Introduction

What is a Dam?

A dam is a barrier constructed for the retention of water, water containing any other substance, fluid waste, or tailings, provided the barrier is capable of impounding at least 30,000 m³ of liquid and is at least 2.5 m high. Height is measured vertically to the top of the barrier
(i) from the natural bed of the stream or watercourse at the downstream toe of the barrier, in the case of a barrier across a stream or watercourse; or
(ii) from the lowest elevation at the outside limit of the barrier, in the case of a barrier that is not across a stream or watercourse.

Generally the Canadian Dam Association uses the term dam to include appurtenances and systems incidental to, necessary for, or connected with the barrier. Furthermore, the definition may be expanded to include dams less than 2.5 m high or with an impoundment capacity of less than 30,000 m³ if the consequences of dam operation or failure are likely to be unacceptable to the public, such as dams that create hydraulic conditions posing a danger to the public; dams with erodible foundations that, if breached, could lower the reservoir by more than 2.5 m; or dams retaining contaminated substances.

• Dam safety typically refers to the protection of the public and environment from the effects of dam failure, as well as release of any or all of the retained fluids behind a dam.
• Public safety addresses hazards to the public, created by the presence or operation of a dam, but not associated with structural failure of the dam or with passage of floods.
• Mining dams include a wide variety of dams that are found at mine sites, such as tailings dams, contaminated water dams, freshwater supply dams, seepage collection pond dams and sludge storage dams. 

Advancing Technical Knowledge

The CDA seeks to be the recognized leader in advancing knowledge and practices related to dams, consistent with social and environmental values. Technical expertise related to dams is central to our activities. The Association brings together dam owners, operators, regulators and engineers to learn from each other and develop solutions to dam safety issues. Several technical committees oversee working groups on subjects of interest to members. The process to resolve these complex issues can take years, and knowledge transfer is ongoing. The following schematic diagram illustrates the steps required to resolve technical issues.

The text in blue (below) shows the different stages that we may go through to develop a technical bulletin or other document. In black, you can see some examples of activities or documents produced at each stage. Note that some issues, like Small Dams or Dikes and Levees, did not progress beyond the discussion/investigation stage through to technical bulletin status, while others, such as Dam Safety Reviews, Public Safety and Mining Dams, eventually became technical bulletins.