american municipal power

Willow Island Cofferdam & Excavation

St. Marys, West Virginia

The Willow Island Cofferdam and Excavation Project is located on the West Virginia side of the existing Willow Island Locks and Dam. This structure is located along the Ohio River approximately 162.4 river miles downstream of Point Bridge in Pittsburgh, Pennsylvania and ten miles upstream of Marietta, Ohio.

The existing Willow Island Dam consists of:
  • 8 tainter-type dam gates with individual hoisting equipment for each gate
  • Concrete gate piers supporting the gates, hoists & bulkhead crane bridge
  • Concrete stilling basin
  • Uncontrolled overflow weir lanward from the gated section of the dam 

The Ruhlin Company acted as the Design-Build contractor, supported by a design team consisting of Mueser Rutledge Consulting Engineers, E.L. Robinson Inc., and GeoComp Corporation. This team was responsible for the design and construction of cellular cofferdams, soil betonite, dewatering and instrumentation systems, seepage cutoff wall to facilitate construction of the powerhouse in the dry. Preparing the foundation for a powerhouse to be constructed after completion of the project; and design, supply, installation and operation of a dewatering system for the cofferdam enclosure. Additionally the project consisted of a 1,350 l.f. Bentonite slurry cutoff wall, extensive excavation (over 750,000 c.y.), rock removal and installation of 2,650 sheet piles comprising 16 cofferdams.


American Municipal Power (AMP)

Read more on the design, installation & removal process. 


The Ruhlin Company  |  6931 Ridge Road  |  P.O. Box 190  |  Sharon Center, Ohio 44274  |  Phone: (330) 239-2800  |  Fax: (330) 239-1828