These data were collected in support of a multi-agency effort to evaluate the feasibility of using carbon dioxide to create a barrier and prevent upstream passage of invasive fish through navigational locks. The auxiliary lock at Lock and Dam 14 on the Mississippi River near Pleasant Valley, Iowa, was chosen for a field-scale trial of the carbon dioxide barrier to be conducted in 2018. In preparation for this trial, the mixing in the lock chamber during routine operations and the fate and transport of lock water released to the pool downstream was studied using a dye tracer. In June 2017, the U.S. Geological Survey (USGS) performed two injections of Rhodamine WT dye into the auxiliary lock chamber as the lock was filled. The dye was injected directly into the fill water at the upstream valves on both sides of the lock. The first injection of 0.82 liters of Rhodamine WT (0.41 liters per intake) occurred at 9:50 am on June 13, 2017. The second injection of 0.25 liters of Rhodamine WT (0.125 liters per intake) occurred at 12:11 pm on June 13, 2017. Both injections started approximately 1 minute after filling of the lock began and the injections took approximately 2 minutes to complete. The total time to fill the auxiliary lock in both cases was 6 minutes. All times are in Central Daylight Time (CDT). The distribution of dye within the lock chamber and downstream of the lock was measured using eight Turner Designs C3 submersible fluorometers (1 in vertical profiling mode in the lock chamber, 6 at fixed locations downstream of the lock, and 1 mounted on a mobile survey vessel).
This data release is comprised of a time series of dye concentration measured by a mobile survey vessel that mapped the dye plume downstream of the auxiliary lock chamber at Lock and Dam 14 on the Mississippi River near Pleasant Valley, Iowa, on June 13, 2017 and June 14, 2017. The measurements were obtained using a Turner Designs C3 submersible fluorormeter (SN 2300150) mounted on the mobile survey vessel at a fixed depth of approximately 0.5 meters below the water surface. All parameters (dye concentration, turbidity, and temperature) were sampled at 1-second intervals. These data were georeferenced using a time-synced Global Positioning System (GPS) receiver with sub-meter accuracy mounted on a mast above the instrument.