Drone technology is changing the way the world does business.
U.S. Army Corps of Engineers (USACE) team members are using new tools to complete mission essential tasks like mapping, surveying, and construction and infrastructure inspections.
The Galveston District’s (SWG) Advanced Data Section is now utilizing Unmanned Aircraft Systems (UAS) and Unmanned Survey Vessels (USV) to deliver innovative solutions in data collection and analysis for projects, according to Heng-Wei (David) Tsai, P.E., Advanced Data Section chief.
“The team excels in developing and imparting workflow expertise, ensuring staff is proficient in deriving systematically derived products from diverse data sources,” Heng-Wei said. “Our strategic planning involves long-range plans and programs, encompassing large-scale surveys and innovative data gathering techniques.”
The Advanced Data Section is eager to share its data collection services with the district, Tsai said.
“Collaboration is key to our success, as we work closely with internal district representatives and private industries to develop long-range survey acquisition plans and strategic frameworks for UAS, topographic, and shallow water hydrographic practices within the district boundary,” Tsai said.
The Advanced Data Section is dedicated to pushing the boundaries of remote sensing methodologies and delivering impactful, forward-thinking solutions, Tsai said.
One of the Advanced Data Section’s latest surveys took place on the Trinity River, upriver from the Wallisville Lake Project office, Nov. 14 through16, 2023. Team members surveyed the area to provide engineers information about the river for use in an erosion mitigation project.
“We’re out here with what we call the Z-boat, which is a remote hydrographic survey vessel – that’s just a lot of words to say that it’s a drone that’s also a boat,” said Rebecca Capps, Advanced Data Section physical scientist and drone operator.
Capps and her coworker Roger Stillick worked as a team to measure depths on the small section of the Trinity River. Stillick drove the Z-boat and Capps monitored data collection on a connected laptop.
“We’re collecting single beam sonar (and) we’re getting depths from the water bottom,” Capps said. "We’re actually able to do that with two different frequencies; we have a low and a high frequency.”
High frequency sonar measures depths down to the top of the mud layer and low frequency sonar penetrates through mud and to true bottom, Capps said.
The Z-boat is a great tool for shallow water and hard-to-reach projects, Capps said.
“The Z boat is really the tool of choice … for ponds or really any sort of small, contained water body as well,” Capps said. “Up against docks or harbors as well, would be a good place for a Z boat survey.”
Stillick has been a survey technician with USACE since 2017, with one year in Galveston and the rest in the Portland District (NWP).
The Z boat is useful for surveying placement areas when they are flooded, which prevents an effective aerial survey, Stillick said.
“Sometimes it will rain, and the placement area will get flooded, and sometimes when they’re placing dredge material, it will have water in it,” Stillick said.
After surveying with the Z boat at the Trinity River site, Capps then piloted an aerial drone, a Skydio X2D quadcopter, over the site to gather photogrammetry – three-dimensional photography – of the area.
The Advanced Data Section can then combine the bathymetry from the Z-boat’s sonar system with the topographic data from the photogrammetry flight into one seamless model of the job site.
For jobs in tighter and congested project sites that don’t allow a fixed-wing aircraft, the district utilizes the Skydio X2D quadcopter which can take-off and land vertically, is capable of photogrammetry and has a 30-minute flight time, Capps said.
For larger job sites, the Advanced Data Section will deploy the Sensefly eBee TAC.
“We have the SenseFly eBee TAC, that’s a fixed-wing drone,” Capps said. “It looks like an oversized model airplane.”
The TAC is valued for its 90-minute flight duration, 20 megapixel camera and lightweight design, Capps added.
The Skydio and TAC’s cameras take hundreds to thousands of overlapping pictures which team members run through software to make 3D reconstructions of the existing site conditions, with elevation values, Capps said.
The collected data will be provided to other sections responsible for engineering and drafting to update as-built schematics and other design requirements for the project, Tsai said.