Session 5: Dredging in sensitve areas CEDA dredging days – October 2008 Session 5: Dredging in sensitve areas Date: 2 Oct 2008 Time: 10:50 – 11:10 Author: Jeroen Gheysens CEDA dredging days Oct 2008 1

Overview Main project information Dredging in sensitive areas Environmental monitoring Dredging of contaminated materials Reclamation area layout CEDA dredging days Oct 2008 2 2

Geographical Location SÃO PAULO RIO DE JANEIRO BRAZIL Reclamation Area Dredging Area SEPETIBA BAY CEDA dredging days Oct 2008 3

General Info on Project CLIENT: ThyssenKrupp CSA Companhia Siderúrgica CONTRACTOR: Consorcium Dredging International nv – Boskalis International bv EXECUTION PERIOD September 2006 – April 2008 CEDA dredging days Oct 2008 4

Access Channel Harbour Basin Length 4,3km Bottom width 128m RECLAMATION AREA Access Channel Length 4,3km Bottom width 128m Dredging depth -14,5m CD Volume 6.600.000 m³ Harbour Basin Turning circle 250m Volume 4.500.000 m³ DREDGING AREA CEDA dredging days Oct 2008 5

Large Cutter Suction Dredger (CSD) Boosters Cosel: 5.500 kW DI 509: 4.475 kW Nieuwe Merwede: 2.984 kW Large Cutter Suction Dredger (CSD) Vlaanderen XIX: 8.358 kW CEDA dredging days Oct 2008 6 6

Confined Disposal Facilities CDF 1 135.000 m³ CDF 2 141.000 m³ Contaminated Material Volume 131.000 m³ Capping Material Volume 54.000 m³ CEDA dredging days Oct 2008 7

Environmental CSD Beaver St. Lawrence Cutter Power: 171 kW Pump Power: 839 kW CEDA dredging days Oct 2008 8 8

Overview Main project information Dredging in sensitive areas Environmental monitoring Dredging of contaminated materials Reclamation area layout CEDA dredging days Oct 2008 9 9

Dredging in sensitive areas Sepetiba Bay: historical contamination, mainly heavy metals – Mangroves - Fishery Environmental effects Spreading and settlement of resuspended solids Impact on soil organisms during operation Alteration of bathymetry Changing shoreline configuration MINIMISE THE ENVIRONMENTAL EFFECTS! CEDA dredging days Oct 2008 10

Dredging in sensitive areas Minimise the environmental effects Understand the environmental situation and identify the most sensitive areas Selection of dredging equipment Identification of environmental impacts Selecting the most appropriate working method Well trained, experienced and environmental aware crew Environmental management and monitoring plan CEDA dredging days Oct 2008 11 11

Overview Main project information Dredging in sensitive areas Environmental monitoring Dredging of contaminated materials Reclamation area layout CEDA dredging days Oct 2008 12 12

Environmental Monitoring Water quality monitoring Suspended solids dewatering < 500mg/l Capping of CDF’s Capping layer of 1m with ‘no contamination’ Noise level monitoring < 65dB (background level) CEDA dredging days Oct 2008 13 13

Environmental Monitoring Baseline monitoring Identification of the situation before the start of the works Relationship turbidity – suspended solids Background monitoring Weekly basis (background locations) Identify turbidity from other sources River discharges Heavy rainfall Seasonal fluctuations CEDA dredging days Oct 2008 14 14

Environmental Monitoring Water quality monitoring Daily measurements at fixed locations Turbidity (~ Suspended Solids) Water temperature Salinity Instrument Depth DREDGING AREA RECLAMATION AREA CEDA dredging days Oct 2008 15 15

Fixed points in the river São Francisco TSS (mg/l) = 1,14 NTU CEDA dredging days Oct 2008 16 16

Fixed points in the Sepetiba Bay TSS (mg/l) = 2,74 NTU CEDA dredging days Oct 2008 17 17

Points around the dredger TSS (mg/l) = 2,74 NTU CEDA dredging days Oct 2008 18 18

Overview Main project information Dredging in sensitive areas Environmental monitoring Dredging of contaminated materials Reclamation area layout CEDA dredging days Oct 2008 19 19

Confined Disposal Facilities CDF 1 135.000 m³ CDF 2 141.000 m³ Contaminated Material Volume 131.000 m³ Capping Material Volume 54.000 m³ CEDA dredging days Oct 2008 20

Dredging of contaminated materials Minimise spillage, turbidity and turbulence Minimise storage by high concentration dredging Minimise noise and unpleasant smells Optimise precision for accurate and selective thin layer dredging CEDA dredging days Oct 2008 21 21

Dredging of contaminated materials Environmental Sweep Dredger vs Environmental Disc Cutter CEDA dredging days Oct 2008 22 22

Overview Main project information Dredging in sensitive areas Environmental monitoring Dredging of contaminated materials Reclamation area layout CEDA dredging days Oct 2008 23 23

Reclamation area layout Mangroves (high environmental sensitive area) Protect from salt water of the dredging process Risk of bund wall failures (Monitoring!) Reduce suspended solids dewatering Maximise travel distance of water on the area Weir boxes (managing water levels on the area) Monitoring! CEDA dredging days Oct 2008 24 24

CEDA dredging days Oct 2008 25 25