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  California Water Science Center

Prototype River Equipment


All surveys begin with a reference point. Any stream gager knows how cableways swing, sag, and sway, especially when the cablecar is attached to a lead weight swimming in flood water. Although the movement is tolerable for approximate depth measurements and average velocity, the movement biases readings from accurate sensors. To obtain a steady reference point, one can abandon cable suspension in favor of a semi-rigid boom and vertical support-pipe system.

Vertical support-pipe system 83 Kb .jpg

The shore-mounted aluminum boom pivots in vertical and horizontal axes. Velocity meters and sonar transducers are mounted at the bottom of the vertical-support pipe. Relative elevation is determined by level sight to the staff plate on the boom.

Velocity meters19 Kb .gif

This sketch describes velocity meters and sonar transducers mounted on the vertical-support pipe.

Velocity meters

Taken from a video source, this image shows three velocity meters mounted on a fiberglass frame and attached to a steel vertical-support pipe. A sonar transducer is connected to the bottom of the pipe.

black boxes for velocity measurements

Two of the black boxes for velocity measurements are shown inside a gage house. The meters are connected to the boxes by cable longer than 100 feet. Output from the boxes is acquired to a personal computer with a standard data-acquisition program.

pressure-differential bedload samplers 83 Kb .jpg

Wide-mouth, pressure-differential bedload samplers have been developed by Dallas Childers, USGS, to accommodate gravel bedload. The opening on this model is 6 x 12 inches.

Suspended Platform 83 Kb .jpg

A platform suspended over the river allows bedload samples to be collected adjacent to the mobile sonar track. Three pipes in the water have sonar transducers for longitudinal profiles or for stationary monitoring of bedforms.

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Page Last Modified: Wednesday, 05-Oct-2011 15:16:12 EDT