WDM Water Works moves to protect lakes from pollution
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Purple Martin Lake. Photo: Linh Ta/Axios
West Des Moines Water Works (WDMWW) wants to protect four lakes as drinking water sources before industrial development moves farther into the area and potentially threatens the supply.
Why it matters: Water from Maffitt Reservoir and Crystal Lake already helps offset high nitrate levels in the Raccoon River and serves as drought backup.
- Purple Martin Lake is slated to become a drinking water source soon, and Hallett Lake — quarries to the east — could follow.
State of play: Central Iowa Water Works (CIWW) and WDMWW are working to develop a "chain of lakes" as interconnected drinking water sources for the McMullen Water Treatment Plant, which helps serve roughly 600,000 metro customers.
- The nitrate levels in these lakes are lower than those in the Raccoon River, one of the metro's main drinking water sources. Water from the Raccoon River is pulled from collector wells into the McMullen plant. It's supplemented by water from the lakes, which brings drinking water nitrate levels down.
Yes, but: The area south of Purple Martin Lake is experiencing industrial and warehouse development, and formal protections for the waters don't exist yet.
- In 2024, a fertilizer company considered building near Purple Martin Lake, raising concerns from WDMWW about potential water quality impacts. The project ultimately moved elsewhere.
- Since then, WDMWW has worked to create a state-approved source water protection plan covering all four lakes, says general manager Christina Murphy.
Zoom in: The protection plan, recently approved by the Iowa Department of Natural Resources, outlines threats to the four lakes and recommends ways to address them, including stricter review of nearby development, stormwater safeguards, restrictions on certain chemical storage and manufacturing, and new zoning restrictions.
The intrigue: The area once eyed for future office development has shifted toward more warehouse and manufacturing.
Between the lines: Source water protection plans offer guidance and are not mandatory.
- The West Des Moines City Council has the power to approve zoning rules that would support the protections. WDMWW will work with them once the CIWW board approves the plan, Murphy says.
What they're saying: "Source water protection isn't just an ag issue," Murphy says. "It's everyone's issue, and it's important that we take care of things here at home and do our part as well."
The other side: Local developers from Knapp Properties and Denny Elwell Co. say they want to work on water quality, but they acknowledge that protections can add financial barriers for new construction and push development away, per the Business Record.
What's next: The plan will go before the CIWW board in July for approval.
- CIWW plans to apply for the Iowa DNR water withdrawal permit, which will officially allow them to use Purple Martin Lake for drinking water.