Drainage authority moves forward on improvement petition for County Ditch 38A after engineer and DNR review

The Nicollet County Drainage Authority held a public hearing on a petition to improve two tile segments of County Ditch 38A and voted to proceed to a final engineer’s report and viewers’ benefit determination.

Scope of the proposal: Houston Engineering project engineer Chris Otterness presented the preliminary engineer’s report (PER) for an improvement petition submitted May 29, 2024, that seeks replacement of two specific tile segments of County Ditch 38A: Branch 4 (and lateral B) and Branch 1 lateral D (including Spur 1). The drainage area for the two segments is approximately 425 acres, and staff said the original system was constructed in 1904 with improvements recorded in 1955.

What the project would do: The PER recommends replacing deteriorated tile with new dual‑wall polyethylene pipe, increasing pipe sizes in some locations (up to 24 inches where needed) to achieve a target drainage coefficient (roughly a half‑inch per day design recommended for row‑crop drainage). New inlets and reconnections to public and private laterals were proposed; the new mains would generally be installed parallel and offset 10–15 feet from existing tile to maintain flow while work proceeds. Engineers said the design calls for at least 3 to 4 feet of cover over new tile where feasible to protect against agricultural equipment.

Environmental and downstream review: Houston Engineering reported it evaluated alternatives (do‑nothing, repair at current sizes, storage/ponding, and the preferred up‑sized tile alternative). The firm modeled downstream impacts at the tile outlets and at Hayman Creek (about 2.5 miles downstream) and estimated increases in peak flows at the outlet sections ranging from less than 1% up to about 9% depending on location and recurrence interval; those increases were modeled to correspond to small changes in water surface elevation (engineer cited increases measured in hundredths of a foot). The firm concluded the outlet channels and downstream reaches showed sufficient capacity and that the proposed work would not cause significant environmental impacts. The project will require a Minnesota Pollution Control Agency construction stormwater permit and development of a pollution prevention plan.

DNR advisory letter and responses: The Minnesota Department of Natural Resources submitted an advisory report that acknowledged the system’s age and disrepair but raised questions about peak flow increases (noting a 9% increase at Branch 4 for certain recurrence intervals), hydrograph modeling, potential overtopping at a downstream crossing for larger events, compatibility with the county local water management plan and consideration of best management practices (BMPs) to reduce volumetric flow or improve water quality. Houston Engineering responded point‑by‑point in the hearing, noting anticipated velocity increases would be small, that typical agricultural field crossings are designed for smaller recurrence events, and that the project as proposed would reduce sediment delivery by stopping ongoing pipe blowouts and failures. The engineer said the project team will continue coordination with DNR during preparation of the final engineer’s report.

Cost estimates and alternatives: The engineer’s preliminary cost estimates listed construction costs of about $643,000 (which includes a 20% contingency), plus estimated legal, engineering, administrative and viewing costs of about $184,000 for a total project estimate of approximately $827,512. The engineer also presented a separable repair-only cost (replace tiles at current sizes) estimated at about $739,000; staff recommended the viewers consider separating the cost of repair‑level replacement from the improvement costs that provide additional capacity.

Public input: The petitioners’ attorney, Dean Zimmerli, urged the authority to proceed to the next step (final engineer’s report and viewers). A landowner, John Lokey, described crop losses and replanting needs in recent years, expressed concern about sediment movement during heavy rains, but did not oppose proceeding. The DNR hydrologist visited the site and provided the advisory report summarized at the hearing; Houston Engineering addressed those concerns during its presentation.

Authority action: After discussion, the drainage authority voted to: (1) find the petition properly filed and that the project appears necessary, feasible and of public and private benefit; (2) proceed with the improvement proceedings and direct preparation of a final engineer’s report; (3) appoint Houston Engineering (already engaged) to prepare the final engineer’s report and to appoint viewers (Mark Baron and team, Barons Group) to prepare a viewers’ report and determine benefits. The motions passed on recorded voice/roll votes.

What’s next: The authority directed staff to draft findings and orders to be considered at the next meeting and to continue coordination with the DNR and landowners as the final engineer’s report and viewer’s report are prepared. When bids and finalized costs are available those figures will be presented for further action.

Details in brief: Petition filed 05/29/2024; PER dated 12/31/2024; DNR advisory letter dated 02/06/2025; construction estimate (PER): ~$643,000 (plus 20% contingency), total PER estimate ~$827,512; repair‑only estimate: ~$739,000; viewers appointed: Barons Group; final engineer: Houston Engineering.