Spencer Peck of ISG presented the updated preliminary engineer's report to the Joint Drainage District 6 board, saying the district’s downstream open ditch — the existing outlet for the tile system — was built privately and is not formally part of JDD 6, so “any work that we do to that ditch would potentially require some administrative work by JDD 6 to potentially annex that land” and acquire right of way.

That finding drove the rest of ISG’s analysis. Donald Oltenbrun, a project manager at ISG, described recent surveying: “We did survey in May and June where we gathered some topo information of that downstream ditch,” which helped the team map tile depth and cover and identify three main areas of concern where the existing tile is unusually shallow.

Why that matters: where tile cover is less than about 2 feet, ISG warned, a surface-channel treatment or replacing tile without improving the downstream outlet risks exposing or crushing the pipe. “The existing system is pretty shallow in a few different locations,” Peck said, and that lack of depth limits low-cost surface-channel options unless some tile is replaced or the downstream ditch is deepened.

ISG laid out three principal approaches: (1) full tile replacement and deepening of the main and Branch 76 tiles, (2) constructing a new open ditch (6–7 feet deep) to serve as the main outlet, and (3) a surface-channel (grass waterway) approach with two sub-options — 3A, which pairs surface channel with more extensive tile replacement, and 3B, a lower-cost phased approach that deepens the downstream ditch, installs a surface channel where feasible, and replaces only the tile sections that must be replaced now.

Costs and consequences differ by choice. ISG said the downstream ditch deepening and annexation will add acquisition costs and potential severance damages for landowners; the firm estimated annexing the downstream ditch could add on the order of hundreds to roughly 1,000 acres into the district depending on the final delineation. ISG also noted ongoing maintenance needs: full-depth open-ditch cleanouts are infrequent (decades), but surface waterways typically require maintenance on roughly five-year intervals.

Board members asked technical and practical questions — how much land annexation would add, whether bridge or culvert capacity at 290th Street could handle increased flow, and how severance damages and crossings would be handled. ISG said initial bridge capacity checks showed no immediate concerns but that culvert sizing and coordination with county road departments would be required for any option that changes flows at the county line.

The board directed ISG to proceed with the preconstruction reclassification and to refine annexation and right-of-way numbers, and members agreed to hold another informational landowner meeting before filing a final engineer’s report and scheduling a public hearing.

The joint meeting recessed after the presentation; ISG said it will invite potential annexation landowners to the next informational meeting so they can hear how changes might affect access and field crossings.