National Dam Safety Program. Floyd Lake Dam (MO 30744), Mississippi - Kaskaskia - St. Louis Basin, Washington County, Missouri. Phase I Inspection Report.
Abstract
Floyd Lake Dam has been classified by St Louis District, Corps of Engineers (SLD), as having a high hazard potential; we concur with this classification. The SLD estimated damage zone length extends approximately eight miles downstream of the dam. Within the potential downstream damage zone are 4 dwellings within the first mile and the town of Old Mines, approximately 2 mi downstream. The dam is classified small due to its 50 ac-ft storage capacity. The dam is 21 ft high. The classification for small size dams is based on a height between 25 and 40 ft of a storage capacity between 50 and 1000 ac-ft. The visual inspection and available information indicate the dam is in generally poor condition. The principal deficiencies noted were the inadequate spillway capacity, potential erosion at the toe of the dam by the flow in the discharge channel, and very dense vegetation on the downstream slope of the dam, obscuring the face from a thorough inspection. Seepage and stability analyses comparable to the requirements of the 'Recommended Guidelines for Safety Inspection of Dams' were not available, which is a deficiency that should be rectified. Hydraulic and hydrologic analyses indicate that the dam will be overtopped by the 10 percent probability-of-occurrence event (10-yr flood), and by a flood of greater than 5 percent of the PMF event. The PMF is defined as the flood event that may be expected to occur from the most severe combination of critical meteorological and hydrologic conditions that are reasonably possible in the region.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1980
- Accession Number
- ADA105539
Entities
People
- Leonard M. Krazynski
- Richard G. Berggreen