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Speaker: Considered an engineering marvel for its time, the Colorado River Siphon on the Yuma Main Canal has been delivering Colorado River water to the Yuma Valley for nearly 100 years.
This is the Yuma Main Canal above the siphon inlet. At this location we're about 4 miles below Siphon Drop Power Plant, where the Yuma Main Canal is diverted from the All-American Canal.
This is the canal that enters the siphon inlet. In the foreground is a trash rack that is equipped with automatic cleaning system.
This is our inlet gage located just below the trash rack. This gage is where we measure the canal or forebay elevation before it enters the siphon.
This is the Yuma Main Canal as it enters the Colorado River Siphon. The inlet conduit is approximately 17 feet in diameter and carries the water down 100 vertical feet before it makes a 90-degree bin to the south to cross under the river.
This is the canal as it exits the siphon. Just downstream on the right bank is our outlet or tallrace gage.
Here's another view of the canal as it exits the siphon. The outlet conduit is approximately 23 feet in diameter and, like the inlet conduit, travels down vertically 100 feet to meet the 14-foot diameter horizontal portion of the siphon.
The rated control for this station is the head difference on the siphon. The head value is computed by subtracting the tallrace elevation from the forebay elevation.
In order to provide real-time strength flow data, the head value must be computed at site. To do this, the data collection platform must measure the forebay stage and tallrace stage concurrently to compute the difference. Due to the site limitations, the forebay stage sensor is measured via a line-of-sight radio.
Here we are back at the inlet, standing in-between the east- and westbound lanes of Interstate 8, so a shot of our inlet gage or forebay gage. There is our line-of-sight radio antenna that we use to communicate with the DCP at the tallrace gage.
We'll pan around here and show you our line-of-sight conditions. We have the interstate and then a lot of heavy vegetation along the river. A park on there is on the side with quite a few tall cottonwoods. The outlet gage is right about in there somewhere. We can see that our line of sight there is very, very poor. Because of this, we end up losing quite a bit of data.
A quick trip back to the tallrace gage. Here's a shot of our line-of-sight radio antenna that's connected to the DCP. We can pan around back towards the north here and get an idea of what the line of sight looks like from the Arizona site.
The inlet gage is on the other side of the interstate, just about on the other side of that clump of salt cedar right there. Just another view of the poor line of sight conditions we have at this site. Because of the poor communications, we end up losing about half of our gage height record at this site.
Due to the problems in collecting reliable gage height data from the inlet gage and the fact that there is no good stage discharge relationship below the siphon due to variable backwater from several check stations downstream, we have installed a SonTek side-looking acoustic Doppler velocity meter. The velocity meter is installed just above stream at the tallrace gage. The mount allows us to raise and lower the acoustic meter for cleaning and maintenance.
This particular model of side-looker has an internal tilt-and-roll sensor along with a compass. This made it very easy to deploy. We were able to get the sensor perfectly plumbed, which is essential when you're using the vertical beam stage sensor.
This is a screenshot of the deployment beam check. As you can see, we have good correlation between the X and Y beams. This screenshot also shows that we're sampling about 40 feet up from the instrument. That happens to be about half of the channel.
This is a screenshot of about a month's worth of data collected by the ADVM. As you can see, the data is very clean. And even at low velocities, there is not a lot of acoustic noise. At this point, all diagnostics point towards an excellent deployment. We are confident that once this station is rated, we will have good, solid, reliable stream flow record.
This is a shot of the old Medicine Street Bridge. It's about 1000 feet downstream of the outlet gage. This is the bridge in which we used to make all of our current meter measurements from.
Unfortunately in-between the gage and the measuring section is the city of Yuma intake. This is where the city diverged for their municipal supply. Because of this diversion between the control and the measuring section, all current meter measurements had to be coordinated with the city of Yuma so that they could keep track of their pumping right during the measurement. The pumping right was provided in million gallons per day and was added to total on the discharge measurement which introduced some error.
With the use of an ADCP, we're now able to measure above the city of Yuma diversion, therefore eliminating the error involved in adding the diversion back to our measurements.
Today we're using the RDI Rio Grande 1200-kilohertz ADCP mounted in the Ocean Science trimaran to make the measurement. You can see we have a permanent tagline installed just below the gage and they're using a radio-controlled cable rover to make the transects. The cable rover works real good. It allows us to maintain a very constant boat speed.
The transects are smooth and steady. We anticipate the station to be 100% hydroacoustic within the next few months. We are confident that the record will be greatly improved.
Title: Hydroacoustics for Collecting Streamflow Data
Description: The USGS Yuma Field Office demonstrates how hydroacoustics are helping them collect accurate streamflow data.
Location: AZ, USA
Date Taken: 3/22/2010
Video Producer: U.S. Geological Survey
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