Assessment of siltation processes& implementation of nautical depth
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The document details a project led by Dr. Faustino Manso of the Antea Group, focusing on assessing siltation processes and implementing nautical depth strategies in Cochin Port, India. It outlines a comprehensive methodology involving field data acquisition, numerical modeling, and sediment management to optimize navigation safety and mitigate siltation issues. Key findings suggest that numerical models and tailored sediment management can significantly enhance harbor operations and navigation conditions under severe siltation challenges.
Assessment of siltation processes& implementation of nautical depth
- 1. Dredging days, 9-10 Nov 2017 Dr. Faustino Manso Senior Marine Advisor Assessment of siltation processes & implementation of nautical depth in the Port of Cochin, India
- 2. Who are we? How we did it? Results Conclusions INDEX
- 5. 5 “Our People are The Reason Behind Our Success” Our team • Multidisciplinary & multinational (comprehensive overview) • Broad international background • Academic & PhD researchers with commercial drive • Experienced project managers
- 6. 6 International Expertise WorldwideOur competences – coastal & marine • Offshore Cables & Pipelines • Navigation and Shipping • Data Acquisition and Management • Environmental Impact Assessment • Other Services • Coastal & Port Engineering • Climate Adaptation & ICZM • Numerical Modelling • Dredging & Sediments • Geospatial (GIS) services
- 7. 7 Our Clients PORT AU PRINCE Haiti
- 8. Client Cost >1m € Period 2015-2016 Kerala’s backwaters CPT © Cochin city Willingdon Island International Container Transshipments (ICT) Terminal Liquefied natural gas (LNG) Terminal Vallarpadam Island Where? Cochin Harbour Consortium N
- 9. How? Methodology Desktop study Data acquisition fieldworks & survey design Navigation studiesHydro sedimentary studies 2D numerical modelling (hydro & sediment) Scenario simulations Physical modelling 3D simulation Detail siltation understanding Safety navigation 1. Implementation nautical depth concept 2. Optimization sediment management tasks Preparation Goals
- 10. Phase 1 field data acquisition April 2015 to April 2016 • Currents vel & direction (ADCP) C1-C5 flow balance tributaries C6 flow balance channel (horizontal) C7 & C8 offshore • Suspended sediment (water samples, niskin): C1-C8 • Wave climate (height & direct.): C7 & C8 • Water level T1 harbour T2 outside • Wind (speed and direction): T2 harbour entrance C7 outside • Meteo (Temp + pressure + humidity) T1 Inside harbour T2 Outside harbour • Bathy (dual freq. echo sounder) + silas & sediment (RheoTune): monthly In harbour (loose mud) Out harbour (longshore transport) CPT © Willingdon Island ICT Terminal LNG Terminal N C3 C4 C5 C2 C1 C6 T2 T1 C7 C8 C3 C4 C5 C2 C1 C6 C7 C8C7 C8 T2 C7 T1 T2
- 11. Phase 2a Hydro sedimentary studies A B C D m m E • hydrodynamics, waves propagation & sediment transport/morph. • Multi-phase approach: 1. pre-processing stage 2. 2D general models (development & calibration) 3. 3D local models for stratification effects 4. analysis of simulation results 1km 1km
- 12. • Physical modelling: Towing tank • 12 combinations of layer thickness, density, viscosity and tide • 3 designs of vessels: Container carrier/Tanker/Cargo vessel • 3D simulation: Local pilots calibrate the model assisted by specialists Phase 2b Navigation studies
- 13. • schematize processes • 95% of siltation in the harbour is marine originated (entrained by Monsoon) • Harbour channel acts as sediment trap • Sediment enters inner harbour through the Gut • Other applications • simulate behaviour disposed material • suggest methods for arresting siltation • Keeping sediment navigable • Keeping sediment out • Keeping sediment moving • outer harbour construction suggestions Phase 3a siltation understanding
- 14. • Criteria for nautical depth: Safety navigation • Approach: Field data (acoustics + ρ probe) applied in navigation models • Definition: shallowest depth with the following safety limits: 1. Minimal UKC: 10% of the ship’s draft above hard bottom 2. Maximum penetration of keel in loose mud: 12% of ship’s draft 3. Maximum density of loose mud: 1170 gr/l (acceptable level of mud yield strength & max. mud strength tested) Phase 3b safety navigation 5 11 15 ρ= 1030 ρ (gr/L) Top of mud, 210 kHz, ±1050 gr/L ρ= 1150 Top of hard bottom, 33kHz. ±1350 gr/L Nautical depth ???? gr/L“Consolidate mud” “loose mud” Depth (m)
- 15. Results–Implementation of nautical depth N CPT © Willingdon Island ICT Terminal LNG Terminal Channels (Ernakulam & Mattancherry) Additional dredging effort Terminals: LNG: Reduce dredging effort ICT terminal: Reduce slightly dredging effort General: Schedule critical manoeuvres at high tide Inner channel Additional dredging required for bigger vessels during Monsoon Northern part of Gut slightly deeper Outer channel Offshore: Additional dredging required for bigger vessels Nearshore Additional dredging required for bigger vessels during Monsoon
- 16. Results–Optimization sediment management tasks Nearshore part outer channel & both terminals (LNG & ICT): high siltation related to sediment traps: • Over dredging does not help. • Optimize efforts: • Pre-Monsoon: remove the consolidated mud • Monsoon & post-Monsoon: remove denser part of the loose mud combined with WID below nautical depth support navigation allow current flushing sediment Disposed material: shifting disposal site reduces probability of return but low ROI IHC systems tms
- 17. Conclusions When conditions in harbours with severe siltation problems are known: 1. Numerical models support decision making in harbours • source and causes of siltation • evolution of disposed material • scenario simulations to quantify issues (within the intrinsic uncertainty) 2. Nautical depth can be determined: • objectively (towing tank under controlled conditions) • subjectively (simulation with human operator) 3. Optimizing sediment management activities is feasible
- 18. 18 Thank you For further information please contact: Dr. Faustino Manso faustino.manso@anteagroup.com +32 492251286