2007 – Improving safety and hydraulic efficiency of dams with physical model studies

Steven L. Barfuss and Blake P. Tullis

An important aspect of improving the safety of dams is selecting designs that are both hydraulically efficient and cost-effective. A powerful tool that can be used as part of the hydraulic structure design process is a physical model study. To obtain maximum benefit from the model, it should be implemented as a part of the design process rather than as a post-design verification phase. A model study included early in the conceptual design phase can also provide increased flexibility to the designers.

Hydraulic model studies can often provide cost-effective answers to difficult problems. Some of the issues that can be efficiently resolved using model studies include optimizing spillway head-discharge relationships to increase reservoir storage while minimizing upstream flooding potential, controlling downstream scour, quantifying hydraulic uplift forces and/or overturning moments of dam structures, evaluating alternatives for structure retrofit or repair, and optimizing control gate sequencing during floods. Model studies also allow the engineer to simulate prototype performance (e.g., three-dimensional flow patterns, velocities, pressures, scour potential) over the full range of expected discharges. Quick and easy changes to the model can be made at minimal cost when evaluating the performance, safety and economic impact of various design alternatives.This hands-on model study approach to dam safety represents a tool that in some cases is underutilized.

Brief discussions of several physical model studies conducted at the Utah Water Research Laboratory, Utah State University in Logan, Utah, USA, are presented to illustrate key points of the paper. The primary objective of each of these model studies was to provide and/or improve the safety of the dam and the spillway while minimizing construction costs. This paper discusses the cost-effectiveness and hydraulic improvements that can be achieved through physical model studies.

Keywords: Physical models studies, design, hydraulic efficiency, dam safety, construction costs