Nicola Lake Health: Our Scientific Monitoring Scope
Our Guardians Volunteer Testing teams test bi-weekly in partnership with the Ministry of Environment and Parks, the BC Ministry of Water, Land and Resource Stewardship. Sampling helps us understand nutrient loading, water quality trends, and seasonal watershed impacts. Our goal is evidence-based stewardship to better understand what is happening in Nicola Lake with the goal to explore practical restoration solutions.
Guardian Water Quality Testing
Secchi Testing
Measuring the clarity of the water.
Water Sampling
Testing for nutrient levels, particularly phosphorus and nitrogen
Dissolved Oxygen Levels
Measuring oxygen levels in the water at different depths.
Cynobacteria Testing
Testing and monitoring blue-green algae levels to identify toxic bloom triggers.
What We Learned from Recent Scientific Discussions
The Guardians recently met with lake biologists and limnologists to better understand the causes behind algae blooms and water quality concerns on Nicola Lake. One of the clearest messages was that Nicola Lake is facing a combination of long-term pressures, not a single cause. Scientists explained that Nicola Lake is being affected by both:
- External nutrient loading — nutrients entering the lake from the watershed
- Internal nutrient loading — nutrients already stored in lake sediments being recycled back into the water
This means that even if outside nutrient inputs are reduced, the lake may continue to experience algae blooms because the lake itself contains decades of accumulated nutrients.
Internal Loading: A Significant Finding
Scientists confirmed that Nicola Lake is experiencing internal nutrient loading. In simple terms, nutrients such as phosphorus are being released from lake sediments back into the water column. This process can intensify algae and cyanobacteria blooms. Internal loading is important because it reflects decades of nutrient accumulation and means the lake is not simply reacting to one recent source. The lake is effectively recycling nutrients that have built up over many years.
Wind Does Not Remove Algae
One important clarification shared by the scientists is that wind does not remove algae blooms. Instead, wind physically mixes the upper layers of the lake. This can make blooms appear to disappear temporarily when they are dispersed beneath the surface. However:
- Cyanobacteria can still remain present in the water
- Blooms may return to the surface during calm conditions
- Clear-looking water does not always mean risk-free water
This is important for members to understand when evaluating lake conditions during the summer.
Mild Winter Conditions May Have Helped
Interestingly, the scientists noted that Nicola Lake’s relatively mild winter and reduced ice cover may have had one temporary benefit. When lakes remain frozen for long periods:
- Oxygen becomes trapped beneath the ice
- Bottom waters lose oxygen
- Sediments release nutrients into the lake
Because Nicola Lake had very limited ice cover this winter, oxygen mixing likely continued throughout much of the season. This may have reduced winter nutrient release compared to years with heavy ice. However, this does not eliminate the risk of summer blooms.
Hot, Calm Summers Create Higher Bloom Risk
While winter conditions may have helped, scientists cautioned that:
- Warm temperatures
- Calm water
- Reduced inflows
- Longer periods of lake layering can still create ideal conditions for cyanobacteria blooms.
If the lake develops low-oxygen conditions at depth during summer, nutrients may again be released from sediments. This is one reason continued monitoring is so important.
Climate Change
Climate change is another cause of Nicola Lake’s algae and cyanobacteria issues as it makes existing nutrient problems worse.
- Warmer water temperatures: Extend the bloom season and favour cyanobacteria.
- Reduced snowpack and lower inflows: Results in less flushing of the lake.
- Drought conditions: Create stagnant, nutrient-rich water that supports blooms.
- Wildfire ash inputs: Add phosphorus directly to the lake.
- Weather swings: Can trigger nutrient pulses from runoff after heavy rain.
Key takeaway: climate change is not creating the nutrient problem. It is amplifying existing ones. Existing phosphorus + warmer water + reduced flushing = higher bloom risk.