Devastating erosion caused by western wildfires across 160,000 acres led to the current project for Albuquerque District’s Hydrologic Engineer Stephen Brown, now collaborating at the Engineer and Research Center’s Coastal and Hydraulics Laboratory (CHL) in the ERDC University pilot program.
This pilot initiative is sponsored by ERDC’s Directorate of Human Capital and the Office of Research and Technology Transfer (ORTT) as an opportunity for Engineer Research and Development Center (ERDC) subject matter experts and district selectees to partner on applying and implementing technical solutions.
Chosen as one of eight district and division researchers for the inaugural class of ERDC University, Brown joins CHL’s Researchers Mike Follum and Ian Floyd for a six-month project creating a Gridded Surface Subsurface Hydrologic Analysis simulation for the Las Conchas wildfire region in northern New Mexico, with widespread future application opportunities.
Brown applied for ERDC University to deepen his hydrology and numeric modeling skills and was paired with CHL researches in his major area of interest. “My branch chief was supportive knowing that I would be returning to Albuquerque with additional knowledge and tools to solve district problems,” Brown said.
Brown shares his goals as an ERDC University student to “become more fluid in fundamental hydrology and increase capabilities in numeric modeling and Python programming.”
CHL’s Follum and Floyd will join Brown in New Mexico in October to conduct field investigations of debris flows and geomorphology evolution resulting from the Las Conchas wildfire. The field work will collect critical physical data for numeric model validation.
Enhanced data collection
The team will be exploiting novel uses of off-the-shelf technologies to affordably collect data that would be difficult or impossible to capture using traditional methods. Detailed 3-D topographies will provide snapshots in time for HEC-RAS and AdH model validation.
Within the past year, Brown led the development of a prototype stream gage and worked on multiple aspects of post wildfire flood analysis and protection measures. This gage will provide autonomous discharge calculation in mobile bed systems supplying critical data for improving hydrologic, hydraulic and sediment model accuracy. These improvements will aid in flood forecasting for emergency operations and protection of critical infrastructure.
Partnering with the Civil Air Patrol (CAP), Bureau of Land Management and University of New Mexico, a photogrammetric sensor array was assembled and installed on one of CAPs aircraft. The system will collect high resolution orthophotos and generate 3-D point clouds via post processing. Data collected by this piloted aircraft will further enhance numeric model validation by allowing affordable high frequency flights after flood events.
Key model parameters can be extracted from robust gage networks and photogrammetric surveys before and after flood events, including channel geometry changes, velocities along cross sections and vegetation influences on roughness in channels, as well as overbank and hydrologic lag time.
Assisting USACE engineers
Floyd related that the 2011 Las Conchas wildfire in northern New Mexico was the largest in the state’s history. “It was equivalent to dropping an atomic bomb into a natural system. The forest has experienced full crown burn, killing most of the mixed conifer. A deciduous regime is taking its place dramatically altering the hydrologic, hydraulic and sediment balance of the system.”
“It is a challenge to monitor sub-basin forest health in remote and steep watersheds, specifically slope stability and hydrologic infiltration of top soil. Conducting periodic sediment and reach scale surveys of main channels and high flow tributaries will provide critical data for model validation,” said Brown.
The GSSHA model Brown is creating as part of ERDC U will allow the Albuquerque District to better quantify dynamic post wildfire environments. “This numeric modeling will allow a greater depth of understanding of the Rio Grande watershed and wildfire impacts to infrastructure,” Brown said of the project supported by federal, regional and local agencies as well as multiple tribal nations.
Linking GSSHA and AdH will paint a detailed picture of sediment transport dynamics. “An important deliverable for USACE will be sediment bulking probability curves to assist basin managers with operations and management decisions. Creating quantitative sediment transport recurrence probabilities will help USACE engineers estimate life expectancy of reservoirs with heavy sediment loading and can assist with dredging operations and management planning,” Floyd said, adding that he was looking forward to working with Albuquerque District to address pressing sedimentation and infrastructure concerns.
Future plans for ERDC U
In his briefing to the university selectees, ERDC Director Dr. Jeffery Holland shared goals for the program expansion to 20 participants in FY17, as opportunities increase for USACE and ERDC engineers and scientists to collaborate and partner on developing technical solutions.
Antisa Webb, ORTT chief of technology advancement and ERDC U facilitator, said “Participants serve as a member of the interdisciplinary research and development team reporting to lead project managers and/or research and development direct program managers. The incumbent supports, and possibly leads, any number of activities to develop R&D technologies related to solutions in support of multiple Corps business line areas.”
“This is an exciting opportunity for the incumbent to help shape the future of the Corps’ technical knowledge-base. It is also an opportunity to become a leader in scientific and engineering technical areas to be applied in the incumbents’ home organization while building a collaborative partnership with ERDC, and is considered an investment in the future of the Corps,” Webb said.