Work session: Des Moines County reviews broad rewrite of floodplain development ordinance; supervisors press for clarified valuation, variance and mapping rules

Des Moines County land-use staff on March 17 led supervisors through a detailed work session on a proposed update to the county's floodplain development ordinance, highlighting procedural changes tied to new FEMA mapping, clarified technical definitions and new management standards for certain uses.

Jared (land-use staff) reminded the board the county's floodplain ordinance dates to 1993 and is routinely readopted when FEMA insurance rate maps change. The draft update lists each FEMA panel and effective date explicitly so the ordinance cites the exact panels being updated; staff noted the Skunk River and Lost Creek panels include forthcoming changes.

Key technical and policy changes in the draft include: - Definitions and terminology: removal of redundant language for terms such as "lowest floor," addition of the insurance term "repetitive loss" (two NFIP claims in 10 years with repair costs at or above 25% of market value), and a clarified category for "maximum damage potential development" that adds "emergency response facilities" alongside power installations. - Management standards: tightened standards for residential access in areas that would become isolated by flooding (previous exceptions tied to "sufficient flood warning time" were removed), updated treatment of bridges and culverts consistent with changes to state code, and a new set of requirements for private RV campgrounds in floodplains to maintain evacuation plans and defined notifications. - Non-conforming uses: the draft adds a new article formalizing grandfathering rules. Uses lawful before the ordinance may continue, but if a use is discontinued for six consecutive months, future use must conform. The draft also states that nonconforming structures damaged by flood or other causes may not be reconstructed if the repair cost equals or exceeds 50% of the structure's market value unless the rebuilt structure complies with the ordinance. Variance procedures remain available for exceptional cases.

Supervisors' questions focused on operational details and potential burdens on property owners and county staff. Members asked whether a six-month discontinuation period is too short for property owners recovering from a disaster; Jared and other staff said the six-month rule is meant to distinguish voluntary discontinuance from temporary damage and that variance procedures can provide relief in specific cases. The board discussed using the county assessor's valuation as the practical baseline for "market value" when determining substantial-damage thresholds; staff stated assessors' valuations are commonly used in practice and agreed to confirm the approach with the Iowa DNR and clarify the ordinance language.

Supervisors also raised concerns about new administrator duties that trigger notification to FEMA if development in unmapped zones (for example Zone A/AE with no designated floodway) causes more than a one-foot rise in base flood elevation. Members cautioned that hydraulic modeling to demonstrate changes can be expensive and technically complex; staff said these triggers are intended for infrequent, large-scale projects and that they will seek additional guidance on implementation and costs.

On RV campgrounds, board members sought assurance the rule would not unintentionally impose new requirements on county conservation parks. Staff said the draft targets new or expanded private campgrounds and is not retroactive to existing uses unless they are enlarged; staff will consider clarifying language to specify private entities where appropriate.

Jared said he will follow up with the Iowa DNR to clarify a few outstanding technical points (including the six-month and valuation questions, DNR's expectations for an annual federal report, and whether particular phrases should be removed to align the local ordinance with current model language). Staff aim to proceed with public notices and schedule formal ordinance readings in April to allow time before the new FEMA maps take effect.

"The ordinance was first adopted in '93 after the flood that year...the ordinance also needs to be updated so that it includes a reference to the most recent maps," Jared said. "A lot of these edits are procedural and minor, but there are a few items where we need further clarification from DNR."