Lake conditions at the present time

RLB produces a regular report on the conditions that prevail in the lake. This data can be consulted  by anyone who is interested in learning about the quality of the lake. 

Here are the latest readings taken by RLB

Lake Conditions: October 14 2019

Condition: Open
Secchi: 2.5 metres
Transparency: Murky
Temperature: 13.8 Celcius
Risk of bloom: Light
Comments: Clarity increases with the cold

A bit more on this subject

 A good indicator of the health of the lake is the measurement of the clarity of the water. To achieve this, RBL regularly monitors the transparency of the water, using the black and white Secchi disck. A Secchi disk measures 8 inches in diameter and is alternately painted white and black. It is lowered into the water by rope  until it can no longer be seen; the depth thus reach is considered as a measure of the clarity of the water. 

According to recognized scientific protocols, this measurement must take place in the deepest part of the lake (along the bottom trench), between 10:00 and 15:00.

 Renaissance Brome Laker reports the information on a panel on-line for the benefit of all citizens who would like to personally evaluate the risks of cyanobacteria, starting with the measured quality of the water in the lake. It is a recognized fact that when transparency is less than 2 metres due to water full of sedimentation and colonies of blue-green algae, this is an indicator of a coming ”bloom” and that citizens should be on alert. However, when a body of water such as Brome Lake indicates a clarity depth of 3.5 – 4 metres, the possibility of an algae bloom explosion is unlikely. RBL does its rounds of the lake on a regular basis. 

Secchi readings are usually conducted at 7 to 10 day intervals, weather conditions permitting. For safety reasons, the planned dates are carried forward when there is a storm or violent winds. These readings can vary according to the  visual capacity of the observer, the degree of light, the presence of waves and even turbulence caused by rain or motor boat circulation.

The clarity of the water is commonly used as a global indicator of its quality (even if the measure is approximate). In the case of Brome Lake, any value exceeding 4 metres is considered to be very good. A reading of less than 2 metres frequently leads to a prediction of a looming blue-green algae bloom and this could result in the closing of the lake for reasons of public health.

We must ensure that the lake is not subject to a public health warning or a restricted use alert. Public health authorities can, on recommendation by the ministry of the environment and following negative water quality results, issue a public health warning. In this case, the lake may be partially or totally subject to a use interdiction (drinking water, swimming, any activity where contact with the water is involved, etc.) 


To find out more