Digging into details of groundwater management

New software promises better process for large-quantity water withdrawal requests

As part of National Groundwater Awareness Week, MI Environment is featuring an article from the 2025 State of the Great Lakes report, by Groundwater and Geologic Services Manager Lena Pappas, at the Michigan Department of Environment, Great Lakes, and Energy (EGLE).

Preserving the Great Lakes is a collaborative endeavor, where each state and province within the basin adheres to the Great Lakes Agreement and Compact to protect this vital shared water resource. Sometimes, protection also requires new perspectives and new tools.

Historically, management efforts have often considered each Great Lake in isolation, overlooking the critical hydrologic connection between these surface waters and groundwater.

But groundwater within Michigan is comparable in volume to Lake Huron. It’s not a separate system but an essential and unifying component of the earth-and-water puzzle that defines the Great Lakes Basin. In Michigan alone, more than half of all residences and businesses depend on groundwater.

Ensuring the long-term viability of state water resources including groundwater requires tools flexible enough to account for diverse hydrogeologic conditions and accessible enough to ensure transparency and reliability for those who use them.

Local, state, and federal partnerships are critical to co-developing tools that can encompass these needs. Recognizing this, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) collaborated with the U.S. Geological Survey (USGS) and the Wisconsin Department of Natural Resources (WDNR) to develop a new software tool called pycap-dss. This tool fills the current gap by providing insights into how surface water and groundwater interact: pycap-dss can estimate both groundwater drawdown and related reductions to streamflow.

In addition to providing robust, accurate information to agencies responsible for ensuring the long-term sustainability of Michigan’s water supply, these tools must help build trust with users.

The USGS published pycap-dss in line with open software principles for transparency and regulatory accountability that help ensure these goals are met. Michigan’s Water Use Program, which regulates large quantity water withdrawals, works with the Water Use Advisory Council (WUAC) to advance and improve the Michigan Water Conservation and Efficiency Program established in 2008 to meet the state’s obligations under the Great Lakes Compact and Agreement. The WUAC and its Water Conservation and Efficiency Committee play key roles in water management and water conservation and efficiency in Michigan. WUAC Tri-Chair Pat Staskiewicz said the release of open-source decision support software is a great example of USGS leadership in water management.

Staskiewicz, who serves as public utilities director of the Ottawa County Road Commission, also said improvements to the speed and accuracy of decision making by regulators are important, and doing so openly and transparently is vital for trust among regulated communities.

Large-quantity withdrawals (defined as 100,000 gallons or more per day) from Michigan groundwater or surface waters are prohibited from adversely impacting the waters of the state.

When someone applies to EGLE to establish or enlarge a large-quantity withdrawal, the Water Withdrawal Assessment Tool (WWAT) models the potential impact on nearby water resources. It’s central to Michigan’s process for regulating large-quantity withdrawals.

In the fall of 2025, EGLE announced the release of the redeveloped WWAT that integrates the pycap-dss software. This updated WWAT will serve as the interface for more than half of Michigan’s large-quantity water withdrawal registrations. Water users who register pumps that can draw more than 2 million gallons a day are required to apply for a 327 Permit as opposed to registering within the WWAT. This updated tool will make it easier for users who are interested in evaluating their registration options and integrating public or privately collected data into the process.

Its streamlined, user-friendly platform not only visualizes resource availability but also supports data-driven, collaborative decision making, aligning regulatory requirements with recommendations from the WUAC.

Stakeholders include the agricultural community. Michigan produces more than 300 commodities, making it the second-most agriculturally diverse U.S. state, according to the Michigan Farm Bureau. The group supports transparent, science-based management of water resources to protect natural resources and provide the water needed to grow crops and raise livestock.

Laura Campbell, Farm Bureau senior conservation and regulatory relations specialist and WUAC tri-chair, said she’s encouraged by the implementation of software tools like pycap-dss to improve the WWAT and increase flexibility in water withdrawal decisions. WUAC Tri-Chair Dr. Bryan Burroughs said the new tool reinforces the integrity of important regulation, bolstering trust and confidence in outcomes.

The challenge of groundwater science and resource management is not unique to Michigan. Every state and province within the Great Lakes Basin must estimate local groundwater levels as part of efforts to protect the sustainability of shared water resources.

Originally developed for WDNR and EGLE, pycap-dss shows promise for increasing regional coordination. Since its release, the tool has garnered interest from the Minnesota Department of Natural Resources for use in its water resource assessments.

EGLE remains committed to collaborative, science-based regulation of Michigan’s water resources – work that continues to play a critical role in supporting the state’s economy, environment, and communities.