Abandoned Hydro Power Plant in TN

McMinnville Hydroelectric Station, McMinnville Tennessee

Date added: October 11, 2023 Categories: Tennessee Power Plant Hydroelectric Power

Dam and hydrostation powerhouse, looking east (1989)

The McMinnville Hydroelectric Station is the kind of small-scale, vernacularly designed steel-reinforced concrete hydroelectric engineering projects typical throughout the initial days of electrical power development in the state of Tennessee. Its design - especially when considering its water intake system - shares consistency in construction materials, genre, temporal limits, and utilitarian functions with other Pre-TVA Hydroelectric sites on Tennessee's smaller rivers. Hydroelectricity was produced there, with intermittent interruptions from 1907 to 1949, supplying McMinnville's early industrial and domestic electric needs. Today the dam, intake structure, forebay, powerhouse, tailrace, and supporting walls downstream from the powerhouse are still extant. The station has been abandoned since 1949.

Site Description

The McMinnville Pre-TVA Hydroelectric Station is located on the Barren Fork River at river mile 6.3 in Warren County (population 16,251), at McMinnville, Tennessee, the county seat. The major features of the site consist of a dam, an intake channel, and a powerhouse on the east (left) bank of the Barren Fork River. Access to both sides of the dam is by unimproved roads off State Highway 108 which crosses the river about 300 feet downstream. An L&N railroad bridge crosses the reservoir just upstream. Presently, the dam's chief purpose is to maintain the reservoir for the city's water supply.

Electricity was supplied to McMinnville by a steam-powered generator until 1907 when the Walling Light and Power Company "installed a generator in the Old Falcon Flour Mill on Barren Fork River...." It was, as in the example of Sparta, Tennessee, an impromptu affair and was utilized for only a few months until a new facility was built on the other side of the river, later in the same year. After floods in 1922 destroyed these facilities, the current powerhouse was constructed in 1923. It housed a Leffel Francis-type turbine rated at 380 HP and 164 RPM which was connected to a 250kW generator manufactured by General Electric. TEPCO purchased the site in 1925 and it was transferred to TVA in 1939 ten years later and sold back to the City of McMinnville in 1949 when it was retired. It stands today on the Barren Fork River and, although abandoned, it is a good example of what can be termed "early-twentieth-century-vernacular-concrete-hydro style." The McMinnville Hydroelectric Powerhouse (1923) is built of reinforced concrete, while the 320-foot long dam is twenty feet high and represents an unusual combination of concrete gravity and timber crib design overlain with concrete, similar in arrangement to the smaller dam in Manchester, in Coffee County on the Duck River. In 1929, a major rehabilitation of the right side of the dam took place. The right section is an ogee-shaped concrete gravity structure which ties into a railroad support at the right abutment. The railroad bridge was constructed in 1910. The left section of the dam is the original rock-filled timber crib and the face is very rough and covered by small vegetational growth. The extant, but now empty, hydro station contained a Leffel Francis-type reaction turbine, rated at 380 horsepower and 164 RPM, which was connected to a 250 kW General Electric generator. The intake channel is located on the left bank of the Barren Fork River, conveying water seventy-five feet downstream to the powerhouse. A TVA study explains that the:

walls and floor [of the intake channel] are concrete except for the upper half of the wall nearest the bank which is formed by the limestone block foundation of an old building. [sic] A steel slide gate is in place at the channel entrance, and a wooden slide gate, used for dewatering purposes, is located on the wall nearest the river. A trashrack structure minus the steel trashracks is situated about 12 feet from the powerhouse with two empty slots for stop logs at the powerhouse. A lifting mechanism for the sluice gate is in place. The channel has deteriorated over the years with trees and other smaller vegetation growing in the floor and wall nearest the bank. A large hole is present where the dam joins the channel wall. Water which leaks into the channel near the entrance disappears through the floor.

The tailrace is found directly downstream from the powerhouse and is parallel to the river. It is full of silt and debris and is approximately fifteen feet wide and is bounded by a short concrete wall on one side and the river bank on the other.

The powerhouse itself is a concrete structure with three floors. The turbine sat on the second floor and discharged water into the lower level which directed the flow into the tailrace. The upper, or third, floor incorporated the governor, controls, generator, and all electrical equipment. Doors and window glass are missing, and all machinery has long since been removed. The small substation used by this facility is extant and located about 200 feet from the powerhouse on a nearby hill. The Maloney transformers are in place. Some small transmission lines radiate from the substation, and other lines cross the river at the railroad bridge, State Highway 108 bridge, and over the powerhouse.