April 15, 2026, Construction Update

Since Monday March 16, SumCo has been monitoring water levels at the Bel Air Dam site. Water remained high for the last two weeks in March due to spring runoff and rain events. Due to the high water levels, sediment excavation at the site and related air quality monitoring has been paused temporarily. SumCo regularly conducts visual inspections and has not observed any large sediment plumes discharging from Bel Air Dam, or substantial sediment in the water discharging through the cut in the dam.

In late March/early April SumCo added a temporary riprap cofferdam (a temporary dam made of stones) upstream of the existing Bel Air Dam and excavated the area between this new cofferdam and the existing dam, creating an area where water can pool and sediment can settle. Since installing the temporary cofferdam, SumCo has been slowly deconstructing  the existing Bel Air Dam in order to lower the water level of the flooded area. Once the water upstream of the temporary cofferdam is sufficiently lowered, SumCo will divert water away from areas where they will continue to excavate sediment. Air quality monitoring will resume once sediment removal is underway again. Once the planned amount of sediment is removed, they will create the new stream channel and banks and install plantings.

Pumping may be needed to further lower the water level in the impoundment upstream of the Bel Air Dam and temporary cofferdam. When pumps are running,  SumCo will measure  turbidity (amount of soil particles suspended in the water) in the discharge to confirm that it remains within acceptable limits.

As noted in the March 16 update, the majority of planned sediment excavation at the site has been completed since the project began in summer 2025. Completion of sediment excavation is anticipated by late spring/early summer 2026.

Sediment testing has continued throughout the process, and sampling has not identified any material characterized as PCB remediation waste.