KNOW YOUR STREAMFLOW: The power behind flooding

Streamflow is the volume of water flowing past a certain point on a waterway at any given time of day. Heavy rains and snowmelt can produce runoff at a rate that exceeds the drainage capacity of streams, which results in flooding. Landslides occur as soil and rock are over saturated by excess runoff, causing mass movement.

For example, when air temperatures are high and snowpack melts too quickly, flooding and landslides may create life-threatening situations. These kinds of events not only carry large amounts of water, they can also carry sediment, silt, and rockfall that can alter the natural channel of a river and destabilize the landscape in rock slides and debris flows. Summer monsoons have the same effect on rivers and streams when a lot of rain falls in a short period of time.

Sediment flow into the Uncompahgre River between Ridgway and Ouray during an unusually wet September 2022 created undercuts in riverbanks where tree roots now hang exposed.

sediment flow due to flodding in Uncompahgre River

USGS stream gauges located throughout the Uncompahgre River watershed measure the discharge of water in cubic feet per second. The following stream gauge chart demonstrates a flood event on July 27,2010. Note the peak discharge of 828 cfs that occurred at 6:15 p.m.

USGS graph of streamflows