As requested, our hydrologists Stan Leake, Jesse Dickinson, Don Pool, and Nick Paretti have conducted a technical review of Pima County report "Impacts of the Rosemont Mine on Hydrology and Threatened and Endangered Species of the Cienega Creek Natural Preserve" by Powell et al. The report documents an analysis of the potential impacts of the Rosemont mine on the hydrology of lower Cienega Creek and Davidson Canyon. The potential impacts described in the report are changes in base flow and length of wetted stream length. The approach used to assess the impacts include regression models with groundwater level as the explanatory variable and base flow and wetted length as response variables. Base flow and wetted length changes are predicted from the regression models for potential drawdowns of -0.1, -0.2, and -0.25 at Cienega well and potential drawdowns of -0.1, -0.2, -0.25, -0.31, and -0.98 at Davidson #2 well.
U.S. Geological Survey. 2014d. Technical Review of Pima County report "Impacts of the Rosemont Mine on Hydrology and Threatened and Endangered Species of the Cienega Creek Natural Preserve". In Letter from James Leenhouts, Director, USGS Arizona Water Science Center, to Jim Upchurch, Forest Supervisor, Coronado National Forest. Tucson, Arizona: U.S. Geological Survey. September 30.