Sodom and Shearer Dam Removals – Monitoring
Background and History
(from the Calapooia Watershed Council’s website)
The digging of Sodom Ditch in the late 1800s to divert high flows from Thompson’s Mills on the Calapooia River resulted in the low-flow dewatering of the Calapooia River downstream of the bifurcation of the two waterways. Starting in 1890, a push-up dam was constructed on Sodom Ditch to divert water during low-flow into the Calapooia River. The push-up dam was replaced with a log crib dam, then the concrete structure pictured above in 1957.
Shearer Dam was constructed (initially as a push-up dam) to divert water from the Calapooia River to a mill race for Thompson’s Mills. The concrete structure pictured above was constructed in 1956.
Both dams were equipped with fish ladders, but neither met current fish passage criteria.
See the Calapooia Watershed Council project page link for more details.
Calapooia River and Sodom Channel discharge: spreadsheet (updated 1/4/16)
With the removal of Sodom and Shearer dams on the Calapooia River and Sodom Ditch, an opportunity exists to investigate the effectiveness of and the biological, physical, and engineering outcomes of dam removal. The overarching objectives are to:
- evaluate the effectiveness of the project in meeting objectives to inform maintenance and modification, and
- investigate the spatial and temporal effects of removing Sodom and Shearer Dams on habitat and fisheries of the Calapooia River.
More details on specific monitoring plans are outlined in the Sodom and Shearer Dam Removal Monitoring Proposal – Nov. 2010.
Resources and Pertinent Links