One-Dimensional Transport with Equilibrium Chemistry (OTEQ) - A reactive transport model for streams and rivers
OTEQ is a mathematical simulation model used to characterize the fate and transport of waterborne solutes in streams and rivers. The model is formed by coupling a solute transport model with a chemical equilibrium submodel. The solute transport model is based on OTIS, a model that considers the physical processes of advection, dispersion, lateral inflow, and transient storage. The equilibrium submodel is based on MINTEQ, a model that considers the speciation and complexation of aqueous species, acid-base reactions, precipitation/dissolution, and sorption.
Within OTEQ, reactions in the water column may result in the formation of solid phases (precipitates and sorbed species) that are subject to downstream transport and settling processes. Solid phases on the streambed may also interact with the water column through dissolution and sorption/desorption reactions. Consideration of both mobile (waterborne) and immobile (streambed) solid phases requires a unique set of governing differential equations and solution techniques that are developed herein. The partial differential equations describing physical transport and the algebraic equations describing chemical equilibria are coupled using the sequential iteration approach. The model's ability to simulate pH, precipitation/dissolution, and pH-dependent sorption provides a means of evaluating the complex interactions between instream chemistry and hydrologic transport at the field scale.
This report details the development and application of OTEQ. Sections of the report describe model theory, input/output specifications, model applications, and installation instructions. OTEQ may be obtained over the Internet at http://water.usgs.gov/software/OTEQ.
Citation Information
Publication Year | 2010 |
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Title | One-Dimensional Transport with Equilibrium Chemistry (OTEQ) - A reactive transport model for streams and rivers |
DOI | 10.3133/tm6B6 |
Authors | Robert L. Runkel |
Publication Type | Report |
Publication Subtype | USGS Numbered Series |
Series Title | Techniques and Methods |
Series Number | 6-B6 |
Index ID | tm6B6 |
Record Source | USGS Publications Warehouse |
USGS Organization | Colorado Water Science Center; Toxic Substances Hydrology Program |