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ERDC researchers developing low-cost, rapid watershed assessment

Shea Hammond, a member of the U.S. Army Engineer Research and Development Center (ERDC) Environmental Laboratory’s (EL) Unmanned Aerial Systems (UAS) team, monitors a Light Detection and Ranging (LiDAR) data-collecting aircraft as it begins its survey of a section of the Bayou Pierre watershed near Vicksburg, Mississippi. Researchers from the ERDC’s Coastal and Hydraulics Laboratory recently collaborated with the EL UAS team for a project to develop a rapid watershed assessment approach using the remote sensing technology.

Shea Hammond, a member of the U.S. Army Engineer Research and Development Center (ERDC) Environmental Laboratory’s (EL) Unmanned Aerial Systems (UAS) team, monitors a Light Detection and Ranging (LiDAR) data-collecting aircraft as it begins its survey of a section of the Bayou Pierre watershed near Vicksburg, Mississippi. Researchers from the ERDC’s Coastal and Hydraulics Laboratory recently collaborated with the EL UAS team for a project to develop a rapid watershed assessment approach using the remote sensing technology.

Kenneth Matheson, a member of the U.S. Army Engineer Research and Development Center (ERDC) Environmental Laboratory’s Unmanned Aerial Systems (UAS) team, prepares a flight plan for a UAS data collection mission over a section of the Bayou Pierre watershed near Vicksburg, Mississippi. Researchers at the ERDC are currently developing a rapid watershed assessment approach using the remote sensing technology, and plan to compare the newly collected Light Detection and Ranging (LiDAR) data against existing LiDAR data to determine if any changes have occurred along the channel.

Kenneth Matheson, a member of the U.S. Army Engineer Research and Development Center (ERDC) Environmental Laboratory’s Unmanned Aerial Systems (UAS) team, prepares a flight plan for a UAS data collection mission over a section of the Bayou Pierre watershed near Vicksburg, Mississippi. Researchers at the ERDC are currently developing a rapid watershed assessment approach using the remote sensing technology, and plan to compare the newly collected Light Detection and Ranging (LiDAR) data against existing LiDAR data to determine if any changes have occurred along the channel.

VICKSBURG, Miss. (August 10, 2020) – Researchers from the U.S. Army Engineer Research and Development Center (ERDC) have partnered with the U.S. Army Corps of Engineers (USACE) Vicksburg District to develop and test a low-cost, rapid watershed assessment using remote sensing technology to evaluate problems associated with watershed instability including erosion, sedimentation, flooding and environmental degradation.

The project, which leverages existing data and resources, takes Light Detection and Ranging (LiDAR) data collected from previous field studies and compares it to new LiDAR data that has been collected using unmanned aerial systems, or UAS.

“We’re going to use drone-derived LiDAR that the UAS team from the ERDC Environmental Laboratory (EL) collected to compare against the existing LiDAR data to see if there have been significant channel changes within watersheds,” said Dr. Christopher Haring, a research physical scientist with the ERDC Coastal and Hydraulics Laboratory. “It’s very typical to complete a geomorphic assessment using terrain data based on real x, y, z coordinates.”

During the past month, the EL UAS team flew LiDAR-collecting aircraft over three different watershed areas in Mississippi, including sections of the Big Black River, Clear Creek and Bayou Pierre.

“We know there’s channel degradation and bank migration, so we’re going to use this new LiDAR data to compare against the existing LiDAR data from 2012 or 2106 to see what changes have occurred since,” said Haring. “We can identify channel degradation and see how far that channel degradation has progressed upstream by looking at the LiDAR water surface profile or in some cases channel bottom grade if there is little or no water present during LiDAR collection.”

Although LiDAR has its limitations with vegetation and obstructions, Haring said accuracy hasn’t been an issue. “The technology is getting so good that there are ways the LiDAR sensors can shoot through some of the vegetation openings and get at ground surface elevations,” he said. “The technology is starting to rapidly move forward, especially with the ability of the UAS system to collect data.”

Haring says this type of rapid assessment capability can reduce time and cost. “A typical stream channel survey would take a field crew several days to complete, comparative to a UAS survey with LiDAR that takes two or three hours,” he said.

“From a cost perspective, we’re looking at trying to develop methodologies that are more cost effective and more time sensitive, so that you can collect data very quickly and potentially at a lower cost,” he continued. “Indications are — at least at this point — as the technology keeps developing, the drone with LiDAR footage collection will outpace traditional survey opportunities with a field survey crew.” 

Funding for the project was provided by the Regional Sediment Management (RSM) Program. RSM provides both coastal and inland funding for research and development purposes to address sediment issues and support sustainable solutions to meet the needs across USACE missions, including navigation and dredging, coastal and flood risk management and ecosystem restoration, while also supporting emergency management operations.

“I think this really is going to be the way forward in completing geomorphic assessments,” said Haring. “Streams are not static and are ever changing, so another advantage associated with the drone capability and LiDAR survey is you could actually go out the week of construction and update your construction plans based on new LiDAR data collection.”

“I think that LiDAR data has been underutilized in the past, and that there’s a lot more uses from a geomorphic analysis perspective using LiDAR than past research has provided,” he said. “That’s where this technology is going to really help out. I think the EL UAS team is going to get a lot busier with this type of work.”