By Karla MarshallFebruary 24, 2013
KANDAHAR AIRFIELD, Afghanistan -- The U.S. Army Corps of Engineers awarded three projects under one contract for Kajaki Dam water management improvements in late January 2013.
USACE developed the projects to rehabilitate inoperable or poorly working components of the Kajaki Dam which will enable the dam's managers to better control water flow out of the dam.
"We awarded a contract in late January for Kajaki Dam improvements that will give Afghans better control of water stored in the Kajaki Reservoir," said U.S. Army Col. Vincent V. Quarles, the Afghanistan Engineer District-South commander. "Currently the intake to the irrigation tunnel has an inoperable gate; the downstream valves and the emergency closure valves are in need of maintenance and repair."
If the emergency control system (valves and gate) fail, there would be no way to stop water from freely draining into the Helmand Valley either.
"The Kajaki Dam was constructed in the 1950s; because of decades of war and neglect, the dam has not had the benefit of sufficient, periodic upgrades and maintenance," explained Quarles.
One of the projects includes rehabilitation of the three 84-inch roto valves located inside the irrigation tunnel and replacement of the three 84-inch jet valves located at the outlet end of the irrigation tunnel.
"Rehabilitating and replacing the roto and jet valves is a first, critical step to managing the volume of water released from the dam and improving the reliability," said Water and Infrastructure Program Manager Linda Murphy.
She explained that a roto valve is designed to open and close relatively easily, despite high fluid pressure. Jet valves are part of the outlet structure, and decrease the pressure of the water exiting the bottom of the dam, which prevents erosion and scouring. Currently neither the roto or jet valves operate as designed.
The purpose of the piezometer project is to perform an evaluation of the embankment to see if it is performing as designed or whether a dam safety concern exists said Murphy, who deployed from USACE's Louisville District.
The third USACE project at Kajaki Dam includes increasing the capacity of the existing crane and rehabilitating the existing intake structure components.
The project includes the rehabilitation of the intake bulkhead gate, steel sliding gate, crane, crane hoist assembly, lifting assembly, embedded parts, and hydrology gage. The gates currently do not close, so no maintenance can be performed on the gates or the irrigation outlet tunnels, explained Tim Morris the South District's project manager who leads the project delivery team.
The three projects at the dam are scheduled for completion in late 2014.