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The Demand Node Inputs: Modeling to Calculate Water Demand for the Next 50 Years

The “Demand Node Inputs” show irrigation water deliveries at various reservoirs and canals from 2019 and includes projection through 2072. There are different models based on water year types – low median, low dry, high wet, high median, high dry, baseline median and baseline dry.


The California Department of Water Resources (DWR) has developed a computer program to calculate agricultural and urban water demands at a river basin.  NID has used this in preparation of information for the Plan for Water modeling process.

Each model run will generally include:

  • An IDC demand model application, with inputs, executables, and outputs
    • IDC is DWR’s “IWFM Demand Calculator,” a standalone module of their Integrated Water Flow Model (IWFM) that is used for calculating demand from ag, urban, and other land uses (based on weather data, crop parameters, urban water use characteristics, etc.).
  • A database (with accompanying python scripts) that contains the processed IDC results, together with information about land use, NID’s customers and parcels served, the canal/distribution system (below NID’s reservoirs), and other geospatial information that helps us to identify how much and where demand is generally occurring in NID according to our model.
  • Results spreadsheets (the summaries already shared), which summarize the results of our model at each of the outflows from NID’s reservoirs (which is incorporated into the ResSim reservoir model)

These detailed calculations are available here:

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