Archive for December, 2010

Real-time flows on the Santa Clara and Virgin Rivers

Tuesday, December 21st, 2010 By: bret

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This page contains real-time flow data for two sites on the Virgin River and the mouth of the Santa Clara River, all near St. George, Utah. Discharge is hydrologist-speak for flow in the river. It is measured in cfs or Cubic Feet per Second. One cfs is equal to about 7 gallons per second.

Dec 16-22 Virgin River Flows in St. George at I-15

Dec 16-22 Virgin River Flows in St. George at I-15

The above (not real-time) graph, courtesy of USGS, shows flows for Dec 16-22 for the USGS gaging station on the Virgin River near Interstate 15 in St. George, Utah. Note the peak flow on Tuesday the 21st of about 18,000 cfs. In perspective this is:

  • 1/63 the average flow of the Yangtze
  • 1/25 the average flow of the Mississippi
  • 1/10 the average flow of the Nile

In the content below click on the links labeled “Discharge” or “Gage height” to pull up a graphing tool that will allow you to navigate the water data back and forth in time. Data from each of these stations comes from the USGS, the federal agency that also owns and operates the stations that measure this data.

Real-time data from these stations is transmitted one time each hour via a satellite radio link. The hourly data transmission contains flow values averaged at 15 minute intervals.

During extreme water events like this week, the gaging station equipment or site may sustain damage or undergo changes that make the automated measurements inaccurate. The site on the Santa Clara and the Virgin River site above the gorge seem to have intermittently reported data yesterday (Tues Dec 21) and today (Wed Dec 22).

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This USGS gaging station is right above the confluence of the Santa Clara and the Virgin Rivers, 0.8 miles upstream from mouth. This is near Interstate 15 in Saint George, Utah.

I think gage is next to bridge on Dixe Drive

I think gage is next to bridge on Dixe Drive

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This gage is located just upstream from the I-15 freeway bridge and just below the confluence with the Santa Clara River.

Virgin River gaging station next to the I-15 freeway bridge

Virgin River gaging station next to the I-15 freeway bridge

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This sensor is downriver from St. George about 8 miles. It’s located where the Virgin River enters “The Gorge”.

USGS Gaging station site.  8 miles Southwest of St. George.

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Short video of the Santa Clara at the confluence with the Virgin. This was taken on 21-December-2010 (Tuesday) at about 11AM. Flows were near their estimated peak of 4,000-5,000cfs. Camera pans from upstream shot of foot bridge to downstream shot of the confluence with the Virgin.



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Video clip of the Virgin just below the confluence with the Santa Clara and below the Interstate 15 bridge. Note the huge standing wave. Video was taken on Tuesday 21-Dec-2010 at about 11AM. Across the river is a paved bike path/walking trail which had sections eroded away in the 24 hours after this video was shot. Flows in the Virgin were near the estimated event maximum of 18,000cfs