Source: Berkley Design Professional, https://www.berkleydp.com/

Grading for a new road entering private land for a new office building abutting a state highway was determined utilizing a drone survey. The civil-surveyor neglected to field check benchmark elevations from the aerial survey with actual elevations at the interface of the property to the state highway. The new road was constructed according to civil plans which did not properly reflect actual grades of the state road. Significant rework was necessary to correct drainage problems on both the new and existing roadways. Berkley Design Professional paid $250,000 on behalf of the policyholder and $35,000 in defense costs. The policyholder paid a $25,000 deductible.

Lessons learned:

Confirm the accuracy of existing utilities, site setbacks and current or pending improvements to adjacent properties. When using drones or other aerial survey techniques, perform on the ground confirmation of critical spot elevations.