TWM was contracted to provide a topographical survey for design engineering of approximately 3,500 linear feet of storm sewers under an urban roadway in St. Charles, MO. Mobile LiDAR was chosen as the primary data collection method to provide an efficient deliverable given the complexity of the project at hand. A dense point cloud of over a half billion points make up the project area. Semi-automatic breakline extraction, point gridding, and feature extraction were some tools used to complete this survey. Deliverable was Civil3D dwg file to be used by engineering. Design engineering is underway to modernize the storm sewer system to mitigate frequent flooding.