Dam Seepage Monitoring System Installed to monitor Lake Ouachita's Blakely Mountain Dam.
In May 2006, a risk assessment screening was performed for Blakely Mountain Dam as part of the Corps-wide dam safety initiative.
Earthen Dam Safety Action Classification (DSAC) have 5 Ratings - I, II, III, IV, V . - I is Urgent And Compelling and V is normal.
Blakely Mountain Dam was classified as DSAC II largely due to recently discovered anomalies in the under-drain system which occurred during construction of the dam.
DSAC Class II - (Urgent) – Dams where failure could begin during normal operations or be initiated as the consequence of an event. The likelihood of failure from one of these occurrences, prior to remediation, is too high to assure public safety; or the combination of life or economic consequences with probability of failure is very high.
The Corps of Engineers installed a monitoring system to keep an eye on seepage at Blakely Mountain Dam. The monitoring system is part of the analysis and response to the 2005 inspection within the overall dam safety program.
In the wake of the regular 2005
inspection, engineers discovered that a layer of filter material had
been installed incorrectly when the dam was originally built in
1953. Filter material is designed to aid normal seepage under the
dam. Without it, the seepage must be monitored more closely over
“The Dam has performed well over its 50 years of service and we believe at this time that it is functioning normally, however; we need to watch the seepage issue more closely as the Dam continues to age”, said Bob Fitzgerald, Dam Safety Officer for the Vicksburg District.
In order to install the monitoring system the Corps worked with Entergy
to lower the level of Lake Hamilton during the normal winter
drawdown of 2008 - 2009 the draw down will required the
maximum allowed drop of 9 feet in Lake
Hamilton. Nine foot drawdown had occurred three times since 1997
to help control aquatic weed growth.