Story County engineer outlines data‑driven reclassification for Warren No. 11; landowners dispute fairness and levy timing

Bolton & Menk project manager Tyler Conley walked trustees and attendees through a preliminary reclassification of Drainage District Warren No. 11 during the Story County Drainage District Trustees meeting May 18.

Conley said the reclassification uses LiDAR Digital Elevation Model (DEM) data obtained by the State of Iowa ("the claimed accuracy of the LiDAR Digital Elevation Model (DEM) is plus or minus three inches") fed into a GIS. He described a five‑factor method to calculate units of benefit per parcel: area (how much of a parcel lies within the district watershed), proximity to district facilities, the parcel's use of district facilities (how much of the facility the parcel uses), soil wetness (parcels scored on a high/dry/wet/swamp scale), and runoff or land use (agricultural, developed, roads). Conley said the highest‑benefit parcel is set to 100% and all other parcels receive a percentage relative to that parcel.

Conley displayed maps that, he said, show a significant per‑parcel shift of costs away from only the parcels on the open ditch toward parcels that benefit under the five‑factor model. He emphasized the process is "repeatable" and transparent and noted the classification is preliminary until it is vetted by three commissioners (Conley plus two disinterested Story County landowners) and then adopted at a public hearing prior to final trustee action.

Several landowners urged caution. Randy Hill said classification methods used in the past favored large farmers and that more private tile has increased flooding on his brother Jerry Hill's land. He told trustees the district is "too big" and argued smaller district boundaries should be used so downstream landowners do not pay for upstream work. Hill also raised concerns about undersized bridges that "back water onto Jerry's land." Trustee Murken said bridge sizing is outside the drainage district's purview.

Drainage Clerk Scott Wall reported the district currently carries a deficit of $94,932.93 and told trustees the county bookkeeping office estimates the balance will generate about $7,000 in interest by the time levies are due and payable Sept. 30. Wall said a levy to be due and payable Sept. 30 must be approved before June 1; auditing staff recommended levying the district this year for the current shortfall and estimated interest to avoid greater interest and the addition of construction costs to the shortfall. Auditor's Office representative Crystal Becker described that levying now could save the district as much as $15,000 to $20,000 overall, while several landowners, including Risdal and the Hills, urged waiting until the new classification is adopted so assessments are based on the updated methodology.

Trustee Latifah Faisal moved and Trustee Lisa Heddens seconded a directive for Conley to proceed with a final reclassification; the motion carried unanimously. Conley said the final classification will be available for landowner review before the trustee public hearing when the trustees may adjust numbers if they deem it appropriate.