Construction Plans Summary

This construction plans document supports the Iowa Department of Agriculture and Land Stewardship's Division of Soil Conservation and Water Quality solicitation for the Mah751636C Nutrient Reduction Wetland Project in Mahaska County, Iowa. The project encompasses construction of a traditional breakpoint nutrient reduction wetland across approximately 6.6 acres, requiring selective clearing, excavation, grading, riser outlet installation, tile and outlet structure construction, riprap placement, and seeding. The scope includes approximately 24,926 cubic yards of earthwork, 368 linear feet of tile installation, concrete and nyloplast structures, 310 tons of riprap, and 25 cubic yards of grout. Bid submissions are due October 28, 2025, at 3:00 PM via the IMPACS online bidding system. A pre-bid conference is scheduled for October 7, 2025, at the Oskaloosa Library. Construction work, excluding seeding, must be completed by November 15, 2026, with seeding completion required by December 15, 2026. The successful bidder must execute a performance bond of 100% of the contract award within 14 days of receiving the Notice-of-Award, valid for one year following final acceptance.

The estimated construction cost range is $250,000 to $350,000, with liquidated damages assessed at $175 per day for delays in main work and $125 per day for seeding delays. Contractors must submit a 10% bid bond and be registered with the Iowa Department of Inspections, Appeals & Licensing, providing evidence of financial data, previous experience, equipment ownership, and performance records. Non-Iowa corporations must provide proof of authorization to do business in the state prior to contract execution. Materials purchased for the project are exempt from sales and use taxes, with contractors receiving a specific sales tax exemption certificate. The project features a comprehensive nutrient reduction strategy with a water control structure, principal spillway, drawdown structure, and drainage tile modifications, serving a total drainage area of 181 acres with a wetland pool area of 1.99 acres.