BEN SCHOEMAN DOCK BERTH DEEPENING Specialist ... - Transnet

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3735000 Very Fine Sand (0.063-0.125mm) Fine Sand (0.125-0.250mm) Medium Sand (0.250-0.500mm) Coarse Sand (0.500-1.0mm) 3740000 Very Coarse Sand (1.0-2.0mm) Bedrock Robben Island Blouberg Rocks Table View 3745000 no data on bedrock no data on bedrock Milnerton 3750000 no data on bedrock Diep River 3755000 Mouille Point Green Point Sea Point Cape Town Harbour Salt River Clifton Beach Camps Bay 0 km 2.5 km 5 km 3760000 65000 60000 55000 50000 45000 Figure 2: Sediment and bedrock distribution in Table Bay (after Woodborne 1983) During summer upwelling cold water (9 - 13°C) invades Table Bay from the Oudekraal upwelling centre, south of Table Bay. Temperatures can increase rapidly to >20°C during relaxation phases of the upwelling cycle as water flows into Table Bay from the north and north west (CSIR 1997). Winter temperatures are more uniform than those of summer and fall in the narrow range of 14 - 16°C. This is a result of no upwelling and strong mixing driven by storms. 9
5.1.3 Biological communities The major force driving the ecology of the region containing Table Bay is coastal upwelling. This is forced by equatorward winds which, at the latitude of Table Bay, predominantly occur in the spring/summer period (e.g. Shannon 1985). The upwelling process supplies inorganic nutrients to the euphotic zone and results in rich blooms of phytoplankton and dense stands of macroscopic algae such as kelps and associated understorey algae. These directly and indirectly provide food sources for the welldeveloped biological resources on the west coast including pelagic (pilchards, anchovy) and demersal (hakes, kingklip) fish stocks, near shore fisheries (linefish, rock lobster, abalone), mammals (seals and whales) and seabirds (penguins, gannets, cormorants etc). This review on the biological communities in Table Bay and their ecology draws on various published scientific studies and general reviews, non-published reports from several institutions, and discussions with specialists in relevant fields. It has to be noted, though, that there is a general paucity of information regarding the biota specific to Table Bay, and thus some of the descriptions of the different biological communities are based on information drawn from the wider West Coast. 5.1.3.1 Habitats Marine ecosystems comprise a range of habitats each supporting a characteristic biological community. Figure 3 shows that Table Bay habitats include: o Sandy beaches extending from the Salt River mouth north past Blouberg o Rocky shores extending south of the harbour past Sea Point, at Blouberg Rocks and at Robben Island o Artificial surfaces of the harbour itself plus the shore protection extending towards Salt River o Subtidal sand substrata and o Subtidal rock substrata in the bay itself o The water body in Table Bay, and o The water body in the port. The descriptions of the biological communities in each of these habitats is focused mainly on the benthic macrofauna (benthos), mammals and resident seabirds as these would probably face the largest risks from the proposed port development activities. For completeness, however, short descriptions on pelagic communities are also provided. 10
Page 1 and 2: BEN SCHOEMAN DOCK BERTH DEEPENING S
Page 3 and 4: the test organisms. The EC 5 is usu
Page 5 and 6: Turbidity Upwelling Vulnerable Wrac
Page 7 and 8: Another important issue is the poss
Page 9 and 10: 6.2.1.3 Settlement of material susp
Page 11 and 12: 2 METHODOLOGY For the assessment tw
Page 13 and 14: The proposed deepening of the Ben S
Page 15 and 16: 4.3 Cumulative effects Table Bay re
Page 17: undetectable in 80% of the measurem
Page 21 and 22: Supralittoral fringe (Littorina zon
Page 23 and 24: Niambia sp. Coleoptera Diptera Tylo
Page 25 and 26: Midlittoral zone - The intertidal o
Page 27 and 28: Fish - Nearshore and in the sandy b
Page 29 and 30: 2000 at Robben Island revealed furt
Page 31 and 32: Table 2: Common whales and dolphins
Page 33 and 34: Table 3: Site, time, mean count (co
Page 35 and 36: 150000 125000 100000 Kg 75000 50000
Page 37 and 38: sensitive because of its conservati
Page 39 and 40: Schoeman Dock occurred in 1971 (Pro
Page 41 and 42: Table 7: Hydrocarbon distributions
Page 43 and 44: care concentration ranges for cadmi
Page 45 and 46: SS mg/l Boxplot for TSS 80 60 40 20
Page 47 and 48: The mean values calculated above ar
Page 49 and 50: o o possibility of the dredge spoil
Page 51 and 52: The gravel sized component of the s
Page 53 and 54: Table 12a: London Convention Annex
Page 55 and 56: Benthos distributions in Block #1 -
Page 57 and 58: 40 40 30 Site 1A 30 Site 1B % Speci
Page 59 and 60: 2 Cluster Dendrogram and MDS ordina
Page 61 and 62: the well developed ripples in the c
Page 63 and 64: 6 IMPACT IDENTIFICATION AND ASSESSM
Page 65 and 66: Accordingly the potential environme
Page 67 and 68: Impact Assessment Table No Mitigati
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are summarised in the table and it
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Figure 21b: Predicted number of day
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considered to be low. Further, the
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A A B B B Figure 23a and b: Predict
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dependent on these include the harm
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structures. The apparent lack of su
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Diving birds such as cape cormorant
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Figure 24: The predicted worst case
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Figure 25 depicts the simulation mo
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6.2.3.2 Alteration of benthic biolo
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Impact Assessment Table No Mitigati
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Nature of impact - Turbid plumes of
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Figure 26b: Predicted worst case ex
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Figure 27b: Predicted worst case ex
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suspended sediment concentrations i
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Figure 28a: Dredge spoil dump site
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6.2.3.6 Elevated water column turbi
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The evaluation with mitigation is:
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Figure 29a: Predicted exceedance in
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6.3 Cumulative Impacts The proposed
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Impact summary Table (cont.) Impact
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Impact summary Table (cont.) Impact
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mitigated by ensuring that the Cutt
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operations at Coega Port. Prepared
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Glassom D., K. Prochazka and G.M. B
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Protekon 2006. Port of Cape Town co
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BEN SCHOEMAN DOCK BERTH DEEPENING Specialist ... - Transnet

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