Toxic Substances Hydrology Program
U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting Charleston South Carolina March 8-12,1999--Volume 1 of 3--Contamination From Hard-Rock Mining, Water-Resources Investigation Report 99-4018A
Transport Modeling of Reactive and Non-Reactive Constituents from Summitville, Colorado: Preliminary Results from the Application of the OTIS/OTEQ Model to the Wightman Fork/Alamosa River System
By James W. Ball, Robert L. Runkel, and D. Kirk Nordstrom
This report is available in pdf format: Ball.pdf 518KB
Reactive-transport processes in the Wightman Fork/Alamosa River system downstream of the Summitville Mine, south-central Colorado, were simulated under low-flow conditions using the OTIS and OTEQ solute transport modeling programs. Simulation results revealed that Ca, Cu, Mg, Mn, Na, Zn, Cl, F, and SO4 are conservative in the stream reach, whereas pH, Fe, and Al are non-conservative. Simulations that allow precipitation of Fe(OH)3 and Al(OH)3 match observed water quality more closely than conservative simulations. The pH could not be adequately simulated without assuming that tributary inflows had pH values of about 8 or higher and alkalinities of 50-110 milligrams per liter (mg/L). Subsequent sampling confirmed these predictions.