On October 20-21, 2015, the U.S. Geological Survey conducted a dye study on the Des Plaines River at Brandon Road Lock and Dam (BRLD) near Rockdale, Illinois. The purpose of this dye study was to assess the mixing, advection, and dispersion of dye within the BRLD lock chamber and in the approach channel downstream. These data will inform designs of potential strategies for preventing upstream transport of invasive Asian carp through the BRLD. Dye was injected into the intakes for the lock chamber at the start of the filling process. The dye was injected through grates atop the intake channels on both sides of the lock. Injection began at 10:24 on October 20, 2015, and ended at 10:30 on October 20, 2015. A total of 4 liters of Rhodamine WT in a 20 percent solution was injected (2 liters on each side of the lock). The target dye concentration in the lock chamber was 9 parts per billion (ppb). Following filling of the lock, the lock was emptied, releasing the dyed lock water downstream. In addition, a 17-minute flushing operation was performed by the U.S. Army Corp of Engineers to assess lock flushing efficiency. Submersible fluorometers were used to measure dye concentrations in the lock chamber and downstream of the lock in the approach channel throughout this process. Fluorometers were deployed at five fixed locations downstream of the lock and two additional fluorometers were mounted to two mobile survey vessels that surveyed the dye plume exiting the lock chamber. Within the lock chamber, vertical profiles of dye concentration were measured at 15 fixed stations.
Key operation changes occurred at the following times: 10/20/2015 10:22 (start filling the lock chamber); 10/20/2015 10:43 (end filling the chamber); 10/20/2015 12:26 (start emptying lock chamber); 10/20/2015 12:43 (lock chamber empty, downstream gates remain closed); 10/20/2015 14:00 (downstream valves opened to drain leakage into lock chamber); 10/20/2015 14:08(downstream gates opened); 10/20/2015 14:15 (lock chamber flushing procedure started; 1/4 opening of upstream valves); 10/20/2015 14:32 (flushing procedure ended); 10/20/2015 15:32 (begin filling lock chamber); 10/20/2015 15:49 (begin emptying of partially filled lock chamber); 10/20/2015 16:00 (Lock reopened to normal navigational traffic). All times are in Central Daylight Time.