Water quality is processes are modelled in links and for certain node types which have storage associated with them (see Nodes SRG for more information on these).- SRG). Most node types have no storage and at these the mass balance of each water quality constituent being modelled is maintained with no decay or deposition processes.
Routing Models
Two approaches are provided for routing constituent movement through a reach. The first approach assumes the constituent is fully mixed within a reach. This approach can be appropriate where the user is interested in monthly or annual loads. A particle tracking method that is also provided routes the constituent at the velocity of flow (Close, 1996). This method is more accurate and is suitable where the user is interested in concentrations or loads at shorter time stepssmaller scales.
More information on these is methods is available via Constituent Routing Type - SRG.A range of options are available for representing in-stream
Processing Models
Constituent processing models represent water quality modification processes process in links . The in-stream models act on each constituent in the river, in and storages, and act in a manner similar to the processing of each constituent by filter models. These comprise decay models (see Decay SRG) and modelling constituent filtering models in catchments. Two types of constituent processing models are currently available in Source:
- A decay model (see Constituent Processing Models SRG) and,
- In links only, modelling of surface water-groundwater exchange fluxes (see Flux SRG).
Simple storage nutrient and sediment deposition models have also been provided that can be used when modelling appropriate node types as well as links. More information on these is available via Decay SRG.
The above material has been sourced from Welsh, Welsh et al. (2013) with adaptations to suit the needs of the SRG.
References
Welsh, W.D., Vaze, J., Dutta, D., Rassam, D., Rahman, J.M., Jolly, I.D., Wallbrink, P., Podger, G.M., Bethune, M., Hardy, M.J., Teng, J., Lerat, J. (2013) An integrated modelling framework for regulated river systems. Environmental Modelling & Software, 39: 81-102.
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