McKay’s Point Reservoir Sedimentation Rate Study
cbec was contracted by NCPA to perform a Sedimentation Rate Study at McKay’s Point Reservoir.
cbec performed a bathymetric survey to document existing conditions in October 2011 and developed a set of plan drawings. The existing conditions data was compared to previous bathymetric surveys performed in 1997, 2000, and 2005, and used to characterize sedimentation rates of the reservoir. Stage versus storage volume relationships were developed.
The bathymetric survey of McKay’s Point Reservoir was performed by a 2‐person crew, aboard a 14‐foot aluminum survey boat over the course of 3 days, from October 11‐13, 2011. The survey boat was equipped with an Ohmex Sonarmite single beam echo sounder, which measured the distance from its mounting position on the stern of the survey boat to the bottom of the reservoir. The echo sounder was integrated with a Trimble R8 GNSS RTK GPS receiver that recorded the horizontal and vertical position of the echo sounder unit as it recorded depth measurements. To improve measurement accuracy, a static base station was established on the top of the dam for use as a reference station for the roving Trimble GPS unit aboard the survey boat. A Trimble TSC2 Data collector with Survey Controller was used to synthesize the measurements from the GPS unit, the echo sounder, and a static vertical offset between the two into one data point for each bathymetric sample.