Water Levels on Sydenham Lake

The Cataraqui Region Conservation Authority (CRCA) has the responsibility for a large area of the eastern Ontario watershed, including the catchment area for Sydenham Lake.  Their initial and primary mandate is flood control; however, this is balanced by maintaining wetlands as well as recreational use of the lake.  As such they control the water level in Sydenham Lake.  They do this in conjunction with the Ministry of Natural Resources (MNR) and Ministry of the Environment (MOE).  As well these agencies share information and data collection, which helps form the basis of the water cycle control often referred to as the rule curve.

The water engineers at the CRCA try to maintain the water levels in Sydenham Lake to match the data in the rule curve currently established between 429.5 (spring & summer) and 428.5 (autumn & winter) feet above sea level.  This one foot (30.5 cm) differential was established through historical record, legal agreement, consultation with the Sydenham Lake Association and the general public. The current rule curve has been in effect, with minor changes from time to time, since the mid 1980’s.  Depending on the amount of rain, snowmelt, the length of dry spells, the amount of sunny weather and the temperature, the CRCA tries to maintain water levels along this rule curve.

Sydenham Lake levels are managed through the dam located in the Village of Sydenham.  “Stop Logs” (square wood timbers) are raised or lowered as needed to control water flow through the dam.

The CRCA purchased the dam structure in the late 1970’s, and rebuilt the dam in1977.  The surrounding park, the mill structure, as well as the water rights to the lake were purchased by the CRCA in the late 1980’s.  From 2005 to 2009 the CRCA undertook extensive renovations to the dam to reduce leaking and upgrade structural integrity, including replacing the stop logs, excavating and stabilizing the park where the old mill structure was located, and rebuilding the dam spillway.  Funding from the MNR enabled recent improvements including telemetry to remotely monitor lake levels, rain fall, stream flow and evaporation.  There is also a new direct read gauge attached to the old gauge on the dam structure.  Water levels are also monitored upstream from Sydenham Lake and snow pack information is gathered every two weeks over the winter months.

As Sydenham Lake is now a reservoir for the Village of Sydenham the CRCA has completed a number of source water protection studies including a Water Budget Study to define the extent of water available in the water shed.  Although the CRCA controls the water level in the lake and indirectly “owns” the water rights, the MOE issues a Permit To Take Water to the Township specifying the maximum amount of water that can be removed for the water plant in Sydenham.  This permit is issued for 10 years and will be renegotiated in 2014.

Spring levels are closely monitored to control excess flow over the dam which could cause flooding downstream, yet keep enough water in the lake to maintain the wetlands and recreational use, while also minimizing flooding potential around the lake.  The CRCA also responds to summer storms which can quickly raise levels.  As well, they hold lake level as high as possible as a hedge against drought.  During the autumn the lake level is brought down to the winter holding level to provide “room” for more water during the fall rain storms and spring melt. Lake levels are even monitored during the winter to ensure the integrity and safety of the ice.  Too much water will push the ice up, whereas lower levels will allow the ice to collapse; either way creating a safety hazard for recreational users of the ice surface.
Through this delicate balancing act the CRCA engineers try to maintain the appropriate water level for the time.  They deal with excess rain fall, drought, snow melt, ice levels and manage to maintain consistent water levels in the lake.