Rehabilitation of dams with geomembranes has stopped seepage in more than 200 dams worldwide. In the 1990s, the US Army Corps of Engineers recognized that geomembranes could arrest seepage in many structures but many structures in the U.S. could not be dewatered for installation. Subsequently, a 2 phase design and testing program with the US Army Corps of Engineers adapted geomembrane system details for underwater installation. The first underwater installation occurred in 1997 at Lost Creek dam in California stopping the seepage through the dam for the first time in 70 years. The Lost Creek project is still in service after almost 20 years without any maintenance. Subsequent underwater installations around the world have all been successful to stop seepage, including installations exceeding more than 100,000 sq. feet installed underwater. These underwater installations have relied on using compression fittings to join geomembrane panels together underwater. The underwater applications of geomembrane have also been adapted to cover joints and cracks on dams. These applications have been done in the USA, Canada, Italy, Greece, and Laos.
For dams, the water typically has no substantial flow. About 10 years ago, the issue of repairing levees and canals became more important around the world and many of these structures cannot be dewatered. After years of research and development a geomembrane system for placing geomembrane panels underwater in flowing water during operation has been developed. This advancement required the development of a special watertight zipper. Then additional testing was done to develop a complete system and deployment procedure for these geomembrane panels. This system has now gone from testing into implementation phase and promises to provide a mechanism to fix leaking structures underwater even in flowing water. The first test installations have been done on canals in Italy and Egypt.
The Webinar will discuss the testing and installations along with results of geomembrane systems installed underwater.
John Wilkes, P.E.
President, CARPI USA
John Wilkes, PE has installed more than 40 dam geomembrane systems worldwide. He holds a BS degree from University of Virginia, MS degree from Duke University, and MS degree Johns Hopkins University. He managed the first underwater geomembrane system on a complete dam at Lost Creek dam in 1997; the world’s largest geomembrane installation geomembrane at Olivenhain dam in 2003; the Gem dam geomembrane system in 2007 which won the 2008 ASDSO Rehabilitation Project of the Year. He has also managed geomembrane installations on hydraulic structures in UK, Iceland, Canada, Australia, and New Zealand.