UF/IFAS Mako sUAS
Indian Prairie Canal/Fisheating Bay
5-cm pre-treatment orthomosaic and post-treatment orthomosaic acquired 6 weeks later
As part of an ongoing USACE invasive aquatic species management program on Lake Okeechobee, numerous mapping flights were made pre- and post-treatment to assess the effectiveness of their species-targeted herbicide treatments. Target species include luziola (Luziola subintegra), water hyacinth (Eichhornia crassipes), and water lettuce (Pistia stratiotes). Continued monitoring flights are ongoing to evaluate long term treatment effects on native plant communities.
In addition to developing operational procedures to effectively monitor environmental changes over time, the Lake Okeechobee missions have also proven valuable in establishing real-world timelines for acquiring and processing UAS-derived geospatial products. This information is now used by UF and USACE project managers to more efficiently plan monitoring programs with realistic estimates instead of lofty academic projections.
Finally, supervised classification techniques were performed on the imagery sets to automatically identify and quantify relative abundances of invasive and indigenous plant species.
Classified pre-treatment orthomosaic
Loxahatchee
2.5-cm orthomosaic of bird islands in Loxahatchee NWR
Managed by the US Fish and Wildlife Service, the Arthur R. Marshall Loxahatchee National Wildlife Refuge is the home to numerous colonies of wading birds and other wildlife. The research focus in this area is on mapping the geographic extent of individual bird islands, automatically determining colony populations, and precisely locating and monitoring individual nesting sites during and across nesting seasons. The high positional accuracy and optical resolution afforded by the Mako sUAS allows biologists to not only identify multiple species from aerial images, but to count individual eggs within each nest site.
L-6 Levee
Google Earth plot showing 2 executed flight paths along the levee path
The USACE-administered L-6 levee project in South Florida was flown as an investigation into optimal flight planning for mapping long, linear features as would be typical for many infrastructure monitoring applications. During these flights, trials were conducted determining flight timing to minimize surface glare on open water, evaluating the effectiveness of a mobile ground station for continuous operation within FAA-mandated visual line-of-sight minimums, and determining minimum required optical resolution/flight altitudes for accurate infrastructure condition assessment.
Picayune Strand
(Clockwise from top left) Road degradation, pump station construction, and invasive vegetation imagery collected over Picayune Strand
Part of the Comprehensive Everglades Restoration Plan (CERP), Picayune Strand is the site of USACE efforts to restore sheet flow to an area previously drained by canals and prepared for housing development in the 1960s. In anticipation of the restored flow and the subsequent change in habitat type, the Corps is also engaged in removing invasive and historically non-native species, including Brazilian pepper (Schinus terebinthifolius) and cabbage palm (Sabal palmetto).
Monitoring flights are engaged in pre-, during, and post-degradation assessments of sample vegetation plots as well as along roads and canals as they are degraded to their historical state. Due to the variety of ground targets and applications for aerial imagery, Picayune Strand has been an ideal proving ground for data collection assessments including geometric resolution, color infrared (CIR) vegetation classification, and flight path efficiency evaluations.
Additional flights were undertaken to monitor the ongoing status of road degradation work as well as construction on a flow control pump station.
Lightning Lab
120m x 60m grid of aerial calibration targets
To assist in sensor and payload calibration and benchmarking, a precisely surveyed grid of 32 aerial targets was established at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida. This site is ideal for evaluating potential and existing payloads and provides a very accurate assessment of both optical (geometric) and navigational (position and orientation) fidelity for determining appropriate system parameters for photogrammetric post-processing.
Herbert Hoover Dike
3D terrain model of levee with projected mosaic
The 143-mile-long USACE-administered Herbert Hoover dike around Lake Okeechobee has been an ideal location for developing effective flight planning methods to provide accurate three-dimensional topographic models of linear terrain features. Similar to work done on the L-6 levee, the Herbert Hoover Dike monitoring flights were useful in evaluating stereographic flight planning techniques and determining optical resolution requirements for infrastructure monitoring. The program is currently completing a mission to detect/measure physical characteristics indicative of leaks, seeps, and boils in dikes and levees.
Levee monitoring is currently supported by visual inspections performed by field personnel. The UAV will augment these efforts by providing a permanent record of the levee's condition in unprecedented resolution. The data can also be photogrammetrically processed to produce a 3D geospatial model of the levee and seamless orthomosaic views. This comprehensive data set directly impacts the decision making process by providing crucial information that can be continuously evaluated as conditions change. New analysis can be performed on demand, above and beyond the work performed by field personnel during the initial inspection. Utilizing this imagery, the Corps of Engineers can increase the effectiveness of its monitoring efforts. These deliverables will prove to be an important contribution to the long-term infrastructure monitoring efforts performed throughout the Corps.