Salem Water Department Plans for Deep Drawdown and Enhanced Filter Resiliency

The City of Salem Council meeting on July 28, 2025, focused on critical water treatment challenges and preparations for an upcoming deep drawdown of the Detroit Reservoir. Public Works Director Brian Martin presented detailed insights into the operation of slow sand filters, which are essential for the city's water treatment process. These filters, spanning approximately 2.5 acres, utilize a layered system of materials to effectively remove contaminants from source water, relying on low turbidity levels for optimal performance.

Martin highlighted the impending drawdown, mandated by the National Marine Fisheries Service, aimed at aiding juvenile salmon and steelhead migration. This drawdown will lower lake levels significantly, exposing sediment and potentially increasing turbidity levels, which could adversely affect the filtration process. Previous drawdowns in the region have resulted in turbidity levels exceeding 200 NTUs, far above the acceptable threshold of 10 NTUs for the city's water treatment.

To mitigate the anticipated impact, the city is exploring alternative water supply sources, including existing wells and an aquifer storage facility. However, the current capacity falls short of the average demand, necessitating immediate action to enhance water supply resilience. Plans include drilling additional wells and improving interconnections with neighboring cities for water sharing.

The council discussed the urgency of these preparations, as delays in procurement could extend beyond the drawdown timeline. An emergency declaration was proposed to expedite the procurement process, allowing for quicker action on drilling and equipment acquisition. The estimated budget for these improvements is around $8 million, with funding sourced from utility rates.

Council members expressed concerns about potential water conservation measures and the need for public education on water usage. The discussion underscored the importance of building a resilient water system to withstand future challenges, including the effects of the drawdown and other environmental factors.

In conclusion, the council's proactive approach aims to ensure the city's water supply remains safe and reliable amid significant operational changes. Regular updates on progress and budget management will be provided to the council as preparations continue.