County staff proposes opening tile to open ditch at Willard Milner county farm after erosion

County staff told the Clinton County Drain Board that heavy rain and ongoing erosion have damaged a 24-inch clay tile on county farm property in the Willard Milner watershed and recommended converting the failing closed tile to an open, two-stage ditch to reduce future tile breaches.

The proposal matters because the open-drain conversion would change how runoff moves through the county farm and could increase flows into neighborhoods downstream. "We repaired the hole, but there's a significant amount of erosion across the farm property," said Dan, a staff member, describing the damage after a storm. He said the existing grate intended to collect debris was "completely full," and crews had repaired the immediate tile hole but not the broader erosion.

Dan told the board he and a colleague had discussed options and asked for the board's blessing to pursue contractor pricing. He said one short-term approach is to replace the exposed pipe section to provide access and avoid repeated holes, while a longer-term plan would open the drain across the farm and possibly through adjacent backyards. "I've always thought we really need to look at maybe opening that up all the way through," Dan said, adding that such work would require engineering so the county can understand how much additional water would be released downstream into neighborhoods and the highway department's drainage network.

Staff provided technical ideas and a preliminary cost estimate. They described specifications for an open-ditch option as a 3-foot flat bottom with 45-degree (1:1) side slopes and estimated a ballpark cost of at least $20,000 for initial work. Dan also described a two-stage (shelving) ditch as a way to add temporary storage and slow flow, and said a contractor was preparing pricing for an open-ditch conversion and a shelving option.

Staff identified other constraints: the existing tile sits about 4 to 5 feet deep; some gullies on the site are roughly 4 feet deep; excavation would generate large volumes of topsoil that the county could spread on site; and cattle historically used the parcel. Dan also noted the need to maintain farm access across the ditch for the land operator and said staff might coordinate with the county highway department for in-house work.

Board members asked where the open ditch would transition back to tile at property lines and how far the shelving would extend; staff estimated hundreds to perhaps a thousand feet of channel work but did not provide exact engineering measurements. Dan cautioned that opening the drain could cause runoff to reach downstream neighborhoods faster during high-flow events while potentially reducing some overflow at a local location (Gota Drive). He said engineering would be prudent because "there are quite a few homes in North Timber Line subdivision up there — about 30 homes on the ground — which could be impacted by what we do here."

Next steps: staff will obtain contractor proposals for an open-ditch conversion and for a two-stage/shelving design and return to the board with cost figures and engineering recommendations. No formal vote or contract award occurred at the meeting; the board treated the item as discussion and direction to gather proposals, with staff to return with detailed pricing and potential engineered plans.