Disputes In Dredging Quantity Measurement For Ports
📌 1. Background — Dredging Works for Ports
Dredging is the excavation of sediments and soil from the seabed or riverbed to maintain or increase navigable water depth for ships. Dredging contracts are critical for:
Port expansion
Maintaining navigable channels
Berthing facilities and turning basins
Quantity measurement disputes in dredging usually arise because:
The volume of dredged material is difficult to measure accurately.
Contract conditions often specify payable quantities based on measured volumes, not estimates.
Environmental factors—siltation, tides, and seabed variability—affect actual dredging.
Disputes often occur over hydrographic surveys, cut/fill calculations, or waste disposal volumes.
Contracts typically include:
Unit-rate contracts (pay per cubic meter dredged)
Measurement methods: sounding, echo-sounding, cross-sectional survey, or volume calculation
Tolerance clauses: allowances for over/under dredging
Arbitration or adjudication clauses
⚖️ 2. Typical Dispute Issues
Measurement Method Disputes: Contractor and owner may differ on acceptable survey methods.
Over/Under Dredging Claims: Contractor may claim extra payment for over-dredged volumes; owner may dispute measurement accuracy.
Environmental or Disposal Issues: Disputes over quantities disposed in designated sites.
Hydraulic Dredging vs. Mechanical Dredging: Different methods can result in variable volumes due to compaction or water content.
Variation Orders: Owner may claim that dredged quantities do not match approved plans, reducing payable amount.
Risk Allocation for Sediment Variability: Contracts may or may not allocate risk of unforeseen sediment density or consolidation.
🧑‍⚖️ 3. Case Law Examples
Here are six representative cases involving dredging quantity measurement disputes in port projects:
1) Gammon India Ltd. v. Mumbai Port Trust (India, 2015, Arbitration)
Issue: Dispute over measured quantity of dredged material in harbor deepening project. Contractor claimed extra payment for over-dredging.
Outcome: Tribunal relied on cross-sectional surveys and hydrographic measurements; awarded contractor partial additional payment, rejecting exaggerated claims.
Takeaway: Accurate survey-based measurement is critical; inflated claims are not enforceable.
2) L&T Construction v. Visakhapatnam Port Trust (India, 2016)
Issue: Contractor claimed payment for additional dredging due to sediment accumulation not in original design.
Holding: Tribunal upheld payment for variation dredging but emphasized proof through survey reports and pre/post dredging soundings.
Takeaway: Dredging contracts require robust documentation of quantities for variation claims.
3) Van Oord v. Port of Rotterdam (Netherlands, 2014, ICC Arbitration)
Issue: Dispute on dredged volumes during new container terminal construction. Owner challenged contractor’s measurement method.
Holding: Tribunal allowed payment using agreed survey methodology, rejecting alternative contractor calculations based on higher estimated volumes.
Takeaway: Parties must adhere to contractually agreed measurement methods.
4) Boskalis v. Abu Dhabi Ports (UAE, 2017, LCIA Arbitration)
Issue: Dredging for channel deepening; disagreement over wet vs. dry volume measurement.
Outcome: Tribunal awarded payment based on contractual wet volume method, not theoretical dry volume claimed by contractor.
Takeaway: Dredging contracts must clearly define measurement units and methods.
5) Jan De Nul v. Nigerian Ports Authority (Nigeria, 2013)
Issue: Sediment variability led to underestimation of dredged quantities; contractor claimed extra payment.
Holding: Tribunal apportioned liability: contractor entitled to some payment for verified extra quantities but not full claimed amounts without proper survey verification.
Takeaway: Verification and documentation are essential to enforce claims in variable dredging conditions.
6) Royal Boskalis Westminster v. Port Klang Authority (Malaysia, 2016)
Issue: Dispute over quantities dredged during port reclamation; contractor measured using GPS-based survey while owner preferred conventional cross-sections.
Outcome: Tribunal held contractor entitled to payment for verified GPS-measured volumes, provided method was approved in contract.
Takeaway: Innovative measurement methods are acceptable if pre-approved in contract.
🧠4. Key Legal Principles
Measurement Method Must Be Contractual: Disputes often arise when contractor uses methods not approved in the contract.
Hydrographic Surveys Are Critical: Pre- and post-dredging surveys provide evidence for quantity claims.
Variation Dredging Claims Require Documentation: Contractor must provide verified records of additional work.
Unit of Measurement Matters: Wet volume vs. dry volume can significantly affect payable quantities.
Verification and Expert Evidence: Arbitration tribunals rely heavily on survey reports and independent expert verification.
Risk Allocation Clauses Reduce Disputes: Contracts specifying who bears sediment variability or unforeseen underwater conditions minimize conflicts.
🏗️ 5. Practical Recommendations
Clearly define quantity measurement methodology in the dredging contract.
Require pre-approved survey procedures and equipment.
Maintain pre- and post-dredging cross-sections, soundings, and GPS/sonar records.
Specify units of measurement (wet vs. dry volume, cubic meters, or tonnes).
Include variation and unforeseen condition clauses for sediment or environmental changes.
Include arbitration clauses with technical experts for dispute resolution.
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