Hidden lake Water Balance
Hidden Lake has risen more than 4 meters since the ACES class began recording information on the lake in 1991. The ES class in 1994 began more detailed studies focusing on water quality. In the early winter of 1994 the ES class conducted a bathometric study by laying out a 20 m grid on the ice lake and drilling and measuring water depth at each intersection. The class visited the lake 7 days later to complete study on the the lake dried up and the class |
The lake level increase has killed all the trees adjacent to lake below water level. ES classes also conducted dendrochronology studies on six of these trees. They were an average of 130 to 140 years old. This indicates that the lake has not risen to this level for the past 130 – 140 years. Hidden lake exfiltrates and the rise in the lake is due to the substrate of the lake coated with layers of algae resulting from the periodic blooms. The rise in the lake coincides with the beginning of IWL release of effluent. The age of the trees shows that this lake level event has not happened over the past 130 to 140 years. If the concentrations of phosphates in Porter Creek were dependent of background level, and had not been impacted by IWL, we could have expected lake levels to have raised in the past. The tree ages show this is an unlikely event. This indicates two things; that the background nutrient levels had not resulted in raised lake levels, but, the nitrates and phosphates added to the system by IWL to the system have resulted in the lake flooding.