Abstract |
This Phase I Inspection/Evaluation Report details the results of a visual dam inspection of the Marshall Steam Station Coal Ash Retention Dam (MA01161) located on State Route 150 in Catawba County, North Carolina. The inspection was performed on May 28, 2009 by GZA GeoEnvironmental, Inc (GZA). The Marshall Steam Station Coal Ash Retention Dam has a maximum structural height of dam of approximately feet. In accordance with the U.S. Army Corps of Engineers (COE) guidelines, this dam is an Intermediate size structure. However, under criteria listed in the North Carolina Dam Safety Regulations, the dam would be classified as a Large size structure. The original Hazard Potential Classification for the Marshall Steam Station Coal Ash Retention Dam was Low under the COE and State of North Carolina criteria. Damage to North Carolina Highway 150 could possibly occur should there be a failure, and loss of life was not expected. However, the State of North Carolina revised the Hazard Potential Classification to High in 1984 due to the probable environmental damage to the adjacent waters of Lake Norman, the public financial loss, and the interruption of services from a dam failure. Per the EPA criteria the hazard classification would be considered Significant. The dam was judged to be in FAIR condition in GZAs opinion. At the time of the inspection water was flowing over the Discharge Tower Structure stoplogs, and the outlet in the discharge canal to Lake Norman was submerged. |