SRF served as the lead designer on the Edward Kramer and Sons design-build team on two U.S. Army Corps of Engineers projects at Lock & Dam #3 on the Mississippi River. The projects included an 800-foot extension of the existing lock guide wall to improve navigational safety for commercial tows and recreational boaters traveling downstream and more than two miles of embankment improvements to raise and improve low and weak embankments below the dam. SRF designed each project approximately six months after receipt of Notice to Proceed.
Unusual design challenges included designing the guide wall end cell for a 2,000,000 pound extreme impact and two-dimensional hydraulic modeling for multiple flow events to determine velocities and flow direction for the re-contouring and armoring of the navigation channel.
Due to the nature and location of the embankment and guide-wall improvements, significant environmentally sensitive components were addressed:
- Protection of old-growth trees and sensitive flora within the project limits
- Restrictions of construction operations for fish spawning, bald eagle nesting, protection of mussel beds, and construction related sediment transport associated with unusually high river flows
- Provision of adequate fish passage into the adjacent lakes
The project required significant communication and coordination with multiple agencies, including the Minnesota Pollution Control Agency, Minnesota Department of Natural Resources, Wisconsin Department of Natural Resources and the US Fish and Wildlife Service. The Federal 401 Certification (Chapter 30 Certification with WisDNR) imposed a number of conditions that were met including substantial in-water Best Management Practices for limiting sediment transport downstream and avoiding mussel bed disturbance during construction.
Construction Administration and Project Delivery