Estacada council reviews guaranteed-maximum-price for new wastewater plant; directs staff to draft contract amendment

Estacada City Council on Monday reviewed a guaranteed-maximum-price proposal for the city's new wastewater treatment plant and voted to direct staff to prepare a contract amendment with the construction manager, Sladen Constructors Inc.

The council workshop, led by the project team from Sladen and engineering firm Kennedy Jenks, presented a construction GMP of about $57.26 million for Sladen's scope and an estimated $2.4 million for Kennedy Jenks' construction-phase services, putting the project's projected construction and construction-support cost near $59.66 million.

The project team said the GMP is based on the city's 90% design documents and includes several defined allowances and contingencies intended to limit the need for formal change orders. Major budget items discussed included a 2.5% design-evolution allowance (about $1.14 million), a 5% construction contingency carried in the CMGC contract, and a $500,000 tariff allowance to address fluctuating import duties on materials. The team also carried a $350,000 allowance for structured demolition of the existing plant after construction of the new facility.

Why this matters: the GMP locks the city's construction exposure for the core build while preserving city control over contingency and allowance disbursements. Council approval to update the Sladen contract is the next formal step toward mobilizing construction.

Details and changes explained at the workshop

- Digester tank: The team recommended reverting to a concrete digester after bids showed the glass-fused steel option came in far higher than budgetary estimates. The team said a resized concrete tank would be roughly $55,000 more than the steel tank but would offer greater durability and longer life; the city would convert the digester scope to an allowance and finish the 100% design before bidding that piece.

- Admin building: Prefabrication aimed at cost savings did not materialize; the single prefab bid was about $450,000 higher than expectations. The team recommended conventional on-site framing, expecting similar or lower cost and fewer design constraints.

- Archaeology and special inspections: Permitting reviews added a requirement for archaeological monitoring in targeted excavation areas. The team said a monitoring plan and an inadvertent discovery plan would be used if artifacts were found; any on-site monitoring-related standby costs would be treated as a change in conditions and covered by contingency or specific allowances.

- Outreach and local participation: The project received 125 bids across 63 bid packages. The team reported roughly $1.1 million in subcontract awards estimated to go to businesses in Estacada and an additional roughly $5.4 million in awards to nearby communities (Canby, Clackamas area) in the broader subcontracting circle.

Schedule and permitting

The project team presented a proposed mobilization date in early August 2025, conditional on permitting. Construction start was targeted for August 2025 with commissioning in October 2027 and a final punch-list wrap in February 2028; demolition of the old plant was slated for early 2028. The schedule assumes that the Oregon Department of Environmental Quality (DEQ) will approve a schedule extension for the project outfall; project staff said DEQ staff are aware of the requested extension and that DEQ typically coordinates timing with CM/GC projects.

Rate study and funding

City staff and the project team updated a rate forecast showing a $60 million project baseline. The city has applied for a $10 million state grant; staff said even a partial award (for example, $5 million) would materially reduce projected sewer rates and could bring annual residential sewer charges below $100 in some growth scenarios. The city also plans to pursue DEQ loan financing at 1% interest to help close the funding gap.

Council action

After the workshop presentation and questions from council, the council voted to direct staff to develop a contract amendment with Sladen Constructors for the GMP and construction of the wastewater treatment plant. The motion was seconded and passed by voice vote.

Quote

Chris, an operations staff member who participated in the workshop and will operate the new plant, told council when asked whether the facility will meet operational needs, "Yes, sir. It will."

What happens next

Staff will prepare a formal contract amendment reflecting the GMP and return to council with the contract documents and accompanying materials (loan documents, grant status, and updated rate information) for formal approval. The project team said that several items remain on allowance or contingency until 100% design is complete, at which point the city will be asked to authorize use of those funds with documented scope changes.

Sources: workshop presentation by Sladen Constructors and Kennedy Jenks; Estacada city staff presentation (project summary and rate analysis).