Remote Boat Water Depth Calibration - July 2

Current Opened Gates: Automatic for 3.0 ft water depth

Water depth was set 3.0 ft with automatic gate operation and 3.04 ft water depth was shown in the PLC screen at 11:20 am.

During the last weekend (29-June to 1-July), east gates #1~6 were opened to wash sediment deposition on concrete lining front of the intake structure.
East diversion gates were closed, while west side gates were opened for water depth survey.
Approximately 90.2 cm of water depth on the concrete lining was surveyed with a scaled paddle on a kayak. Echo sounder on the remote boat 
was driven to same line of the kayak. As shown in Figure 1, average 83.0 cm of water depth was surveyed with the echo sounder and it is 7.2 cm 
shorter than the ruler surveyed value.  However, the echo sounding transducer is submerged about 8.5 cm under the water surface, when the remote boat is moving. 
Therefore, the difference (7.2 cm) seems a reasonable error (1.3 cm = 0.5 inches). 
For the next calibration, add 7.0 cm of the offset of the echo sounder (Sonarlite). 
   
   Figure 1  Figure 2