Going with the flow … measured, unregulated and natural

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Colorado River through mountains

When talking about Colorado River hydrology, the term “flow” is used in several different contexts. Although the term may sound complex, the concept is fairly simple and primarily relates to the way water flows into Lake Powell.

Here’s your explainer to our various “flow terms.”

Measured flows are actual flows measured at a certain time and location. They include effects from all upstream diversions, return flows (water redirected back into the river or reservoir) and reservoir releases. Measured flows reflect natural processes and human activities over time as climate, vegetation and land use in the Basin change.

Unregulated flows are measured flows corrected for upstream reservoir regulation.             

Natural flows are measured flows corrected for both upstream reservoir regulation and diversions. They are an estimate of what the unimpaired flows would be without human interference.

Hydrology Flows Infographic