The Hydrology 201 Webinar consists of four one-half hour segments. The first segment is a brief review of Hydrology 101 emphasizing some of the important hydrologic issues. The second segment will concentrate on the NRCS procedures to determine the loss rate function and the dimensionless unit hydrograph as it is utilized to transform excess rainfall into runoff. Different methods of determining time of concentration and lag time will be cove...

The purpose of the webinar is to provide an overview of the process required to developing field investigation programs for design of new dams or rehabilitation of existing dams. The presentation will include the four phases that are typical of field investigations for new and existing dams. The presentation will highlight the important aspects of each phase from plan ning to execution, including defining the goals of each phase. Site Reconna...

The webinar will discuss the basics of various non-destructive evaluation (NDE) methods and their applications for investigating dam, spillway and conduit conditions such as freeze-thaw cracking, void, seepage, corrosion of reinforcing, anchor bolts, strength/moduli, and stability. Guidance will be provided as to which NDE methods are useful for diagnosing various conditions of concrete, masonry, earthen and steel materials. The webinar will...

This webinar is a follow-up to the first in this series, Risk Assessment Basics for an Individual Dam. It is recommended that the two webinars be viewed in order if possible, and both are available in the On-Demand section of the website. Risk Management for a Portfolio of Dams explains how risk assessment is being used by some owners and regulators to improve the management of dam safety for a portfolio of dams in the context of the owner...

In 1980, Roller Compacted Concrete (RCC) was utilized to construct the Willow Creek gravity dam in Oregon. Since that time, there have been over 200 RCC projects in the United States. With applications such as gravity dams, overtopping protection, buttresses, guide walls at locks, and service spillways, RCC has proven to be a durable and economical solution to difficult engineering problems throughout the US. Internationally, RCC gravity and...

The Webinar consists of two basic parts: • A history of filter design practice including theoretical design considerations • A step-by-step design process with criterion for the design of a critical filter for one example soil type The primary topics covered in the first part of the Webinar are: 1. Early filter designs that addressed only interparticle seepage and piping. 2. The historical research performed by Sherard et al to deve...

Fluid Mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. Hydraulic topics include concepts such as pipe flow, dam design, pumps, hydropower, flow measurements, and open channel flow. The flow of water in an open channel in natural rivers is common, however, the solution to estimate water surface elevations can be a difficult problem when everything is considered, especially...

Hydrology is the study of the movement, distribution, and quality of water throughout the Earth, and thus addresses both the hydrologic cycle and water resources. A practitioner of hydrology is a hydrologist, working within the fields of earth or environmental science, physical geography or civil and environmental engineering. Broadly, hydrology is classified into two groups. The scientific hydrology is concerned mainly with the academic aspec...

Seepage models for earth dam projects require estimates for the coefficient of permeability for each zone in the cross-section. Models also require an estimate of the anisotropy of the permeability in the zone (anisotropy is the ratio of the horizontal to vertical permeability values of the permeability). Computations of drain designs require accurate estimates of the permeability of filter and drainage materials. Empirical estimates provide...

Quality control activities are important during the construction of an earth dam. The quality control program is intended to ensure that the compacted fill meets or exceeds all the specifications for the earth fill in the construction contract. The two primary specifications involve the degree of compaction and the acceptable range of water content for each zone in the compacted fill. This Webinar provides guidance on common pitfalls in the q...