YOU WERE ASKING ! WATER LEVEL

The following information on the Oastler Lake Dam Operating plan was provided to Lynda Marsland by Steve Taylor. Steve is a Water Management Specialist at the Ministry of Natural Resources. He can be reached via email at Steve.taylor@mnr.gov.on.ca. Please note that the article refers to a colour coded rule graph which illustrates preferred water levels. The rule graph is not included with this newsletter.

Oastler Lake Yearly Operating Plan

As for most regulated lakes in the Ministry of Natural Resources, Parry Sound District, the Oastler dam is operated under a prescribed Operating Plan.

The associated Rule Curve graph illustrates the target or preferred water level (green line). The operating range (orange lines) represents the range of operation that typically occurs with varying environmental conditions from year to year (i.e. wet Vs. Dry). Extreme rainfall events or severe drought conditions can cause the lake to fall above or below the normal operating range. All lake elevations are expressed in meters above sea level, Geodetic Survey Canada (GSC).
The Plan provides water level objectives throughout the seasons for any given year. Generally, stable summer levels are maintained for the summer recreational season. To minimize the potential for spring flooding, a fall drawdown is made to ensure some storage for the spring runoff (freshet) period during the snow pack melt and spring rain period. The lake level during the spring will peak at higher levels due to the spring freshet.

The following is a brief explanation of the typical operating phases for the Oastler Lake dam to meet the objectives of the Plan:

Fall
On or about October 31st, the top log is removed for the duration of the winter
Spring
Just before the onset of the spring freshet, the second log is removed and the valve is opened. This is completed just prior to the opening of the Otter lake dam.
In average years, with lake water passing over the dam wing wall, the level should not generally exceed an elevation of 204.80 m
In high flow years, an additional stop log may be removed. Care is taken to ensure no flooding concerns are created downstream on the Boyne River
Summer
As the spring freshet begins to recede and lake elevation approaches 204.50 m, all but one log is replaced in the dam.

Once lake level falls to about 204.50 m, the valve is closed off.