Thurlow Dam

Thurlow Dam. Alabama Power. , Construction began on Thurlow Dam in 1928 and the dam went into operation on December 31, 1930 as part of Alabama Power Company's development of the Tallapoosa River The dam was named in honor of Oscar. G. Thurlow, a Chief Engineer, Vice President and Director of Alabama Power., Thurlow Dam was built at the site of the 19th-century Tallassee Mills Dam The Tallassee Mills Dam generated power for the local cotton mill of which only ruins remain. , The Thurlow Dam Complex is eligible for listing in the National Register of Historic Places, based on its unique architecture and engineering and for significant events in the history of hydroelectric power in Alabama. In 2018, Alabama Power began to replace the dam's original spillway crest gates, known as flashboards. The original spill way automatic flashboards operated or "tripped" when the reservoir elevation reached a certain point during flood conditions. Once the flood conditions were over, Alabama Power would lower the reservoir to a certain elevation in order for the gates to stand back up. Due to age and other factors, these gates frequently did not reset on their own. When this occurred, dam personnel had to manually reset them from a barge. This posed a risk to Alabama Power staff because of the weight of the gates and the fact that the work had to be performed over the water., Alabama Power elected to replace the original flashboards with steel Obermeyer gates, which operate using adjustable, inflatable air bladders. Air is supplied to the bladders by compressors connected to the air bladders by piping, which is embedded in the dam crest. The Obermeyer gates can be raised and lowered gradually, which allows Alabama Power to better manage reservoir levels and spill during flood events. Further, there will be no need to lower the reservoir after spill events. , As part of the Obermeyer gate installation, Alabama Power removed the 36 original flashboard gates and corresponding concrete piers and constructed Obermeyer gate panels and five new piers. The various gates and piers wore designed, following consultation with the Alabama Historical Commission, to minimize visual impacts to the historic character of the dam when possible. For example, the steel gate panels of the Obermeyer gates were painted a color close to that of the original wooden gates, and the concroto was colorized to match the original concrete as closely as possible. Also, the new piers mimicked the design of the original piers to some extent by simulating the tapering and sloping as it extends downstream of the gate crest., Photo captions: , Top left: Alabama Power President Thomas W. Martin, Captain William Patrick Lay (Founder of Alabama Power) and Alabama Power Chief Engineer Oscar G Thurlow (Alabama Power Archives Collection 1939) , Top middle: Tallassee Mills Dam (Alabama Power Archives Collection, 1925) , Bottom left: Flashboards and Piers Extending Across the Top of Thurlow Dam , Bottom 2nd from left: Flashboards 1-7 and Piers , Bottom 2nd from right: Removed Flash Board June 2019 (28 feet wide, 12 feet high) , Bottom right: Typical Obermeyer Gate, Unless otherwise noted, photos provided by University of Alabama, Office of Archaeological Research, 2016 , Background image: completed project November 2019