Sioux City advances $400 million WWTP reconstruction under CMAR model amid budget pressures

Sioux City advances $400 million WWTP reconstruction under CMAR model amid budget pressuresThe city's Phase 1 wastewater treatment plant upgrade is currently estimated at $400.1 million—43% over its initial budget—as officials prepare to bid out trade packages to meet strict state consent order deadlines.

Kiewit's 60% cost model for the Phase 1 WWTP upgrade sits at $400.1 million, a reduction from an earlier $552.3 million estimate but still above the 2023 facility plan budget of $285 million.

The project is being delivered using a Construction Manager at Risk (CMAR) approach, with Kiewit leading pre-construction services and Hazen advancing the 90% design.

The city is under a state consent order that carries a $5,000 daily fine for delays, prompting an expedited pre-qualification and bidding process for major trade packages.

Kiewit is expected to submit a Guaranteed Maximum Price (GMP) to the City Council in June 2026.

Sioux City, Iowa, is moving forward with the massive Phase 1 reconstruction of its Wastewater Treatment Plant (WWTP), navigating significant cost escalations and state-mandated deadlines. During recent WWTP Reconstruction and Design Advisory Committee meetings, officials reviewed a 60% cost model from pre-construction manager Kiewit that prices the project at $400,179,000. While the $400.1 million figure represents a steep drop from the 30% cost model of $552.3 million—achieved through civil scope reductions and independent local contractor validation—it remains approximately 43% over the 2023 facility plan budget of $285 million. Public Works Director Thomas Pingel noted the budget challenges, while committee members highlighted significant price hikes for process mechanicals, including pumps for the final lift station and mechanisms for the new primary and final clarifiers. The project is utilizing a Construction Manager at Risk (CMAR) delivery method, noted by Pingel as the first of its kind for the state. Kiewit is managing the pre-qualification and bidding of multiple trade packages, including site demolition, deep foundations, clarifier concrete, and process piping. Kiewit will procure major high-risk equipment and may self-perform select support packages. Hazen, the project's design engineer, submitted 90% plans to the city in December 2025 and an Iowa Department of Natural Resources (IDNR) construction permit application in February 2026. The city is operating under a strict state consent order carrying a $5,000-per-day fine for delays, underscoring the urgency of the procurement schedule. Kiewit evaluated trade package qualifications in March and is expected to submit a Guaranteed Maximum Price (GMP) to the city in June 2026. If the City Council rejects the GMP, the project may revert to a traditional design-bid-build approach. Alongside the Phase 1 reconstruction, the city is executing emergency structural repairs to existing primary clarifiers using ARPA funds and advancing a separate digester project that includes a new high-strength receiving station designed to increase biogas production and improve odor control.