Close to Critical Flow

A bathymetry and velocity survey was recently performed of irrigation channel upstream of the gauging weir at Gila Gravity Main Canal. Survey control at the measurement site was established by performing static surveys at two predefined bench marks with Stonex S900A Smart Antenna. The bathymetry and velocity data of the survey area was collected using Hypack with HydroSurveyor and rQPOD. The velocity mapped upstream of gauging weir shows typical velocity distribution when the flow transitions from a shallow to a deeper section in the channel. The shallow section upstream in the channel is the remains of cofferdam that was constructed during the constructions of the gauging weir. The last survey line was performed just upstream of the gauging weir crest, with the increase in velocity depicted in the measurement results.