Wright County supervisors seek independent estimate of drainage-tile risk from seismic testing; ask developer to pay assessment

Wright County supervisors said they want an independent estimate of potential damage to drainage tile and crop yields before allowing expanded seismic testing, and that the company pushing for different setback rules should pay for the study.

The board discussed a proposal from Jacob Hagen and Tyler Deering of Agravia to produce a county-level, conservative estimate of two categories of potential loss: repair costs for crushed or damaged drainage tile and crop-yield losses where drainage effectiveness would decline. Agravia described a methodology using county GIS, historical work orders and soil-type yield tables to produce an initial “big‑number” estimate that could be refined if landowners later file claims.

The issue matters because Twin Rivers — a developer proposing underground testing across roughly 400 miles of county roads, according to the discussion — asked the county to accept a smaller buffer around test points than the current 250 feet allowed where the county receives data. Supervisors said they want engineering analysis to support a narrower boundary before changing county standards.

Jacob Hagen, an Agravia consultant, said the study would be two parts: an estimate of physical damages to district and private tile (using GIS and past public contract costs) and a modeled crop-yield loss using Iowa State spreadsheets tied to soil types. He described beginning with a conservative countywide “worst‑case” figure, then narrowing it if specific broken-tile claims emerged.

"We thought of was let's kind of break it out in two steps — actual damages to the tiles, and then the second one would be crop yield loss due to damaged tile," Hagen said during the meeting.

Supervisors emphasized practicality: the county does not have complete private-tile maps, and some tile damage might not show for years. Board chair Rick Rasmussen said the county would treat Agravia as an outside reviewer and would expect the company pressing for reduced setbacks to pay for the work.

"To be for their work to be paid for, I would request that Twin Rivers pays for them," Rasmussen said. Board members agreed the company seeking changes should bear the cost of assessment, not taxpayers.

Agravia outlined assumptions described repeatedly in the meeting: a 250-foot initial damage radius around test points for county review; use of soil-type mapping to estimate patterned private-tile density; selection of representative 20–30‑mile sections to extrapolate per-mile averages; and then multiplication across the roughly 400 miles Twin Rivers wants to test to derive an escrow target.

Supervisors said the escrow would be a neutral account (an escrow agent) where farmers or the county could apply for reimbursement if field inspections tied a specific GPS point and test area to a broken tile or measurable crop-loss claim. Supervisors discussed using the county’s GPS traces, the seismic test logs (which Twin Rivers would supply), and the county's existing work-order records to adjudicate claims.

Board member Betty Ellis said she liked the approach but stressed negotiations with Twin Rivers would determine whether the company would accept the study and escrow arrangement and what distance the company finds acceptable.

The board asked Agravia to continue work on an initial estimate and to meet with Twin Rivers and county officials. Supervisors indicated they want Agravia's calculations before considering any change from the current 250-foot practice and that the company wanting tests closer to infrastructure should fund the analysis.

No formal ordinance or resolution was adopted; rather, supervisors agreed to pursue further talks with Twin Rivers and to press for the developer to fund the independent assessment.