Glossary

Hydrographic

Pertaining to the mapping and charting of water bodies, including rivers, lakes, and oceans, often for navigation or resource management. 

Hydrological

Relating to the study or science of water movement, distribution, and properties within the Earth’s atmosphere and surface. 

Hydrometeorological

Relating to the combined study of atmospheric and hydrological processes, including precipitation, evaporation, and their impact on water resources and weather patterns. 

Inflow

The quantity or amount of water flowing into a stream, river or water body that comes from spring snowmelt and rainfall.

Percentile

A type of statistical representation of a value in terms of percentages.  For example, the 10th percentile is the value below which 10% of historical flows or levels are found, and above which 90% are found.

Probability of Occurrence

The chance or likelihood that an event will happen over a period of time.

Reservoirs

An area upstream of a dam where water is or can be stored for a long period of time (several weeks and sometimes months). A large reservoir can regulate (or alter) the flows in the downstream river section.

Run-of-river Dam

A type of hydroelectric facility where no or little water is stored. A dam is built to cause water to pond upstream, ensuring the river water is high enough to enter the pipes leading to turbines. A run-of-river facility has little ability to regulate (or alter) the flows in the downstream river section.

Synonym: run-of-river facilities. 

Runoff

The excess water, from rainfall or snow melt, that isn’t retained in the ground and flows into the surrounding streams.

Tributaries

A stream or river that flows into a larger lake or river, for example, the Petawawa and Gatineau rivers.