Flood Zones and Levee Protection in Pottawattamie County, Iowa

The Council Bluffs Levee System: scope and history

The Council Bluffs Levee System, built by the US Army Corps of Engineers in stages between 1946 and 1954, runs approximately 28.5 miles along the Missouri River and its Indian Creek and Mosquito Creek tributaries, providing direct flood-risk reduction to roughly 64% of the city's incorporated area, according to the Corps' own programmatic environmental assessment for the levee program. This is a mature, decades-old federal flood-control system, not a recent or informal earthwork -- which also means its design standards, maintenance history, and current federal accreditation status are all things a buyer can and should ask about specifically for a parcel near the levee's protected footprint, rather than assuming the levee's mere existence answers the flood-risk question.

What "levee-protected" does and does not mean

A levee accredited by FEMA as providing 100-year (1%-annual-chance) flood protection can move the land behind it out of a mapped Special Flood Hazard Area on the current Flood Insurance Rate Map (FIRM) -- which matters directly for mandatory flood-insurance requirements on a federally backed mortgage. But accreditation is not permanent or automatic: it depends on the levee continuing to meet FEMA's structural and maintenance standards, and a levee that loses accreditation (due to deferred maintenance, a certification lapse, or a FEMA remapping study) can put previously "unmapped" land back into a Special Flood Hazard Area with little advance public notice. It also does not mean zero risk in the event of a flood larger than the levee's design standard, or in the event of an overtopping or breach -- a levee reduces the frequency of flooding, not the consequences of the rare event that exceeds it.

For a specific Pottawattamie County parcel, this means two separate questions worth asking directly: (1) what does the current FEMA FIRM show for this specific parcel, accounting for the levee's current accreditation status, and (2) independent of the FIRM, does the parcel sit within the levee's actual protected footprint, or just near it. A parcel just outside the levee's protected area, or downstream/upstream of its endpoints, can carry materially different risk than one squarely behind it, even if both are a similar distance from the riverbank on a map.

The 2011 flood: a real test of the system, with real costs

The system's most significant recent test came in 2011, when a historic Missouri River flood -- driven by heavy snowpack and rainfall across the upper basin and extended releases from upstream Corps reservoirs -- kept the river above the 100-year flood elevation in the Council Bluffs area for approximately 90 consecutive days. Pottawattamie County prepared an evacuation plan covering roughly 30,000 residents within the levee-protected area as a precaution, and county-road damage alone was estimated at $40 million, separate from any damage to private property, city infrastructure, or agricultural land. Regionally, the 2011 flood caused five deaths and flooded more than 4,000 homes across the affected states.

The Missouri River flooded again in 2019 in an event that was, regionally, even more extensive -- more than $2 billion in agricultural damage and over 460 affected businesses across Iowa, Nebraska, Kansas, and Missouri combined, according to contemporaneous reporting -- though county-specific Pottawattamie figures for that event were not confirmed in this research pass. Two significant flood events within a decade is a meaningful pattern, not an isolated incident, and it argues for treating flood risk here as an active, recurring consideration rather than a historical footnote.

What to check before you buy

Pull the current FEMA Flood Insurance Rate Map for the specific parcel, and separately confirm with Pottawattamie County Planning and Development whether the parcel sits within the Council Bluffs Levee System's protected footprint and what the levee's current federal accreditation status is. Ask specifically whether any FEMA remapping study is underway or planned for the area -- levee-accreditation reviews and remapping can change a parcel's flood-insurance requirement even without any change to the land itself. If the parcel is near the Missouri River, Indian Creek, or Mosquito Creek but outside the incorporated City of Council Bluffs, also confirm whether it falls within the county's own floodplain-development-permit jurisdiction or the city's, since the two-mile extraterritorial-review zone around Council Bluffs (covered on our Pottawattamie County hub) can affect which office actually reviews a specific project.