Newsletter
Spring 2026
Part 1 of 2
We respectfully acknowledge that we are on the traditional, ancestral, and unceded territory of the Syilx (Okanagan) Peoples, and specifically the lands of the Upper Nicola community. We honour their enduring connection to these lands and waters.
Dear Members,
As we move into spring and prepare for another lake season, we wanted to share an update on Nicola Lake conditions, recent discussions with lake scientists and biologists, and current information regarding lake levels and water quality.
Over the past several weeks, the Guardians have met with limnologists (study freshwater environments), biologists, watershed specialists, provincial partners, and dam operators to better understand what is happening in Nicola Lake and how we can continue to support evidence-based stewardship.
The information below is intended to provide members with a clear summary of what we know today.
Part 1 of the Spring Newsletter focuses on the science behind what is happening in Nicola Lake. Part 2 will focus on what we can do as good stewards of the lake.
Here are your elected Board of Directors for 2025-2026.
1
Executive Committee
  • President: John Arnold – Quilchena on the Lake
  • Vice President: Dawne Tomlinson – Nicola Bay RV Resort
  • Treasurer: Brent Pascall – Harmon Estates
2
Directors at Large
  • Peter Schmid – Quilchena on the Lake and Jack Ranch; Merritt Resident
  • Dan Emerson – Nicola Bay RV Resort
  • Lisa Schlagintweit –Lakeshore Estates
  • Doug Stoneson - Lakeshore Estates
Our board members are volunteers, and represent diverse areas around the lake, ensuring community voices are heard as we continue to focus our efforts on the health of Nicola Lake and its watershed. The Board meets regularly throughout the year in addition to an annual AGM where all members are encouraged to attend.
Help Save our Lake
The more members we have, the stronger our collective voice when working with local and provincial governments, as well as other organizations. Please consider encouraging family members, friends, and neighbours to sign up. A larger membership helps ensure our concerns are heard and taken seriously. Sign up at www.guardiansofnicola.ca
Annual General Meeting
SAVE THE DATE: JULY 9, 2026
We are hopeful many of our members will be able to attend.
July 9 @ Best Western Hotel, Merritt B.C.
6:00-7:00 Check In for Members
7:00 Meeting Starts
Remember that members have access to all of the Society minutes and other information on the website at: www.guardiansofnicola.ca
Current Lake Levels and Water Conditions
Many members have been asking about Nicola Lake levels and what to expect heading into the 2026 season.
Freshet has begun and the lake is rising!
The dam operators have advised that they are currently working to fill Nicola Lake to Full Supply Level (FSL), which is 625.83 metres above sea level.
Due to very low snowpack and forecast inflows estimated at roughly 40% of normal, lake levels are expected to rise more slowly than usual.
Current expectations suggest:
  • Lake levels may rise approximately another 1.2 metres
  • Full Supply Level may not be reached until sometime in July
  • Outflows have been reduced significantly to retain water in the lake
  • Once full, lake levels may remain near peak for a shorter period than in a typical year before seasonal drawdown begins
This means that lake conditions may look different from what members are accustomed to seeing in a typical year.
As always, lake conditions can change depending on weather and inflows, and these projections are based on current forecasts.
We will continue to provide updates as additional information becomes available.
 
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:
  1. External nutrient loading — nutrients entering the lake from the watershed
  1. 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 as an Accelerator
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.
Expanded Water Testing for 2026
The Guardians are pleased to report that expanded monitoring is planned for 2026. The Guardians Testing Team have been bumped up to Level 3 Water Testing by the Ministry of Water, Land and Resource Stewardship. In addition, they will be performing additional testing under the guidance of Larratt Aquatic Consulting.
A number of organizations are now working together to build a more complete scientific picture of Nicola Lake and its watershed.
Guardians Testing Team + Larratt Aquatic Consulting
Monthly lake water chemistry sampling
Surface & deep-water sampling
Historical data comparison
Oxygen, temperature & stratification monitoring
Nicola Watershed Governance Partnership
This partnership includes Water, Land and Resource Stewardship, Ministry of Environment partners, Upper Nicola Band, and watershed scientists.
Monthly creek and inflow sampling
Watershed-based water quality monitoring
Stream chemistry and nutrient tracking from upstream sources
Why Coordination Matters
Share data and avoid duplication
Coordinate sampling timing across groups
Build a complete watershed-wide picture
Together, these efforts will provide one of the strongest scientific foundations Nicola Lake has had to date.
Nicola Lake Impact Chart – Working Hypothesis
As part of our ongoing discussions with scientists, biologists, watershed experts, and local observations, the Guardians have developed an evolving impact chart to help identify the likely contributors influencing algae blooms and water quality challenges in Nicola Lake.
This chart is a working hypothesis.
It is not intended to present final conclusions or assign blame, it is an evolving framework designed to:
  • Organize current understanding
  • Identify likely nutrient sources and stressors
  • Guide future monitoring priorities
  • Support evidence-based discussion
  • Help identify where education, stewardship, and action may be most effective
Importantly, this framework has received input and refinement from limnologists and biologists, including Heather Larratt and other scientific partners, and will continue to evolve as more monitoring data becomes available.
Click below to review nutrient sources and stressors. This chart is vital in understanding and guiding our work.

IDENTIFIED NUTRIENTS AND SOURCES

The table reflects the current working understanding of contributing factors influencing Nicola Lake water quality and algae bloom conditions. Impact Level Source / Threat Why It Matters Potential Actions Prime Responsibility Very High Internal Loading Nutrients accumulated in lake sediments over many decades can be released back into the water column, fueling blooms. Continued monitoring, nutrient budgeting, oxygen studies, lake-layer monitoring. Scientists, NWPG, Guardians Very High Cattle Access to Watershed Manure, bank trampling, sediment disturbance, and runoff contribute phosphorus and nutrient loading. Fencing, off-stream watering, riparian restoration, setback practices. Ranchers, TNRD, Upper Nicola Band, Guardians High Bank Erosion Sediment entering the lake carries phosphorus and destabilizes shorelines. Vegetated buffers, stabilization, erosion monitoring, reduced shoreline disturbance. MoE, DFO, Guardians, Residents. Boaters High / Moderate Dam Operations Water level management affects temperature, residence time, flooding, erosion, and lake mixing conditions. Adaptive flow discussions, thermocline monitoring, coordinated planning. MoE, Guardians, Dam Operators Moderate Logging / Pine Beetle Salvage Soil disturbance and exposed slopes can increase runoff and nutrient transport. Erosion-control practices, monitoring, rapid reforestation. FLNROD, Forestry Operators Moderate Agricultural Fertilizer Runoff Fertilizer use may contribute nutrients to watershed inflows. Buffer strips, nutrient management, reduced phosphorus use. Farmers, MoE, Guardians Moderate Septic Systems (Failing / Outdated) Aging or poorly functioning systems may contribute nutrients to groundwater and nearshore areas. Education, inspections, maintenance awareness, potential upgrades. Interior Health, TNRD, Guardians, Residents Moderate Climate Change Warmer temperatures, drought, and longer low-flow periods create favorable bloom conditions. Temperature tracking, adaptive planning, watershed resilience. MoE, Guardians Moderate Reduced Freshet Lower snowmelt runoff reduces flushing and allows nutrients to remain in the lake longer. Snowpack monitoring, inflow forecasting, coordination with lake operations. MoE, Guardians Moderate Snowpack Changes Changing timing and volume of runoff affects lake levels and nutrient transport. Long-term snowpack tracking and forecasting. MoE, Guardians Moderate Altered Riparian Vegetation Loss of natural vegetation reduces filtration and shoreline stability. Native replanting, shoreline stewardship, education. TNRD, Guardians, Residents Lower Hydrophobic Soil Runoff Water bypasses normal soil filtration after wildfire or drought, increasing localized runoff risk. Buffering, runoff containment, restoration. Municipalities, Landowners Lower Yellow Perch Invasive species concern with limited direct effect on algae but possible ecosystem impacts. Monitoring, prevention education, targeted removal where appropriate. BC Invasives, First Nations Note: Nicola Lake is influenced by multiple overlapping factors. The goal is to better understand not only what is happening in Nicola Lake — but why.  

A Long Road Ahead — No Quick Fix
It is important to recognize that Nicola Lake did not reach this point overnight. Scientists emphasized that the conditions we are seeing today are likely the result of more than 100 years of accumulated impacts across the watershed and within the lake itself. Nutrients build slowly over time. Sediments store phosphorus and organic material for decades, and the lake can continue recycling those nutrients long after they first entered the system.
We are monitoring several technologies and restoration approaches being used elsewhere, including oxygenation systems, circulation methods, and lake treatment strategies. We have found that many of these technologies will not work in Nicola Lake for various reasons.
As well, scientists have advised that it would be premature to move toward large-scale intervention without first completing a stronger scientific picture.
The current priority is to:
  • Build a complete nutrient budget
  • Understand oxygen conditions throughout the lake
  • Measure seasonal layering and chemistry
  • Confirm the relative importance of different nutrient sources
  • Establish reliable long-term data
Once that picture becomes clearer, future restoration or management options can be evaluated with greater confidence.
The Guardians remain committed to taking an evidence-based approach that balances urgency with sound science.
Challenges Facing Nicola Lake
  • Nicola Lake is a large waterbody, meaning some restoration or treatment technologies designed for small lakes are not practical or effective here.
  • The lake is deep in several areas, creating complex water movement and seasonal layering.
  • Conditions change significantly throughout the year, making monitoring and management more challenging.
  • Internal nutrient loading and watershed inputs interact in complex ways, making it difficult to identify a single source or solution.
  • Wind can strongly influence water movement, sediment disturbance, and algae distribution.
  • Long-term financial sustainability is needed to support monitoring, research, and stewardship efforts.
  • There are many stakeholders involved, including fisheries agencies, provincial ministries, residents, farmers and ranchers, and Indigenous communities.
Our Path Forward - Science and Data
01
Build a complete nutrient budget
02
Understand oxygen conditions throughout the lake
03
Measure seasonal layering and chemistry
04
Confirm the relative importance of different nutrient sources
05
Establish reliable long-term data
Once that picture becomes clearer, future restoration or management options can be evaluated with greater confidence. The Guardians remain committed to taking an evidence-based approach that balances urgency with sound science. We appreciate the continued support of our members and the growing commitment to protecting Nicola Lake and its watershed. Together, we are building both knowledge and stewardship. Thank you for being part of this effort.
There are things we can do to help right now. Stay tuned for part 2 which focuses on what we can do to help.
Guardians of Nicola Lake & Watershed Society