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Flow of a River - Hydrology
Factors of flow: Seasonal variability (pg 2 of 11)

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Of all factors of flow, perhaps the most important is climate. The amount of precipitation is responsible for the volume of flow through a stream over time. The seasonal timing of snow, snowmelt, major rainfall, and dry periods determines the seasonal pattern of streamflow.

These anticipated changes in streamflow throughout the year are called seasonal variability, also referred to as intra-annual variability. In the upper midwest and northeast, snowmelt and spring rains correspond with what are normally the highest streamflows of the season, what is normally referred to as the "spring flood." Stream levels generally decline during the summer and autumn, and during winter reach base flows, that is, a more stable low level fed mainly by groundwater or water stored in lakes and wetlands.

A hydrograph is a picture that depicts the seasonal or intra-annual variability of streamflow.


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Factors of flow
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