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APPENDIX B <br /> A Summary of the Major Construction History of Lake Decatur Dam <br /> The City owns and operates the Lake Decatur Dam located on the Sangamon River just west of <br /> Business Route U.S. 51. Built in 1922, the dam provides an impoundment for the City's source of <br /> drinking water. In 1955 bascule gates were added to the concrete spillway to increase the lake level <br /> from elevation 610 to 614.5. The following table summarizes the history of major construction <br /> projects for the Lake Decatur Dam: <br /> Year Activity <br /> 1922 Original Construction <br /> 1950's Fish ladder removed <br /> 1954-55 Flashboards removed and bascule gate installed <br /> Sluice ate replacement and trash racks installed <br /> 1955-1996 Sluice gates reconditioned <br /> 1955-1996 Resurfaced downstream face of spillway access platform <br /> 1995 Overlay placed on downstream face of spillway <br /> 1996 Shotcrete applied to left and right abutment walls <br /> 1998 North bascule gate hydraulic cylinders refurbished (Cylinders 1 thru 4) <br /> 2000 South bascule gate hydraulic cylinders refurbished (Cylinders 5 thru 8) <br /> 2000 Approximately 30 concrete panels on upstream slope of right embankment replaced <br /> 2000 Pile cap and all concrete panels along the downstream right riverbank training wall <br /> re laced. <br /> 2001 New joints saw cut into spillway overlay to match original dam joints <br /> 2001 Spalling along upstream face of outlet works and downstream face of spillway <br /> atched <br /> 2001 New riprap placed downstream of stilling basin and along the left river bank <br /> 2004 New sluice gate lift mechanism at the lower tail water dam <br /> 2005 Spalling along upstream face of outlet works structure patched <br /> Page 15 <br />