California Hydrology Model

CAHM has many features:

  • US-EPA HSPF computational engine

  • Includes long-term precipitation data for each selected County

  • Includes new and improved elements

  • Includes GIS Import and WDM Maintenance

  • Improved charts for analysis

  • Works with Windows 7, Windows 10, and Windows 11


CAHM is a custom version of WWHM4 with these differences:

  • purchased for one county at a time.

  • each county includes one or more precipitation gages to choose from.

  • several PERLND Parameter files are included to choose from.

  • is free to municipalities (see below).

  • does not include the CAD Pond, SWMM or Hydraulic elements.

  • does not include the LID Toolbox (at this time).

Requires Activation to unlock all features and edit project settings.

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