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...

This webinar will provide participants with an understanding of the hidden dangers at low head dams and effective strategies for improving public safety. The instructors will illustrate their presentation with several examples drawn from their own experiences as hydraulic/civil engineers, expert witnesses, authors and engineering designers. Lessons learned from experience with litigation related to drownings at low head dams will be presented...

Historically, concrete dam analysis focused much of the attention on material property assumptions, which has been and continues to be important. But more recently, the focus is primarily on the modes of failure experienced by these types of dams. This webinar will present a more in-depth review of stability evaluation methods for concrete dams; the basics of which was first presented in the previous webinar entitled “Introduction to Co...

Labyrinth weirs are widely used in spillway rehabilitation to upgrade existing dams to meet updated spillway design flood criteria. In addition to increasing discharge capacity, these weirs are also well suited to regulating upstream pool elevations for flood control or at intake structures. The hydraulic design of a labyrinth spillway requires the consideration of complex flow characteristics and optimization of multiple geometric parameters...

Effective energy dissipation of flows from outlet works and spillways is an extremely important component in dam safety. Undersized or ineffective structures can lead to damage and failure, possibly endangering the dam or the flow channel and properties downstream. Generalized design criteria for many different types of energy dissipaters and/or stilling basins exist from several different government agencies, both federal and state (including...

It is widely accepted that monitoring programs are important for dam safety. Monitoring programs provide the information necessary to understanding the on-going performance of the dam, as well as the ability to detect a change in this performance, which can be critical in identifying the need to take actions to avoid the consequences of a dam failure. Monitoring programs generally consist of visual observations and measurements of specific pa...

This webinar will focus on the many applications of RCC in dam engineering, including RCC dams, RCC overtopping protection, and RCC use in cofferdams. Other topics to be covered will be RCC for raising and rehabilitating existing concrete dams and RCC for grade control structures and stilling basin erosion protection. Emphasis will be placed on small to medium volume RCC projects including hints on cost effective design and and estimating. In...

Evaluation of potential seepage failure modes in embankment dams and in particular around outlet works penetrations is a very important aspect of dam safety evaluations. Assessing potential seepage failure modes typically requires designing and evaluating investigation and instrumentation programs, and a variety of engineering analyses. Experience has shown that adverse seepage and piping conditions can develop and remain difficult to detect u...

This webinar provides an introductory discussion of the processes governing earth and vegetated earth spillway design and performance. Topics include the history of vegetated earth spillway use by the USDA and the associated design criteria, the concept of stability and integrity design, the importance of maintenance, and the erosion processes quantified in the SITES program. Examples from USDA NRCS experience and USDA ARS research will be use...

Physical models have been used as part of the design process for spillways and other hydraulic structures for centuries. Their use has proven to be extremely effective for validating hydraulic design schemes for new and rehabilitated spillways, for the discovery of hydraulic design problems that previously had not been expected, and in reducing construction costs. Physical modeling is also important for public relations, for reducing risk and...