National Dam Safety Program. Johns Creek Number 2 (Inventory Number VA 04501), James River Basin, Craig County, State of Virginia. Phase I Inspection Report.
Abstract
Johns Creek No. 2 Dam is a zoned, earthfill dam approximately 650 feet long and 51 feet high. The dam, located approximately 18 miles southwest of New Castle, Virginia is used for flood control. Johns Creek No. 2 Dam is an 'intermediate' size - 'significant' hazard structure as defined by the Recommended Guidelines for Safety Inspection of Dams. Using the Corps of Engineers' screening criteria for initial review of spillway adequacy, the 1/2 Probable Maximum Flood (1/2 PMF) was selected as the spillway design flood (SDF). The SDF was routed through the reservoir and found to overtop the dam by a maximum depth of 2.1 feet with an average critical velocity of 3.8 f.p.s. Total duration of dam overtopping would be approximately 3.2 hours. The dam and appurtenant structures were found to be in generally good overall condition. No conditions indicating embankment instability were detected during the field inspection and office analyses. Seepage at the toe of the dam is not considered serious; however, it is recommended that the rate be checked for increase at higher reservoir levels. The safety factors determined during design are greater than those required for minimum accepted stability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1979
- Accession Number
- ADA077465
Entities
People
- James A. Walsh