Abagold WEC BAR - Anchor Environmental

Probability ofoccurrence withmitigationCumulative impactwith mitigationSignificance withmitigationPossibleMediumMEDIUMA.3. POTENTIAL IMPACTS TO MARINE BIOTA: NOISE FROM BLASTING AND DRILLING (Alternative 3)Nature of impact Noise will be generated by the drilling and blasting activities duringconstruction. Cetaceans have highly developed acoustic sensory systems,which enable them to communicate, navigate, forage and avoid predatorsin the marine environment where hearing is a much more important sensethan vision. Increased noise levels may mask acoustic signals or reduce therange at which mammals can detect the signals. This may impact theirability to maintain biological functions such as feeding, mating andprotecting and raising young. Marine mammals are likely to avoid the areaand may potentially change behaviour or become stressed due to the noisegenerated by blasting and drilling activities. Given the high densities ofsouthern right whales in the Walker Bay / Hermanus area over the winterand spring and the sensitivity of the whales to disturbance during calving,the potential impacts of construction in the sea area during this period arepotentially high and appropriate mitigation measures must beimplemented.StatusNegativeExtentRegionalDurationMedium termIntensityHighProbability ofDefiniteoccurrenceCumulative impact prior Highto mitigationSignificance prior to HIGHmitigationDegree to which impact Mediumcan be mitigatedProposed mitigation No blasting in the sea may be conducted during the period between 30June and 31 December as southern right whales are likely to be in thevicinity of Walker Bay. Observations with binoculars must be sited on key vantage pointsimmediately before the intended blast. Blasting should only commencewhen cetaceans are not seen to be diving or resting on the sea surfacewithin two kilometres of the blast site. All blasting must be conducted using a rock breaking technology knownas NoneX (www.nonex.co.za). This is not an explosive technology butrather a propellant compound encased in a cartridge which reacts very56