Recent improvements in the computational capacity of computers and in the availability of high-quality terrain data have allowed 2D hydraulic models to become highly valuable tools in dam and levee safety analyses. Today, there are several free and commercially-available 2D models on the market. This webinar will provide a background on 2D hydraulic modeling theory, identify steps to set up a 2D model, describe important specifications for 2D...

Inadequate spillway capacity, significant hydrologic loadings on embankments and structures, and operation and maintenance are common dam safety issues, instigating the need for risk-reduction measures and/or rehabilitation. 3D weirs, or weirs with a crest length greater than the spillway width, are a particularly efficient approach to reduce these concerns. These weirs are also commonly used in new dams and may be useful as levee spillways. I...

During the last 10 years, there have been unparalleled levels of activity in dam and levee foundation remediation. This has been triggered mainly by the U.S. Army Corps of Engineers’ evaluation of their dam and levee portfolio following the disastrous flooding of New Orleans and surrounding areas in 2005. Remedial diaphragms walls have been in installed in dams in the US since 1975 when Wolf Creek Dam, in Kentucky, was repaired for the...

Dam failures typically result from interactions of human and physical factors which extend over years or decades. Understandably, engineers and others involved with dams normally focus on the physical factors. However, because physical systems such as dams are subject to physical laws and do not make ‘mistakes’, it may be asserted that dam failures (and incidents) are fundamentally due to human factors. The other side of this coin...

The field of hydrology experienced its most dramatic period of development from the late 19th century to the mid-20th century. While the theory and equations used to estimate watershed runoff have remained relatively unchanged since that time, the availability of Geographic Information Systems (GIS) software and geospatial data has modernized the methods used to evaluate watershed characteristics and develop input parameters. Today’s hy...

Slopes on the upstream side of dams are subject to wind-generated waves. Likewise, levees along river banks experience wind waves, boat wakes and current forces. This webinar will describe how winds produce waves in reservoirs and other enclosed bodies of water. Wave heights and periods resulting from winds blowing across the water surface will be calculated as a function of wind speed, duration, water depth and fetch distance. Wakes produced...

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. Evaluation of the seismic stability of these dams to future anticipated earthquakes require an understanding of seismic hazards, site exploration methods, soil behavior under seismic loading, and seismic stability analysis techniques. This webinar will cover the fundamentals of these topics to p...

Event tree analysis is commonly used in dam safety risk analysis. Event trees are tools used to aid in understanding, analyzing, and communicating dam safety risks and for informing dam safety decisions. Like all other tools they are imperfect and their potential value depends on the skills of their user. Event trees can be used to obtain quantitative estimates of the probability of dam failure and its associated consequences. This can be don...

Plant and animal intrusions represent a common but often overlooked threat to the long-term safety of embankment dams throughout the U.S. In fact, these hazards have been attributed to dam failures and near dam failures in the past. Proper identification, treatment, and long-term management of these dangers are important to the overall health of embankment dams. This webinar will provide engineers, owners and dam safety officials with an unde...

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...