Wood Lake Dam Overview (managed by the Ministry of Natural Resources)
The original Wood Lake Dam was constructed of timber in 1949 by the Department of Public Works and was reconstructed in 1983 by the Ministry of Natural Resources. The frame of the old timber dam was kept in place to support the existing bridge owned by the Town of Bracebridge. The dam was constructed to maintain a range of water levels for recreation on Wood Lake. In July 1973 a staff gauge was established to assist operators in making dam adjustments. A preferred water level was negotiated with the Wood Lake Cottagers’ Association President at the time and the preferred water level was established at a level of 100.00 local datum. In GSC datum that is an elevation of 301.00.
The normal stop log complement for the Wood Lake dam is 3 x 12 inch stoplogs and either a 6" stop log or a 9" stop log on top. Depending on the amount of rain and the water level trend the 6" or 9" log are switched to attenuate the rate of change in water levels and facilitate more appropriate discharge for the dam considering the size of the lake and how quickly it can react to changes. When we receive a large amount of precipitation and water levels trend up extremely fast the top log will be left out of the dam until water levels return to those considered more normal for that time of year. Later in the fall, usually by mid-November, all but two of the stoplogs are removed from the dam to lower water levels for the winter. The bottom two stoplogs are never removed for normal operations. However, someday they may be replaced if needed.
Rule Curve/Operating Plan for Wood Lake
The Rule Curve above shows the Normal Operating Zone of Wood Lake (between the red and black lines) and the actual water level (blue line) as measured by an automated data logger at the dam. Under normal watershed conditions water levels are managed by MNR within the Normal Operating Zone of the lake. Seasonal objective outlined on the rule curve include: spring - higher water to store in case of a dry summer and provide downstream flow for ecological purposes; summer - recreation and downstream flow for ecological purposes; fall - draw down to provide storage and reaction time for fall rains; winter - low water levels for infrastructure protection.
