Ontario Power Generation

LAKEFIELD GENERATING STATION

PLANT GROUP: Small Hydro Division
DRAINAGE BASIN: Lake Ontario
RIVER: Trent
TRIBUTARY: Otanabee River
NEAREST POPULATION CENTRE: Lakefield
IN SERVICE DATE: June 1928
ACQUIRED BY HYDRO-ELECTRIC POWER COMMISSION OF ONTARIO: 1936
FROM: Canada Cement Company
Asset Transferred to Ontario Power Generation: April 1, 1999
NUMBER OF UNITS: 1
CONTROL: Northbury

POWERHOUSE:
The powerhouse is located at right angles to the canal and discharges into the main river. With the exception of the crane and roof beams, the construction is of reinforced concrete. A 23 tonne (25 ton) crane with a 4.5 tonne (5 ton) auxiliary hoist was installed for erection purposes.

FOREBAY AND HEADWORKS:
The headrace was constructed by building a concrete wall about 533.4 m (1,750 ft) long from the Government Dam upstream to the powerhouse. The upper end of this wall is parallel to and about 24.4 m (80 ft) distant from the north bank of the river. The intervening space was excavated to give a depth of 3.0 m (10 ft) and the shore side protected with rip-rap where necessary. The headrace wall is anchored to the rock and thoroughly grouted on both sides to prevent seepage from the headrace into the river. For most of its length, the wall was located on exposed rock so that very little cofferdam was required.

The headrace is watered through the most northerly four 6 m (20 ft) sluices of the Government dam. These sluices can be sealed with 35.6 cm (14 in) square wooden stoplogs; the river side of the dam is equipped with five steel gates equipped with electric hoists.

INTAKE:
Water is delivered from the headrace to the turbine pit through three 4.3 m (14 ft) wide sluices equipped with wooden stoplogs located about 1.2 m (4 ft) outside the plant wall. The sluice sills are 6.1 m (20 ft) below normal headwater level. Steel racks located just outside the sluice ways protect against the entry of foreign objects. The intake structure is covered with a concrete deck.

Water flow into the intake is at right angles to the direction of flow in the headrace.

CANAL:
This plant has no canal except the headrace canal described under "Forebay and Headworks".

DAM(S):
The main powerhouse dam is located about 21.3 m (70 ft) downstream of the powerhouse. This concrete dam is 4.9 m (16 ft) high and about 38.1 m (125 ft) long with four control sluices 6.1 m (20 ft) wide and with sills 3.6 m (12 ft) below normal headwater level. Three sluices are equipped with wooden stoplogs, the fourth with a steel gate and electric hoist to control forebay water levels when the generator is shut down. The total flow of the river is normally regulated by these sluices. The gates in the Government dam are only used during very high river flow periods.

The Tailrace - On the tailrace side of the plant, 4.3 m (14 ft) wide steel gates are installed which can be lowered by means of a portable hoist when their use is required.

SITE:
The development consists of a headrace, single unit powerhouse, switching bay and a control dam. The transformer station is located outside the building on the east side.

The development is located adjacent to Lock 26 on the Trent-Severn Waterway. The drainage area of the watershed at Lakefield is approximately 6994 km2 (2,700 miles2), the river being regulated for navigational purposes by Parks Canada (formerly the Department of Railways and Canals).

CONSTRUCTION:
Specifications for the design and development were prepared by J.G.G. Kerry of the firm of Kerry and Chace (the designers of Sidney, Frankford, Seymour, Healey Falls and Auburn in earlier days) in conjunction with Mr. Shirley Barr, Chief Engineer of the Canada Cement Company and Mr. W.G.H. Cam, its Chief Electrical Engineer. Canada Cement Company's construction department carried out the construction of the works.

The concrete plant consisted of overhead bins discharging directly into the mixer. The aggregate was unloaded from cars directly into the bins. The concrete was placed by means of buggies.

All foundations were carried to rock; the formation consisting of bedded limestone quite often badly broken up and shattered.

Lakefield generating station, when constructed, supplied power to the Canada Cement Company's Mill Number 7 at Lakefield. It operated in parallel with the company's developments at Youngs Point (see Retired Hydroelectric Stations) (450 kVA) located at Lock 27, 9.3 km (5.8 miles) upstream (2.2 m (7.3 ft) head) and Douro (1000 kVA) located at Lock 24, 3.7 km (2.3 miles) downstream (3.6 m (12 ft) head). Douro was retired from service July 1, 1943 and Youngs Point was retired January 5, 1944.

The plants were purchased by the Commission in the latter part of 1936 as part of the general clean-up of some franchises and privately owned developments in the Trent Valley.

MISCELLANEOUS:
The head of this plant varies to as much as 25.7 m (16 ft) under dry conditions when tailwater level is low. To cope with this situation, a moveable blade runner was installed. By changing the angle of the blades, high efficiency can be maintained over a range of net head conditions.