LAKE SUPERIOR OUTFALLS

AMI provided topographic, bathymetric, side scan sonar, commercial diving, conceptual design, cost estimating, and hydrodynamic modeling services for the Lake Superior Outfalls project in Duluth, Minnesota.

Topographic, bathymetric, and side scan sonar surveys were conducted focusing on the historical outer harbor submerged breakwall structure, shoreline, and proposed retrofitted outfall structure locations.

Commercial diving operations were conducted to characterize the outer harbor crib breakwater structure, seafloor materials, and obtain sediment samples for lab analysis.

A comprehensive design report was developed, and several conceptual design options and cost estimates were developed with the feasibility of each option addressed and presented to the owner.

The hydrodynamic modeling involved analyzing varying lake water levels (in particular, recent high-water levels), storm surge effects, and varying wave conditions with respect to storm event return periods and the effects of storms on material transport and plugging of outfall pipes.

AMI provided the client with significant wave heights, peak wave periods, mean wave directions, and material transport rates to which the proposed retrofitted outfall structures would be exposed.