Storm water and flooding comprise major and growing risks to cities, transportation systems, people, and the environment. Flooding has long been the major cause of property damage, and recent catastrophes such as hurricanes Matthew, Sandy and Katrina have exacerbated the total losses and created chain effects in the economy. While storm water control was considered a drainage issue in the past, it has expanded to include regulation under the C...

Federal agencies are required by statute and executive order to purchase certain products with specific environmental or energy attributes. “Green purchasing” or “sustainable acquisition” refers to purchasing products with these attributes, and purchasing services under which these products will be supplied or used. In this course, we will examine additional options for minimizing the environmental impact of your acquis...

This webinar will review the current state of the practice for rehabilitation of embankment dams to address seepage issues. Seepage rehabilitation measures can generally be grouped into two categories: seepage reduction / limitation measures and seepage collection measures. Seepage reduction / limitation measures include such features as foundation grout curtains, low permeability blankets, and seepage barrier walls. These measures are intend...

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...

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...

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...