Sepetiba dredging and reclamation works CEDA dredging days

Sepetiba dredging and reclamation works 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

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

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

Sepetiba dredging and reclamation works General Info on Project • CLIENT: Thyssen. Krupp CSA Companhia Siderúrgica • CONTRACTOR: Consorcium Dredging International nv – Boskalis International bv • EXECUTION PERIOD September 2006 – April 2008 CEDA dredging days Oct 2008 4

Sepetiba dredging and reclamation works RECLAMATION AREA • Access Channel – – Length 4, 3 km DREDGING AREA Bottom width 128 m Dredging depth -14, 5 m CD Volume 6. 600. 000 m³ • Harbour Basin – Turning circle 250 m – Dredging depth -14, 5 m CD – Volume 4. 500. 000 m³ CEDA dredging days Oct 2008 5

Sepetiba dredging and reclamation works • Boosters – Cosel: – DI 509: – Nieuwe Merwede: 5. 500 k. W 4. 475 k. W 2. 984 k. W • Large Cutter Suction Dredger (CSD) – Vlaanderen XIX: 8. 358 k. W CEDA dredging days Oct 2008 6

Sepetiba dredging and reclamation works • 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

Sepetiba dredging and reclamation works • Environmental CSD Beaver St. Lawrence – Cutter Power: 171 k. W – Pump Power: 839 k. W CEDA dredging days Oct 2008 8

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

Sepetiba dredging and reclamation works 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

Sepetiba dredging and reclamation works 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

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

Sepetiba dredging and reclamation works Environmental Monitoring • Water quality monitoring – Suspended solids dewatering < 500 mg/l • Capping of CDF’s – Capping layer of 1 m with ‘no contamination’ • Noise level monitoring – < 65 d. B (background level) CEDA dredging days Oct 2008 13

Sepetiba dredging and reclamation works 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

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

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

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

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

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

Sepetiba dredging and reclamation works • 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

Sepetiba dredging and reclamation works 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

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

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

Sepetiba dredging and reclamation works 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

Sepetiba dredging and reclamation works CEDA dredging days Oct 2008 25