Investigator: Greg Desmond Scope of Work

Summary

The objective of this project is to conduct a topographic survey of Water Conservation Area 2 (WCA-2).

The USGS-developed Airborne Height Finder (AHF) instrument will be used to collect elevation data points approximately every 400 meters in a grid pattern covering WCA-2. This system utilizes Global Positioning System to accurately position the hovering helicopter relative to reference base stations. The operator then mechanically deploys a plumb bob to the terrain surface and measures the distance between the ground and helicopter platform. The plumb bob is reeled in after the measurement is made and reset. The helicopter continues along each transect repeating the process to measure an elevation point every 400 meters. These data are then processed to calculate elevation values for each point measured and are referenced to the North American Vertical Datum (NADVD88). It is important to note that the AHF system does not perform bathymetric surveys, so large extents of open water are excluded from using this method.

Scope of Work

• 2003