Thermal infrared images of groundwater discharge zones in the Farmington and Housatonic River watersheds (Connecticut and Massachusetts, 2019)(ver. 3.0, January 2023)

Locations of focused (or ‘preferential’) groundwater discharge to surface water are often hydrologically and ecologically important, yet our ability to predict the spatial distribution and water quality of preferential riverbank discharges is limited at the scale of river networks. To advance the understanding of the physical controls on riverbank groundwater discharge processes, discharge zones can be mapped efficiently using handheld and drone-based thermal infrared cameras. Groundwater discharge locations can be identified based on ‘anomalous’ thermal signatures, such as relatively cold riverbank zones in summer and warm riverbank zones in winter. Thermal infrared imaging can be combined with concurrent direct riverbank measurements to identify discharge zones with confidence and to evaluate local sediment properties, groundwater flux rates, and discharge water quality. The ground- and watercraft-based river data contained in this data release were collected from June through October during 2019, 2020, and 2021 to characterize the spatial distribution of riverbank groundwater discharges along river reaches within the Farmington and Housatonic River Watersheds. This data release contains GPS locations of mapped riverbank discharge zones, thermal infrared and visible-light image data, and direct riverbank measurements. This data release also contains bank soil parameters, temperature, and discharge water dissolved oxygen concentrations at a subset of groundwater discharges. This release also contains drone-based thermal infrared data collected over a wetland site in western Connecticut on 04/04/2019, and over a reach of the Farmington River in Farmington, Connecticut on 02/22/2019. These drone-based thermal image data should be interpreted as 'apparent'; potentially useful for qualitatively showing thermal contrast and anomalies but are not suited for more quantitative purposes without additional post-calibration steps. This updated dataset contains 12 main files: 1) SalmonBrook_FLIR.zip is a zipped directory containing thermal infrared and real color images collected by handheld cameras along Salmon Brook, a third-order stream located in the Farmington River Watershed. 2) SalmonBrook_Image_Details.csv contains attribute information for each thermal image in the Salmon Brook dataset that pertains to a mapped streambank preferential groundwater discharge locations. TIR image names and numbers are related to images in the SalmonBrook_FLIR.zip folder. 3) PDP_Images.zip is zipped directory containing thermal infrared and real color images collected along reaches of the mainstem Farmington and Housatonic Rivers. 4) PDP_2021_Main.csv contains attribute information for each thermal image and mapped riverbank preferential groundwater discharge location along the Farmington and Housatonic Rivers. 5) FldMsrmnts_11032021.csv contains attribute information of water and sediment characteristics at a subset of mapped riverbank groundwater discharge locations along the Farmington River. 6) FarmSN_PDPs.csv contains attribute information for characterizing lateral extent of groundwater discharges mapped along the Farmington River, along with bank locations were discharge zones were not identified at 1-m nominal resolution. 7) Hous_PDPs.csv contains attribute information for characterizing lateral extent of groundwater discharges mapped along the Housatonic River, along with bank locations were discharge zones were not identified at 1-m nominal resolution. 8) raw_drone_IR is a zipped directory of uncalibrated thermal infrared data collected via drone at two sites. 9) processed_drone_IR is a zipped directory of processed (apparent) thermal infrared orthomosaic images. 10) bank_discharge_locations_Farmington_TIR_2019_2021.shp is an ESRI shapefile of the groundwater discharge locations derived from the river field surveys for demonstration purposes. This shapefile indicates the lateral riverbank extent of mapped discharge zones along the Farmington and Housatonic River reaches at the 1-m nominal resolution, but only notes the occurrence of a mapped discharge zone along the Salmon Brook reach, and does not indicate lateral extent along that reach. Locations of TIR images at sampled groundwater discharges related to Farmington_2019_2021_TIR_RC_Images were merged to the attribute table. Files associated with this shapefile include: the shapefile bank_discharge_locations_Farmington_TIR_2019_2021.shp, database file bank_discharge_locations_Farmington_TIR_2019_2021.dbf, the projection bank_discharge_locations_Farmington_TIR_2019_2021.prj, and the geodatabse file bank_discharge_locations_Farmington_TIR_2019_2021.shx. 11) Farmington_2019_2021_TIR_RC_Images.zip is folder the contains 3 sub folders for each TIR camera (FLIR_A, FLIR_B, FLIR_540). Each folder contains TIR and real-color images of groundwater discharges along reaches of river throughout the Farmington River Watershed. Camera information is described in the Methods section. 12) Farmington_2019_2021_TIR_Image_Details.csv is a comma-separated data file containing lat/lon coordinates, direct temperature measurements (deg C), and TIR image number of groundwater discharges throughout the Farmington River Watershed. TIR image number corresponds to TIR images in Farmington_2019_2021_TIR_RC_Images.zip