Good with acceptable delays and spare capacity Acceptable delays and spare capacity C 29 to 42 Satisfactory Satisfactory but accident study may be required D 43 to 56 Operating near capacity Near capacity and accident study may be required E 57 to 70 At capacity, requires other control mode F Greater than 70 At capacity, requires other control mode Source: Guide to Traffic Generating Developments, RTA 1993 Measuring traffic volume and delays Traffic delays were estimated using an intersection modelling package. The stop/slow traffic control was simulated as traffic signals with one phase for each direction, and a lengthy all-red time to simulate the time needed for vehicles to clear the work area before the opposite direction can proceed. For more information on this process refer to Volume Two of the Environmental Assessment. Traffic volumes were taken from the traffic surveys recently conducted on Anzac Parade and Military Road Traffic impacts local delays The following summarises the expected traffic flows and associated delays during construction. In each study area, the worst case scenario was tested for the peak hour traffic flows and expected delays under manual traffic control delays. Bunnerong Peak hour traffic flows and expected delays (Military Road site) for the busiest part of the route (Stage A) under manual traffic control delays are summarised in Table 11. Botany Bay Cable Project Environmental Assessment 77

11 7 assessment of key environmental issues Table 11: Bunnerong stage A: Traffic volumes and forecast delay during construction Location Traffic volumes Northbound Southbound Military Road (west of Bunnerong Rd) Note: Volume includes forecast spoil trucks Average delay (secs/vehicle) The average delay figures shown in Table 11 assume that the eastern carriageway would be open for northbound and southbound traffic flow on a rotational basis approximately every 75 seconds. The results show that during the peak hour, the traffic conditions at the work site would operate with a level of service (see Table 10), which is acceptable for temporary road works. None of the Bunnerong work sites would experience delays greater than those shown in Table 11. Similar delays have been forecast for Bunnerong stage D. A combined peak hourly traffic flow of almost 400 vehicles results in an average forecast delay between 40 and 50 seconds per vehicle. In addition, the weekend traffic volume in Section D is higher than the weekday volume, particularly between 10am and 12noon, due to the high tourist and recreational visitation to the La Perouse headland. Construction work during the weekend peak hours would be undertaken in accordance with an approved traffic management plan. Kurnell Peak hour traffic flows and expected delays for the busiest part of the route (Stage D - Captain Cook Drive) under manual traffic control delays are summarised in Table 12. None of the Kurnell sites would experience delays greater than those shown in Table 12. Table 12: Kurnell stage D: Traffic volumes and forecast delay during construction Location Traffic volumes Northbound Southbound Captain Cook Drive Note: Volume includes forecast spoil trucks Average delay (Secs/vehicle) The average delay figures shown in Table 12 assume that the eastern carriageway would be open for northbound and southbound traffic flow on a rotational basis approximately every 75 seconds. The results show that during the peak hour, the traffic conditions at the work site would operate with a level of service (see Table 10), which is acceptable for temporary road works. Trenches may remain open for longer periods at jointing bay locations Pedestrian and cyclist impacts In the Bunnerong section, pedestrian access would be maintained on both sides of the road during construction. There are some instances when pedestrians may be detoured onto the opposite side of the road, such as at the creek culvert south of Gillooly Avenue. Along Stage E and part of Stage D, a footpath is provided on the opposite side of Anzac Parade. In the Kurnell section, pedestrian access along the southern footpath of Prince Charles Parade would be maintained during construction. Pedestrian access along Silver Beach Road on the verge would be maintained along the side opposite the works. As the work occurs on the road carriageway, pedestrian access along the verge would be maintained 78 EnergyAustralia

12 on Captain Cook Drive. The bicycle lane on Captain Cook Drive south of Torres Street would be closed during construction and cyclists diverted via the traffic lane Local access and parking impacts Vehicle access to properties will be maintained during works, although there may be short delays experienced by drivers while work is underway directly outside their properties. It may be necessary to close roads to through traffic while some work is in progress. Street parking alongside work sites will be restricted Public transport impacts Overall, bus impacts would be greatest in the Bunnerong section within the vicinity of the La Perouse bus terminus on Anzac Parade. Bus layover would have to be relocated temporarily to the eastern side of Anzac Parade on the loop road at La Perouse Headland, requiring a temporary bus zone. The first bus stop may also require temporary relocation. The exact location would be agreed with the State Transit Authority prior to the commencement of works. Buses would use the loop road to turn around. There would need to be localised relocation of bus stops as the trenching moves along Anzac Parade and Bunnerong Road. No bus stops would be impacted within the Kurnell section. However, buses would be affected by the stop/slow traffic control and access would need to be managed by staging the works at the intersection of Captain Cook Drive and Bridge Road Mitigation measures Traffic would be managed in accordance with the Construction Traffic Management Plan which would be developed before construction begins. The Plan would be based on the indicative Traffic Management Plans which have been prepared for this Project and which are contained in Appendix A of the Traffic and Transport Report in Volume Two. 7.2 Noise and vibration Consulting company Wilkinson Murray carried out the noise study for this Project. The consultants considered the possibility of vibration being an issue for this Project but concluded it would not be, for the following reasons: During construction, the major possible source of vibration would be a rock breaker. This would be used only intermittently, if at all. In fact the report recommends that its use be avoided due to potential noise impacts. Measurements indicate that vibration from a typical rock breaker would be within recommended criteria for a residence during the daytime if the residence is 10 metres from the rock breaker. Given that the nearest residence to any construction work is a distance of 15 metres, vibration impacts from construction can be considered insignificant. The only potential vibration impact from operational sources would be from the proposed additional transformers. These are at least 150 metres from the nearest residences, at which distance vibration would be imperceptible. The Wilkinson Murray report is summarised below. The summary sets out: the ambient noise levels; projected noise levels; a comparison of projected noise levels against government noise guidelines; and finally, measures to ensure acceptability of noise impacts. A copy of its report in its entirety is located in Volume Two of the Environmental Assessment Ambient noise levels Long-term ambient noise levels were monitored at three locations, selected to cover the range of environments in the potentially affected areas. The locations are presented in Table 13 and shown in Figure 19. Botany Bay Cable Project Environmental Assessment 79

13 7 assessment of key environmental issues Table 13: Long term noise monitoring locations Site 1 2 Address 1593 Anzac Parade, La Perouse 10 Prince Charles Parade, Kurnell 3 26 Tasman St Kurnell Relevant noise noted on site visits ocean and local traffic occasional local traffic, distant port activity Captain Cook Drive traffic; industrial noise from refinery 80 EnergyAustralia

14 Figure 19: Noise measurement locations in the context of the Project In all cases, noise monitoring was conducted between Friday, 21 July and Friday, 28 July The noise monitoring equipment used for these measurements consisted of environmental noise loggers set to A-weighted, fast response, continuously monitoring over 15-minute sampling periods. This equipment is capable of remotely monitoring and storing noise level descriptors for later detailed analysis. The equipment calibration was checked before and after the survey and no significant drift was noted. Botany Bay Cable Project Environmental Assessment 81

15 7 assessment of key environmental issues The logger determines L A1, L A10, L A90 and L Aeq levels of the ambient noise. L A1, L A10 and L A90 are the levels exceeded for 1%, 10% and 90% of the sample time respectively (see Glossary for definitions). The L A1 is indicative of maximum noise levels due to individual noise events such as the occasional passage of a heavy vehicle. The L A90 level is normally taken as the background noise level during the relevant period. Table 14 summarises the results, for daytime, evening and night time periods as defined in the NSW Department of Environment & Climate Change s (DEC) NSW Industrial Noise Policy (INP). The summary values are: L Aeq,Period the overall L Aeq noise level measured over the assessment period; and RBL Rating Background Level is a measure of typical background noise levels which are used in determining noise criteria. Table 14: Summary of measured noise levels using logger Noise logging site Daytime 7am-6pm RBL (dba) Evening 6-10pm Night time 10pm-7am Daytime 7am-6pm L Aeq, Period (dba) Evening 6-10pm Night time 10pm-7am The values shown in Table 14 are considered typical for the relevant areas. In addition to long term noise monitoring, a number of operator attended noise measurements were conducted along the route in nearby residential areas. These measurements consisted on 15 minute noise sample during normal daytime hours. The purpose of the measurements was to ensure that there are no areas along the route that are subject to a significant variance from the results determined from noise logging. Table 15 presents the results of these measurements on the southern side of the route. Table 15: Noise measurement, operator attended, on southern (Kurnell) side of route Location Time L Aeq L 90 9 Bridges Street 12: Silver Beach Road 12: Prince Charles Parade 13: In summary, the results revealed that background noise levels along the southern route during measurements were 48 to 52dBA. These levels compare to established RBL s of 41 and 42dBA at noise logging sites 2 and 3 respectively. It is considered that the higher operator attended measurements are likely to be the result of daily variations indicating that adoption of criteria based on the noise logging results is acceptable and appropriate. Table 16 presents the results of these measurements on the northern side of the route. 82 EnergyAustralia

16 Table 16: Noise measurements on northern (La Perouse) side of route Location Time L Aeq L 90 2 Grose Street 8: Cnr Bunnerong and Yarra 9: Hastings Avenue 9: Wassell Street 14: In summary, the results revealed that background noise levels along the route during measurements were 43 to 47dBA. These levels compare to establish an RBL of 43dBA at noise logging site 1. It is considered that the adoption of the noise logging site 1 result is generally consistent with operator attended measurements and this noise level should be used in establishing criteria along the northern route Acoustic performance criteria The following sections detail the applicable site specific noise criteria based on the guidelines of the NSW Department of Environment and Climate Change. Construction noise criteria The assessment of construction noise is dependent on the duration of construction in the vicinity of the potentially affected residential receiver. The Department of Environment and Climate Change in chapter 171 of the Environmental Noise Control Manual (ENCM) suggests the following noise control guidelines: Level restrictions (i) Construction period of four weeks and under. The L 10 level measured over a period of not less than 15 minutes when the construction site is in operation must not exceed the background level by more than 20 db(a). (ii) Construction period greater than four weeks and not exceeding 26 weeks. The L 10 level measured over a period of not less than 15 minutes when the construction site is in operation must not exceed the background level by more than 10 db(a). Time restrictions Monday to Friday 7am to 6pm Saturday 7am to 1pm (if inaudible at residential premises) 8am to 1pm (if audible at residential premises) No construction work to take place on Sundays or public holidays Silencing All possible steps should be taken to silence construction site equipment. It is particularly important that silenced equipment should be used on road or rail works where 24 hour operation is necessary. Where the construction period is likely to be over 26 weeks, a construction noise goal based on a background plus 5dBA approach is usually adopted. Table 17 presents the applicable construction noise criteria. Botany Bay Cable Project Environmental Assessment 83

17 7 assessment of key environmental issues Table 17: Construction noise criteria dba Construction duration (daytime) Receiver area Up to 4 weeks 4 to 26 weeks > 26 weeks Industrial noise criteria The only site where additional noise producing equipment is proposed is at the Kurnell STS where construction works are necessary to house new electrical switchgear and apparatus. Operational noise criteria have been established for this site, based on noise measurements at that location. The NSW Industrial Noise Policy (INP) recommends two criteria, Intrusiveness and Amenity, both of which are relevant for the assessment of noise. In most situations, one of these is more stringent than the other and dominates the noise assessment. An intrusiveness criterion applies for residential receivers only. The intrusiveness criterion requires that the L Aeq noise level from the source being assessed, when measured over 15 minutes, should not exceed the RBL by more than 5dBA. Where the noise level from the source varies over time due to changes in operating conditions, meteorological conditions or other factors, the upper 10 th percentile of 15 minute L Aeq noise levels can be used for comparison with the criterion. The amenity criterion sets a limit on the total noise level from all industrial noise sources affecting a receiver. Different criteria apply for different types of receiver (e.g. residence, school classroom); different areas (e.g. rural, suburban); and different time periods, namely daytime (7am to 6pm), evening (6pm to 10pm) and night time (10pm to 7am). The noise level to be compared with this criterion is the L Aeq noise level, measured over the time period in question, due to all industrial noise sources, but excluding non-industrial sources such as transportation. Where a new noise source is proposed in an area with negligible existing industrial noise, the amenity criterion for that source may be taken as being equal to the overall amenity criterion. However, if there is significant existing industrial noise, the criterion for any new source must be set at a lower value. If existing industrial noise already exceeds the relevant amenity criterion, noise from any new source must be set well below the overall criterion to ensure that any increase in noise levels is negligible. Methods for determining a source-specific amenity criterion where there is existing industrial noise are set out in the Industrial Noise Policy (INP). Determination of site specific industrial noise criteria Table 18 presents the relevant industrial noise criteria for this Project based on an urban area classification. 84 EnergyAustralia

18 Table 18: Industrial intrusiveness & amenity criteria Receiver Area 3 Time period Daytime (7am to 6pm) Evening (6pm to 10pm) Night time (10pm to 7am) RBL (dba) Intrusiveness criterion L Aeq,15min (dba) Level of existing industrial noise, L Aeq,period Projectspecific amenity criterion In this case, there is industrial noise existing in the area associated with the Caltex refinery and other surrounding facilities. Operational noise from the site would be present on a 24 hour basis, and as a result the night time amenity criterion of 43dBA would, in effect, be the controlling noise criterion on site Noise source levels Noise sources that are likely to be associated with the construction and operation of the development are identified in the following sections. Construction noise sources Typical Sound Power Levels (SWL) of the plant likely to be used during earthworks, construction and cable laying are identified in Table 19. These SWLs have recently been measured at other similar construction sites. Table 19: Typical construction plant sound power levels (SWL) Plant SWL, dba Excavator 107 Dump trucks 112 Rock breaker 122 Concrete trucks 112 Saws 116 Saw cutter 115 Small excavators 90 Water truck 110 Vibratory rollers 110 Concrete trucks 109 Bulldozer 119 Graders 109 Botany Bay Cable Project Environmental Assessment 85

19 7 assessment of key environmental issues Plant SWL, dba Smooth drum roller 107 Small generators 95 Front end - low loader 112 Compressor 100 Large diesel water pump 112 Tug boat 108 Table 20: Typical HDD construction plant sound power levels (SWL) Plant SWL, dba Excavator 107 Power pac (treated) 100 Mud pumps 110 Generators 110 Vertical sump pumps 83 Operational noise sources Typical noise sources associated with the plan proposed for the Kurnell STS are shown below. This data has been supplied by the transformer manufacturer Wilson. Transformer Type 132kV/33kV kV/11kV 71 SWL (dba) Construction noise assessment Assessment of likely construction noise has been based on the four main construction operations that are proposed. These construction activities would be spread out over a relatively long distance. As such, each area can be assessed separately, as noise from each operation would not be cumulative at a particular residence. Operations are: trenching and cable laying horizontal directional drilling at the La Perouse site submarine trenching and cable laying across Botany Bay building works at Kurnell and Bunnerong STSs. All operations are to be generally conducted during normal construction hours, as detailed in Section 3.4.4, thereby affording residences respite from any construction noise during night periods and on Sundays. The operations are assessed in the following sections: 86 EnergyAustralia

20 a) Trenching and cable laying This construction process consists of cutting and excavating a trench in the roadway to lay cable along the specified route. With the exception of the sandstone section between the horizontal directional drilling site and Elaroo Road, all excavation would be in sand. As such the excavation, laying and filling process with be relatively short. It is anticipated that residences along the cable route would be exposed to construction noise for less than four weeks. The trenching is likely to be conducted in 500 metre lengths on the southern section and 1000 metres lengths on the northern side of the site. In the section between the La Perouse HDD site and Elaroo Avenue, a rock saw would be required to cut the trench. Predicted noise levels at residences are based on the equipment considered likely to be operating during any 15 minute period, which comprise: excavator for 10 minutes dump truck for five minutes rock saw for five minutes (for the La Perouse to Elaroo Avenue rock section only). This results in overall plant sound power levels of 109dBA and 113dBA for the sand and rock trenching lengths, respectively, and noise levels at residences along the route have been predicted on this basis. The noise predictions are based on distance attenuation and noise shielding provided by any topographical features. Table 21 presents the predicted likely construction noise levels due to trenching at nearby residences along the route. Table 21: Predicted noise levels at residences along trench route - dba Section Distance to residences Distance attenuation Barrier Resultant Criteria Exceedance Kurnell STS to Captain Cook Drive 35m Silver Beach Road 15m Prince Charles Parade 16m HDD site to Elaroo Avenue 20m Canara Avenue 21m Little Bay Road 200m Willis Street 130m Wassell Street 90m These initial calculations indicate the construction noise criteria are likely to be exceeded during the trenching phase at residences in close proximity to the route. Exceedances of construction noise criteria are quite common for construction projects, and given the relatively short duration of construction work compared to the life of the development, some tolerance is usually provided. Botany Bay Cable Project Environmental Assessment 87

21 7 assessment of key environmental issues It is recommended that the use of rock breakers be avoided, with rock saws being preferred. This is particularly significant in the section from Goorawahl Avenue to Elaroo Avenue, where the trench is to be cut into rock. Further, best practice noise management techniques should be adopted to ensure that all plant is in good working order. Noise management is addressed later in Section b) Horizontal directional drilling (HDD) The compound which is proposed to contain the horizontal direction drilling rig would be likely to accommodate the following plant: two power packs (in acoustic containers) two generators one HDD drilling unit three mud pumps five vertical sump pumps. In addition, occasional equipment deliveries and dump trucks would visit the site. It is envisaged that the HDD site would operate for a period up to six months. Based on the equipment noise levels presented in Table 19, the total sound power level of equipment on site would be in the order of 118dBA. Accordingly, a resultant construction noise level of 78dBA is predicted at nearby residences to the north and west of the site, assuming the HDD site is located adjacent to the bus turning circle. A reduction in construction noise of 25dBA would be required to comply with the established 4 to 26 week noise criterion of 53dBA. Noise control measures that would be adopted to reduce noise levels at residences are: install a noise barrier around the compound on the side facing residences practically reductions in the order of 10 to 15dBA can be achieved provide enclosures around the individual items of plant. It is likely that a combination of the above measures would be required to ensure the acoustic amenity of nearby residences is protected during this stage of the Project. Being stationary plant, there is much more scope for noise controls than for moving construction equipment. As a result of this assessment it is important that the contractor identifies specific noise control measures that would achieve the required noise levels at residences. c) Submarine trenching and cable laying Noise associated with submarine cable lying would result from equipment mounted on a barge that would be manoeuvred by a tug boat. Items of plant likely to be associated with this construction process are: tug boat two power packs (in acoustic containers) 750 Hp water pump (diesel) compressor. A sound power level of 111dBA has been established for the barge equipment and tug. Maximum construction noise levels associated with submarine cable laying operations are predicted to be: 88 EnergyAustralia

22 La Perouse residences - 36dBA (assumes a closest distance of 380 metres at nearest point and shielding provided by the headland) Prince Charles Drive residences 65dBA (assumes a distance of 80 metres at nearest point). The noise predictions indicate that noise from marine operations would be well below the noise criteria at residences in La Perouse at all times. In the case of the residences on Prince Charles Drive nearest to the marine section of cable, a 4dBA exceedance of noise goals is predicted at the nearest point. This exceedance is considered marginal, given that much of the time the barge would be working at a greater distance from the shore. Accordingly, the noise associated with the barge is considered manageable. It is recommended that noise from plant associated with the barge operations is reviewed at assembly to ensure that noise emissions are in accordance with these findings. d) Subtransmission substation building works Building works are to be conducted at both the Kurnell and Bunnerong STSs. The following sections detail the likely construction works and the associated noise emissions. Kurnell STS works Predicted noise levels at residences from STS construction activities are based on the following equipment operating during any likely 15 minute period: excavator for 10 minutes concrete truck for 10 minutes dump truck for five minutes small compressor on site for 15 minutes. Based on a total sound power level of 110dBA, the resultant construction noise levels at residences on Tasman Road are predicted to be in the order of 58dBA. This noise level represents an exceedance of the 4 to 26 week noise goal of 52dBA by 6dBA. Mitigation of noise from these activities can be achieved by the installation of a plywood barrier or hoarding on the northern end of the STS construction site. A barrier in the order of 2 to 2.5 metres should provide sufficient noise reduction to result in general compliance with the established noise criteria. Bunnerong STS works Proposed construction works at Bunnerong STS consist of the installation of the cables on the site and connection to existing electrical equipment. Resultant noise levels from construction activities at the nearest residences to this site, being residences in Moorina Avenue at a distance of 350 metres, are predicted to be in the order of 36dBA. This level is likely to be inaudible at these residences Operational noise assessment The Kurnell STS would be upgraded to accommodate the new cables. The upgrade would include the following transformers: An existing 132/33kV transformer this transformer is located adjacent to the two existing transformers already operating on site. This unit would service as a backup to the two existing units. Two new 132/11kV low noise transformers are to be installed as part of the relocation of the existing zone substation from the eastern side of Captain Cook Drive to this site. Botany Bay Cable Project Environmental Assessment 89

23 7 assessment of key environmental issues A worst case prediction of operational noise levels at the nearest residential receivers to the north on Tasman Street has been conducted based on all additional transformers operating simultaneously. Predictions are based on: equipment noise levels as supplied by Wilson distance attenuation over 150 to 220 metres. Based on the above, the overall contributed noise level associated with the new transformers would be in the order of 26dBA. In addition, application of a penalty of 5dB, to allow for a 100 Hz tonal component that is typically exhibited by transformers, can be applied to the predicted noise levels. When comparing the total adjusted operational noise with the night time criterion of 43dBA, compliance is indicated Summary of findings This noise assessment has established noise criteria appropriate for construction and operational noise based on ambient noise monitoring. A combination of engineering and management measures would be required to minimise noise emissions. Engineering measures recommended include noise barriers and enclosures. The requisite measures are set out in Section Construction activities are likely to exceed established goals along the trenching route and adjacent to the horizontal directional drilling site. Accordingly management of this issue would require attention in minimising the acoustic impact at residences. Noise from the operation of additional plant at the Kurnell STS has been assessed and it has been determined that compliance with DECC noise criteria would be achieved. Construction noise Noise from construction activities would potentially exceed established noise goals. Therefore, the planning and management of construction activities would take into account the sensitivities of surrounding residents to minimise the impact of construction noise at these receivers. Table 22 summarises the findings of the construction noise assessment. Table 22: Summary of construction noise findings Activity Trenching and cable laying Horizontal directional drilling Marine cable laying Kurnell STS works Bunnerong STS works Findings Exceedances up to 16dBA are predicted whilst equipment is adjacent to residences along the route. Noise impact would be greatest at residences in close proximity to the route. Noise impact could be mitigated by short time period of construction. Exceedances such as the above are at times unavoidable in construction situations. Exceedances up to 25dBA are predicted adjacent to residences, without suitable measures in place. Contractor would be required to establish noise attenuation measures. See mitigation measures below. General compliance except when barge is adjacent to Prince Charles Parade where a small exceedance is predicted Exceedances up to 6dBA are predicted at Tasman Street residences No exceedance of criteria is indicated. Construction noise is likely to be inaudible at residences 90 EnergyAustralia

24 Operational noise Noise from the operation for new facilities at Kurnell STS (i.e. transformers) has been determined to meet acceptable noise levels at nearby residences Mitigation measures These are as follows: Land trenching and cable laying: best practice noise management of plant would be adopted rock breakers would be avoided in preference to rock saws. Horizontal directional drilling The contractor would be required to adopt significant noise controls such that a LA10 (15 minute) noise level of 53dBA is not exceeded at the nearest residential receivers. Control measures include: suitable barriers/hoarding would be erected at the HDD site HDD plant would be treated acoustically, if required, to attain the noise level above. Marine cable laying Noise levels of plant associated with the barge operations would be reviewed at assembly. Kurnell STS A 2 to 2.5 metres high plywood barrier/hoarding would be installed on the northern end of the STS construction site. Kurnell STS operations Noise levels are projected to be acceptable at the nearest residences, however, noise monitoring would be undertaken to ensure operational noise remains within the required levels. General A Noise Management Plan would be included in the Environmental Management Plan for the Project. The plan would address the following areas: Noise monitoring Response to complaints Responsibilities Monitoring of noise emissions from plant items Supplementary noise monitoring and long term noise monitoring Reporting and record keeping Non compliance and corrective action Community consultation and complaint handling. 7.3 Sediment plumes The study of sediment plume generation was conducted by consulting company Cardno Lawson Treloar. The relevant sections of the report are summarised here. A copy of the report in its entirety can be found in Volume Two of this Environmental Assessment. Botany Bay Cable Project Environmental Assessment 91

25 7 assessment of key environmental issues Sediment plume generation Installation of the submarine cables using the trenching methods described in Section 2 would disturb the sea bed and most likely lead to suspension of a fraction of sea bed sediments. This process was investigated by developing realistic operational scenarios and then using the tidal model of Botany Bay to describe the plumes of suspended sediment in the upper water and lower column. Geotechnical sea bed profiles of Botany Bay show clay lenses near Molineaux Point at a depth of about 2.5 metres below the sea bed (Kinhill 1991). However, no clay lenses were included in sediment plume analysis despite the fact that they may occur along the route of the Project. Typically, there is only 5% to 8% of fines (<64µm) in Botany Bay sands, but there is no data for the proposed corridor The sediment plume model Modelling locations Two locations along the proposed cable corridor were selected for plume modelling. They are shown in Figure 20. The first was south-east of La Perouse, located where the cable bundles would emerge from the directionally drilled northern section in a water depth of about 10 metres. The second was near Silver Beach in a water depth of about two metres. These locations were selected because the currents, depths and proximity to sensitive sites are different. Plume model and inputs The Delft3D model of Botany Bay was operated in three dimensional (3D) mode with seven vertical layers and the silt load from the trenching work introduced at each site near the sea bed. To model sediment plume generation, it was necessary to develop a submarine trenching scenario. The following parameters were set as inputs for the model: A work period for active trenching of 20 days with eight working hours per day. An in-situ density of 1,600kg/m 3 for sea bed sediments. Eight percent of disturbed solids put into suspension (based on Barnard, 1978) leading to a suspended sediment production rate of 0.3kg/s over the dredging work periods. A sediment particle size (D 50 ) of 64µm. 92 EnergyAustralia

26 Figure 20: Locations at which sediment plume analysis was conducted Plume model findings Plume generation at the maximum flood (high) tide for both locations is presented in Figure 21 and Figure 22 for the surface and sea bed situations, respectively. Plume generation at the maximum ebb (low) tide is presented in Figure 23 and Figure 24 for the surface and sea bed situations, respectively. Each plume represents about six hours of accumulated suspended sediment discharge, with deposition accounted for. As a point of comparison, it should be noted that the concentration of suspended solids in this region of Botany Bay is typically about 5mg/L (Kinhill 1991). Botany Bay Cable Project Environmental Assessment 93

27 7 assessment of key environmental issues At the La Perouse site, it is projected that there would be no visible surface plume but near the sea bed at low tide suspended sediment concentrations would reach 20mg/L. At the site off Silver Beach at Kurnell, the model indicates that a small plume may be visible due to the shallower water there, however suspended sediment concentrations at the surface would generally be less than 5mg/L. The plumes would most likely only persist for several hours and would disappear completely overnight (in the absence of night-time trenching operations). The impacts of sediment plumes on aquatic ecology are discussed in Section Other findings When undertaking the Environmental Impact Assessment for the Sydney Airport third runway, Kinhill (1991) took seven cores from locations relevant to dredging undertaken for construction of the third runway and analysed them for contamination of the sediments. Results from these cores identified some contamination in the form of heavy metals and organochlorines. However, the observed concentrations of heavy metals all lay within the accepted range for uncontaminated sediments in the Sydney region; being towards the lower end of this range. It can therefore be concluded that all metal contamination identified in these analyses occurred naturally in the Bay sediments. Organochlorine concentrations for the majority of sea bed sediments in the tested area were below the detection limit. However, some surface samples showed elevated levels, including chlordane, dieldrin and DDT (Dichlorodiphenyltrichloroethane). Of the twelve samples tested, however, only those closest to Penrhyn Estuary and the Mill Stream channel showed any organochlorines. The sample closest to the Project was taken near the entrance to Port Botany, and displayed no elevated organochlorine levels. Hence, it is unlikely that any would be identified within the corridor identified for the Project. 94 EnergyAustralia

28 Figure 21: Sediment plume generation at the water surface for the maximum flood (high) tide Botany Bay Cable Project Environmental Assessment 95

29 7 assessment of key environmental issues Figure 22: Sediment plume generation at the sea bed for the maximum flood (high) tide 96 EnergyAustralia

30 Figure 23: Sediment plume generation at the water surface for the maximum ebb (low) tide Botany Bay Cable Project Environmental Assessment 97

31 7 assessment of key environmental issues Figure 24: Sediment plume generation at the sea bed for the maximum ebb (low) tide Conclusion Plumes of suspended sediment would be generated by trenching operations during the construction of the submarine cable section of the Project. However, these would be minimal at the surface, and disperse relatively quickly. No long term effects are predicted 98 EnergyAustralia

32 as a result of suspended sediment generation during the construction phase of the Project, because no heavy metal or organochlorine contamination is likely to be encountered along the proposed route. Once the construction phase is finished, no further sediment plumes of any kind would be generated as a result of the Project. It is possible that occasional small lenses of clay may be encountered along the route, thereby leading to periods of more intense suspended sediments Mitigation measures The sediment plumes generated from the submarine cable laying works are projected to have minimal impacts on the environment. The reasons for this projection are detailed in Section The main reasons are the separation distances between the plumes and important marine habitats and the low level, short term nature of deposition of transported sediment on seagrass beds in comparison with natural occurrences. 7.4 Aquatic ecology This Section summarises the report on aquatic ecology prepared by Marine Pollution Research Pty Ltd, which can be found in its entirety in Volume Two. There are two main aspects to this aquatic ecology assessment: potential impacts resulting from disturbance of the bed of Botany Bay potential impacts resulting from sediment plumes generated as a result of trenching operations. The focus of the Section below, however, is on threatened and endangered species or populations, as their situation influenced habitat mapping and field studies Threatened and endangered species or populations Appendix A of the main aquatic ecology report contains a list of the aquatic birds, marine mammals, reptiles and fish known or likely to occur within three nautical miles of the Project, considered to be threatened or endangered. The list was compiled from searches of the threatened species data bases held by the Commonwealth Department of Environment and Heritage administering the Environment Protection and Biodiversity Conservation Act 1999, the NSW Department of Primary Industries administering the Fisheries Management Act 1994 and the NSW Department of Environment and Climate Change administering the Threatened Species Conservation Act There are 80 listed species comprising 15 sea birds (including two tern species), 21 wader and shore bird species, 12 cetaceans (whales and dolphins), three reptiles (turtles and sea snakes), four sharks and 25 fish (mainly seahorses and pipe fish). Many of these species are listed under more than one Act: Four species (three sharks and a rock cod) are listed under the Fisheries Management Act sea, shore and wading birds plus four marine mammals and one marine reptile listed under the Threatened Species Conservation Act species listed under the Environment Protection and Biodiversity Conservation Act 1999; 12 sea birds, eight wading birds, 11 cetaceans, three reptiles and 24 fish (23 pipe fish or sea horses). Two recent Botany Bay projects, the Towra Point Spit rehabilitation project and the Port Botany expansion project, have considered the likely impact of those projects on threatened and listed species under Environment Protection and Biodiversity Conservation Act 1999, Fisheries Management Act 1994 and Threatened Species Conservation Act 1999 species. They have provided literature and study reviews of the usage of the Botany Bay resources by these species plus provided formal eight-part testing, as required under the Threatened Species Conservation Act 1999, for a number of these species. The results of this exercise are set out in the Environmental Impact Statements which were prepared in Botany Bay Cable Project Environmental Assessment 99

33 7 assessment of key environmental issues respect of these projects. Based on a consideration of the species list in Appendix A of the aquatic ecology main report against the overall Botany Bay utilisation reviews provided in these two EISs, only one endangered species, the Black Rock Cod (listed under the FM Act), could be expected to reside in the study corridor (in sub-tidal reef habitat at Watts Reef, Bare Island Reef or Astrolabe Cove). Of the pipe fish and sea horse species listed by Section 284 of the EPBC Act a number could be expected to occur in the seagrass beds off Silver Beach and in the rocky reef areas. These species are all mobile and there is adequate similar habitat available immediately adjacent to the proposed route to support these species should they be displaced by the works. Accordingly, it is concluded that these species would be able to move out of the area of cable laying without any significant impact on the species. The lack of any significant impact on the EPBC listed species also means that there is no need to refer the Project to the Commonwealth Minister for the Environment under the approval provisions of the EPBC Act Aquatic habitat mapping and field studies The most recent available published mapping of major aquatic habitats of Botany Bay was undertaken by DPI Fisheries using aerial photography obtained in 1995 (Watford and Williams 1998). DPI Fisheries provided electronic shape files showing overall marine vegetation (mangroves, seagrass and kelp) distribution limits and these shapes were superimposed over a rectified aerial photograph prepared for this Project for use in aquatic habitat mapping. Preliminary and targeted boat based Differential Global Positioning System surveys were undertaken to map the locations and extent of rocky reefs in Astrolabe Bay, at Watts Reef and off Silver Beach, and to map the extent of seagrass beds off Silver Beach. Diver/biologists, in conjunction with surveyors, provided accurate location undertook the following additional field surveys in Botany Bay: Mapping plus overall description of sub-tidal rocky reefs and rocky reef limits plus specific searches for listed threatened and protected fish and shark species for the reef systems in Astrolabe Bay, for the western extension of the reef system from Bare Island, for Watts Reef (off Sutherland Point) and for the shallow sub-tidal to intertidal reef system along the shore between Silver Beach and Sutherland Point. Spot dives along the preferred cable route from the shallow to depths of 17 metres (i.e., either side of the dredged entrance channel) to confirm sea bed type and condition. This was particularly relevant for the area of mixed seagrass and rock reef habitat between Watts Reef and Sutherland Point where Differential Global Positioning System survey data indicated some possible additional rock outcrops. Detailed mapping of seagrass species and overall density for the seagrass bed off Silver Beach plus examination of possible alternative routes through and around the Silver Beach seagrass bed. Seagrass density measurements within the main Posidonia bed off Silver Beach Aquatic habitats The aquatic habitats that would be potentially impacted by the Project are described below. The habitats are located on or adjacent to the proposed Project works, going from the Kurnell STS to the Bunnerong STS. a) Kurnell subtransmission substation site The site has intertidal mangrove habitat on the western edge and there is a tidal creek with mangroves and coastal swamp habitat to the north. There is coastal swamp habitat to the south. 100 EnergyAustralia

34 b) Kurnell subtransmission substation to Silver Beach intertidal Marton Swamp, located north of Solander Street, is connected to Quibray Bay via a graded freshwater to estuarine drainage system. The lower portion of the creek connecting the Swamp to Quibray Bay is tidal and supports mangroves, both grey and river mangroves, plus a variety of coastal salt marsh riparian species including She-oak. The creek is utilised by estuarine fish including schools of juvenile fish. Stormwater from the Polo Road sub catchment is piped under Prince Charles Drive and discharges directly to Silver Beach into a beach sand discharge scour hole below the pipe. This scour hole acts as a small lagoon and contains a very sparse freshwater aquatic fauna, mainly mites and beetles. There is a rock groyne constructed from the beach into shallow sub tidal waters some 100 metres east of the Australian Oil Refinery wharf. The groyne comprises large sandstone blocks which provide crevices and spaces suitable as shelter for crabs and other mobile aquatic species. The lower shallow sub tidal portion of the rock groyne provided some substratum for algae and encrusting or attached marine biota plus high tide crevice shelter for fish. c) Shallow sub tidal habitats Silver Beach to Sutherland Point Main habitat types include: bare shallow sub tidal sand seagrass beds intertidal to shallow sub-tidal rocky shores mixed sub tidal vegetated habitat comprising patchy seagrass exposed basement rock supporting algae and bare sand habitat. d) Silver Beach shallows The beach plus the intertidal sand zone off Silver Beach comprises shelly sand with progressively more silt content off shore. Field observations indicate that the intertidal beach sands support a burrowing benthic fauna typical of this habitat including amphipod and cumacean crustaceans, bivalve molluscs and some polychaete worms. e) Silver Beach seagrass bed The preferred route from Kurnell would require trenching through a mixed seagrass community. A towed diver Differential Global Positioning System controlled survey was undertaken to determine the perimeter of this bed. The main seagrass bed is shown in Figure 25. It is around 10.6 hectares, with six hectares of patchy seagrass plus mixed reef fringing the main bed and extending from the main bed to Watts Reef. However, post the assessment survey, consideration of the potential effects of the Project on the Posidonia australis in the seagrass bed has led EnergyAustralia to consult further with DPI Fisheries which stated that preference would be given to a route around the edges of the bed, however, because the seagrass bed is dynamic the final cable alignment would have to be determined during the design and construction phase of the Project via the strategies adopted for the Seagrass Management Plan described in Section Reference should also be made to Section Posidonia bed options. Figure 25 indicates a corridor for the potential route through the seagrass bed. Botany Bay Cable Project Environmental Assessment 101

35 102 EnergyAustralia Figure 25: Main Silver Beach seagrass bed potential cable position to be within the area bounded by the yellow dotted lines 7 assessment of key environmental issues

36 The seagrass bed contains Strap weed, Posidonia australis, which is a significant seagrass species in Botany Bay. For this reason, the seagrass bed was the focus of additional field mapping and ground-truthing work including cover and density measurements in September and October Figure 26 shows the mean percent cover for the seagrass and algae within the main bed. The sampling sites are shown in Figure 27. Results may be summarised as follows: The main bed comprises mainly dense Strap weed (Posidonia australis) with paddle weed (Halophila spp.) locally abundant, generally at the edges, and includes both sparse and patchy eelgrass (Zostera capricorni) and a sparse and patchy distribution of the pest algae species (Caulerpa taxifolia). Strap weed cover varied from 20 to 80% with a mean and median cover of 50%. Cover was generally similar throughout the bed (at around 50%), but slightly higher in the middle of the bed (58%). Remaining seagrass and Caulerpa cover were much lower; mean paddle weed cover was 1.7%, eelgrass mean cover was 0.6% and Caulerpa cover was 0.5%. Median cover for all these species was zero Zostera Halophila Posidonia Caulerpa 45 Mean Percent Cover C1 C2 C3 C5 All Silver Beach East Site Figure 26: Mean percentage cover for seagrasses and Caulerpa main seagrass bed Botany Bay Cable Project Environmental Assessment 103

37 7 assessment of key environmental issues Figure 27: Seagrass sampling sites main seagrass bed There are several large patches of seagrass located between the main bed and the Australian Oil Refinery jetty to the west. Spot checks of these patches indicate that the inner shallow patches are Halophila, the mid-depth patches are Posidonia australis and fragmented outer patches are Halophila. This bed has been mapped and described a number of times since the 1970's with quite different descriptions of the seagrass community makeup: NSW State Pollution Control Commission (1978) described the bed as "a monotypic Halophila bed" and mapped the bed as "predominantly Halophila". This mapping was based on both aerial photography interpretation (1977 to 1978) and field ground truthing in NSW Fisheries (now DPI Fisheries) in their 1985 state wide aquatic vegetation mapping (West et al 1985) indicated the bed to be "Posidonia australis". The statewide mapping was based on both aerial photography interpretation (1978 to 1979 photography) and field ground truthing (in 1981). 104 EnergyAustralia

38 More recent NSW Fisheries' mapping undertaken specifically for Botany Bay and including extensive ground-truthing (Watson and Williams 1998) indicated the bed (in Zone 7) to be "mixed Halophila". The bed in "Zone 7" is described as follows (Watson & Williams 1998) "In contrast some P. australis was noted in the Mixed Halophila beds along the eastern end of Silver beach (region 7) but the area was considered too small to warrant inclusion in this class" (p19). "Halophila was the dominant species in the two regions closest to the mouth of the bay, regions 1 and 7, where 39 hectares of Mixed Halophila occurred. A small, but unquantified amount of P. australis was contained in the Mixed Halophila of region 7. (p25). On the face of it, these results would indicate that there have been some large fluctuations in the amount of Posidonia australis in this bed, with the current bed being more like the 1981 mapping than the 1978 or 1998 mapping. There was an infestation of sea urchins in Botany Bay in the early 1980s which decimated large portions of the Posidonia beds along the outer and middle Silver Beach sections. It may well be that the change from the West et al (1985) mapping in 1985 and the 1995 mapping is related to that event. However, this 1980s change does not account for the earlier change from "predominantly Halophila" (NSW State Pollution Control Commission 1978) to "Posidonia bed" (1981). The recent cover and density work indicates that the Posidonia australis in this bed is growing vigorously. There are clear runners radiating out from beds into bare or sparse areas, flowering was prolific, with an estimated one flowering shoot per two square metres surveyed (September 2006). f) Watts reef and habitats south of Watts Reef to Sutherland Point Watts Reef is located some 300 metres off the mainland intertidal rocky shore and the closest edge of this reef is some 90 metres north-west of the preferred trenching line. It has an estimated area of around 1.7 hectares. The reef comprises irregular rock with some large isolated boulders. Watts Reef provides a mosaic of shallow kelp bed habitat, bare rock habitat and deeper sponge garden habitat (as per Underwood et al 1991, Andrew and O-Neill (2000) and comprises (in decreasing order of area) kelp bed reef, bare rock and small areas of sponge garden. The latter zoned habitat is generally located at the base of the reef on the deeper northern side. The reefs support a typical reef benthic and fish fauna as described in NSW State Pollution Control Commission 1981a, NSW State Pollution Control Commission 1981c. A number of spot dives and searches were made around and on Watts Reef with the specific aim to locate threatened or listed species: No grey nurse sharks were observed, and no suitable permanent habitat for grey nurse sharks (i.e. wide sandy gutters) occur on the reef. However, there is an abundance of reef fish around the reef and occasional foraging by grey nurse sharks from the known habitat area at Magic Point, Maroubra could be expected. No black cod were observed but several male blue grouper and at least three female blue grouper were observed indicating suitable habitat for black cod. No weedy sea dragons were observed although there are relatively large kelp beds to support them and they are known from the inshore (Sutherland Point) kelp beds. g) Deep water habitats - Watts Reef to Bare Island Reef A number of spot dives onto the deeper sea bed were made along the preferred cable route between the 7.5 metre contour lines on either side of the Bay. These dives indicated that the preferred route across the deeper portions of the Bay does not support any marine vegetation. Botany Bay Cable Project Environmental Assessment 105

39 7 assessment of key environmental issues h) Shallow water habitats - Astrolabe Cove The Astrolabe Cove riparian shore comprises an exposed rocky headland with a two to three metres cliff face above a lower wave cut shelf and an intertidal rocky shore. The main sub-tidal aquatic habitats in Astrolabe Cove comprise intertidal and shallow sub tidal rocky reef with a small area of paddle weed seagrass. The reef supports a reef fish fauna typical of wave exposed marine rocky shores (NSW State Pollution Control Commission 1981c, Jones and Andrews 1990). A number of spot dives and searches were made around and on the Astrolabe Cove reefs with the specific aim to locate threatened or listed species: No grey nurse sharks were observed, and no suitable permanent habitat for grey nurse sharks (i.e. wide sandy gutters) occurs on the reef. Whilst occasional foraging by grey nurse sharks from the known habitat area at Magic Point, Maroubra, could be expected around the Bare Island Bumbora and the deeper Bare Island reefs, foraging around the shallower reefs of Astrolabe Cove is considered less likely. Whilst no black cod were positively identified for the survey one possible specimen was observed on one occasion. At lease one male blue grouper and several female blue grouper were observed on a number of occasions indicating suitable habitat for black cod. No weedy sea dragons were observed although there are relatively dense kelp beds to support them and they are known from the inshore Bare Island kelp beds. i) La Perouse to Bunnerong STS The trenching route from La Perouse to Bunnerong STS would be generally confined to existing road alignments and there is only one creek crossing, at the corner of Bunnerong Road and Little Bay Road. This creek is unlikely to support any native fish species (other than eels). There would be no threatened fish or aquatic macroinvertebrates, as currently listed under the NSW Fisheries Management Act (1994), residing in the creek system, as the creek does not provide any suitable habitat for these organisms Potential impacts The two key elements of possible impact for aquatic communities are direct disturbance of aquatic habitats for trenching plus indirect impacts on aquatic habitats from sediments derived from trenching and cable laying related activities. These potential impacts are discussed below. a) Submarine cable route - direct impacts With regard to the proposed trenched route across Botany Bay there are mixed seagrass beds off Silver Beach including large mono-specific areas of Strap weed (Posidonia australis), areas of exposed rocky reef with patchy algae and adjacent areas of deep reef with suitable habitat for at least one threatened species (Black Cod) and a number of protected species (known plus observed). The horizontal directional drilling on the Bare Island side of the Bay would emerge in bare sand overlying smothered rock with adjacent areas of deep reef which provide suitable habitat for at least one threatened species (Black Cod) and a number of protected species (known plus observed). There is a very patchy distribution of the pest algae species (Caulerpa taxifolia) throughout the whole seagrass bed and in the mixed shallow rock and seagrass area described above. With respect to direct impacts of submarine trenching along the proposed cable laying route, the three prime areas of direct impact are considered below: 1. The seagrass bed off Silver Beach. 2. The area of mixed seagrass algae and soft sediment habitat between the Silver Beach seagrass bed and Watts Reef. 106 EnergyAustralia

40 3. The intertidal, shallow sub tidal and deep sub-tidal unvegetated soft sediment habitats. Silver Beach seagrass bed There is a dense, mono-specific Strap weed bed off Silver Beach, as shown in Figure 25. This bed is around 200 to 250 metres wide. Seagrasses are protected under the NSW Fisheries Management Act (1994) and Posidonia australis is usually afforded special protection and consideration, due to its slow growth and poor recovery after damage. Large areas of Posidonia have already been lost from Botany Bay, as well as throughout NSW and Australia. Currently, it is reported that recovery of damaged Posidonia meadows may take decades or longer, depending on the extent of impact. Further damage to Posidonia meadows in Botany Bay must be considered as potentially threatening to the species survival and treated accordingly. Other seagrass species, such as Zostera and Halophila, are faster growing and can be expected to recover relatively quickly (within a few months or years). As a result of the concern about possible impacts on the seagrasses adjacent to the Kurnell peninsula, a framework of a Seagrass Management Plan for the site has been prepared. The aim of this plan is to minimise damage to seagrass beds, in particular the Posidonia meadow, and to apply the most advanced mitigation techniques available to assist the site to recover from the expected impact. While the Project is likely to have some impact on the seagrass meadows off the Kurnell peninsula, the extent of that impact can be minimised during the design and implementation stages. For example, it may be possible to reduce the width of the cable corridor to less than a metre and to mitigate the impact through developing best practice restoration techniques. In preparing the Seagrass Management Plan, the objectives of EnergyAustralia are to: map and document the condition of the seagrass beds prior to works minimise possible impacts on seagrasses, particularly Posidonia australis monitor the impact through a detailed on ground assessment investigate and develop seagrass restoration techniques mitigate the effects on seagrasses by restoration works within the impacted areas monitor longer-term condition of seagrass meadows, including areas mitigated, over a three year period after the works, or until the area has become stabilised. A framework for the Seagrass Management Plan in relation to impacted seagrass meadows adjacent to the Kurnell peninsula is outlined in Appendix D. The Plan would take cognisance of the strategies to protect seagrasses, as set out in the Seagrass Habitat Protection Plan, issued under the auspices of the DPI Fisheries. Furthermore, consideration to the use of HDD would be assessed if early indicators and/or monitoring outcomes indicate that work close to, or around the seagrass bed proved to be problematic (refer Section Posidonia bed options). Note that it is considered that the exit route for the HDD on the northern side of the Bay is located at a sufficient distance from the Bare Island and Astrolabe Bay rocky reef system such that there would be no direct impacts of trenching at that location on the north bayside rocky reef systems. This includes the aquatic habitats and biota of the Cape Banks Aquatic Reserve. Area of mixed sand, rock and seagrass habitat There is a mosaic of exposed rock reef with algae plus shallow sand bodies supporting mixed and very patchy seagrass, mainly paddle weed (Halophila spp.) with some very patchy (Caulerpa taxifolia), located north east of the main seagrass bed at Silver Beach. The proposed submarine trenching route traverses this area for a distance of around 300 metres. Botany Bay Cable Project Environmental Assessment 107

41 7 assessment of key environmental issues Trenching through this area may require cutting through rock which would remove some low profile basement rocky reef with Sargassum algae and some very patchy seagrass habitat. The algae losses could be mitigated to insignificance by re-creating rock reef habitat out of the cut rock over or along the proposed trenching route. The patchy seagrass in the locality is almost all paddle weed with some scattered eelgrass. There are some isolated Strap weed shoots close to the main Strap weed bed. Given that the paddle weed distribution through this area is very patchy (although widespread), and given that paddle weed and eelgrass are considered colonising species (i.e. they rapidly colonise suitable habitat), these grasses can be expected to grow back over buried cable. On balance therefore the overall loss of mainly paddle weed with a very small amount of eelgrass in this location is not considered significant. Soft unvegetated sediments There are several areas of soft unvegetated sediment along the proposed cable route; the beach and intertidal sands off Silver Beach, the shallow sub tidal sands off shore from Silver Beach, the deeper sands across the Bay between Watts Reef and Astrolabe Cove and the shallow sub tidal sands around the horizontal directional drilling exit point. In general terms trenching through these habitats via jetting would result in the temporary displacement and loss of benthic invertebrate fauna, mainly from direct loss to removal from the substratum and indirect loss to predation by fish and other opportunistic predators. Following cessation of trenching works the benthic community would be expected to recolonise from adjacent sediments and from settlement out of the plankton (Maurer et al 1981a,b, 1982) with complete re-colonisation occurring, but over an indeterminate period of time (see AMBS Consulting s 1998 report for further discussion of re-colonisation timing). Overall, given the relatively small area of soft sediment habitat to be disturbed when compared to the available area of this type of habitat in the Bay, it is concluded that the direct impacts of jet trenching for the proposed submarine cables would be insignificant. b) Submarine cable route - indirect impacts Potential indirect impacts from/on the following are discussed below: sediment plumes disturbing the pest algae species (Caulerpa taxifolia) aquaculture facilities. Potential impacts from sediment plumes The main indirect impact on aquatic ecosystems arising from trenching works for the submarine cable is the possibility of smothering from sediment plumes arising from jetting activities for cable burial. Cardno Lawson and Treloar has modelled sediment mobilisation from the trenching activity along the preferred route and provided the following plume generating parameters: overall trenching time for laying submarine cables 28 days (at eight hours per day) possible trenching rates of 20 to 100 metres per day (translating to 2.5 to 12.5 metres per hour for an eight hour work day) assumed in-situ density of sediments to be trenched is 1600 kg/m 3 assume around 8% of disturbed sediments would be put into suspension background suspended solids concentration is around 5 mg/l. Based on these parameters Cardno Lawson Treloar (2006) modelled plume generation for a number of tide and wind combinations and concluded that the submarine trenching works could generate a plume of up to 20 mg/l which could persist for a few hours and that, 108 EnergyAustralia

42 based on available sediment pollution quality data, there would be no significant mobilisation of pollutants to the water column. Given that Botany Bay s rocky reef and seagrass bed habitats are known to be subjected to periods of high suspended solids during major stormwater outflow events, it is concluded that the imposition of a suspended solids concentration of 20 mg/l over a few hours is not expected to have a significant impact on the aquatic habitats of the Bay. With regard to possible smothering impacts from deposition of the suspended solids loads, the above assumptions have been used to examine the possible depth of sediment which could be deposited over different circular areas of aquatic habitat around the trenching works. Cardno Lawson Treloar assumed 8% of material would be put into suspension from the sediment to be trenched with a density of 1600 kg/m 3. For this examination three different silt generation rates (8%, 12% and 16%) plus three different in-situ silt deposition densities (800 kg/m 3, 1200 kg/m 3, and 1600 kg/m 3 ) giving different sediment deposition depths per deposition area were considered. Initial modelling showed that for any deposition area greater than one with a radius of 10 metres there was insignificant deposition (<1 millimetre) for all simulations. Accordingly, only small areas of around three metres radius (25 square metres), five metres radius (80 square metres) and 10 metres radius (320 square metres) were considered further. The results are shown graphically in Figure 28, as outlined below: For deposition areas greater than 10 metres radius there was insignificant deposition depths (< two millimetres depth) for all simulations. For the 10 metre radius deposition area, deposition depth ranged from two millimetres to nine millimetres (with the maximum depth arising for a silt generation rate double the Cardno Lawson Treloar (CLT) rate plus a silt deposition density half the CLT estimate. For smaller deposition areas, (radius three metres and radius five metres) deposition depths varied from 8.5 millimetres (five metres radius, 8% silt and 1600 kg/m 3 ) to 120 millimetres (three metres radius, double the silt generation factor and half the bulk density). Botany Bay Cable Project Environmental Assessment 109

43 7 assessment of key environmental issues 1000 D800A25 D1200A25 D1600A25 D800A80 D1200A80 D1600A80 D800A320 D1200A320 D1600A320 Depth of Sedimentation (mm) 100 Deposition Area with Radius about 3 m Deposition Area with Radius About 5 m 10 Deposition Artea with Radius about 10 m Proportion of Silt Load in Bulk Sediments (Percent) Figure 28: Sensitivity analysis for sedimentation from trenching Given that practical trenching rates are estimated to range from 2.5 metres per day to 12.5 metres per day (Cardno Lawson Treloar 2006) and that jetting methods generally result in a well mixed plume, it is considered unlikely that mobilised sediments would in fact be deposited into such small confined areas around the trenching works. That is, it is considered that deposition areas are more likely to be in the order of 100 metres radius areas around the trenching works rather than the smaller radius areas. The stronger tidal flows away from the modelling points (which are relatively close to the shore) would also assist with plume dissipation. This conclusion is consistent with the results of the sediment plume analysis shown in Cardno Lawson Treloar (2006) which shows deposition plumes with that order of size. With regard to practical off sets from important rocky reef aquatic ecosystems the present trenching route is located: 110 EnergyAustralia

44 100 metres from the Astrolabe Cove deep reef habitat 250 metres north west of the Bare Island west reef extension 80 metres south east of Watts reef deep reef extension. These separation distances are considered sufficient to protect the deep and shallow rocky reef habitats and biota from indirect impacts of horizontal directional drilling and inshore trenching. The extent of possible smothering impacts of trenching works on seagrass beds is hard to determine at this stage when final cable laying methods and indeed final route selection have yet to be made. However, the consideration of direct impact has assumed a cable laying width of 15 metres which would likely incorporate the lower radius sedimentation analyses (three and five metres radius) presented above. With regard to the lower levels of sedimentation actually expected from the works (in the order of one to two millimetres), seagrass in this area is already subjected to pulse impacts of sediment loads during periods of high wave energy and it is considered that smothering impacts from short term turbidity plumes as described in the Cardno Lawson Treloar (2006) report would not have any significant impact on seagrass in the locality. Potential impacts arising from trenching through the pest algae Caulerpa taxifolia There is a widespread occurrence of the listed pest algae species (Caulerpa taxifolia) throughout Botany Bay and the species has been observed in very small areas (but widespread) throughout the shallow sub tidal sandy habitats of the study area on the Kurnell side of the Bay. Trenching using jetting methods would undoubtedly disturb Caulerpa plants and introduce fragments to the water column which could be transported to other parts of the Bay to settle and grow. However, given the widespread occurrence of this species throughout the Bay and given the time that this species has had to colonise suitable habitats through the Bay it is considered that the spreading of this species as a result of jetting sand for trenching would not be significant when compared to the existing ability for fragmentation and dispersal due to wave action during major storms. Notwithstanding this conclusion, there would still be an obligation to minimise possible spread of this species outside Botany Bay via spread from fragments collected onto or by machinery, vessels, anchoring gear and cable laying equipment. This could be achieved by producing a Caulerpa Management Plan which would set out the requirements for inspections, methods for collecting and dealing with collected fragments and methods for cleaning machinery and vessels to prevent the spread of Caulerpa. Possible impacts on aquaculture facilities There are currently two aquacultural activities underway in Botany Bay, oyster farming in Woolooware plus Quibray Bays and fish farming in Botany Bay (off Silver beach just west of the Australian Oil Refinery wharf). The fish farm west of Australian Oil Refinery wharf is currently used for growing Jewfish and it is anticipated that two fin fish species (jewfish and kingfish) will be farmed in 2007 (John Hedison personal communication). Mr Hedison is also currently investigating the use of the remainder of his lease to accommodate longline aquaculture for Akoya pearls. It is anticipated that one hectare would be used for the fin fish operation and three hectare for the long-line operation. With respect to possible fin fish impacts from the cable laying components of the Project, there are no direct impacts on aquaculture arising from the Project. With regard to indirect impacts the only possible impact is from turbidity plumes arising from the trenching works. As modelled by Cardno Lawson and Treloar (2006), it is not expected that plumes generated from the trenching works would introduce any significant water borne sediment load to the aquaculture facility off Silver Beach and there is no impact expected on oyster aquaculture which is located further to the west. Notwithstanding this conclusion, the Project would need to incorporate a Water Quality Management program which would include monitoring of plume direction and sediment concentration plus outline methods to prevent excessive sedimentation from reaching the fin fish aquaculture operation. This could include, interalia shutdown of trenching works under unfavourable conditions and/or provision of silt curtains to protect the fin fish farm. Botany Bay Cable Project Environmental Assessment 111

45 7 assessment of key environmental issues Impacts on threatened and endangered species or populations As noted in Section 7.4.1, there are 80 threatened, endangered or listed species known from within six kilometres of the proposed cable route, comprising 15 sea birds (including two tern species), 21 wader and shore bird species, 12 cetaceans (whales and dolphins), three reptiles (turtles and sea snakes), four sharks and 25 fish (mainly seahorses and pipe fish). Based on a consideration of the combined literature review for relevant studies in Botany Bay plus consideration of the results of the additional field studies undertaken for this Project, it is concluded that only one threatened species (the Black Cod) would likely reside in the study corridor. Whilst this species has not been reported from the study area there is good habitat in the Bare Island reef complex and in the Watts Reef complex. However, given the separation distances between the proposed works and these habitats it is concluded that there would be no impacts on the species or on the habitat of this species arising from the Project. Of the Environment Protection and Biological Conservation Act 1999 (Section 284) listed fish species (pipe fishes and sea horses), a number would be expected to occur in the trenching corridor as well as on adjacent rocky reef. Those occurring in the trenching corridor would be expected to be disturbed by trenching activities. Whilst most would be able to move away from the works a few could be exposed to jetting with consequent damage. Given the total area of the habitats likely to be affected (soft sediment and sediment plus seagrass habitat) the potential loss of individuals of these species is considered insignificant. Notwithstanding this result, there would be an aquatic Habitat and Boita Management Plan prepared for the Project, which would consider ways to avoid potential damage to fish along the trenching route. With respect to marine mammals, reptiles and seabirds, it is concluded that whilst a number of dolphins, whales, marine turtles and reptiles are irregular visitors to Botany Bay, their usage of the Bay is generally confined to the mouth of the Bay and to the southern seagrass and shallow sand bar complex off Towra Point. Whilst there are no direct impacts expected on these species arising from the Project there may be some potential disturbance due to noise or physical presence. It is recommended that the Aquatic Habitat Management Plan include a section on Marine Mammal and Reptile Interactions. There are a number of wader and shore birds plus fishing birds which utilise the shore and shallow areas within the cable corridor as part of their wider use of the Bay for feeding and roosting. Based on the review of aquatic bird usage of the Bay presented earlier tin this section, it is considered unlikely that proposed cable laying works would have any significant impact on any of these species Conclusions With regard to the proposed trenched route across Botany Bay the proposed route traverses mixed seagrass beds off Silver Beach including large areas of Strap weed (Posidonia australis). There are areas of shallow to deep rocky reef adjacent to (but remote from) the proposed route; at Watts Reef, Bare Island and Astrolabe Cove. These three reef systems provide suitable habitat for at least one threatened species (Black Cod) and for a number of protected or listed species. Horizontal directional drilling would be used on the La Perouse side of the Bay to avoid any damage on the rocky reef habitats of Astrolabe Cove and the off-set distances from the proposed trenching works to the remaining reef systems are judged sufficient to prevent any significant impact on these reef systems and their biota. Trenching would impact benthic fauna and possible some of the mobile (fish and invertebrate) fauna along the soft sediment route but the impact is considered short-lived and insignificant and recolonisation would occur. Proposed trenching works through the seagrass bed at Silver Beach has the potential for significant impact via loss of seagrass and seagrass habitat if remediation measures are not taken. To minimise any damage to seagrasses, particularly Posidonia australis, EnergyAustralia would prepare a Seagrass Management Plan that sets out the practical measures that would be undertaken to minimise and remediate damage. Details of the 112 EnergyAustralia

46 Plan s framework have been provided in Appendix D. The Plan would take cognisance of the strategies to protect seagrasses, as set out in the Seagrass Habitat Protection Plan, issued under the auspices of the DPI Fisheries. Refer also Section Whilst 80 threatened, endangered or listed species have been recorded within six kilometres of the proposed cable route, comprising 15 sea birds (including two tern species), 21 wader and shore bird species, 12 cetaceans (whales and dolphins), three reptiles (turtles and sea snakes), four sharks and 25 fish (seahorses and pipe fish), only one species (the Black Cod) would likely reside in the study corridor. Of the Environment Protection and Biological Conservation Act 1999 (Section 284) listed pipe fish and seahorse species, a number would be expected to occur in the corridor. A number of marine mammals, reptiles and seabirds are irregular visitors to Botany Bay with their usage of the bay generally confined to the mouth of the Bay (the study area) and to the southern seagrass and shallow sand bar complex off Towra Point. These species are all mobile and there is adequate similar habitat available immediately adjacent to the proposed route to support these species should they be displaced by the works. Accordingly, it is concluded that these species would be able to move out of the area of cable laying without any significant impact on the species. The Project would incorporate a Water Quality Management Plan and an Aquatic Habitat and Biota Management Plan Mitigation measures To manage the aquatic ecological impacts of the Project, EnergyAustralia would: utilise construction methods for the proposed building and excavation works at Kurnell STS that both prevent any significant damage to adjacent wetland habitats and prevent any runoff or spillage into these habitats undertake the two creek crossings of the land cable trench (one draining Marton Swamp to Quibray Bay at Kurnell and one draining urban areas at Little Bay to Yarra Bay at Bunnerong) in line with published NSW DPI guidelines for creek crossings minimise the damage to Posidonia australis by undertaking measures set out in a Seagrass Management Plan. Details of the framework for this Plan are provided in Appendix D consideration of the use of HDD would be assessed if early indicators and/or monitoring outcomes indicate that going around the edges of the Posidonia proved to be problematic (refer Section Posidonia bed options) prepare and utilise a Water Quality Management Plan and an Aquatic Habitat and Biota Management Plan to take into account the potential for threatened, endangered or listed species in the area during construction. 7.5 Terrestrial flora and fauna Molino Stewart undertook the terrestrial flora and fauna assessment for the Project. Its report is summarised below. The summary covers the study methodology, the results of both desktop and field investigations, the potential impacts on terrestrial flora and fauna and mitigation measures to manage impacts so that they are acceptable. A full copy of the report is located in Volume Two of the Environmental Assessment Methodology A desktop analysis was undertaken to identify constraints and issues requiring further consideration. In addition, as required under the Commonwealth s EPBC Act 1999, a Protected Matters Report was generated (see Appendix D of the Terrestrial Ecology Report in Volume Two for a copy of this report). Field investigations were undertaken along the proposed cable route and at the Bunnerong and Kurnell STSs and their immediate environs. This involved a floristic survey and a general fauna survey with several purposes: Botany Bay Cable Project Environmental Assessment 113

47 7 assessment of key environmental issues to validate previous studies to determine the likelihood for direct or indirect impacts on threatened species and/or their habitat to determine the possible extent of any such impacts. The scope of flora and fauna assessment is outlined below. Kurnell STS The cable entry route options together with the proposed building layout were assessed for the Kurnell STS. Bunnerong STS Two cable options were assessed at Bunnerong STS. These are illustrated in Figure 11. Inspection of an area of vegetation to be cleared for the expanded compound area but covered by a separate approval process was also undertaken. Cable route Assessment of discrete sections of the terrestrial cable route was undertaken and a photographic record of each section compiled along with ecological values which may require consideration. The sampling locations are illustrated in Figure EnergyAustralia

48 Figure 29: Ecological assessment sampling locations Desktop findings Subject species A search of the NSW Wildlife Atlas, Australian Museum specimen database and other records for the area was conducted, identifying species within a five kilometre radius of either Bunnerong or Kurnell STS. This, along with the flora and fauna assessment undertaken for Bunnerong STS (Total Earth Care 2006), provided a preliminary list of threatened flora and fauna species. Further analysis of the potential for the Project to have Botany Bay Cable Project Environmental Assessment 115

49 7 assessment of key environmental issues an impact on threatened species in the initial database reduced the species under consideration to those shown in Table 23. The reduced list of species constitutes the subject species which warrant further consideration: Table 23: Subject species and communities for terrestrial ecological assessment Scientific Name Common Name Location Ninox strenua Powerful Owl Bunnerong STS Xanthomyza phrygia Regent Honeyeater Bunnerong STS Kurnell STS Litoria aurea Green and Golden Bell Frog Kurnell STS Lathamus discolor Swift Parrot Bunnerong STS Pteropus poliocephalus Saccolaimus flaviventris Miniopterus schreibersii Myotis macropus Acacia terminalis sub sp terminalis Syzygium paniculatum Grey-headed Flying Fox Yellow-bellied Sheathtail-bat Common Bent-wing Bat Large Footed or Southern Myotis Sunshine Wattle Magenta Lilly Pilly Endangered Ecological Communities Eastern Suburbs Banksia Scrub The Shorebird Community occurring on the relict tidal delta sands at Taren Point Coastal Salt Marsh in the NSW North Coast, Sydney Basin and South East corner bioregions Sydney Freshwater Wetlands in the Sydney Basin Bioregion - Endangered Ecological Community Swamp Sclerophyll Forest on coastal floodplains of the NSW North Coast, Sydney basin and South East Corner bioregions Swamp Oak Floodplain Forest of the NSW North Coast, Sydney Basin and South East Corner bioregions Bunnerong STS Kurnell STS Bunnerong STS Kurnell STS Bunnerong STS Kurnell STS Bunnerong STS Kurnell STS Bunnerong STS Kurnell STS Kurnell STS Bunnerong STS Kurnell STS Kurnell STS Kurnell STS Kurnell STS Other ecological matters An assessment of other ecological matters revealed that the Kurnell STS is located immediately adjacent to a RAMSAR designated wetland, the Towra Point Nature Reserve, and that species records exist for species that, whilst not threatened, are subject to international agreements including JAMBA and CAMBA. These matters could require liaison with the Federal Government if affected by the Project. Figure 30 shows the location and extent of the Towra Point Nature Reserve, 116 EnergyAustralia

50 Figure 30 Location of Towra Point Nature Reserve An examination of the NSW DECC Recovery Plan for Eastern Suburbs Banksia Scrub revealed that parts of the Bunnerong STS are identified as possessing significant stands of the Endangered Ecological Community. EnergyAustralia has entered into an agreement with NSW DECC to appropriately manage the remnants of the Endangered Ecological Community within the STS and a site specific management plan has been prepared by EnergyAustralia for the site Field findings a) Bunnerong subtransmission substation The Bunnerong STS is just over 7.2 hectares in area. It consists of a network of internal roadways, parking areas and walkways along with two discrete, fenced, substation compounds (north and south) containing switching gear and associated buildings. Significant areas of vegetation remain on the site. The levels of fragmentation and disturbance of these areas of vegetation vary. An eastern section of the southern STS compound would be expanded to accommodate switching gear. This compound expansion would require the removal of an area infested by Bitou Bush. This activity is the subject of a separate development application (Total Earth Care 2006). Flora Forty plant species were identified in the two site inspections of Bunnerong STS. Almost half of the plants detected were introduced species. Three species declared as weeds under the Noxious Weeds Act 1993 (NSW) were identified on the site. These were: Bitou Bush (Chrysanthemoides monilifera): Class 4 - Locally Controlled Botany Bay Cable Project Environmental Assessment 117

51 7 assessment of key environmental issues Pampas Grass (Cordateria selloana): Class 4 - Locally Controlled Lantana (Lantana camara): Class 5 - Restricted These species require control in accordance with a Plan of Management published by the Randwick Weed Control area. Invasion of native plant communities by Bitou Bush is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995 (NSW). As a result, a draft Threat Abatement Plan has been prepared by the NSW Department of Environment and Climate Change (formerly NSW Department of Environment and Conservation 2006a). Sunshine Wattle (Acacia terminalis ssp) terminalis was identified as a potential subject Threatened Species for the Bunnerong STS site, however, no specimens were identified during the site inspections. Site inspection confirmed the presence of the Eastern Suburbs Banksia Scrub Endangered Ecological Community at Bunnerong STS. Its distribution was found to be as recorded by the NSW Department of Environment and Conservation (2004a, 2004b, 2006b) now known as DECC. Other patches of vegetation on the site have been previously identified as regrowth (Total Earth Care 2006), however, elements of Eastern Suburbs Banksia Scrub Endangered Ecological Community may be present in some of these patches despite the heavy infestation of Bitou and other weeds. The Project is not expected to have any direct impact on the currently identified Eastern Suburbs Banksia Scrub Endangered Ecological Community at Bunnerong STS, because the proposed cable routes are confined to existing roadways. The patch of regrowth vegetation to be removed subject to a separate development application has been assessed by Total Earth Care (2006). This development application was required in respect of preliminary works at the Bunnerong STS that need to be in place before the construction phase of the Project begins. Total Earth Care concludes that there would be no significant impact on the Eastern Suburbs Banksia Scrub Endangered Ecological Community as a result of this clearing. It should be noted, however, that this community is capable of regenerating from soil seed bank on cleared sand where the soil profile remains intact (NSW Department of Environment and Climate Change 2004a). Elements of Eastern Suburbs Banksia Scrub may persist within the soil seed bank across other vegetation patches on the Bunnerong STS site. As a result, any future proposed vegetation removal or modification should be carefully assessed even if outside the currently mapped Eastern Suburbs Banksia Scrub Endangered Ecological Community areas. The retention of other vegetation on the site and implementation of the management plan for the Eastern Suburbs Banksia Scrub Endangered Ecological Community in accordance with the National Recovery Plan for the Endangered Ecological Community would appropriately manage existing vegetation of significance. Implementation of the NSW Threat Abatement Plan for Bitou Bush would manage this serious pest. Fauna A general fauna survey was undertaken for the Bunnerong STS. This revealed that the Project is unlikely to affect any of the subject species identified in Table 23. The Common Bent wing Bat (Miniopterus shreibersii), Yellow-bellied Sheathtail-bat (Saccolaimus flaviventris) and Large Footed or Southern Myotis (Myotis adversus) have been detected within a five kilometre radius of the subject site. It is likely that these three species are occasional visitors to the Bunnerong STS site, foraging amongst canopy trees. No trees with hollows were detected on the site and no obvious likely roosting or nesting sites were observed. As a result, the impact of the Project on these species is likely to be minimal. If lighting conditions on the site changed, feeding behaviours and site utilisation could be affected. The Grey-headed Flying Fox (Pteropus poliocephalus), Regent Honeyeater (Xanthomyza Phrygia) and Swift Parrot (Lathamus discolour) are wide ranging and/or migratory species that utilise flowering Eucalypt species such as Swamp Mahogany (Eucalyptus robustus). Occasional foraging use of these components of the subject site is only likely to 118 EnergyAustralia

52 supplement the more extensive foraging habitat required by these species in the local area and during their wider migratory behaviours. Because of their migratory behaviour, the Bunnerong STS land is unlikely to form significant habitat to these species. The Project would not alter the extent of foraging vegetation at Bunnerong STS, so would have a minimal impact on these species. The Powerful Owl (Ninox strenua) is distributed over a large area of eastern Australia, generally occupying heavily timbered country of varying vegetation types. In developed areas the species has shown, on occasion, an ability to occupy patches of fragmented but vegetated land. The Powerful Owl nests and roosts in very large, hollow trees. As this habitat is non existent on the Bunnerong STS site, the Project is unlikely to have any impact on this species. In addition to the subject species discussed above, the She Oak Skink (Cyclodomorphus michaeli) was identified. Although not listed as a threatened species, its presence could have conservation significance, as it is the closest remaining population to Sydney City. Once much more widespread and patchily distributed around Sydney many of these patches have now been extirpated. Remnant patches of the species still occur in Royal National Park south of Sydney, in the Blue Mountains west of Sydney, at Dapto and Shellharbour on the Illawarra coast and around Tuggerah on the Central Coast. b) Kurnell subtransmission substation The Kurnell STS covers approximately 2.1 hectares, and sits on reclaimed land. Other than the section at the front of the subject land the Project is to be confined to the existing cleared compound comprising the Kurnell STS proper. No works within the current fenced STS area would impact on the subject species identified in Table 23. As a result, only the potential impacts of the proposed buildings outside the currently fenced area and the northern (blue) cable route approach options are discussed. Flora A general flora survey of the subject land at Kurnell revealed a very low species diversity comprising only approximately 10 species, along with a variety of weeds and introduced grasses. The most common weeds are Bitou Bush (Chrysanthemoides monilifera) and Lantana (Lantana camara). Most of the native plants occurring on the elevated pad of land comprising the sub transmission substation appear to be planted although some specimens may be regrowth from the neighbouring natural vegetation communities. Within the currently fenced compound, the only vegetation present is a mown grass area. The northern and south western concrete bund revetment boundaries front onto vegetation that conforms to Coastal Salt Marsh Endangered Ecological Community and is continuous with and includes the mangrove wetland vegetation forming part of the adjacent Towra Point Nature Reserve and RAMSAR designated wetland. This vegetation merges with Swamp Sclerophyll Forest vegetation on the eastern boundary where it is influenced by the creek line on the eastern side of the property. The Magenta Lilly Pilly (Syzigium paniculatum) is not present on the site and would not be impacted by the development. Suitable provenance specimens of this species for planting in any site landscaping could be a beneficial. The area to the front of the Kurnell STS compound fronting Captain Cook Drive, where works are proposed as part of the Project, contains a number of species. These include scattered Swamp Mahogany (Eucalyptus robusta) and Swamp Oak (Casuarina glauca). Where the drainage line north of the STS extends beneath Captain Cook Drive from the oil refinery opposite, a stand of juvenile and/or root sucker regrowth of Casuarina glauca exists which is contiguous with the mature street front stand. Both of these species are elements of the Swamp Sclerophyll Forest Endangered Ecological Community. However, it appears that they are intentional streetscape plantings undertaken at the time of the original land reclamation and Kurnell STS development. Botany Bay Cable Project Environmental Assessment 119

53 7 assessment of key environmental issues As a result, the loss of some specimens during construction of the Project could be readily offset with re-plantings and appropriate positioning of such plantings to compensate for tree losses and offset associated habitat losses. Fauna A general fauna survey was undertaken at the Kurnell STS. None of the species identified in Table 23 were detected during the site surveys however this is not surprising given the extent of habitat present and the habit of these species. Green and Golden Bell Frogs (Litoria aurea) have been detected at a number of sites across the Kurnell peninsula and the Kurnell Key population is identified in the National Recovery Plan for this species as having high conservation significance. The species has been identified within the Kurnell refinery lands and at other nearby properties along Captain Cook Drive and the adjacent Towra Point Nature Reserve. No Green and Golden Bell Frogs were observed during site inspection. Whilst no Green and Golden Bell Frogs have been observed on the site, given the proximity of other recent records, there is potential for the species to utilise the creek and drainage lines from time to time. With care in design of the cable approach, all potential impacts on these threatened species would be either eliminated or, if required, compensatory or offsetting measures would keep impact to very minor levels. c) Proposed cable route The Bunnerong and Kurnell sections of the proposed cable route are depicted in Figure 29 together with sampling locations. Ecological constraints or issues observed along the road reserve routes were documented. La Perouse/Matraville The proposed cable route on the Bunnerong side of the bay would be confined to the road reserve along Anzac Parade, Bunnerong Road and Military Road. No vegetation would be removed and no ecological impacts are envisaged for these sections. The section crossing Botany Bay National Park at the La Perouse headland would be constructed using horizontally directionally drilled bores. No ecological impacts are envisaged from this subterranean section of the cable installation. There is potential for the proposed cable to have indirect impacts at the creek/drainage line crossing just south of Little Bay Road. This creek flows into Yarra Bay and although no specimens were identified in site inspection, Green and Golden Bell Frogs (Litoria aurea) have been previously recorded in its catchment. Disturbance to this creek line could impact on the local population if it still persists. This potential impact could be ameliorated by carefully planning the cable trench at this location. Installation of microhabitat features for the species in the vicinity could further limit potential impact. Kurnell The proposed cable route at Kurnell would be confined to the road reserve along Captain Cook Drive and the formed suburban streets of Kurnell. No vegetation would be removed as part of this process and no ecological impacts are expected. From the car park area adjacent to Silver Beach trenching across Silver Beach would be undertaken to connect with the submarine component of the cable route. The only potential terrestrial ecological impacts are temporary disturbance to foraging shore birds along this portion of Silver Beach in the vicinity of the mechanical works that would be in operation. Silver Beach has high human visitation from residents and visitors to the Captain Cook Historic Heritage section of Botany Bay National Park. Following cable installation and burial, no permanent impacts are likely. Threatened species, including Sooty Oyster Catchers and Pied Oyster Catchers, are present in the vicinity but both generally forage further east on rocky sections of the foreshore. 120 EnergyAustralia

54 7.5.4 Application of EPBC Act and TSC Act Bunnerong STS The proposed works at Bunnerong STS incorporates feeder cable routes that follow existing internal roads and avoid any further disturbance to vegetation on site. A recent proposal for some minor works at the site, including removal of a small vegetation patch, was assessed under the EP&A Act. This vegetation clearing action has been the subject of a separate assessment by Total Earth Care (2006) that concluded there would be no significant impact on Eastern Suburbs Banksia Scrub EEC, the only threatened species known or likely to occur on the site with the potential to be significantly impacted by either proposal. Eastern Suburbs Banksia Scrub is an Endangered Ecological Community, listed as such under both State (TSC Act) and Commonwealth (EPBC Act) legislation. The vegetation patch in question is a virtual monoculture of Bitou Bush (Chrysanthemoides monilifera) and only three native species are evident. EnergyAustralia was consulted during the preparation of the National and State Recovery Plan for ESBS EEC. Surveys were undertaken by DEC (now DECC) at the Bunnerong site and the extent of the highest quality ESBS EEC patches were mapped and analysed. Subsequently, the DEC (now DECC) undertook to have these mapped patches of the ESBS EEC declared as critical habitat and the public exhibition phase for this process was completed in March Notwithstanding this, the loss of the Bitou Bush infested and unmapped patch of vegetation is not significant. Other vegetation on the site is to be retained and the previously prepared management plan for the ESBS EEC on site would be implemented in accordance with the National Recovery Plan for the EEC and the NSW Threat Abatement Plan for Bitou Bush. The EEC does not warrant further concern under TSC Act requirements nor referral to the Commonwealth Minister for Environment and Water Resources on the basis of the Bunnerong component of the Project. Management strategies for the onsite vegetation are intended to consider the possibility that some of the Swamp Mahogany specimens could be occasionally utilised as foraging habitat by migratory and wide ranging threatened species such as the Regent Honeyeater (Xanthomyza Phrygia), Swift Parrot (Lathamus discolour) and Grey-headed Flying Fox (Pteropus poliocephalus). Any required slashing or burn strategies required as part of management of the site and the ESBS EEC would also give consideration to the remnant and highly significant local population of the She Oak Skink (Cyclodomorphus michaeli). The summary position is that the Project will not have an impact on vegetation, including the ESBS, at this site, as no vegetation is proposed to be disturbed as a result of the Project at the Bunnerong STS. Kurnell STS This component of the Project is largely confined to the reclaimed PAD of land on Captain Cook Drive Kurnell. The majority of this site is cleared and maintained as a grassy mown compound containing switching gear and associated buildings. The perimeter of the reclaimed land has been designed to eliminate the risk of the STS being inundated and so is surrounded by a created creek line, drainage ditches and swales. These perimeter areas have been planted out with non local native species or have developed some re-growth vegetation. The only component of the site where it is proposed that some vegetation would be removed is the unfenced component fronting Captain Cook Drive. This part of the site has scattered Swamp Mahogany (Eucalyptus robustus) and Swamp Oak (Casuarina glauca). Whilst both these species are elements of the Swamp Sclerophyll Forest EEC, it would appear that they are intentional streetscape plantings undertaken at the time of the original land reclamation and STS development. There are also areas along the drainage depression on the north eastern corner of the site where there are numerous root suckered re-growths of Casuarina glauca. These specimens would be removed as part of this component of the development. It is proposed that landscape and supplementary/compensatory plantings of these species would be undertaken at completion of the development to improve the sites overall streetscape appearance from Captain Cook Drive. These plantings would more than offset Botany Bay Cable Project Environmental Assessment 121

55 7 assessment of key environmental issues any possible negative impacts on the possible occasional utilisation of the site by wide ranging threatened species such as the Regent Honeyeater (Xanthomyza Phrygia), Swift Parrot (Lathamus discolour) and Grey-headed Flying Fox (Pteropus poliocephalus). Whilst no Green and Golden Bell Frogs (Litoria aurea) have been observed on the site, given the proximity of other recent records, there is potential for the species to utilise the creek and drainage lines from time to time. All four of the above threatened species are listed under both State and Commonwealth legislation but the Project, as described, is likely to have minimal if any impact on any of them. No EECs would be significantly affected by the Kurnell STS component of the Project and EEC elements would be incorporated into street plantings as a proactive measure. The nature of the Project means it would have no direct impact on the adjacent Towra Point Nature Reserve and RAMSAR declared wetland. The wetland is the only groundwater dependent ecosystem of any significance that could be impacted the Project. The only potential for impacts to the wetland arise from possible indirect effects due to groundwater changes, runoff from the site during construction or lighting from the site, once operational. Based on the details of the Project, and the safeguards intended to be in place during the construction phase of the development, these impacts are considered to be negligible. Building heights and compound security lighting have the potential to impact not only on aesthetic considerations but also possibly movements and foraging behaviour of microbats and migratory shorebirds utilising the wetland and adjacent airspace. These details would be considered in the building design phase along with operation of lighting on completion. The above subject threatened species do not warrant further specific concern under either TSC Act requirements or referral to the Commonwealth Minister for Environment and Water Resources on the basis of the Kurnell STS component of the Project, if affected as described. Bunnerong cable route The Bunnerong (northern) cable route is proposed to be confined to the road reserve along Anzac Parade, Bunnerong Road and Military Road. No vegetation would be removed by these works and no ecological impacts are envisaged by any of the road reserve installation. The only section of the northern cable route installation where there is potential for indirect impacts is at the creek/drainage line crossing, just south of Little Bay Road. This creek flows to Yarra Bay and the catchment of this creek has records of the Green and Golden Bell Frog (GGBF). These records are not old but no specimens were detected at the creek crossing during the site inspection. Consequently disturbance to the creek line could potentially impact on the local GGBF population if its still persists. An appropriate ameliorative action would be to take due care in the installation process at this crossing and undertake installation of microhabitat features for the species in the vicinity as part of the process and any rehabilitation of areas where protective measures are installed during construction. The section crossing the La Perouse Historic Heritage section of Botany Bay National Park would be under bored from the unformed car park adjacent to Goorawahl Avenue. No ecological impacts are envisaged from this subterranean section of the cable installation. No significant impact on threatened species would arise out of the Bunnerong cable route component of the Project. Kurnell cable route The Kurnell (southern) cable route is proposed to be largely confined to the road reserve along Captain Cook Drive and the formed suburban streets of Kurnell. No vegetation would be removed as part of these works and no ecological impacts are expected or likely. From the car park area adjacent to Silver Beach it is understood that trenching across Silver Beach itself would be undertaken to connect with the submarine component of the cable 122 EnergyAustralia

56 route. A report by Douglas Partners (2006) indicates that potential for acid sulphate soil issues does not exist in this area. Consequently, it is envisaged that the only potential terrestrial ecological impacts would be temporary disturbance to foraging shore birds along this portion of Silver Beach in the vicinity of the mechanical works that would be in operation. Silver Beach has high human visitation from residents and visitors to the Captain Cook Historic Heritage section of Botany Bay National Park Following installation and burial of the cable no permanent impacts are likely and the temporary impacts considered negligible. Threatened species noted from the vicinity include Sooty Oyster Catchers and Pied Oyster Catchers but both are generally foragers further to the east along the rocky sections of the foreshore. Consequently no significant impact on threatened species is likely to arise out of the Kurnell cable route component of the Project Conclusion The individual assessments of the Project components above in respect of threatened species indicate that none of the threatened species considered (either under the TSC or EPBC Acts) would be adversely impacted by the Project provided the commitments below are followed Mitigation measures Construction phase management plans would be prepared to ensure the threatened species habitat values in the vicinity are not inadvertently impacted during the development/construction/installation. A landscape plan would be developed as part of the Project at both STS sites and possibly at Yarra Bay Creek as required. The landscaping plan for the Kurnell site would incorporate microhabitat features that are suitable for the Green and Golden Bell Frog. Suitable plantings would be carried out using local provenance species and perhaps the locally occurring threatened plant Magenta Lilly Pilly (Syzygium paniculatum) as a biodiversity investment, be planted in a 5:1 offset ratio for any specimens removed the details of which should be incorporated into the site Landscape Plans. Similar features would be incorporated at the Little Bay/Yarra Bay creek crossing of Bunnerong Road during trenching and cable installation as a component of any reparation that may become necessary. Any trenching that may be required across the Yarra Bay Creek would be undertaken with appropriate safeguards to downstream water quality and habitat that may be present (appropriate and suitably maintained erosion and sediment control). The potential for indirect impact from run off due to possible drainage line modifications be considered in contingency at Kurnell STS and dealt with in a best practice approach to Soil Erosion Mitigation Guidelines. Potential for installed lighting to have impacts on microbats at both STS sites and perhaps migratory bird species at Kurnell STS would be given consideration in the detailed design of the Project. The potential for indirect impact from run off due to possible drainage line modifications would be considered as a contingency at the Kurnell STS. Indirect impacts that could arise due to carelessness or unawareness during construction would be given adequate consideration and safe guards would be put in place. This would include the decommissioning, replacement or upgrade of any electrical equipment that has potential to contaminate due to oil spillage as well as the use of machinery in the vicinity of the ESBS and Declared Critical Habitat at Bunnerong. Botany Bay Cable Project Environmental Assessment 123

57 7 assessment of key environmental issues A Management Plan for Eastern Suburbs Banksia Scrub at the Bunnerong STS would be reviewed and updated as necessary as a result of this Project and findings herein reported. And that a time frame for the management plans be produced and details provided to DECC and the Commonwealth DEW as lead agencies in coordinating the implementation of the National Recovery Plan for the ESBS EEC. Management of the Bunnerong STS sites vegetation would give consideration to the local remnant of a highly significant She Oak Skink (Cyclodomorphus Michaeli) population on site. Precise positioning of the cable route at Silver Beach would endeavour to avoid the drainage line outlet onto Silver Beach in that vicinity. 7.6 Heritage Heritage consulting company Navin Officer carried out the heritage study for this Project. Their report is summarised below. The summary sets out the historical context of Botany Bay and surrounds, identifies the Aboriginal and European cultural heritage items in the study area, indicates the impacts on heritage from the Project and recommends appropriate mitigation measures. A copy of the heritage report in its entirety is located in Volume Two of the Environmental Assessment Conduct of the heritage study Aboriginal participation The Botany Bay study area falls within the boundaries of the La Perouse Local Aboriginal Land Council. This group was contacted by telephone and an invitation was extended to the Council to provide a representative to participate in the archaeological field survey of the study area. As a result, Mr Daryl Rook from the La Perouse Local Aboriginal Land Council participated in the field survey. During the survey, an on-site meeting was held with Mr David Ingrey, the La Perouse Local Aboriginal Land Council sites officer. Subsequently, Mr Ingrey assisted in identification of a number of Aboriginal sites on the La Perouse peninsula. Literature and database review A range of documentation was used in assessing archaeological and historical knowledge for the Botany Bay area and its surrounds. This background research was used to determine if known Aboriginal and European sites were located within the area under investigation, to facilitate site prediction on the basis of known regional and local site patterns, and to place the area within an archaeological and heritage management context. The review of written and documentary sources included heritage registers, local histories and archaeological reports. Aboriginal literature sources included the NSW Department of Environment and Climate Change Aboriginal Heritage Information Management System (AHIMS), associated files and catalogue of archaeological reports. Sources of historical information included monographs, historical studies and parish maps. The following heritage registers and schedules were searched: National Heritage List (Australian Heritage Council) Commonwealth Heritage List (Australian Heritage Council) Register of the National Estate (Australian Heritage Council) Aboriginal Heritage Information Management System (AHIMS) (NSW DECC) State Heritage Register (NSW Heritage Office) State Heritage Inventory (NSW Heritage Office) 124 EnergyAustralia

58 Maritime Heritage Online (NSW Heritage Office) Heritage Schedule(s) from the Randwick Local Environmental Plan (LEP) 1998, Sutherland LEP 2000, and Kurnell Peninsula Regional Environmental Plan (REP) 1989 NSW DECC s170 Heritage and Conservation Register Register of the National Trust of Australia (NSW) Field work Fieldwork was conducted over three days in June The field survey was conducted on foot and involved inspection of all areas of ground surface visibility within the Project area. Recording parameters - Aboriginal sites The archaeological survey aimed at identifying material evidence of Aboriginal occupation as revealed by surface artefacts and areas of archaeological potential not associated with surface artefacts. Potential recordings fall into three categories: 1. Isolated finds (background scatter) An isolated find is a single stone artefact, not located within a rock shelter, and which occurs without any associated evidence of Aboriginal occupation within a radius of 60 metres. Background scatter is a term used generally by archaeologists to refer to artefacts that cannot be usefully related to a place or focus of past activity. 2. Sites A site is defined as any material evidence of past Aboriginal activity that remains within a context or place that can be reliably related to that activity. 3. Potential archaeological deposits (or PADs) These are defined as any location where the potential for subsurface archaeological material is considered to be moderate or high, relative to the surrounding study area landscape. Recording parameters - historical sites As with Aboriginal archaeological field surveys, the effectiveness of historical archaeological field survey is to a large degree related to the obtrusiveness of the sites being sought and the incidence and quality of general and ground surface visibility. The methods used to investigate sites are based on trained observation, skilled interpretation and accurate recording of the physical remains, combined with the archaeologist s own experience of what is likely to be found. Unlike Aboriginal archaeological field surveys, in many instances historical surveys are aided by the availability of historical documents that assist in locating sites. In this regard, a range of historical research techniques may include the use of early town and rural directories, land title searches, analysis of early maps, photographs and aerial photographs, technological encyclopaedia, immigrant s guides, trade and popular journals, mail order catalogues, bankruptcy records, government records and other specialised sources. In some instances, oral histories may also be available to assist the archaeologist to locate sites Aboriginal context The information available about the occupation and use of Botany Bay by Aboriginal people comes from a variety of sources. References to the Aborigines of the Sydney region are found in the journals, diaries and general writings of the early colonists, explorers and settlers. Natives were one of the main subjects of interest to those who arrived in the First Fleet and all the journals contain frequent references to them (Fitzhardinge 1961). Other information sources include reports, published documents and histories, oral information retained by the local Aboriginal community, and the traces of past generations left in the Botany Bay Cable Project Environmental Assessment 125

59 7 assessment of key environmental issues landscape of Botany Bay that have been identified and interpreted by archaeologists to provide a context for Aboriginal occupation of the area. The linguistic and tribal boundaries and size of areas attributed to the various Sydney region Aboriginal groups vary between different interpreters. Kurnell falls within Dharawal linguistic and/or tribal boundaries and Gwiyagal linguistic boundaries. Meanwhile, Tindale has an Eora tribe, which was closely linked to the Tharawal (Dharawal) tribe, extending from the northern shores of Port Jackson to the edge of the plateau overlooking the Hawkesbury River and south to Botany Bay and the Georges River. Contemporary reviews now place the Kurnell peninsula in the territory of the Gweagal band of the Eora people. Today, Local Aboriginal Land Council boundaries are situated so that the Kurnell study area is located entirely within the boundaries of La Perouse Local Aboriginal Land Council. The earliest observations of Aborigines at Botany Bay were made in April and May of 1770 by Captain James Cook and Joseph Banks. The French voyager Peron also made observations in Botany Bay in Rich summarises observations made by Cook and Banks in her report on an archaeological excavation at Yarra Bay (Rich 1986). The Endeavour was moored in Botany Bay for eight days (April 29 to May 6, 1770). For seven of the eight days Cook and Banks were on, or around, the bay, only spending one day exploring the countryside further a field. It can be surmised therefore that most of their observations about the Aborigines pertain to Botany Bay. Cook comments that The land naturally produces hardly anything fit for Man to eat, and the Natives know nothing of Cultivation (Cook, in Reed 1969). Rich notes that this assumption by Cook about the paucity of food resources around the bay probably biases his observations of Aboriginal lifestyle. Cook and Banks noted the presence of Aboriginal camps in a number of locations including two open sites with huts on both points of Botany Bay, and two shell middens with fires and shells, one of which was reported to be near the shore (Cook in Reed 1969). Cook also made the general observation that the Aborigines did not live in large groups but were dispersed along the water side. Cook observed Aborigines fishing and collecting shellfish. He thought that shellfish, principally oysters, mussels and cockles, formed the main component of the Aboriginal diet. Fish were caught by spear or hook and line, but it appears that stingrays were not eaten. A relatively large number of canoes were observed on the Bay. Other foods, particularly plant foods, were also eaten, but neither Cook nor Banks appears to think that they were important. Material culture observed by Cook and Banks included fishing and hunting spears, fish hooks and lines, a shield, and spear throwers. Stone tools and other wooden items such as digging sticks were not mentioned. Comments were made on the types of Aboriginal shelters observed. These were described as consisting only of pieces of bark laid together in the form of an oven, open at one end, and very low, though long enough for a man to lie at full length in... they depend less on them for shelter, than on the caverns with which the rocks abound (Tench 1793). Collins (1798) observed that the huts were often large enough to hold six to eight people. These shelters were often grouped together. Disused canoes were sometimes used for this purpose (Collins 1798). Within a short period of time after white settlement, the Sydney Aboriginal population was greatly reduced as a result of two epidemics, (most) probably smallpox. The first epidemic was only a short time after settlement in 1789, and the second from 1829 to 1831 (Butlin 1983). The first outbreak of the disease is believed to have killed 50 per cent of the Aboriginal population (Collins 1798, Ross 1988, Tench 1961, Turbet 1989). Loss of life on such a scale resulted in a major social reorganisation of Aborigines around the area (Ross 1988) with remnants of bands combining to form new groups (Kohen 1986). Therefore, the anthropological observations and other observations by chroniclers of the time do not depict the pre-settlement situation accurately. Within a few days of Phillip s arrival in 1788 a French expedition led by Rear Admiral Jean- François de Galaup La Pérouse (Comte de La Pérouse) entered Botany Bay, established a temporary stockade and commenced cultivation in Frenchmans Bay. During the eight week occupancy of the area by La Pérouse and his sailors the original Aboriginal inhabitants 126 EnergyAustralia

60 were repelled to a principal camping place at Long Bay ( Boora ) with a subsidiary camping ground in caves at Little Bay (Pringle 1979). With the abandonment of the French settlement, the Aborigines gradually returned to the La Perouse area together with people from other tribes who were being repelled by European settlers elsewhere, particularly along the south coast. Numerous middens have been uncovered in the foreshore sand dunes of Congwong bay, Frenchmans Bay and Yarra Bay (Pringle 1979). In the 1880s, a small Anglican mission was established, and on March 30, 1895, seven acres and six and a half perches was gazetted as a Reserve for the Use of Aborigines (AR 22358). The Aborigines Protection Board policy was to make Aboriginal reserves selfsupporting by establishing farms on them and using the inhabitants as farm labour. However, this was not a possibility at La Perouse as the soil was too sandy. Consequently, the La Perouse people had to be self supporting fisherman at Frenchmans Bay beach adjoining the reserve (Williams 1988). About six and a half perches of the reserve were revoked on March 16, 1917 (Crown survey plan portion 181). One acre and one rood of the Reserve (AR 22358) were revoked on November 14, 1930, and then four acres, three roods and twelve perches were revoked on the 9, January 1931 (McGuigan n.d.). A new reserve of eight acres and five perches, situated behind and to the northeast of the original settlement, was gazetted on 2 October, AR (Portions 181 and 1778, Parish of Botany). In , the tin houses of the settlement were sinking in the sand and the reserve buildings were moved from their unstable beach site to this higher ground. By 1976 the Reserve had been developed by the Housing Commission as an Aboriginal Housing project and was administered by the Aboriginal Lands Trust. The Lands Trust was abolished in 1983 when new legislation was enacted to set up Aboriginal Land Councils, and the Aboriginal community finally had some autonomy at La Perouse. In September 1985, Yarra Bay House was handed over to the La Perouse Local Aboriginal Land Council for use as its office European context Botany Bay, Kurnell and La Perouse are to many the most historic localities in Australia. When Captain Cook first entered Botany Bay in April 1770, he landed on its southern shore at Kurnell. His shore party discovered a fresh water stream flowing into the bay on its northern shore, west of Bare Island, (Randwick and District Historical Society 1989). On bringing the First Fleet into Botany Bay 18 years later, Captain Arthur Phillip sought the stream from Cook s report. Less impressed with the bay than Cook, on 26 January 1788, Phillip sailed for Sydney Cove, which offered a more sheltered anchorage. European settlement in the Botany Bay area occurred by extension from Port Jackson (Pringle 1979). Land grants were made to Europeans from the 1820s onwards. Bunnerong House was built on land which was the subject of the first land grant. It was a magnificent sandstone house, built in 1825 by John Neathway Brown, on 13 acres overlooking Botany Bay. The site was later to become the site of the Bunnerong Power Station and subsequently the Port Botany container terminal. From about 1820, troops were stationed on the La Perouse headland to control shipping in Botany Bay. They were initially housed in huts, and then in a stone tower built around From 1831 the tower was used as a Customs House. In 1832 some small huts were erected to the east of the tower. In 1861 and 1863 cottages were constructed for boatmen working at the customs station. An 1867 parish map shows a boat house on the shores of Frenchmans Bay (Kass 1989, in, NSW Public Works Department 1990). Nearby to the northwest, at a sale of Crown Land in 1834, Thomas Kellett bought the land on which he was later to build the Sir Joseph Banks Hotel. The Hotel itself was probably built around 1844 (Silva 1978). The Sir Joseph Banks Hotel still exists today. In the latter half of the nineteenth century La Perouse continued to be developed, principally by extension of existing facilities. The beginning of the twentieth century saw a tramline to La Perouse open in 1902 and a jetty constructed on the western side of the headland in A road linking the tram Botany Bay Cable Project Environmental Assessment 127

61 7 assessment of key environmental issues terminus to the jetty was constructed, allowing visitors to access the area by ferry from Kurnell (Kass 1989). Suburbia slowly moved southwards from Maroubra after the Second World War. The tramline was removed in the 1960s and a new ring road around the headland was constructed. Early industries in the Botany Bay area included the production of shell lime, wool scours, tanneries, market gardening, boat building and, of course, fishing. The earliest reference to market gardening in the area was made by an observer named Backhouse in the 1830s (Larcombe n. d.). Backhouse describes the swamp areas of Botany being converted into gardens. The Botany market gardens were then the main vegetable supply for Sydney - they supplied Sydney with constant fresh produce even during periods of drought (Larcombe n. d.). Photographs of nearby Frenchmans Bay in the first decades of the twentieth century show numerous boatsheds along the beach. The boat building industry in the area was apparently destroyed by the war, when boat construction was centred on the war effort (correspondence - NSW Heritage Office to Randwick City Council S96/1014/3:1999). La Perouse, in particular, has had a long association with recreation and tourism. As early as the 1830s the area was a location for society picnic parties from Sydney. The Sir Joseph Banks Hotel established a long history of sporting recreation and in its heyday it boasted a jetty with bathing houses, five cinder running tracks and a grandstand and stadium that seated several thousand people. In 1882, the tramline was extended to Botany and a tradition commenced where participants and spectators of the annual St Patrick s Day march in the city would journey by tram to the area for a day of sporting events and picnicking (Silva 1978). By the beginning of the twentieth century guesthouses were established at Yarra Bay. The construction of the tramline to La Perouse in 1902 substantially increased tourist visitation to the area. The effects of the Great Depression of the 1930s were felt all over Australia. Unable to pay rents or mortgages, the only alternative was to set up a makeshift home in one of Sydney s many unemployment camps. Unemployment camps sprang up all over Sydney but they tended to be located in the scrubby, sandy, flea infested beauty spots (Workers Weekly 16 March 1934) south of the harbour. There were several of these camps in the Botany Bay, including Happy Valley, Frog Hollow and Hill 60 (Randwick Municipal Council 1985). Happy Valley was the biggest of the camps, containing 130 dwellings and 200 to 300 people. It was established gradually over three years from 1930 in a gully area to the west of Anzac Parade at La Perouse on land leased by the NSW Golf Club (Randwick Municipal Council 1985). Suburbia slowly moved southwards from Maroubra after the Second World War. The tramline was removed in the 1960s and a new ring road around the headland was constructed. Bunnerong Power Station began commercial operation on 2 January By May 1930, all construction work on the buildings and circulating water systems had been finished and the construction staff disbanded. Section A of Bunnerong Power Station was completed (Anderson 1955). In early 1938 the Sydney County Council decided to build the B section of Bunnerong, a completely new boiler house and an extension to the turbine house. Bunnerong B first saw service on 5 September 1939; just days after Britain had declared war on Germany (Wilkenfeld and Spearitt 2004). Figure 31 shows the Bunnerong Power Station in operation during its zenith. The Bunnerong Power Station at Botany Bay was progressively decommissioned between 1977 and Demolition of the power station commenced in 1979/80, with major demolition occurring in 1986/87. In March 1994 the five storey Bunnerong Switching Station or substation was demolished. The site of Bunnerong, the grandest power station of them all, is now part of the Port Botany container terminal (Wilkenfeld and Spearitt 2004). 128 EnergyAustralia

62 Figure 31: Bunnerong power station circa 1950 section A at right and section B at left Source: Anderson (1955) Results of field work a) Aboriginal sites No previously unrecorded Aboriginal objects or sites were identified in the course of the field survey. However, one area of archaeological potential (K PAD 1) was identified along the Kurnell foreshore. The area encompasses the whole of the foreshore from the high water mark to Torres Street. The proposed cable route that enters Kurnell at Silver Beach and continues in a westerly direction along Prince Charles Parade and then south along Silver Beach Road would impact this area. Beneath the disturbance from the roads and landscaping along this part of the route it is considered that there is moderate to high potential for subsurface archaeological deposits to remain in situ. In addition, there is also a moderate to high potential for the presence of burials within this area. b) Historical sites Two previously unrecorded historic sites were identified within the study area: St John Fisher Catholic Church (KH1), Kurnell. The Church in excess of 50 years old and therefore protected under Section 139 of the NSW Heritage Act 1977 as a relic. First Fleet Marine Restaurant and Boatshed Building (LaPH1), La Perouse Inventory of site locations Table 24 sets out all the heritage sites in the vicinity of the Project area. Botany Bay Cable Project Environmental Assessment 129

63 7 assessment of key environmental issues Table 24: Heritage sites in the vicinity of the Botany Bay study area Recording type Recording code Midden Midden Midden & Location (grid references in AMG:AGD 56) Rock engraving Rock engraving to Rock engraving Rock engraving & Shelter with midden Shelter with midden Midden Midden Shelter with art Midden PAD Midden PAD K PAD 1 Historic Church (former) Historic Silver Beach 2 Historic Indigenous Trees Historic Monuments, etc. Historic Captain Cook Drive Historic Prince Charles Pde. Historic Kurnell Headland Historic Wall, Silver Beach Historic Houston s Lookout Historic Maru-yena Road to to to Captain Cook Drive, Kurnell. 3 4 Prince Charles Parade, Kurnell peninsula Prince Charles Parade, Kurnell Kurnell peninsula, Botany Bay Nat Park Note if directly impacted Yes 5 Kurnell peninsula. Yes 6 Kurnell peninsula. Yes ha on southern headland of Botany Bay. 8 Kurnell peninsula 9 10 Kurnell peninsula, Botany Bay Nat Park Kurnell peninsula, Botany Bay Nat Park 130 EnergyAustralia

64 Recording type Historic Botany Bay Entrance Recording code 11 Location (grid references in AMG:AGD 56) 300 ha, comprising La Perouse peninsula and the NE section of Kurnell peninsula. Historic Tomb 12 La Perouse peninsula. Historic Watchtower 13 La Perouse peninsula. Historic Memorial 14 La Perouse peninsula. Historic Museum 15 Anzac Parade, La Perouse. Historic Bare Island Fort 16 La Perouse. Historic Fountain 17 Anzac Parade, La Perouse. Historic Market Gardens 18 Bunnerong Road, La Perouse. Historic Cemetery 19 Bunnerong Road, Matraville. Historic Crematorium Military Road, Matraville. Historic Garden and Lawns Historic Happy Valley Shacks Historic La Perouse Headland 21 La Perouse peninsula 22 La Perouse, Congwong Beach 23 La Perouse Historic Church KH1 60 Prince Charles Drive Historic Boatshed café LaPH1 Frenchmans Bay Note if directly impacted Botany Bay Cable Project Environmental Assessment 131

65 7 assessment of key environmental issues Figure 32: Location of all Aboriginal and historic sites in the vicinity of the Project Findings The Project would necessitate the disturbance of ground within the footprint of the proposed cable route. Any natural ground surface or subsurface deposits would be destroyed by the Project. A majority of the assessment area, however, has been previously disturbed by the construction of roads, landscaping and the industrial developments in La Perouse. 132 EnergyAustralia

66 Aboriginal sites There are 15 previously recorded Aboriginal places (14 sites and one PAD) located in close proximity to the Project area, none of which would be directly affected by the Project. No additional Aboriginal sites or objects were located during the field survey of the Project area. However, one new area of archaeological potential, K PAD 1, was identified on the Kurnell peninsula. This area would be impacted by the Project. The site would need to be investigated before any works take place there. European sites There are 25 European historic sites located in close proximity to the study area. Twenty three are previously recorded sites and two are new sites, the First Fleet Marine Restaurant and Boatshed Building (LaPH1), and St John Fisher Catholic Church (KH1), were identified during this assessment. Parts of two of these sites, Prince Charles Parade and Captain Cook Drive, would be directly impacted by the installation of the new electricity cables as the cable would be installed in the road reserves of these routes. However, the impacts on the heritage significance of the items are considered to be minor Mitigation measures These are as follows. Under the current Project K PAD 1 would be impacted. Archaeological subsurface investigation of the area would be undertaken to determine the nature, extent and integrity of any potential archaeological deposit. Mechanical excavation with an auger is the preferred investigation method. If any archaeological material is found, EnergyAustralia would comply with all legislative requirements. Under the current Project, the previously recorded PAD (PAD 1 on the eastern side of Little Bay Road) would not be affected. However, if the current route is varied so that the cable is required to be laid on the eastern side of Little Bay Road then this PAD would be impacted. If this occurs then the (above) recommendations for K PAD 1 would be followed for PAD 1. EnergyAustralia would implement this recommendation if the route moves to the eastern side of Little Bay Road. The entire cable route is located within landscapes that are considered to be sensitive in terms of their potential to contain Aboriginal sites. To mitigate potential impacts in these sensitive areas, monitoring of cable excavations would be conducted for the whole cable route. Monitoring would be undertaken by a qualified archaeologist and a representative from the Local Aboriginal Land Council. If a site was identified work would be halted until clearance was given to proceed or an alternate method of proceeding was identified. 7.7 Spoil management Spoil would be generated during cable route construction where soil or rock is extracted without restoring it to its original position. This would occur during road trenching and horizontal directional drilling under Botany Bay National Park. It is necessary to ensure that spoil is disposed of in an appropriate manner to avoid potential contamination of surface water and/or local air quality. If sediment is stockpiled on the ground, then rainfall runoff could carry sediment from the site and contaminate surface runoff. Similarly, sediment may become suspended and transported by wind which would contaminate the local air quality Cable trenching During the road trenching works, soil and some rock would be excavated to accommodate the cables. None of this material would be returned to the trench. The total material extracted would be approximately 8,000 cubic metres. Botany Bay Cable Project Environmental Assessment 133

67 7 assessment of key environmental issues The spoil is likely to consist of a mixture of clean sands, man-made filling and other waste material, such as asphalt, concrete, tar, ash and waste, and some sandstone. No spoil would be stockpiled on the ground. Excavated material would be loaded directly into trucks. This measure would reduce the likelihood that surface runoff and/or local air quality are contaminated from the spoil. It is likely that the waste material would be deposited in a local tip, such as the Menai Landfill site. It is expected that these measures are adequate to minimise the potential for contamination to the surrounding environment from spoil storage and disposal during road trenching Horizontal directional drilling Horizontal directional drilling beneath Botany Bay National Park would excavate through sandstone bedrock to accommodate the cables. The rock material would be separated from the bentonite used to lubricate the process, then loaded into trucks and transported to a local tip. The material would not be stockpiled on the ground. It is expected that these measures are adequate to minimise the potential for contamination to the surrounding environment from spoil storage and disposal during horizontal directional drilling Mitigation measures These are as follows: spoil would be loaded directly into trucks, thus avoiding stockpiling on the ground and the associated contaminated run-off issues excavated waste material would be disposed of at a licenced landfill facility. 7.8 Surface and groundwater management Surface water Potential adverse impacts to surface water would include: sediment contaminating rainfall runoff during trenching leakage and disposal of borehole fluid during horizontal directional drilling. EnergyAustralia intends to minimise the risk of contamination runoff by loading spoil from trenching directly into trucks immediately after it is excavated. No spoil would be stored on the ground. In addition, silt traps or hay bales would be put in the drainage paths as a precautionary measure. The potential leakage and disposal of borehole fluid during the horizontal directional drilling process is likely to be a minor risk to surface water. The borehole fluid, which is a mix of bentonite and water, and essentially acts as a lubricant to improve cutting of the rock, is necessary to support the void before a subduct/liner is pulled through and acts as a lubricant to improve cutting. When the rock and sediment is taken from the hole, the borehole fluid is extracted/filtered and re used for further drilling. When the operation ceases, the fluid mix is removed by the drilling company and used on other sites. Another potential minor risk would be a leak of the bentonite liquid from the borehole into the Bay. However, the chemical makeup of bentonite is non-hazardous and as such is unlikely to present a significant contamination risk to water quality in the Bay, should a leak be present in the drill hole. Should any bentonite escape from the borehole, operations would cease immediately and remedial action taken. As the horizontal directional drilling operate on a closed circuit, any loss of pressure would be detected straight away on the instrument console and drilling would cease. 134 EnergyAustralia

68 7.8.2 Groundwater The construction of the cable route would potentially interact with groundwater systems within the terrestrial sections of the cable route. It is feasible that trench excavation activity could pose a risk to groundwater if the trenches were to intersect the water table. The potential adverse impacts from this interaction would include: contamination of clean groundwater by trench material drawing down water from groundwater dependent ecosystems (see Section for impacts on Towra Point wetlands which is the only significant groundwater dependent ecosystem potentially affected by the Project) treatment and disposal of contaminated or saline groundwater. However, these events would be unlikely for the reasons explained below. Bunnerong There are 39 water bores within a one kilometre radius of the cable route, but only one of these is sited within 200 metres of the proposed cable route. Therefore depth to groundwater for most of the proposed cable route is uncertain and inferences are based on regional rather than route-specific data. Data specific to the route is only available in the vicinity of Bunnerong STS where free groundwater has been observed at depths ranging from 0.9 metres to 2 metres. In a bore about 200 metres to the east of the route, east of Botany Cemetery, the water table was recorded at 2.2 metres in sand. It is anticipated that the base of the proposed cable trench, at approximately 1.2 metres deep, would generally be above the water table through the land sections of the proposed route. Accordingly, trenching is not expected to interact with the groundwater system. The aquifer has been seriously contaminated by industry in some areas, including the Botany/Banksmeadow area to the west of Bunnerong STS. The cable route is separated from this area by a bedrock ridge that is expected to prevent the contaminant plume from moving eastwards into the area of interest. Kurnell There are 38 water bores within one kilometre of the proposed cable route, with 10 of these being within 50 metres of the route. Only five of these bores have water table information, with recorded groundwater depths ranging from 1.5 to 2.7 metres. However, it is expected that the planned upgrades to the Kurnell STS would intersect the water table. These upgrades involve the excavation of a basement beneath the existing substation. Considering that the water table is shallow in this area, ranging from 1.5 to 2.7 metres, it would be necessary to develop an appropriate management plan for disposing of any collected groundwater. This issue would be included in the environmental management plan for the Project. Disposal back onto the land or into tankers are two feasible possibilities Potential acid sulphate soils Acid Sulphate Soils are those soils deposited under estuarine conditions and contain the sulphidic mineral pyrite. They underlie many coastal floodplains and wetlands, and if disturbed and exposed to air, they generate sulphuric acid which can cause serious environmental damage including fish kills and habitat degradation (Tulau, 1999). Trench excavation activity has the potential to expose acid sulphate soils if there is a high risk of these soils at depths above the base of the trench. DNR Acid Sulphate Soils Risk mapping indicates that several sections of the route may be affected by potential acid sulphate soils (PASS). The mapping classifies areas as having high, low or no risk of PASS occurrence, or as modified ground. This classification is based on geomorphology and elevation, with Holocene estuarine-derived sediments occurring close to or below sea level typically classified as having a high risk of PASS occurrence. The DNR mapping makes no distinction between different sediment types in modern estuarine environments, Botany Bay Cable Project Environmental Assessment 135

69 7 assessment of key environmental issues whereas in reality PASS occur most extensively in clay or silt-rich sediments and rarely occur in clean sands. The creek crossing of Bunnerong Road and the entire Kurnell section of the route are classed as having a low PASS risk. However, the elevation of the creek crossing is around seven to eight metres, and the possibility of PASS occurring within three metres of the surface at this site is considered highly unlikely. Clean sandy sediments were observed in surface deposits along the Kurnell section of the route during field inspection, and water bore data suggests that sands extend to at least four metres depth. The upper sands (possibly the top one to two metres) have been leached and reworked into dunes. If clean and partially leached sands occur to the depth of trenching (approximately one to two metres) then excavation of PASS is considered unlikely Mitigation measures These are as follows: Surface water Spoil would be loaded directly into trucks and not stockpiled on the ground. Hay bales or similar would be placed in drainage paths as a precautionary measure. Should any bentonite used in HDD escape from a borehole, operations would cease immediately and remedial action taken. Groundwater On the Bunnerong side of the route, trenches would be above the watertable. At the Kurnell STS, the watertable would be intercepted. Water extracted from this site would be handled in accordance with a Groundwater Management Plan prepared for this part of the Project. Interaction with Potential Acid Sulphate Soils is considered unlikely. Acid sulphate soils A contaminated soil and acid sulphate soil management plan would be prepared to identify and manage contaminated soils (including Botany Bay) for implementation during construction including: field investigations to confirm the presence of soil contamination and measures to avoid and mitigate impacts on sites monitoring of water quality methods to classify spoil for disposal in accordance with environmental guidelines procedures to appropriately assess and manage previously unidentified areas of contamination confirming the presence of potential acid sulphate soils and developing management and disposal options for acid sulphate soils consistent with the Acid Sulphate Soil Manual (ASS Management Advisory Committee 1998). 7.9 Safety and risks In this section, safety and risks which emanate from the construction and operation of the Project are looked at from both land and maritime perspectives Land The construction of the Project would generate some risks to the public and to construction personnel, such as open trenches in public roads. EnergyAustralia would manage these risks by requiring its contractor to develop and implement a series of plans that address 136 EnergyAustralia

70 the Project s risks and that accord with internal and external standards. The plans comprise: safety, health and environmental plan quality plan. The plans would cover, but not be necessarily limited to, the following: safety training safety inspection safe work practice near miss accident reporting and modification to existing work methods personal protective equipment in house safety rules inspection and test plan safety check list procedures records test records hazard analysis. The plans would need to conform with: Enerserve s Quality, Safety, Health and Environmental Policy, April 2003 EnergyAustralia s Environmental Guidelines (EG160 Sediment Control November 2000) EnergyAustralia s Network Standard NUS174 (Environmental Procedures) Electrical Safety Rules January Australian Standard AS Manual of Uniform Traffic Control Devices Australian Standard AS 4360:2004 Risk Management Australian Standard AS 2865:2001. Safe Working in a Confined Space. EnergyAustralia would audit the contractor on a three month cycle for conformance or otherwise with the plans Maritime This section considers risks associated with the marine work during construction and operation and is focused on risks to and from others and to infrastructure. It does not consider project risks such as OH&S, costs and on time completion. Construction risks During construction there would be risks to other vessels and to the construction crew, and the laying plant and equipment. The primary strategy for minimising these risks would be through communication and co-operation with the relevant authorities. A number of construction risks have been identified and are discussed as follows. Botany Bay Cable Project Environmental Assessment 137

71 7 assessment of key environmental issues Risk: Collision with other vessels Description The lay barge required for this Project would be of a significant size, length and a weight, possibly exceeding 4,000 tonnes (although it is expected that smaller, locally sourced barges may be used). In addition, there would be supporting vessels including work boats and possibly tugs. The lay barge would be mobilised as it crosses the Bay being moved by winches attached to anchor lines, tugs, or by its own power. There is a risk of collision with commercial vessels and recreational vessels. The risk of collision with recreational vessels is discussed under the risk discussing public safety below. Collision with a commercial vessel could be catastrophic with there being a risk to life and a potentially significant risk to the environment. The risk of obstruction by the anchor lines, which would not be easily seen from oncoming vessels, must also be addressed. Mitigation Commercial vessels entering and leaving the Port are under the control of the Harbour Master. It is proposed that this risk would be mitigated by keeping the Harbour Master fully informed of the Project prior to and during construction. In addition to this, the contractor would have to submit a written description of its construction procedure to the Harbour Master that would describe in detail how the work would proceed. The construction methods described in the procedure would have to satisfy the Harbour Master with regard to the crossing of the shipping channel and no marine work would proceed without the Harbour Master s approval. Risk: Vessels running aground Description The shipping channel is approximately 215 metres wide and there is reasonably deep water on each side of the channel that would allow shallow draft commercial vessels to pass the lay barge. There is a risk that passing vessels could run aground if they stray too far from the channel. This could result in a risk to the environment and to the ship and its cargo. It is thought that a commercial vessel passing the cable laying works in the shipping channel would be an unlikely event as it is expected that the obstruction of the shipping channel would not be of significant duration enough to justify this action, however, it may become necessary if for some (unlikely) reason the cable laying work becomes stalled in the channel. There is also the risk of the floating cable laying barges running aground in the shallower areas. Mitigation Commercial vessels would be under the control of the Harbour Master and passing would only occur with his approval. Mitigation of this risk would be the responsibility of the Harbour Master. The risk of the floating cable laying barges running aground would be minimised by allowing land based civil works to advance as far as possible into the water and by encouraging work from the floating barges to be done at high tide in these shallower areas. Risk: Delay to shipping Description It is possible that commercial vessels could be delayed from entering or leaving the Port resulting in potential losses to the vessel owners. 138 EnergyAustralia

72 Mitigation Through liaison with the Harbour Master it would be possible to predict vessel movements on a given date. This would enable a time to be selected for the work that would minimise as much as possible any delays. Also, it is expected that the rate of placement would be such that obstruction of the shipping channel would be of relatively short duration (less than four hours). If failure of equipment occurs there is potential for a significant delay, however, it would be possible to move the plant using tugs and re-open the channel in a relatively short period of time in this case. The contractors should provide adequate back up plant equipment to prepare for this. Risk: Damage to the cable during laying Description During the laying of the cable, damage to the cable could occur by it becoming looped or kinked. This risk is most likely to occur when the laying process is stopped unexpectedly. The risk is not significant to personnel or the environment but would require re-work and additional costs and is mentioned here to highlight the need for continuous placement of the cable once the crossing work starts. Mitigation To control this risk it is necessary that once installation of a cable commences that it continue, uninterrupted, to its completion point. This needs to be communicated to the Harbour Master through the contractor s work procedure document. Risk: Damage to other services and heritage items Description It is possible that there are obstacles on or just below the surface including active or disused services and shipwrecks. Damage to these could result in environmental damage or loss of heritage artefacts. The heritage register indicates a number of shipwrecks in Botany Bay but their location is unknown. Mitigation A review of services crossing the Bay has identified a number of crossings and the cable has been positioned to avoid these services. Early indication by side scan survey has suggested that there are no shipwrecks or objects along the preferred route, however, further sonar surveys would be undertaken by the contractor. To mitigate this risk the contractor would carry out his own services search as well as a number of surveys of the sea bed including magnetic, sonar and visual surveys. Risk: Damage to plant from buried obstructions Description Obstacles buried below the sea bed could cause damage to the plant and delay to the Project (potentially blocking the shipping channel). Mitigation The contractor would thoroughly survey the sea bed and subsurface conditions to identify any obstructions. Risk: Adverse weather Description Adverse weather conditions could damage the cable laying plant or threaten vessels at sea that cannot enter the port due to the shipping channel being blocked. Botany Bay Cable Project Environmental Assessment 139

73 7 assessment of key environmental issues Mitigation Whilst cable vessels can operate in open waters quite safely it is proposed that no work is carried out under adverse weather conditions. The contractor would liaise with the Bureau of Meteorology and select a suitable weather envelope, season and time to carry out the work. Risk: Public safety Description During the cable laying operation it is likely that spectators would want to view the work in progress. Like any construction project there will be significant risks to public safety if observers come too close to the work site. Mitigation It is proposed that an exclusion zone be established for a nominated distance around the works and the extents of anchors marked by buoys. This would be communicated through public notices, and notices to mariners, and enforced by the NSW Maritime Authority and Water Police. EnergyAustralia and the contractor would co-ordinate with these authorities. Risk: Inadequate burial depth for life of cable Description If the cable is buried with inadequate depth, it is possible that it may become exposed making it susceptible to further damage. Mitigation It will be the contractor s responsibility to ensure that the cable has been installed to the correct depth. Post construction surveys would be carried out to confirm this and any nonconformity identified would be rectified by the contractor. The contractor would investigate the effects of naturally occurring environmental events including wind, wave and coastal processes to ensure the minimum burial depth is maintained during the life of the cable. Operational risks Operational risks would be minimised in the design process as burial is considered to be the most reliable form of protection for submarine cables. It is proposed that the cable be buried to a minimum of three metres in deep water and to a minimum 1.5 metres in shallower water (less than 10 metres deep). The contractor would be required to investigate the minimum burial depths for the site conditions in this location and advise if the burial depth needs to be increased. Risks identified during the operations period are discussed as follows. Risk: Anchor damage to cable within the shipping channel. Description Anchoring is not permitted within the shipping channel however it is possible for vessels to be unknowingly dragging an anchor as it enters or leaves the port although this is thought to be a very rare occurrence. An anchor being dragged along the sea bed can plough below the surface, particularly in sand conditions such as those that occur in this location. Mitigation The cable would be placed a minimum of three metres below the sea bed in the shipping channel. This minimum burial depth is thought to be sufficient, however, the contractor would be required to investigate this further, considering various anchor types and combinations as well as the various subsurface materials, and increase the burial depth if found to be necessary for these conditions. 140 EnergyAustralia

74 Risk: Anchor damage outside of the shipping channel. Description Outside of the shipping channel recreational vessels are permitted to anchor. This is more likely to occur in the shallower waters where the cable is placed 1.5 metres below the sea bed. Mitigation A cable buried 1.5 metres below the sea bed is considered adequate to mitigate any risk of damage from recreational vessels. Risk: Future dredging Description It is understood that Sydney Ports Corporation plans to expand the shipping channel (by widening and deepening) in the future. The timing for this work is uncertain, however, as the plans appear to be very preliminary and the time required for the investigations, assessment and approval process for this type of project would be significant. Dredging work would expose the cable and potentially damage the cable if it is not considered adequately in the dredging process. Mitigation The location of the cable would need to be clearly identified to Sydney Ports prior to dredging. In the vicinity of the cable, dredging would have to be carried out using suitable, low impact methods. The installation of the cable would ensure that there is adequate length in the cable so that it would fall to its new level post dredging. Furthermore, investigation into increasing the burial depth across the shipping channel would be explored with the prospective contractors. The aim of this is to establish whether it is feasible and if there is equipment available (worldwide) capable of increasing the depth of the trench to a level that would negate the need for the provision of additional slack in the cables and thus ease the method of future dredging of the shipping channel. Risk: Exposure of cable by sea bed levels varying with time. Description Whilst Botany Bay has a fairly stable coastal climate, sea bed levels and beach profiles have been known to vary as a result of development within the Bay such as the impact of airport runways. Exposure of the cable due to dynamics in the sea bed level would make the cable susceptible to damage from anchors and sea conditions if the level of cover is reduced. Mitigation The investigation of the cable burial depth would need to consider the possibility of variation in sea bed level. Review of past surveys would indicate previous changes. It would be necessary to monitor sea bed levels in the future to ensure that the cable has adequate cover. Due to the water depth in the shipping channel it is thought that it would be extremely unlikely that the sea bed level would vary with time in this location. It would be necessary to enforce an exclusion zone around the works to ensure public safety. EnergyAustralia would communicate with NSW Maritime and the Water Police about establishing and maintaining the exclusion zones. It is proposed that public notices and notices to mariners would be published prior to commencement to advise the public of this. Botany Bay Cable Project Environmental Assessment 141

75 7 assessment of key environmental issues 7.10 Marine movements Shipping channel and commercial vessels The shipping channel is approximately 200 metres wide and has an approximate depth of 20 metres below chart datum. All commercial and charter vessels arriving at, departing from, or moving within Port Botany, must comply with the provisions of the Ports Act 1995, as amended. All commercial vessels are tracked by an integrated Vessel Surveillance System, combining a network of radar and closed circuit television cameras. On average there are approximately 10 commercial vessel movements a day in Botany Bay (based on SPC figures 3,500 movements a year). These shipping trade movements include container vessels, bulk liquid and gas carriers, and oil tankers. Commercial vessels entering the port usually do so under the control of the Sydney Ports Corporation pilots. Tugs usually pick up vessels entering Port Botany at Molineaux Point and the oil tankers going to the Caltex facilities. Usually three tugs are used for the inbound vessels Recreational users Botany Bay is also used for recreational purposes such as fishing, boating, diving and aquatic events. Commercial fishing has ceased following Botany Bay being declared a Recreational Fishing Haven in 2002, which means that all commercial fishing has been banned from the Bay and this ban is unlikely to be lifted. The Fisheries Management Act does not permit vessels larger than 32 metres to undertake any fishing activity within its waters. There are two sailing clubs in the vicinity of the proposed crossing at Kurnell and at La Perouse. The clubs conduct regattas and other similar aquatic events in and around the Bay, mainly on weekends, but sometimes during the week. These events are scheduled in advance and require an Aquatic Licence issued by NSW Maritime. Recreational vessels may use any part of the Bay, excluding the Port s no-go zones, which are: the waters of the embankment between the airport runways the waters of Brotherson Dock and an area 30 metres off the bulk liquids berth or 30 metres from a tanker secured at the bulk liquids berth waters within 30 metres of any tanker secured at No. 1, 2 and 3 Kurnell (the Caltex facilities). Recreational boats may not anchor within the shipping lanes. Recreational diving occurs in the area and Kurnell is regarded as one of Sydney s most pristine diving sites. The main diving locations are around the Kurnell headland reefs, close to shore, the La Perouse peninsula headland, and off Bare Island. These are usually dived at on weekends, however there is some occasional mid week diving Construction impacts on marine movements The most significant effect of the construction would be the potential for obstruction of the shipping channel by the lay barge, cables and cable laying equipment, and associated support vessels. Once installation of the cable commences, the obstruction created by the associated plant would move continuously across the Bay. The total footprint of equipment in the Bay would also vary between contractors but would include the floating cable barge, any workboats and anchor lines associated with these. It is proposed that this impact would be mitigated by effective communication and consultation between EnergyAustralia, its contractor, Sydney Ports Corporation and NSW Maritime, as described below. It is recommended that a Submarine Cable Installation Management Programme (SCIMP) be prepared by the contractor detailing how all the impacts and risks would be addressed before, during and after cable installation. This 142 EnergyAustralia

76 SCIMP would be sent out to all key stakeholders, including the Department of Planning, Sydney Ports Corporation Harbour Master and NSW Maritime for approval, prior to commencement of the works. Commercial vessel movements The Sydney Ports Harbour Master has been contacted regarding this project to advise him of the details of the Project and possible impacts, and to discuss possible mitigation measures. As was indicated by the Harbour Master, shipping movements are random and subject to commercial, industrial and climatic factors both locally and remotely. Accordingly, at this stage of the Project, with no final details of construction methodology or final timing of the works, it is not possible for the Harbour Master to provide approval for the Project (with respect to impacts on marine movements). However, once the construction methodology is known (in particular the placement rate) and the crossing days become known, the Harbour Master would be more able to predict the requirements of shipping movements and should be able to nominate appropriate times where the effects of the cable installation would have minimal adverse impacts on the commercial shipping movements. To facilitate this process it is proposed that a procedure for communications be developed and enforced under the contract for the cable installation. This would include an obligation for the contractor to develop and follow a construction procedure in liaison with and to the satisfaction of the Harbour Master. EnergyAustralia has prepared a proposed procedure for communications which includes contacting the Harbour Master, public notification and notification to Water Police and NSW Maritime. It is anticipated that it would be unacceptable to the Harbour Master to block the shipping channel for an extended period of time (estimated to be more than four hours subject to confirmation) and it is recommended that the contractor(s) considered for this Project by EnergyAustralia be selected on the basis that their construction methods and would not obstruct the shipping channel for a prolonged period of time. Recreational activities Recreational activities in Botany Bay at the time of construction would consist primarily of smaller craft entering and leaving the Bay, recreational fishermen and sightseers observing the work. There is adequate channel width and water depth for recreational vessels to ensure that they would be able to pass the cable laying plant whilst work is in progress and not be impacted by the proposed work. To ensure the safety of recreational vessels it is proposed that a temporary exclusion zone be enforced around the lay barge and associated plant to ensure vessels remain a safe distance away. It is proposed that this would be done in consultation with NSW Maritime and the Water Police. NSW Maritime was contacted about the Project, particularly in relation to aquatic events in Botany Bay. NSW Maritime indicated that the nearby sailing clubs occasionally conducted regattas that could be impacted by the work but that these could quite easily be relocated to suit. As part of the consultation process with NSW Maritime and the Water Police public notices and notice to mariners would be published for the information of the public. Consideration of marine movements during the construction period The installation of the submarine cable would require a number of crossings of the entrance channel to Botany Bay by a cable laying barge and its associated plant. The lay barge may be up to 80 metres in length and, along with the associated plant, would temporarily obstruct the shipping channel. The works would not require temporary jetties or staging areas. A laying rate exceeding one metre per minute is reasonable in this location (although this would be subject to the selected contractor s work methods) and if this can be achieved it Botany Bay Cable Project Environmental Assessment 143

77 7 assessment of key environmental issues is anticipated that the cable placement across the 200 metre wide shipping channel could be achieved in less than four hours. By providing adequate notice of the commencement of works to shipping, and coordinating through the Harbour Master, (so as to minimise disruption to shipping), it is not expected that the works would have impact upon commercial vessel movements. Potential impacts would be mitigated by facilitating a coordinated approach with the Harbour Master. The Harbour Master would be kept informed prior to and during the works. The contractor for the works would be required to prepare a Submarine Cable Installation Management Plan - a written procedure describing how the works would be carried out for the Harbour Master s and other stakeholders review, and construction would not proceed without the Harbour Master s approval. In this regard the Harbour Master would be notified of the following items to allow notification of waterway traffic: proposed final location of the cable proposed construction period commencement of works completion of works. Furthermore, suitable protective measures to safeguard the cables would be carried out in accordance with discussions with the Harbour Master, to enable future deepening and widening of the navigation channel to its proposed 18 metres below chart datum and a width of 400 metres respectively as illustrated in Figure 33. Figure 33 Proposed channel cross section There would be minimal impact to recreational vessels as there is adequate width and depth in the channel for smaller vessels to safely pass the works. 144 EnergyAustralia

78 Aquatic events in Botany Bay would have to be relocated away from the works area if they happen to coincide with the works. However, such events are not regular and disruption would not be significant Electric and magnetic fields (EMF) The issue of electric and magnetic fields has been an integral part of the process of planning the Botany Bay Cable Project. This section provides a summary of the key EMF considerations for this Project. More detailed information is outlined in Appendix E Electric and magnetic fields Introduction to EMF Electric and magnetic fields (EMF) are part of the natural environment and are present in the earth s core and the atmosphere. EMF is also produced wherever electricity or electrical equipment is in use. Power lines, electrical wiring, household appliances and electrical equipment all produce EMF. EMF is sometimes incorrectly referred to as electromagnetic radiation. The electric field is proportional to the voltage (which can be considered as the pressure with which electricity is pushed through the wires). The magnetic field is proportional to the current; that is, to the amount of electricity flowing through the wires. Both electric and magnetic fields are also dependent on the source geometry (i.e. conductor heights, cable depths, phase separations and so on). All fields decrease rapidly as you move away from the source. Generally, the smaller the object or closer the conductors producing the field, the more rapidly the field will decrease as you move away from the source EMF and health The issue of EMF and health effects has been extensively reviewed over the past 30 years by Australian and international inquiries and expert panels established for the purpose of trying to determine whether or not human exposure to EMF is related to adverse health effects. Consistently, none has ever found a basis for the scientific community to conclude that EMF causes cancer or any other disease. While the balance of evidence is against there being a risk, the possibility cannot be ruled out. The relevant Australian regulatory authority, the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), concludes that On balance, the scientific evidence does not indicate that exposure to 50 Hz EMFs found around the home, the office or near power lines is a hazard to human health" (Australian Radiation Protection and Nuclear Safety Agency 2003). There are currently no Australian standards regulating exposure to these fields. The National Health and Medical Research Council has issued Interim guidelines on limits of exposure to 50/60 Hz electric and magnetic fields. These guidelines are aimed at preventing immediate health effects resulting from exposure to these fields. The recommended magnetic field exposure limit for members of the public (24 hour exposure) is 0.1 millitesla (1,000 mg - milligauss) and for occupational exposure (whole working day) is 0.5 millitesla (5,000 mg) (NHMRC 1989). EnergyAustralia operates its powerlines, substations and other electrical infrastructure well within these interim guideline limits. In December 2006 ARPANSA released a draft new standard for EMF exposure in Australia. Following public comment this new standard is expected to be finalised and implemented in EnergyAustralia s position on EMF Provide balanced, accurate information to our employees and customers, including electric and magnetic field measurements and advice. Botany Bay Cable Project Environmental Assessment 145

79 7 assessment of key environmental issues Take reasonable steps to limit field exposures from new facilities by locating and operating our electrical installations prudently within the latest Australian health guidelines. Closely monitor engineering and scientific research, overseas policy development and major reviews of scientific, medical and engineering research regarding electric and magnetic fields and health. Cooperate fully with any bodies established by governments in Australia to investigate and report about power frequency electric and magnetic fields Mitigation measures EnergyAustralia has taken a number of steps to minimise EMF around the proposed cables. These measures were technically reasonable and within the context of prudent avoidance - doing whatever can be done at modest cost and without undue inconvenience to avoid the possible risk (to health)" (Gibbs, 1991). The mitigation measures include positioning the cables along the chosen route (within the land corridor or road reserve) to minimise EMF exposure and also reducing field strengths by both designing the cables with a reverse phase arrangement and configuring the cables in a triangular formation. For the Botany Bay Cable Project, the proposed cables will comply with the NHMRC interim guidelines, the public exposure limits recommended in ARPANSA s draft EMF standard and in the key international standards set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute of Electrical and Electronics Engineers (IEEE). Further information on mitigation measures can be found in Appendix E EMF calculations EnergyAustralia has carried out a load flow study to determine the expected loads on the proposed new cables to allow calculation of expected EMF around the cables. The modelling of EMF was based on the maximum expected cable loadings during peak summer demand between now and 2012, when other network improvements will reduce loading on the cables. As a result daily exposure would be considerably less than calculated by modelling. The calculations provided a comparison of various construction methods to demonstrate the outcomes of the mitigation measures outlined above. See Figure 34 below. 146 EnergyAustralia

80 A Magnetic field, mg C B D Distance from centerline, m Notes: Magnetic field represents the magnetic field at 1m above the ground. Distance represents the distance measured horizontally from the centreline of the power line. Curve A Underground double 132kV circuit, conduit, trefoil formation (92MVA per circuit normal phasing). Curve B Underground double 132kV circuit, conduit, trefoil formation (92MVA per circuit reverse phasing). Curve C Underground double 132kV circuit, direct buried, trefoil formation (92MVA per circuit normal phasing). Curve D Underground double 132kV circuit, direct buried, trefoil formation (92MVA per circuit reverse phasing). Figure 34: Comparison of projected magnetic fields from underground construction options in relation to EMF As outlined in Section above the proposed cables would comply with Australian NHMRC interim guidelines for EMF exposure and the public exposure limits recommended in the proposed ARPANSA standard and in the international standards prepared by ICNIRP and the IEEE. Further information on EMF modelling is available in Appendix E - Electric and magnetic fields. This includes an independent report verifying EnergyAustralia s calculations Visual impact Consulting company EDAW Pty Ltd prepared the visual impact study. Its report is summarised below. The aspects of the Project considered for their visual impacts were: the cable routes from Bunnerong STS to La Perouse and from Silver Beach to Kurnell STS the construction compound at La Perouse alongside Botany Bay National Park, required for the horizontal directional drilling operation the buildings and associated infrastructure to be constructed at Kurnell STS as part of the Project, as well as the minor work at Bunnerong STS the impact of sediment plumes from the laying of the submarine cable. A full copy of the report is located in Volume Two of the Environmental Assessment. Botany Bay Cable Project Environmental Assessment 147

81 7 assessment of key environmental issues Methodology The visual assessment methodology included: initial desktop analysis a field survey of the proposed cable locations and compilation of a photographic record confirmation of the precise cable route using the photographic record assessing each portion of the route, considering such issues as: visual prominence and impacts of proposed temporary construction infrastructure visual prominence and impacts of proposed buildings impacts on specific landscape elements such as trees and special features compiling visual assessment and recommendations. The visual impact assessment of the components of this Project follow Visual impact of cable laying along the route The visual impact would be directly caused by the presence of machinery and operational equipment necessary for trenching work, cable installation and trench backfilling. However, this impact would only be temporary. It is estimated to last for no longer than one working day for each property. As the cables would be buried and any affected land rehabilitated, the long term visual impacts from the cables installation is considered to be negligible. EnergyAustralia has selected the proposed cable route and location with potential impacts on the roadside trees in mind. For example, if trees are located close to a road, EnergyAustralia has positioned the cable route as far from the road s edge as practical. During the trenching process, EnergyAustralia would take care to minimise any disturbance of vegetation along the proposed cable route and avoid damage to road side trees, by monitoring construction and consulting an aborist should any potential to impact roadside trees be identified. Military Road There is a significant planting of Ficus hilli within the road verge on the western side of Military Road which has a major positive impact on the overall aesthetic quality of the street. A street planting of Eucalypts is also growing in the nature strip along the eastern side of Military Road. The Project would not pose any threat to the row of Ficus hilli growing on the western side of the road. Care would be exercised in respect of the Eucalyptus growing on the eastern side of the road, because if the construction was to sufficiently disturb their root systems, tree death could occur. This would result in a minor short to medium term impact on the visual character of Military Road until replacement plantings were established. EnergyAustralia would engage an arborist to advise on the most appropriate measures to maximise tree health and survival for trees potentially affected by the Project along Military Road. Bunnerong Road Bunnerong Road has a three to four metre wide road verge on each side which would allow excavation for, and installation of, the proposed cables without causing any major long term visual disturbance to the landscape. The verge is predominantly turf grass. Some significant tree stands are present on the western side of the road adjacent to Botany Cemetery. The precautions referred to above to protect trees would be taken. However, should some tree death occur, this would cause a loss of visual amenity provided by the tree canopies, resulting in a moderate short to medium term visual impact on the area. 148 EnergyAustralia

82 Anzac Parade The Project would follow the road alignment on the western side of Anzac Parade to the horizontal directional drilling set-up adjacent to the entry of Botany Bay National Park. The location of the cable in this section does not have any detrimental impact on the visual amenity of this area. The road verge is approximately three metres wide and free from any major street tree plantings which could be affected by excavation of the trench. In addition, there are no significant driveway crossings or pedestrian access ways that would be damaged or obstructed during the proposed construction operations. Silver Beach Minor visible damage to the Silver Beach dune would occur as a result of the excavation carried out to lay the submarine cable to the joint bay in the Prince Charles Parade car park. This damage would be rectified by replanting the species growing in the area at present. These species include Spinifex grasses (Juncus ssp. and Carpobrotus glaucescens). Remediation works to this area would be likely to have a positive overall effect on the dune community overall. Prince Charles Parade The existing footpath to the north of and parallel to Prince Charles Parade contains a community art project. It consists of in situ concrete that has a number of stencil imprints in it. These imprints tell a story about the history of the area and are important elements of the design and aesthetic of the local landscape. It is a significant asset to the visual quality of the Silver Beach area. EnergyAustralia would try to avoid damage to this footpath. If however, damage is unavoidable, it is likely to be restricted to one concrete panel which would be replaced in consultation with Sutherland Shire Council. Silver Beach Road There are a number of large street trees along the western side of Silver Beach Road. These are significant to the visual quality of the street, providing landscape amenity and screening. Given that the proposed cable route lies to the centre of the road, these trees are unlikely to be detrimentally impacted by construction. Captain Cook Drive The proposed cable alignment along Captain Cook Drive is within the road reserve from Silver Beach Road to the Kurnell STS. The cable route follows the road as it turns south east towards the Kurnell STS. The roundabout which is situated on the corner of this section of the road would be removed for the purposes of the cable installation and then replaced once the installation of the cable is complete. With the exception of the roundabout, there are no significant aspects along Captain Cook Drive which are likely to be affected by the cable installation or any works related to the Project in general Visual impact of HDD compound The visual character of La Perouse is important as a cultural amenity for recreation and historical value and should be preserved as much as possible throughout all operations related to the Project. The location of a horizontal directional drilling compound adjacent to Botany Bay National Park would disrupt a line of sight that runs from the entry of the National Park to the sandstone turret structure. The compound is projected to be in place for up to six months. The use of the entire site would be necessary to accommodate all the plant and equipment that is necessary for the HDD operations. The loss of any visual amenity from the compound would accordingly be short term but inevitable. Temporary fencing would be installed to the perimeter of the construction site and covered by a non-transparent, muted-colour material, such as hessian. Should an HDD operation be required on the Kurnell side of the Bay in lieu of trenching around the edges of the Posidonia australis there would be a temporary disruption to the Botany Bay Cable Project Environmental Assessment 149

83 7 assessment of key environmental issues visual amenity at Silver Beach. A compound would be in place for up to six months and is likely to be accommodated in the car park sections within the road reserve Visual impact of STS works Bunnerong STS There is very low potential for significant visual impact in this area as a result of the proposed cable works because there are no trees or structures in this location that would be affected by the cable installation process. Kurnell STS The proposed layout of the works is shown in Figure 35. A new building (Building 1) and transformer wall structure (Building 2) are proposed for the Kurnell STS, as well as an underground retention tank, as part of the Project. Figure 35: Layout of proposed Kurnell STS works The buildings are required for operational purposes and would be a new architecturally designed development that blends with the character of the local area. The transformer plinths and walls are to be of a similar building type to existing structures at EnergyAustralia substations, but with contemporary design similar to other modern substations being developed in Sydney see Figure 36. The exterior design will complement the new Kurnell substation buildings. 150 EnergyAustralia

84 Figure 36: Artists sketch of proposed transformer walls for a modern EnergyAustralia substation Details of the proposed works are provided below: Building 1 Building 1 is necessary for the STS operation. The building would be an architecturally designed masonry structure, to be located approximately eight metres from the front boundary of the Kurnell STS at its closest points. The design responds to the vernacular of the coastal location, reflecting elements found within the Kurnell area through materiality and form. A basement is required to house cables. The proposed building height is between eight and 15.2 metres. This visual assessment has allowed for a one metre maximum basement level given the proximity of the building to the existing Botany Bay water level. Building 2 Transformer plinths and walls 8.5 metres in height are to be located at the ends and between each transformer, and at the back of the structure. The proposed dimensions of floor plate are in the order of 39 metres long by nine metres wide. Underground tank An underground tank is proposed to be installed with approximate dimensions of three by nine metres. The purpose of this tank would be to retain any oil spilt in the event of some untoward event, i.e. it is a precautionary measure. The visual impact of the proposed works at Kurnell STS was assessed from a number of viewing locations in the vicinity. These locations are shown in Figure 37. Botany Bay Cable Project Environmental Assessment 151

85 7 assessment of key environmental issues Figure 37: Locations at which visual impact of building development at Kurnell STS was assessed Captain Cook Drive Building 1 would be visually apparent from Captain Cook Drive. This is in particular due to the substantial size of the structure, even though it is located some distance back from Captain Cook Drive. Building 1 would be a high quality architect design to blend in with the character of the local area. The design process will take into account community feedback on initial concept designs, including feedback on the exterior design and colours. Modern substation equipment and design allows an enclosed style of substation to be built that avoids the need to the traditional outdoor equipment yard characteristic of older style substations. Appropriate landscaping would also be carried out to ensure the best possible visual amenity from Captain Cook Drive. Retention of as many as possible of the existing trees to the existing drainage swale would be important in providing a quick initial screening capacity to the development. Tree planting to the road frontage of the substation would also need to be supplemented to both the south and north of the main entry to facilitate an appropriate level of screening for vehicles travelling from the south into Kurnell. The level of required screening to the road frontage need not be so dense that it blocks all views of the Building 1, but only sufficient to provide a vegetation screen. EnergyAustralia recognises the historical importance of the area and any construction would be planned taking this into consideration. Bonna Point The proposed buildings for the Kurnell substation are unlikely to be visible from within the Bonna Point Reserve site. Tasman Street The proposed Kurnell substation buildings and structures may be visible from some locations in Tasman Street. The tree stands and the mangrove community at the rear of the properties would provide a relatively tall and dense visual barrier that is likely to screen most views of Buildings 1 and 2 from the second storey of a Tasman Street building. No views of the proposed buildings are anticipated from street level. Given the extent of screening between Tasman Street and the site, and the industrial context of the neighbourhood, it is not expected that Buildings 1 and 2 would comprise a significant visual impact if they are viewed from this location. 152 EnergyAustralia