Mapping Groundwater Flow in Riparian Ecosystems Through Thermal and Multispectral UAV Surveys of Surface Water and Vegetation
Presentation Type
Oral Presentation
Category
STEM (science, technology, engineering, mathematics)
Abstract/Artist Statement
Climate change and anthropogenic water demand heighten the need for accurate and efficient groundwater mapping and for understanding relationships between groundwater and ecosystems. To interpret the relationship between groundwater flow in an alluvial aquifer and vegetation development, and specifically whether vegetation distribution patterns can be used to discern areas of groundwater inputs or localized variations in the vertical hydraulic gradient of the aquifer, we are developing a method using UAV surveys and remote sensing. We surveyed the Nyack reach of the Middle Fork Flathead River, a gravel-bed, multi-thread system with active surface water-ground water exchange, using a fixed-wing UAV with thermal, visible light, and multispectral camera, in summer 2020 and spring 2021, complemented by water depth and temperature logging along the length of the reach. Vegetation features and extent within the floodplain are classified according to multispectral signatures from the UAV surveys.
To detect the thermal signature of groundwater upwelling into surface water, based on groundwater’s stable temperature compared to surface water’s daily and seasonal fluctuations, we combined the summer water-temperature time series with reach-scale thermal and visible light maps created during a single August day. We modeled bed topography using the Optical River Bathymetry Toolkit (ORByT). This model showed that the flow depth ranged from 0.05m to 4.5m during baseflow. When compared to thermal maps, deeper water was cooler than shallow water, providing a baseline to locate cool groundwater inputs in shallow water.
To create a more complete picture of interactions between vegetation, groundwater, and surface water, we use spatial inference methods to identify patterns in vegetation distribution that are correlated to groundwater upwelling identified through the combined spatially discrete, season-long surface-water temperature time series and temporally discrete but spatially continuous temperature and vegetation data from UAV surveys. Preliminary results indicate that UAV surveys can be a useful tool in groundwater mapping in mountainous alluvial systems and can streamline the field-data collection required to make informed decisions about river system management.
Mentor Name
Andrew Wilcox
Mapping Groundwater Flow in Riparian Ecosystems Through Thermal and Multispectral UAV Surveys of Surface Water and Vegetation
UC 326
Climate change and anthropogenic water demand heighten the need for accurate and efficient groundwater mapping and for understanding relationships between groundwater and ecosystems. To interpret the relationship between groundwater flow in an alluvial aquifer and vegetation development, and specifically whether vegetation distribution patterns can be used to discern areas of groundwater inputs or localized variations in the vertical hydraulic gradient of the aquifer, we are developing a method using UAV surveys and remote sensing. We surveyed the Nyack reach of the Middle Fork Flathead River, a gravel-bed, multi-thread system with active surface water-ground water exchange, using a fixed-wing UAV with thermal, visible light, and multispectral camera, in summer 2020 and spring 2021, complemented by water depth and temperature logging along the length of the reach. Vegetation features and extent within the floodplain are classified according to multispectral signatures from the UAV surveys.
To detect the thermal signature of groundwater upwelling into surface water, based on groundwater’s stable temperature compared to surface water’s daily and seasonal fluctuations, we combined the summer water-temperature time series with reach-scale thermal and visible light maps created during a single August day. We modeled bed topography using the Optical River Bathymetry Toolkit (ORByT). This model showed that the flow depth ranged from 0.05m to 4.5m during baseflow. When compared to thermal maps, deeper water was cooler than shallow water, providing a baseline to locate cool groundwater inputs in shallow water.
To create a more complete picture of interactions between vegetation, groundwater, and surface water, we use spatial inference methods to identify patterns in vegetation distribution that are correlated to groundwater upwelling identified through the combined spatially discrete, season-long surface-water temperature time series and temporally discrete but spatially continuous temperature and vegetation data from UAV surveys. Preliminary results indicate that UAV surveys can be a useful tool in groundwater mapping in mountainous alluvial systems and can streamline the field-data collection required to make informed decisions about river system management.