Flood Zones in Midland County, Michigan: When the Floodplain Is Also a Superfund Site

How the contamination got there

Dow Chemical's headquarters and original manufacturing complex sit on roughly 1,900 acres in the city of Midland, straddling the Tittabawassee River. Dioxins and furans -- byproducts of chlorine-based chemical manufacturing dating back to the early 1900s -- were historically discharged into the river, and elevated dioxin levels in river sediment and floodplain soil now extend more than 50 miles downstream through the Tittabawassee and Saginaw Rivers into Saginaw Bay. That combined area is designated the Tittabawassee River, Saginaw River & Bay Superfund site, a federal National Priorities List site.

The part of that site most directly relevant to a Midland County land buyer is the Tittabawassee River Floodplain itself: roughly 4,500 acres of land extending about 21 miles along the river below Dow's plant, where contamination sits not just in the river channel but in the ordinary backyard and field soil of hundreds of individual properties.

What the cleanup actually does to a property

EPA and Michigan's Department of Environment, Great Lakes, and Energy (EGLE), with Dow funding and carrying out the physical work, evaluate floodplain properties individually rather than applying one blanket rule. Reporting has described EPA and its contractors assessing more than 700 properties to determine whether cleanup is needed, based on measured dioxin levels and how the land is actually used. A site-specific residential action level of 250 parts per trillion (ppt) applies to soil in homeowners' yards maintained for typical backyard use -- above that level, contaminated soil is dug up, hauled away, and replaced with clean soil, with grass and plants restored. A separate, higher threshold of 2,000 ppt applies to floodplain land used as farms, parks, commercial property, or natural areas, where the response can be either full removal or capping with clean soil rather than complete excavation.

Because so many properties are affected, Dow has separately offered permanent easements to a number of floodplain property owners -- reported figures include $10,000 plus $1,000 per acre -- in exchange for agreeing not to develop the land and for granting access to test and, if needed, remediate contaminated soil. Whether a specific parcel carries such an easement, has already been tested or remediated, or remains untested is exactly the kind of detail this page cannot answer for you -- it varies property by property and changes as the multi-year cleanup continues.

This is still an active, multi-year process

This is not a closed, historical episode. As of the most recent reporting available for this page, EPA, EGLE, and Dow continue active field work: recent seasons have included river channel and bank remediation in specific numbered river segments, floodplain soil cleanup phased across additional segments, and ongoing sediment and soil sampling further downstream in the Saginaw River floodplain to scope future work there. Full delisting from the National Priorities List is understood to be a distant milestone, requiring remedies to be completed across every operable unit and years of post-remediation monitoring before EPA confirms no further federal action is needed.

What to check before buying land near the Tittabawassee River in Midland County

• Ask directly whether the specific parcel falls within the mapped Tittabawassee River Floodplain cleanup boundary -- not every Midland County riverside parcel is included, and the boundary is a specific, mapped area rather than a loose description of "near the river."
• If it does fall within the boundary, ask EPA Region 5 or Michigan EGLE (both have overseen this cleanup jointly with Dow) for that parcel's specific testing and remediation history and status.
• Ask whether the property carries a recorded easement or access agreement tied to the cleanup program -- this can affect development rights and would need to be reviewed as part of a title search, separate from ordinary flood-insurance considerations.
• Separately, run a standard current FEMA Flood Insurance Rate Map (FIRM) check for the parcel -- ordinary flood risk and the Superfund cleanup are related but distinct: a property can be in a FEMA flood zone without being in the dioxin-contaminated floodplain area, or vice versa in some boundary areas, so check both rather than assuming one implies the other.
• For a parcel outside the city of Midland but still along the river corridor downstream (extending toward and beyond the Saginaw County line), confirm whether that stretch is included in the same cleanup program or a related downstream phase -- the affected area is not limited to land immediately adjacent to Dow's plant.