Wednesday, July 18, 2012

Angeghakot Dam


The Angeghakot Dam receives the discharge of the Spandaryan powerhouse, as well as impounding water from the Vorotan River downstream of the Spandaryan Dam. The dam is a concrete gravity structure, about 33 meters high. The dam has an overflow, ungated spillways, as well as a non-ovefflow section. Attachment B contains two photographs of the dam. No information, with the exception of a plan and a profile, was available about the Angeghakot Dam. This dam is the only substantial concrete dam in Armenia; therefore, Armenia does not have a considerable amount of expertise in gravity dams. It is also unclear whether the Angeghakot Dam was reviewed for seismic stability under the more severe criteria. The Vorotan Cascade management voiced concerns that the dam may not meet the stability criteria, but no studies were offered to provide a determination. The instrumentation in a concrete dam the size of Angeghakot is typically less than that found in an embankment dam. However, seepage areas are typically monitored and there is usually a routine formal program of internal and external inspection. It is understood that in 1997 survey marks were checked by the Hydro Design Institute and no substantial movements were detected. However, no report was available for our review. The Angeghakot Dam should also be subjected to a full inspection and re-analysis, including spillway capacity and focusing on whether the dam meets stability criteria under current
earthquake criteria.