Pima County Regional Flood Control District
Riverbed Maintenance and Restoration using Drones
The Pima County Regional Flood Control District is committed to riverbed maintenance and restoration for the Santa Cruz River. During the latest debris removal effort, the county had to recompact the river bed, causing the need for a new topographic map to verify the existing grades.
Due to the remoteness of the project and its size, drones were used for the survey. Flying at an altitude of 250 ft, the Psomas pilot gathered overlapped orthographic imagery using the drone equipped high-resolution digital camera. Once the individual images were taken of the entire site, advanced computer software was used to stitch them together (with a pixel resolution of under two inches) to produce a single aerial image and topographic map.
Psomas provided ortho-rectified aerial imagery, a digital terrain model, and topographic map with one-foot contours. This product was used to verify the recompacted fill and for the maintenance of the natural drainage of the Santa Cruz River and contributing streams. Flood control surveying and mapping was needed to support certification of soil restoration and drainage improvements.