Discharge Into Calderwood Bypass - Little Tennessee River (cfs)
559
Feet Below Pool
0.28
* As of November 21, 2009 at 3:11:00 AM
The Calderwood Development is located in Graham and Swain counties, North Carolina and Blount and Monroe counties, Tennessee on the Little Tennessee River between river miles 43 and 44. The Calderwood Development was completed in 1930 and consists of a dam, powerhouse and pipeline/tunnel. Calderwood Dam impounds Calderwood Reservoir that has a normal full pool area of approximately 570 acres and a drainage area of 1,856 square miles. The normal full pool elevation of Calderwood Reservoir is 1087.8 feet (USGS). About half of Calderwood Reservoir lies in Tennessee, the remainder extends back into North Carolina.
The Calderwood powerhouse is located about one mile downstream of the dam, below the horseshoe-shaped bend in the river. The powerhouse contains three vertical Francis turbine units directly connected to generators. The current licensed capacity of the three units is 140.4 MW and the total station hydraulic capacity is 8,980 cfs. Water for the Calderwood powerhouse is withdrawn through an intake located in rock adjacent to the right abutment of the dam at a centerline depth of 24.8 feet below the normal full pool elevation of the reservoir. From the intake, water is passed through a 2,150-foot long concrete lined tunnel, bypassing a section of the river. Since the implementation of the new License, APGI maintains minimum instream flows in this section of the river, known as the Calderwood Bypass.
Calderwood, like Cheoah and Chilhowee, is operated in a run-of-river mode following the daily-cycle, peaking operations of the Tennessee Valley Authority’s (TVA) Fontana Dam located upstream. Fontana serves as the primary flow control facility for the lower Little Tennessee River and TVA assists Tapoco in determining the daily operation of the Tapoco developments to best match expected flow releases from Fontana. Because of its limited storage capacity, Calderwood is operated with minimal fluctuations in water levels. Calderwood Reservoir is operated with daily pondage and with a maximum drawdown of six feet. There is no seasonal drawdown.
