ABSTRACT
ABSTRACT: Unacceptably high seepage volumes and/or pressures may occur under a dam at any point in its service life. When such events occur long after the dam has been completed, the difficulty of collecting contemporary construction data and memories is a severe challenge to the goal of trying to understand the cause of the problem. The amount of new field investigatory work to be conducted to help understand the cause and characteristics of the problem is correspondingly greater. This paper presents the case history of seepage evaluation and remediation at a 74-year-old concrete dam in New Zealand. The example is used to illustrate the basic steps that should be followed when a “condition” is recognized to exist which may threaten dam safety. These steps apply regardless of the degree of sophistication of the instrumentation and monitoring equipment.
