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Water Quantity Modeling - Click Here

Water Quality Modeling

Water Quality Models are being increasingly used to help understand the effect of pollutants on waterbodies. Models help us understand the movement of pollutants from land-based sources to a waterbody (watershed model) or help us understand the fate, transport, and degradation of pollutants within a waterbody. DWR may use water quality models to help evaluate the effects of a new or expanded waste water discharge, or model the reduction of pollutants needed to restore good water quality to a lake.

The Modeling and Assessment Branch is often involved in models that are developed in support of a Nutrient Management Strategy, or TMDL load allocations. Third party models associated with a NPDES permit also require review by the MAB.                                                                            


Model Requirements
To enable DWR to confidently use water quality models for decision making purposes, DWR requires the following:  

  1. The person(s) planning to develop the model must have a scoping meeting with the MAB. This will ensure that the model will include all parameters needed. 
  2. A modeling plan must be prepared following the scoping meeting with DWR. Guidelines for preparing a modeling plan can be found here.
  3. The model used must be listed in EPA's TMDL Modeling Toolbox, or the model code must remain available to the public. Other methods such as the load duration curve, and simplified tidal prism approach may be used when appropriate. 
  4. A modeling report or other appropriate documentation, along with all associated modeling files, must be submitted to DWR for review. Guidelines for preparing a modeling report can be found here.  


DWR Developed Models:


Models developed under contract:

  • Lower Cape Fear River EFDC Model
  • Jordan Lake Generalized Watershed Load Function (GWLF) Watershed Model Report
  • Jordan Lake EFDC-WASP Lake Nutrient Response Model
  • High Rock Lake Hydrological Simulation Program Frotran (HSPF) Watershed Model (under development)
  • High Rock Lake EFDC-WASP Lake Nutrient Response Model (under development)

Modeling Resources