Hyperspectral image data and field measurements of Rhodamine WT dye concentration were obtained during a tracer study conducted at the Korea Institute of Civil Engineering and Building Technology's River Experiment Center May 17-20, 2017, to support research on dispersion in river channels. The image data included in this data release were acquired using a Nano-Hyperspec (Headwall Photonics, Inc.) mounted on an Aerotestra ATNK09, a small multirotor unmanned aircraft system (UAS). The in situ concentration data were collected using electronic fluorometers (YSI 600-OMS sonde with 6130 Rhodamine WT sensor). Image time stamps were used to link concentration time series recorded by the sondes to specific pixels. The spectra from the locations and times for which image data were available were extracted from the images and used to develop quantitative relationships between concentration and radiance. The image spectra are in radiance units of mWcm-2um-1*sr-1 and the concentrations are in parts per billion (ppb). Two types of image data were collected, one while the platform was hovering to obtain a stationary time series at a single location (i.e., channel cross-section) and the other while the platform was in motion above the experimental channel to construct a spatial image through motion of the aircraft. This data set was used to assess the potential to estimate tracer dye concentrations from remotely sensed data to map contaminants and facilitate dispersion studies.