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Modular Aquatic Simulation System 1D and 2D (MASS1 and MASS2)


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The Modular Aquatic Simulation System (MASS1 and MASS2) models simulate hydraulic temperature, and water quality conditions in rivers and reservoirs in one or 2 dimensions. The models are unsteady and spatially explicit.

Geographic Location

The models are physics based and can be applied to any river/reservoir system. The models have been extensively used in the Columbia River basin and in particular the Hanford Reach.


The models require bathymetric data in the form of surveyed elevation points or cross sections. Accuracy is improved with more detailed data, but the models can use coarse reprentations is data is limited. Hydrologic and meteorological data are needed for boundary conditions. Estimates of substrate type and distribution are needed for sediment transport.


Outputs are time histories and spatial maps of simulated variables such as velocity, depth, and temperature. Output can formatted for use in GIS systems.

Linkage to Other Models

MASS1 and MASS2 have been successfully coupled to other models (watershed, groundwater, 3D computational fluid dynamics). Typically linkage to other models is done using a loose coupling approach through exchange of output files.

Level of Effort

Depending on data availability (particularly the bathymetric surface data), the modeling effort to compare a modest range (4 to 10) of different system configurations could be completed in a 12 month cycle. A high degree of expertise is required to set-up the models and to do the initial QA/QC and calibration. Less skill is required to do subsequent model runs and habitat analyses.

Basin Scale Opportunity Assesment