The first geomembranes were installed on dams in 1959 in Italy and British Columbia: both systems were covered. In the 1970’s geomembranes began to be installed on dams exposed. In the next 20 years exposed geomembrane systems would be installed on more than 2 dozen dams primarily in Europe. The first exposed geomembrane system on a dam in the United States was installed in 1997. The United States now has the largest installed base of e...

The implementation of a successful dam design is predicated on the construction contractor using acceptable construction means and methods when perform the work and the quality control staff performing timely and through inspections. There are many critical work items associated with dam construction which, if not performed correctly, will lead to poor performance, reduced service life, and contribute to potential failure modes. This webinar...

Changing demographics in the vicinity of dams have led to hazard creep in a number of dams worldwide. Many of these dams now have insufficient spillway capacity as a result of these changes in hazard classification from low to significant or high hazard. Stepped chutes applied to the embankment dams offer an advantage by providing increased spillway capacity. This webinar provides an overview on stepped chute research conducted at the USDA-Ag...

This webinar covers the use of sand and gravel filter/drainage systems in embankment dams to protect against excessive seepage pressures, internal erosion in cracks or other anomalies, and piping. Excessive seepage pressures can affect embankment stability related to slope sloughing or failure and piping from progressive removal of soil forming a tunnel feature in or under the embankment. Many seepage issues in dams involve the development of...

This webinar will provide participants with information on the importance of preparing operations and maintenance (O&M) manuals for dams. It will include an overview of some of the key federal agency and state requirements and formats for dam O&M manuals. Operations and maintenance guidelines will be presented for both embankment and concrete dams and key dam appurtenances, such as spillways and outlet works. Many examples will be prov...

Quality control on projects for the construction or rehabilitation of dams is the responsibility of the construction contractor. Contractors have control of the site during construction and are responsible for understanding and complying with the requirements of the contract documents. It would be remiss on the part of the owner however, to solely rely on the contractor for this task. To verify contract compliance, construction of complex and...

Earthquakes represent a hazard to dams in many parts of the United States and therefore are of interest to design engineers and dam safety officials. The hazard from earthquakes includes strong shaking, fault rupture displacements, reservoir seiche and earthquake-induced landslides, all potentially damaging to dams and reservoirs. This webinar will discuss the physics and geology of the earthquake process and the methods used to identify seis...

This webinar is the third and final course in the series on Concrete Gravity Dams. The first webinar entitled “Introduction to Concrete Gravity Dams” (July 2012) presented information regarding the types of gravity dams, historic design and construction practices as well as lessons learned from noteworthy gravity dam failures. The second webinar in this series entitled “Stability Evaluations for Concrete Dams” (Oct. 20...

This webinar will address a wide range of foundation preparation and treatment methods applicable to construction of new dams, rehabilitation of existing dams, and enlargement of existing dams. Topics to be covered include: 1) treatment of surface rock exposures in dam foundations, 2) rock grouting, 3) treatment of foundation soils, 4) foundation seepage barrier walls and upstream blankets, and 5) foundation seepage collection and control methods.

Introduction to Armoring Embankment Dams and Earth-Cut Spillways with ACBs Over the past 23 years numerous embankment dams and earth-cut spillways in the United States have been armored with Articulating Concrete Blocks (ACBs) to provide overtopping protection and to extend the life of the structures. With the current focus on evaluating and rehabilitating dams throughout the United States to pass increased design flows, the use of this const...