The Murfreesboro Water Resources Board approved a change order related to the Wharf wet‑weather improvements and heard staff describe a recent impeller failure and repair at the wastewater treatment plant.

Staff said the wet‑weather improvements aim to increase hydraulic capacity from 60 million to 80 million gallons to better handle storm flows. While excavating, crews found utility drawings were inaccurate and other utilities intruded into the planned route; crews also found there was not a proper connection between two existing lines (one 4‑inch and one 10‑inch). The change relocates the lines to a clear path and creates a proper connection; staff said the change order will not affect the total contract amount or schedule and will be paid from the contract contingency. Staff reported the original contingency was $300,000, of which $54,000 had been used previously, leaving about $221,000; the change requested was described as $24,515 and staff said SSR concurs with the approach.

In other business, staff presented photos and described a catastrophic failure of an aerator impeller at the plant. The impeller — a multi‑ton fabricated component welded to a shaft — failed, sheared and fell; city staff described the repair as requiring heavy cranes and dive crews. Staff said a Kentucky dive/repair crew that had responded after the 2010 flood returned, performed the repair and set elevations on two other impellers; the city purchased a spare impeller because lead times for fabrication are long and parts are made to order.

The board moved, seconded and approved the wet‑weather change order by voice vote and acknowledged the operational briefing on the impeller repair.

Why it matters: the wet‑weather change keeps the project moving while addressing unforeseen underground conflicts; the impeller failure and repair illustrate operational risks and spare equipment planning for critical treatment plant components.