The sluice gates – which are nearly 100 years old – are no longer required for the operation and maintenance of the dam following the replacement of the lower set of ensign valves with clamshell gates in 2004.
The work to improve the long-term safety of the structure will include removing existing cast iron sluice outlet liners; designing, furnishing, and installing watertight bulkheads and frames for installation adjacent to existing sluice gates; furnishing and placing cast-in-place concrete for sluice outlet plugs; and pressure grouting and backfill grouting.
The 107m high concrete arch dam was constructed in 1915.