Data include Rhodamine WT dye concentrations measured every 3 or 10 minutes by means of Turner Designs C-3 and C-6 fluorometers with internal dataloggers at three fixed locations on the Des Plaines River (DPR) (DP-1, DP-2, and DP-3); in three groundwater monitoring wells (ACL-1, WP10-85, and WP9-275); and at two fixed locations on the Chicago Sanitary and Ship Canal (CSSC) (SC-1 and SC-2) (see included Google Earth file AllDeployments_Locations.kmz). The detection limit for these fluorometers is reported to be 0.01 parts per billion (ppb). However, the fluorometer readings were affected by turbidity, and readings of less than about 1.0 part per billion (ppb) were considered to have been influenced by turbidity and variability in background fluorescence rather than indicative of the detection of dye. Measurements began prior to the arrival of dye at all locations (to ensure background concentrations were properly documented) and continued for 3–13 days after tracer injection ceased, depending on the location. Fluorometers were calibrated the day prior to the start of the study by using water from the site where the fluorometer was to be deployed to make the final dilution of the calibration solution. Turbidity sensors were not calibrated and therefore report only relative changes in background turbidity and not absolute turbidity values (all fluorometers either reported relative turbidity values in relative fluorescence units (RFU) or in Nephelometric turbidity units (NTU)). Fluorometers installed in the wells were deployed at the depths of hydraulically active fractures in each well. The fluorometer installed in the CSSC at the bottom of the ACL slip (SC-2) was mounted to a weighted frame and deployed adjacent to the canal wall near a potential hydraulically active fracture on the canal wall. The fluorometer placed upstream in the CSSC (SC-1) was a C-6 fluorometer, and it was deployed at U.S. Geological Survey (USGS) streamgage 05536890 at a depth of approximately 10 feet below the water surface in an attempt to document any dye infiltration upstream of this site. All deployment locations are given in the provided Google Earth KMZ file.