Assessment of Mud-Capped Dredge Pit Evolution on the Outer Continental Shelf (OCS) of Northern Gulf of Mexico

Dredging offshore alters seafloor topography. This has the potential to affect oil and gas infrastructure or other resources of concern located proximal to dredge pits. Direct impacts from dredging are well-understood and mitigated for BOEM’s environmental review and coordination throughout the sand leasing process. However, knowledge of long-term changes in borrow pit geometry is poor in the Gulf of Mexico where targeted sand resource deposits underlie muddy overburden, resulting in relatively deep pits with a “muddy cap” (pit walls are characterized by cohesive muds overlying unconsolidated sands). Though dredge pit evolution is expected (e.g., expansion of pit beyond extent of dredging activity) and mitigations are applied to protect adjacent areas, the effectiveness of mitigations has not been evaluated. This study provides empirical data to quantify mud-capped dredge pit evolution to predict pit evolution based on numerical model simulations. The results are also applied to evaluate the effectiveness of existing mitigations (e.g., setback distances from pipelines) to determine if cultural resources and infrastructure are being protected.

USD: $357,000

2017-10-01 → 2018-09-30