Model:OTEQ

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OTEQ


Metadata

Also known as
Model type Single
Model part of larger framework
Incorporated models or components:
Spatial dimensions 1D
Spatial extent Reach-Scale, Watershed-Scale
Model domain Terrestrial, Hydrology
One-line model description One-Dimensional Transport with Equilibrium Chemistry (OTEQ):

A Reactive Transport Model for Streams and Rivers

Extended model description 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.

OTEQ is generally applicable to solutes which undergo reactions that are sufficiently fast relative to hydrologic processes ("Local Equilibrium"). Although the definition of "sufficiently fast" is highly solute and application dependent, many reactions involving inorganic solutes quickly reach a state of chemical equilibrium. Given a state of chemical equilibrium, inorganic solutes may be modeled using OTEQ's equilibrium approach. This equilibrium approach is facilitated through the use of an existing database that describes chemical equilibria for a wide range of inorganic solutes. In addition, solute reactions not included in the existing database may be added by defining the appropriate mass-action equations and the associated equilibrium constants. As such, OTEQ provides a general framework for the modeling of solutes under the assumption of chemical equilibrium. Despite this generality, most OTEQ applications to date have focused on the transport of metals in streams and small rivers. The OTEQ documentation is therefore focused on metal transport. Potential model users should note, however, that additional applications are possible.

Keywords:

biogeochemistry, water quality,


First name Rob
Last name Runkel
Type of contact Model developer
Institute / Organization USGS
Postal address 1
Postal address 2
Town / City Boulder
Postal code 80303
State Colorado
Country United States
Email address runkel@usgs.gov
Phone
Fax


Supported platforms Unix, Linux
Other platform
Programming language Fortran77
Other program language
Code optimized Single Processor
Multiple processors implemented
Nr of distributed processors
Nr of shared processors
Start year development 1991
Does model development still take place? Yes
If above answer is no, provide end year model development
Code development status Only maintenance
When did you indicate the 'code development status'? 2020
Model availability As code
Source code availability
(Or provide future intension)
Through web repository
Source web address http://water.usgs.gov/software/OTEQ/
Source csdms web address
Program license type Other
Program license type other http://water.usgs.gov/software/help/notice/
Memory requirements
Typical run time


Describe input parameters see user documentation
Input format ASCII
Other input format
Describe output parameters Solute concentrations as a function of space and time
Output format ASCII
Other output format
Pre-processing software needed? Yes
Describe pre-processing software All I/O is done with flat ASCII files; The 'MINTEQ Input file' is created using the Proteq utility; remaining input files may be created using a text editor
Post-processing software needed? Yes
Describe post-processing software All I/O is done with flat ASCII files; Output files are first processed by a utility (posteq) -- resultant files can then be plotted with the user's own software.
Visualization software needed? No
If above answer is yes
Other visualization software


Describe processes represented by the model Physical transport: Advection, Dispersion, Inflow, Transient Storage, and Settling.

Chemistry: Precipitation/Dissolution, Sorption/Desorption, Oxidation/Reduction, aqueous complexation, and acid-base reactions

Describe key physical parameters and equations Partial differential equations describing mass transport (Advection-Dispersion-Reaction equations) and algebraic equations describing chemical equilibria are coupled using the Sequential Iteration Approach
Describe length scale and resolution constraints
Describe time scale and resolution constraints
Describe any numerical limitations and issues see numerical aspects described in Section 4 of the documentation


Describe available calibration data sets see user documentation; also see applications at

http://water.usgs.gov/software/OTEQ/apps/

Upload calibration data sets if available:
Describe available test data sets see user documentation; also see applications at

http://water.usgs.gov/software/OTEQ/apps/

Upload test data sets if available:
Describe ideal data for testing


Do you have current or future plans for collaborating with other researchers?
Is there a manual available? Yes
Upload manual if available: Media:TM6ChB6.pdf
Model website if any http://water.usgs.gov/software/OTEQ/
Model forum / discussion board
Comments


This part will be filled out by CSDMS staff

OpenMI compliant No but possible
BMI compliant No but possible
WMT component No but possible
PyMT component
Is this a data component
Can be coupled with:
Model info
Citation indices OTEQ
Nr. of pubs: 2
Citations: 108
h-index: 2
Qrcode OTEQ.png
Link to this page



Introduction

History

References




Citation indices OTEQ
Nr. of pubs: 2
Citations: 108
h-index: 2



Featured publication(s)YearModel describedType of ReferenceCitations
Runkel, Robert L.; Bencala, Kenneth E.; Broshears, Robert E.; Chapra, Steven C.; 1996. Reactive Solute Transport in Streams: 1. Development of an Equilibrium-Based Model. Water Resources Research, 32, 409–418. 10.1029/95WR03106
(View/edit entry)
1996OTEQ
Model overview 60
Runkel, Robert L.; McKnight, Diane M.; Bencala, Kenneth E.; Chapra, Steven C.; 1996. Reactive Solute Transport in Streams: 2. Simulation of a p H Modification Experiment. Water Resources Research, 32, 419–430. 10.1029/95WR03107
(View/edit entry)
1996OTEQ
Model overview 48
See more publications of OTEQ


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Input Files

Output Files