Amador Water Agency outlines fixes for Ione plant capacity, proposes pipeline to US Mine to handle backwash

Amador Water Agency General Manager Larry McKinney told the Ione City Council on May 6 that the agency’s Ione treatment plant is operating above its maximum day capacity and remains under a declared water shortage emergency for the Ione service area.

McKinney said the agency identified three projects in its 2020 water master plan as the next steps to regain capacity: (1) improvements inside the treatment train at the plant, (2) access and security upgrades required by the Department of Homeland Security, and (3) enhanced backwash handling because higher plant throughput will produce more filter backwash that must be disposed of.

Why it matters: McKinney said the plant currently depends on system storage and conservation to avoid service interruptions on peak days, a situation his board declared an emergency for in January 2024. Restoring reliable capacity is necessary for both existing customers and planned growth in the city, he said.

McKinney told council members the agency initially planned new backwash drying beds on land near Ione Reservoir but instead negotiated with US Mine to take the backwash. He said the new plan would lower construction costs by “several million dollars,” reduce traffic and environmental impacts from trucked disposal, and eliminate the plant’s periodic discharge of a sludgy 10% portion of backwash to the sewer system.

The agency issued bonds in October (a net $19 million bond issuance; the sale was larger when capitalized interest was included) to move forward on the work and is at roughly 50% design on the projects. McKinney said a geotechnical study identified an additional roughly $1.0–$1.5 million of stabilization work at the constrained hilltop site, which has pushed costs higher than earlier estimates. He said the construction schedule still targets roughly two and a half years to completion, subject to final design and permitting.

McKinney also discussed a Department of Water Resources funding award intended to assist agencies that sign voluntary agreements to provide additional dry-year flows to the Delta. The agency directed those funds primarily to water-efficiency measures serving the Ione service area and to piping sections of the Ione Canal to reduce conveyance losses.

Council members pressed McKinney on financing and operational details. McKinney said the bond debt service will be paid from the Amador Water Agency’s net revenue pledged from its entire water enterprise (all systems combined) and that the agency expects to enter takeout financing next spring; long-range planning shows debt service increasing as additional borrowing is completed. He said the proposed backwash pipeline will be sized to handle peak flows up to about 200,000 gallons per day and the alignment concept follows the existing raw-water corridor near Howard Park and crosses Highway 104.

Ending: McKinney said his board will consider a draft final mitigated negative declaration later in the week and that the agency will continue coordination with the city on any pipeline routing through Howard Park. He told the council he will be available for questions and thanked city staff for coordinating on related efficiency projects.