The Smoky Mountain (formerly known as Tapoco) Project, consisting of four developments (Chilhowee, Calderwood, Cheoah and Santeetlah) extends along the Little Tennessee River from about river mile marker 33 located approximately 3,000 feet downstream of Chilhowee Dam to just above river mile marker 60, a little more than a half-mile downstream of the Tennessee Valley Authority’s (TVA) Fontana Dam. The Chilhowee, Calderwood and Cheoah developments and Santeetlah Powerhouse are located on the Little Tennessee River. Santeetlah Dam and Reservoir are located on the Cheoah River, a tributary to the Little Tennessee River. Santeetlah Dam is located approximately 9.3 miles upstream of the confluence of the two rivers, which is located just downstream of Cheoah Powerhouse. The Project Boundary also encompasses much of the Cheoah River corridor downstream of the Santeetlah Dam. The total area within the FERC Project Boundary is approximately 8,300 acres (5,800 acres of water and 2,500 acres of land).
|Project Name||Smoky Mountain|
|LIHI Certificate Number||18|
|LIHI Effective and
|March 20, 2012
March 20, 2020
|Owner||Brookfield Smoky Mountain Hydropower LLC|
|State||North Carolina, Tennessee|
|Location||Located on the Little Tennessee and Cheoah Rivers in Graham and Swain Counties, North Carolina, and Blount and Monroe Counties, Tennessee.|
|Installed Capacity||376.6 MW|
|Average Annual Generation||1,361,821 MWh|
|Facility Type||Santeetlah Reservoir: storage impoundment
Cheoah, Calderwood, Chilhowee: run-of-river mode, following the daily-cycle peaking operations of Fontana
Santeetlah Dam is located in Graham County, North Carolina on the Cheoah River, just upstream of river mile 9. Santeetlah Reservoir consists of 78.8 miles of shoreline and 2,881 acres of water surface at its full-pool elevation of 1,940.9 feet. The drainage area of Santeetlah Reservoir covers 176 square miles.
The installed capacity of the Santeetlah Development is 40.4 MW. The Santeetlah Powerhouse contains two vertical Francis turbine units directly connected to generators.
Cheoah Development is the most upstream of the three Project developments located on the Little Tennessee River. The dam is located in Graham and Swain counties, North Carolina, between river miles 51 and 52, just upstream of the mouth of the Cheoah River. Cheoah Reservoir has 19.6 miles of shoreline and 644 acres of water surface at full-pool (elevation 1,276.8 feet). Cheoah Reservoir has a drainage area of 1,608 square miles.
The installed capacity of the Cheoah Development is 118.0 MW. Following upgrades now underway the installed capacity is projected to increase to 140.0 MW by 12/31/2013. The Cheoah powerhouse contains five vertical Francis turbine units directly connected to generators.
Calderwood Development, the third in the chain of Project developments, is located in Graham and Swain counties, North Carolina, and Blount and Monroe counties, Tennessee between river miles 42 and 44 of the Little Tennessee River. Calderwood Reservoir consists of 16.9 miles of shoreline and 570 acres of water surface at full-pool (elevation 1,087.8 feet). The drainage area of Calderwood Reservoir is 1,856 square miles.
Chilhowee is the most downstream of the Project developments. The development is located in Blount and Monroe counties, Tennessee between river miles 33 and 34 of the Little Tennessee River. Chilhowee Reservoir consists of 26.4 miles of shoreline and 1,723 acres of water surface at full-pool (elevation 874.0 feet). The reservoir covers a drainage area of 1,977 square miles.
The installed capacity of Chilhowee Development is 52.2 MW. The Chilhowee Powerhouse contains three Kaplan turbine units directly connected to generators.
Summary of Reservoir and Selected Infrastructure Attributes by Development
|Development||Reservoir Acreage||Shoreline Miles||Selected Infrastructure Attributes|
|Santeetlah||2,881||78.8||Dam 1,054 ft. long and 216 ft. high.Pipelines and tunnels carry Cheoah River water 5 miles to the Santeetlah powerhouse on the Little Tennessee River.|
|Cheoah||644||19.8||Dam is 750 ft. long and 229 ft. high.A tunnel carries water 450 feet from one intake to four turbine-generator units, and a penstock carries water 490 feet from a second intake to a fifth turbine-generator unit.|
|Calderwood||570||17.1||Dam is 916 ft. long and 230 ft. high.A 2,050 ft. long tunnel carries water from the intake to the powerhouse.|
|Chilhowee||1,734||26.1||Dam is 1,483 ft. long and 88.5 ft. high.A powerhouse integral to the dam is located immediately downstream of the intake.|
Hydropower Project Operations
Santeetlah Reservoir, the largest of the four Project reservoirs, is operated as a storage impoundment in accordance with an annual operating curve, which establishes target seasonal reservoir levels. The current operating curve was adopted in 2004 as part of the Relicensing Settlement Agreement.
Santeetlah Reservoir is operated to maintain high recreational elevations during the summer months, followed by fall drawdown to allow for collection of rainfall and runoff during the late fall, winter and early spring. The current operating curve (below) was developed to also provide protection and enhancement for a variety of other resources and uses, including aquatic species and habitat, water quality, reservoir wetlands, archaeological sites, and scenic appearance throughout the year. During the period April 1 to November 1, the maximum drawdown at Santeetlah Reservoir is five feet. During the period December 1 to March 1, the maximum drawdown is ten feet. APGI has operated Santeetlah Reservoir in accordance with the operations curve since March 1, 2005, with no exceptions.
Prior to the Relicensing Settlement Agreement, there were no regular flow releases from Santeetlah Dam into the Cheoah River. Water from Santeetlah Reservoir was diverted to the powerhouse located on the Little Tennessee River upstream of Cheoah Dam. The drainage area for the Cheoah River below Santeetlah Dam was made up of leakage from the dam, tributary inflow and occasional spills from the dam.
Beginning September 1, 2005 as part of the Relicensing Settlement Agreement, Tapoco has released flows from Santeetlah Dam into the Cheoah River according to Table 1 in Section A – Flows. The aquatic base flow for each month is determined by calculating the average daily inflow (ADI) value for the three preceding months using daily measures of change in reservoir elevation and total discharge. If the ADI value is greater than the historic 25th percentile average flow for that month shown in Table 2 in Section A – Flows, Tapoco releases flows according to Tier A of Table 1. If the ADI is less than or equal to the historic 25th percentile average flow for that month, flows are released according to Tier B of Table 1.
Since TVA’s upstream Fontana Dam serves as the primary storage and flow control facility for the lower Little Tennessee River, operations of the Cheoah, Calderwood, and Chilhowee developments are based on Fontana’s operation and planned discharges and are essentially operated in a run-of-river mode following the daily-cycle peaking operations of Fontana. During periods of high releases from Fontana, these three developments operate 24 hours per day and water is stored at Santeetlah Reservoir, based on available storage, for subsequent releases. During periods of low releases from Fontana, the Cheoah, Calderwood and Chilhowee developments operate a limited number of hours per day at maximum capacity in a modified run-of-river mode. Due to their limited ability to store water, the Cheoah and Calderwood reservoirs are operated with daily pondage and with maximum drawdowns of seven feet at Cheoah and six feet at Calderwood. There is no seasonal drawdown at either development.
Calderwood Powerhouse and Dam are located on a horse-shoe shaped area of the Little Tennessee River known as the Calderwood Bypass. Water from Calderwood Reservoir flows to the powerhouse through an underground tunnel that cuts across the horseshoe area. This diversion of water from the dam creates a “bypassed” reach of the Little Tennessee River main stem that extends from the dam to the powerhouse. Prior to the Relicensing Settlement Agreement, water flow in the bypass was limited to leakage from the dam and inflows from two small tributaries. In accordance with the 2005 FERC license for the Tapoco Project, Tapoco maintains minimum instream flows in the Calderwood Bypass.
The Chilhowee Reservoir is operated with daily pondage, a normal fluctuation range of one to two feet with a minimum outflow, a maximum drawdown of five feet from normal full-pool elevation and no seasonal drawdown. At TVA’s request, the Chilhowee Development is operated from May 1 to October 31 with a minimum daily average outflow of 1,000 cubic feet per second (cfs) into the Chilhowee tailrace. For the remainder of the year, no minimum flow is required downstream of Chilhowee. TVA’s Tellico Dam is located approximately 33 miles downstream of the Chilhowee Dam.
 All elevations are based on the USGS datum. When the Tapoco Project was originally constructed, a local survey datum was used for each development. The full-pool reservoir elevations (USGS/local datum) are as follows: Santeetlah 1,940.9 ft / 1,817 ft, Cheoah 1,276.8 ft / 1,154 ft, Calderwood 1,087.8 ft / 965 ft and Chilhowee 874 ft / 874 ft. Regardless which datum is used, the full-pool reservoir elevation reflects the top of the spillway gate elevation or the maximum normal water level for that reservoir.
March 6, 2013: Alcoa Power Generating Inc. (APGI) has assigned ownership of the Tapoco Project to Brookfield Smoky Mountain Hydropower LLC (BSMH), as per a FERC filing date of 12/3/12. APGI sold the Tapoco Project to BSMH (sale date: November 15, 2012) and FERC transferred the Project license to BSMH. The project has been renamed the Smoky Mountain Hydro Project.
July 26, 2012: The Tapoco Hydroelectric Project continues to meet the Low Impact Hydropower Certification Criteria, and has been recertified for an eight year term, effective March 20, 2012 and expiring March 20, 2020.
March 20, 2012: Alcoa Power Generating Inc. has submitted an application for the re-certification of the Tapoco Hydroelectric Project. A public comment period will remain open until May 20, 2012.
December 1, 2005: The Tapoco Hydroelectric Project has been certified as low impact for an eight year term, effective July 25, 2005 and expiring July 25, 2013. It consists of four powerhouses and four dams and is the largest hydropower project to be certified by LIHI on the east coast.
July 25, 2005: Alcoa Power Generating Inc. has submitted an application for certification of the Tapoco Hydroelectric Project, located on the Little Tennessee and Cheoah Rivers.