In May, 2003, heavy rain led to the activation and failure of a fuse plug spillway at the Silver Lake Dam in a remote area of Marquette County, Mich. The resulting breach emptied the reservoir of 8 billion gallons of water and devastated the downstream river system. Loss of the Silver Lake Storage Basin also resulted in lost electric generation at downstream hydroelectric plants because spring runoff could no longer be stored to help generate power during dry months. The Upper Peninsula Power Co. determined that Silver Lake needed to be reconstructed to continue augmenting flow to the two hydroelectric dams downstream.

Jackson Avenue Bridge Reconstruction

The $15-million reconstruction project abandoned the existing concrete spillway, improved the low-level outlet, built a new concrete spillway, extended and raised the crests of existing earthen dikes, built a new dike, and built a new embankment dam at the channel created by the May 2003 breach.

Key Players

Owner: Upper Peninsula Power Co.
General Contractor: Bacco Construction, Inc., Iron Mountain, Mich.
Design Firm: Paul C Rizzo Associates Inc., Monroeville. Pa.

The project underwent a high degree of scrutiny from the power company and a federal agency. Teamwork between AECOM office management and field staff resulted in a construction project with few deficiencies and without sacrificing the construction schedule and simultaneously keeping all parties up to date on the latest inspection results and test data. Data was primarily shared electronically and through an FTP site.

The biggest challenge was delivering ready-mix concrete to the very remote site. Delivery time from the batch plant the project site was about 1.5 hours. The mixture designs, on-site quality testing, and efficient placing of 3,000 cu yd of concrete were vital to meeting the project specifications.