water supply

Integrated Hydrologic Model


The Integrated Hydrologic Model (IHM) is a sophisticated and powerful computer tool. It estimates how an action in one part of the area’s natural stream or aquifer system affects other parts of the system.

The IHM is used to study surface water and groundwater. Surface water includes streams, lakes, and wetlands. Groundwater includes the shallow aquifer, deep aquifer, and springs. IHM is especially helpful in areas where the shallow aquifer (groundwater-table) is close to land surface.  This single computer model addresses all of the details of:

  • rainfall
  • evaporation from the land and from lakes
  • transpiration from plants
  • stream flows and spring flows
  • surface water and groundwater conditions
  • infiltration of water from land surface into the groundwater system
  • water migration through the aquifer
  • land type and land development features
  • water pumping from wells
  • water captured from rivers

The IHM is used by Tampa Bay Water to help water managers and water utility operators:

  • decide how to use existing water supply facilities
  • evaluate potential new water supply sources
  • study and design special projects like lake or wetland restoration

For example, the IHM helps water managers and regulators estimate how changes in rainfall amounts or groundwater pumping affect streamflow amounts or water levels in lakes.

IHM was prepared through a detailed scientific calibration process. The model is a collaborative effort with the Southwest Florida Water Management District.