RDI Rio Grande ADCP

RDI Rio Grande ADCP General Instructions

• The RDI Rio Grande should be used with an aluminum boat mount / hardware due to it's internal compass
• All nuts/bolts etc. should be stainless steel, aluminum, or titanium to minimize interference with the ADCP compass.
• Compass calibration is required each time the ADCP is used at a new location, or has been moved around or placed near ferrous objects that could effect the compass calibration.
• The Rio Grande can be used with a GPS.
• Note, the blanking distance on the Rio Grande is nearly 1 ft.
• ADCP baud rate should be 115K for Rio Grande. A baud rate lower than 38.4 will result in less data collected. The GPS baud rate should bwe 38.4k or higher for a 10 hz update rate GPS, and 19.2K or higher for a 5 hz GPS update rate.
• Winriver II software is used with the Rio Grande to collect discharge data

RDI Rio Grande ADCP Notes

• Secondary depth: Enter a secondary max depth if you have 1 main deep channel but you have alot of shallow areas that need to be measured (and might not be measured if programed for the deeper depth). Enter the max depth of the shallower areas. The problem in this situation is that you will get noisy data in the deeper section because your bins will be too small.
• Bottom Modes: if you select auto, it will use BM5 unless it is shallow as indicated in the secondary depth, then it could use BM7. BM5 cannot profile in less than 2 ft depth, so if you have shallow water, you will need to use BM7. The downside of BM7 is that it pings slowly, so you need to go very slow during the measurement.
• Water Mode: Use mode 12 custom for shallow, fast water. If you pick Auto, winriver will automatically use either WRM12 or 11 based on the depth and speed selected in the wizard. WM12 is a faster ping rate, but the heading, pitch, and roll sensors are only read once at hte beginning of the sampling period, so changes in theses will lead to velocity errors. So the samplin period needs to be short, 1 second or less. If WM12 is selected, you can change the update rate - how often we want ensembles. WM12 auto will optimize bins based upon the depth we entered in the wizard. For WM12 custom, you can set the bin size yourself based on the depths an water speed. Note that as your bin size decreases, the standard deviation (noise) will increase.