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Hydrologic Enhancement for Michigan (HEMI)

Hydrologic Enhancement for Michigan (HEMI)

The Michigan Department of Environment, Great Lakes, and Energy (EGLE) is partnering with the U.S. Geological Survey (USGS) to improve how we monitor water in Michigan. This includes both surface water, such as rivers and streams, and groundwater, which is stored underground in soil and rock (called an aquifer). Many Michiganders rely on groundwater for drinking water through private wells or public water systems.

Through this project, EGLE and the USGS will upgrade surface water and groundwater monitoring networks across the state and conduct geophysical surveys to study the subsurface. This will increase our understanding of where our water comes from, how it’s currently being used, and how it’s changing over time. The data that is collected will help measure water resources now and in the future.

This project will help answer questions such as:

  • How are water resources changing?
  • Where is additional monitoring needed?
  • How does surface water respond to groundwater pumping?
  • Can a high capacity water withdrawal well be approved in this region?

HEMI Webinar

HEMI Webinar Recording

Project Tasks

This project has several tasks that include:

Existing data and network reviews

The HEMI Project has started with gathering data to describe surface water and groundwater across the state, as a first step toward evaluating where more data is needed.  Data that will be used in this review include:

These data will help identify where additional monitoring is needed to represent the variety of streams, aquifers, and water use settings across the state.

Streamgage Streamgage 04043050 on the bank of the Trap Rock River near Lake Linden, Michigan in the Keweenaw Peninsula. Photo Credit: USGS.

Surface water monitoring networks

Review of Michigan’s current streamflow monitoring network

Review of Michigan’s stream temperature monitoring network

  • Stream temperature is important for aquatic ecosystems and can impact the aquatic species that live there.
  • This review will help identify where more stream temperature data is needed.

Streamflow and stream temperature monitoring network enhancements

  • New, temporary or long-term streamgages will be installed in areas where streamflow data was determined to be needed.
  • Additional monitoring of streamflow during low-water periods will occur at existing streamgages. Rivers and streams are most affected by water use during low-water periods.
  • Upgrades will also be made to current streamgages, including the installation of sensors that can measure stream temperature where needed.

Groundwater monitoring network

Review of Michigan’s current groundwater monitoring network

  • EGLE is developing a statewide groundwater monitoring network that will be used to observe short-term and long-term trends in groundwater across Michigan.
  • This review will help identify where more groundwater monitoring wells are needed.

Groundwater monitoring network enhancements

Hydrologist A U.S. Geological Survey hydrologist measures the water level in a well. Photo Credit: USGS.
WalkTEM A ground-based geophysics survey using WalkTEM (transient electromagnetics (TEM)) is set up and ready to initiate at a site in the Illinois River Basin. Photo Credit: USGS.

Ground-based Geophysical Surveys

  • USGS will conduct ground-based geophysical surveys in multiple counties in southwestern Michigan in October 2025.
  • The geophysical sensors measure the resistivity of the subsurface which can then be used to characterize the sediment and rock type as well as groundwater.
  • The geophysical data will support and complement data collection taking place as part of the larger HEMI project.
  • See the Ground-based Geophysical Survey Fact Sheet for more information.
Helicopter with a geophysical equipment loop deployed below it via slingload used for airborne electromagnetic (AEM) surveys. Technician on ground for scale.

Airborne Electromagnetic Surveys

  • USGS will conduct an airborne electromagnetic (AEM) survey over multiple counties in southwestern Michigan beginning in spring 2026. 
  • AEM surveys are conducted using a helicopter that flies at relatively low altitudes, hundreds of feet above ground. 
  • The helicopter tows a hoop that has sensors attached to it, which collects data about aquifer materials by measuring the resistivity of the subsurface.
  • The helicopter is flying a grid pre-determined flight track based on study locations, so it will be seen several times in the same area.
  • The helicopter will not fly within 500 ft of buildings according to Federal Aviation Administration (FAA) rules, and will make efforts to fly around people or large equipment on the ground.
  • The electromagnetic device will not harm plants, animals, or humans.
Pictured: Helicopter with a geophysical equipment loop deployed below it via slingload used for airborne electromagnetic (AEM) surveys. Technician on ground for scale. Photo Credit: USGS.
Learn more information on the AEM survey
Map depicting boundaries of the Southwest Michigan Model, which is being developed by USGS as part of the HEMI project. This model will use the characterization of subsurface materials provided by the airborne electromagnetic surveys being carried out as part of the project. The boundary of another USGS groundwater modeling effort encompassing the southeastern border of Michigan, the MichIndOh model, is also depicted.

Groundwater Modeling

  • A groundwater model will be developed for southwestern Michigan, including the area of the AEM survey.
  • A groundwater model is a computer model that can provide understanding of hydrogeologic conditions and simulate how the environment responds to different impacts. For example, models can simulate how groundwater, the water table, and streams respond to pumping at well locations.
Pictured: Map depicting boundaries of the Southwest Michigan Model, which is being developed by USGS as part of the HEMI project. This model will use the characterization of subsurface materials provided by the airborne electromagnetic surveys being carried out as part of the project. The boundary of another USGS groundwater modeling effort encompassing the southeastern border of Michigan, the MichIndOh model, is also depicted.

Project Outcomes & Data Access

The upgrades to surface water and groundwater monitoring networks across the state and the geophysical surveys will help:

  • Collect data at high priority monitoring locations
  • Improve understanding of how much water we have in rivers and streams, the temperature of the water and where it’s flowing, and aquifer characterization
  • Understand how surface water reacts to groundwater pumping (such as wells), water use, and climate
  • Improve measurement of groundwater resources

For more information and to access the data as it becomes available, visit the USGS HEMI Project webpage.

Study area for HEMI project, which includes a statewide focus for analysis and enhancement of surface water and groundwater monitoring networks, and a large area of southwest Michigan where airborne electromagnetic surveys will occur.

When and where will this work take place?

The HEMI project is statewide. The enhancements to Michigan’s surface water and groundwater monitoring networks will include work in both the upper and lower peninsulas.  Specific locations are being determined based on the network reviews described above. The geophysical surveys and groundwater modeling will focus on southwestern Michigan. See below for a map of the study area and timeline of the project.

Map pictured: Study area for HEMI project, which includes a statewide focus for analysis and enhancement of surface water and groundwater monitoring networks, and a large area of southwest Michigan where airborne electromagnetic surveys will occur.

View the HEMI project timeline by task

Contact us

EGLE Project Manager: Sydney Ruhala, RuhalaS@Michigan.gov or 517-648-7791