With the 2011 removal of Sodom Dam on the Sodom Ditch and the Shearer Dam on the Calapooia River, Thompson’s Mills historic water delivery system no longer functions as it has in the past. An alternative is necessary to ensure water flows to the mill.
Considerations for the new system include maintaining the mill’s historic and aesthetic qualities, providing an on-site water source that meets firefighting requirements and enabling the mill to continue current operations with the potential for demonstration of machinery.
To address these considerations, during the winter of 2013-2014, contractors under the guidance of Oregon Parks and Recreation Department Engineer Scott Stewart installed an Obermeyer Hydro weir (inflatable dam) just upstream of the Boston Mill Drive bridge and a pump near the tail race on the east side of the mill building. The weir will be maintained in the upright position during dry months to hold water in the mill race. When the water recedes due to evaporation or other issues, the pump will be used to draw water from the Calapooia river to replenish and maintain the water level in the mill race.
To prevent the possibility of trapping migrating fish, park staff and volunteers will lower the mill race as low as possible early each summer and transport any remaining fish to the Calapooia river just downstream of the tail race. Once the fish removal is complete, water will be pumped back into the mill race and maintained over the summer season.
The final phase of this project should be completed this summer and includes lowering the water levels for a period of time to repair the head gates and flume gates.