Dam Seals in North America

or The Little Dutch Boy of Large Concrete Dams

CGLLC has been involved with installing in-situ dam seals with Structural Preservation Systems, Inc. Hanover, MD, for 20 years. Work has been performed for Tennessee Valley Authority, New Brunswick Power, Canada; US Army Corps of Engineers; and Bureau of Reclamation. 

These seals are installed for two primary reasons:

1. Retrofit a dam for failed waterstops as is the case at Folsom Dam (Bureau of Reclamation), CA; Harry S. Truman Dam (USACE), MO; Apalachia Dam (TVA), TN; Big Bend, SD; and Bagnell Dam, MO.

2. For new expansion joints in dams experiencing alkali-aggregate reaction expansion problems. In these situations (TVA and Mactaquac) slots are cut into the dam to relieve internal pressure and seals are installed to control water infiltration. This work has been performed at numerous TVA dams (Hiawassee, Chickamauga, Fontana;) and at Mactaquac Dam (NB Power), Canada.

The latest project, over the past two years, were the replacement of 5 failed waterstops (by a different contractor)  and two new installations of seals at USACE Big Bend Dam, Ft. Thompson, SD

Largest diameter seal installed is 14 inch at Mactaquac Generating Station, Fredericton, NB

Longest seal is in Folsom Dam at 198 feet deep

This technical paper was presented at the 2001 Canadian Dam Association Conference:

Use and Application of Inflatable Dam Seals in Large Concrete Dams and an addendum (2009)

Before and After Video:  Click on the picture

 No endorsement by TVA is intended or implied hereby

Click on the photos to enlarge:

 Folsom Dam, California

 Folsom Dam Seal is down 198 feet, before trimming off and covering with well inspection cover

 Folsom Dam drying out.  Water was leaking 75 feet above just two hours before picture

 Mactaquac Dam, New Brunswich, Canada.  This dam is undergoing the most severe Alkali-Aggregate Reaction seen to date by CGLLC.  Damage is extensive and ongoing.

 Fourteen inch seal being filled at Mactaquac.  Previously, men went down a chair hoist into a 36 inch core to manually install rubber belting as a waterstop.