Best way to create surfaces?

JeremyMurfitt

Hi

I am new to Global Mapper but with 20+ years of GIS experience. I am also a drone operator. I have surveyed (used ground controls  so accurate) a reservoir and from that using the Liddar Module have created a point cloud/DSM/ortho + contours. The reservoir is about 50% full. My task is to calculate the volume of the reservoir for given water levels. Unfortunately they didn't survey the reservoir when built so I am creating a model. I know the floor level. From the data I know the average grade of the inner banks above the current water level. I understand that the banks were a even grade to the base.

What would be the easiest way to extend the slopes down to the floor level?  I was thinking of using something like copy parellel and extend the contours down until they meet the base. Once that is down I can create a new DSM and thereafter do a volume calculation for varying water depths.

Any advice would be greatly appreciated.

Jeremy