Posted on August 15, 2025
Overdredging, or dredging beyond the specified design dredge depth, comes with more risks and undesirable effects — many of which have the power to create cost inefficiencies and even sink profits for contractors.
Often poorly defined or misinterpreted in contracts, the realities of overdredging can be a major source of costs and contention. It also presents a significant, untapped opportunity for potential savings.
Unlike land-based excavation that can achieve millimeter accuracies coupled with visual transparency, tolerances for quantities of material removed underwater are dependent on survey accuracies, soil conditions, the right equipment, and cutting-edge positioning technology to enable operators to accurately, prolifically and safely remove a defined quantity of material to detailed specifications.
Finding a balance begins with clear contractual expectations, as David Kinlan, Principal of Kinlan Consulting Pty Ltd., a Chartered Quantity Surveyor and Queensland Registered Adjudicator, confirms:
“The perennial issue with contract dredging specifications is a lack of detail.
