Grand Canyon National Park, Arizona, South Rim Wastewater Dye Trace Results 2023-2024

A dye trace experiment was conducted between March 2023 and September 2024 to understand the connection between treated wastewater effluent discharged to Bright Angel Wash and 13 springs and associated watersheds from Hermit Creek to Pipe Creek along the South Rim of Grand Canyon, Arizona. This data release includes information on the location of the sites (GCSR_Site_Information), time range of charcoal packet deployment and laboratory results of charcoal packets for the dyes added to the wastewater (GCSR_results), and laboratory quality assurance and quality control results (GCSR_Lab_QAQC).

Charcoal packets were deployed under the water surface at the study sites March 28-30, 2023 and retrieved April 18-21, 2023 to assess background fluorescence before the dye was added to Bright Angel Wash. On April 21, 2023, 2 pounds of pre-mixed sulphorhodamineB dye in liquid form were slowly poured into Bright Angel Wash at location 36.038525, -112.162490 at 18:40, and 2 pounds of pre-mixed fluorescein dye in liquid form were slowly poured into Bright Angel Wash at location 36.049659, -112.151647 at 19:25. Charcoal packets were swapped out following the dye addition at the intervals listed in the GCSR_results file associated with this data release. At some sites, additional packets were deployed at different intervals and these results are presented in the GCSR_Non_Standard_Sites_and_Intervals file.