What is a Carrying Capacity Study and Why is it Important for Lake Windermere?
Steady growth in residents (Selkirk College, 2022), an increasing number of motorized boats on Lake Windermere, and the ongoing increase in travel and tourism to the area continue to strain our aquatic ecosystems. The 2018 Vital Signs Report states, “Our region is located at the Headwaters of the Columbia River, which winds uninterrupted through our communities, connecting us recreationally, economically, culturally and environmentally.”
We must do what we can to better understand how this increase in traffic on our waterways is affecting the health of our lake and the safety of people, as we don’t only depend on these waters for economic benefits but survival as a community.
In 2021, the results of the Windermere Lake Foreshore Integrated Management Plan (FIMP) were published. This study was conducted by Ecoscape Environmental Consultants LTD. and Lotic Environmental. As a result of the study, the report highlighted the need for a Recreational Carrying Capacity Study on Lake Windermere.
The following excerpt was taken from the FIMP
Work with local, Provincial and Federal agencies and First Nations on a recreational usage carrying capacity study which addresses the safety of people and protection of critical habitats. A carrying capacity is a concept of identifying a peak or total amount of an activity that can occur before a tipping point is reached. During peak periods (e.g., when the FIMP was conducted), Windermere Lake was noted to have a high density of motorized boat traffic.
On lakes, there are two essential carrying capacities to consider:
- First: Recreational Carrying Capacity: Total number of vessels that can use the Lake safely.
- Second: Environmental Carrying Capacity: Factors influencing the ability of an ecosystem to maintain its health. Environmental Carry Capacities vary throughout the different habitats along the Lake (e.g., wake overtopping nests, pollution, noise, physical harm—prop scaring or prop wash, beaching boats, etc.).
The carrying capacity of Windermere Lake should be determined considering these two elements. The results will identify the most appropriate areas for recreation, and the quantity or density of vessels a particular space can safely support without harming people or aquatic habitats. (Ecoscape Environmental Consultants Ltd. & Lotic Environmental, 2021)
Why do the Ambassadors believe this study is so crucial for Lake Windermere?
LWA often get calls from community members with concerns stemming from how busy Lake Windermere is becoming. These calls cover a diversity of topics regarding the state of the lake and drinking water, the safety of people recreating, the impact excessive use is having on the lake, and the future of Lake Windermere considering current impacts. Collectively we are observing more and more effects of our changing climate and the increase in anthropogenic pressures on our ecosystems. We as a community need to be proactive in protecting a resource as valuable to this region as Lake Windermere.
A significant stressor on the lake is the ever-increasing number and size of motorized boats. The impact of these vessels is seen in their ability to generate undissipated waves (i.e wake boats), which can erode shorelines, redistribute sediment, ruin spawning beds, damage property and swamp nests and habitats of vulnerable species. Pollution from boats and runoff from land deposits contaminants into the lake. These contaminants settle into bottom sediments where they are locked away and have minimal impact on water quality once buried. As a result of this process, sediments can contain many harmful toxins, metals, pesticides, and other chemicals, typically not affecting the health of the lake if they remain buried and undisturbed. However, wake boats have been shown to resuspend these sediments and their contaminants in the water column and uproot sensitive aquatic vegetation when operating in waters less than 6-8m deep (Davies, 2021). This impact is important to understand because Lake Windermere is, on average, 3-4m deep and around 7m at its deepest point. Therefore, the resuspension of buried sediments can release toxins and phosphorus into the water column, negatively impacting water quality over time (Davies, 2021).
Multiple studies have been done to better understand these impacts of wake-boats on lakes, and specifically their impact on shallow lakes. For example, a recent study by Terra Vigilas Environmental Services (2022) found total phosphorus levels increased by an average of 25% with only two passes of a wake boat in surf mode in waters 4.5-7.6 m deep. A significant concern of these impacts is resuspending toxins and heavy metals in the water column, which can contaminate drinking water sources and have other implications for the aquatic environment. It is also important to note an increase in limiting nutrients such as phosphorus within the water column can also lead to health issues for both humans and aquatic ecosystems. An increase in total phosphorous can cause algal blooms that significantly alter aquatic ecosystems, destroy recreation opportunities and aesthetic enjoyment, and can cause harm to humans and animals (Our Living Waters, 2019). An example of such algae blooms is blue-green algae (made up of cyanobacteria) which can produce liver toxins that are harmful or even lethal to humans and animals if ingested (Our Living Waters, 2019).
The Lake Windermere Ambassadors monitor the total phosphorous in the Lake monthly as a part of our water quality monitoring program. The Ministry of Environment (MOE) recommends the total phosphorus in Lake Windermere not exceed a concentration of 10 μg/L (0.01 mg/L) to protect drinking water sources and aquatic life (Nufeild et al., 2010). Of the total phosphorus samples the Ambassadors took in 2021 on Lake Windermere, 39% exceeded the MOE recommendation of 10 μg/L. These facts are especially concerning for the health of our community and the multiple community waterworks and individual households using Lake Windermere as their water source. There is also an ever-increasing growth in residents, leading to more considerable demands for water from Lake Windermere. Water consumption rates from the East Side Lake Windermere Water System show consumption has almost doubled from 2018-2021. We believe we have a duty to our community and those downriver from us to better understand how we are impacting our waters. It is then our responsibility to determine ways to mitigate those negative impacts.
Our 2021 shoreline fisheries assessment pointed to a potential increasing ratio of Northern Pikeminnow in Lake Windermere from the previous survey conducted in 2007. Pikeminnow are known to be voracious predators often out competing more sensitive native species, especially in highly disturbed aquatic environments. In 2007 the most common fish in Lake Windermere (according to the survey) were Redside shiner making up 84.1% of fish identified, while they made up only 6.5% of fish identified in our 2021 survey. So, what has changed to encourage these differences? During the survey Lotic Environmental pointed out that Northern Pikeminnow were common in all disturbance levels, however Northern Pikeminnow were about three times as common in highly disturbed sites than in sites with moderate or low disturbance (Hildebrand, 2022). In contrast Redside Shiner and other native fish appeared to prefer low disturbance sites. Sediment redistribution, wake, and noise from boating near spawning beds can also negatively impact sensitive native fish species. Though more data and a more extensive survey would be necessary to fully determine if these differences between survey years represent true changes to species assemblage, or if the differences are from natural variation, we can still use these comparisons to begin to develop a picture of what is going on with fish populations in Lake Windermere.
Fish are not the only populations to suffer from this combination of human influences. Species of waterfowl struggle from boat wake drowning nests, and native mussels might be struggling in Lake Windermere as well. In 2021 during our annual aquatic invasive plant survey, Biologist Rachel Darvill made an informal observation on the lack of freshwater mussels in Lake Windermere compared to previous years. Freshwater mussels are often considered a bioindicator species, and their populations are known to suffer from dams, warming water temperatures, sedimentation from motor boats, and declining water quality.
This project will incorporate many sensitive areas into the mapping of preferred boating areas including Kokanee and Burbot spawning beds and rearing habitat, ecologically significant shore wetland habitat, important areas for bull trout, rainbow trout, and westslope cutthroat trout, native mussel beds, and waterfowl nesting sites. By identifying these sensitive habitats and mapping where they are, individual boaters will have the information necessary to adapt their boating behaviour in ways that minimize harm to Lake Windermere’s sensitive aquatic ecosystems, while continuing to enjoy the amazing recreation opportunities our lake offers.
How can we begin to study and mitigate these impacts?
From the 2021 FIMP
Multiple sets of biological data from this assessment [The FIMP Study] can be considered and incorporated to help identify locations where boating recreation will have the lowest impact. For example, it is vital to identify and avoid/restrict use to areas with emergent vegetation important to nesting birds that can be impacted by boat wakes. As well as identify and protect appropriate travel corridors to maintain shallow, littoral areas, which are essential for mussel beds and fish spawning habitat. The Lake is very shallow, and during peak usage, turbidity from prop wash was apparent in the shallow areas experiencing high usage. This result is not unexpected; such sediments are prone to disturbance given the soft lakebed’s size, density, and shallow nature. Identifying appropriate nearshore travel corridors would reduce turbidity and subsequent risks to drinking water quality and fish habitats. The recommendations of the Lake Windermere Management Plan should also be reviewed and reconsidered (Catherine Berris and Assoc 2011). Areas outlining slow no wake zones and no boating zones should be revised using the data from the FIMP report to confirm areas appropriate for different recreational types and densities. (Ecoscape Environmental Consultants Ltd. & Lotic Environmental, 2021)
Multiple carrying capacity studies have been done on different lakes throughout the province, country and North America that should be used to help create the guidelines for Lake Windermere. A carrying capacity study was conducted on Kalamalka and Wood Lake in the Okanagan. Water quality, boat recreation/use, and habitat values were combined to help local governments identify and map areas where recreation was preferred (Schleppe et al., 2016). This data has helped all levels of government engage with different agencies to manage lakes better using the available regulatory processes. An example of how government agencies used this study is Transport Canada was able to help identify and regulate appropriate travel corridors on navigable waterways. (Ecoscape Environmental Consultants Ltd. & Lotic Environmental, 2021)
The Ambassadors believe a Lake Windermere Carrying Capacity Study can be used to better understand how we are impacting Lake Windermere, and map preferred areas for recreation to occur to mitigate damage to water quality while protecting aquatic species, habitats, and drinking water intakes. This study could be referred to by various stakeholders when considering regulations, management and recommendations for Lake Windermere. We think this study can significantly contribute to protecting the lake’s health and the health and safety of the people who depend on it.
If you would like to donate, help support this study, or have any questions, we encourage you to reach out by emailing us at email@example.com.
Davies, J. (2021, April 1). Wake boats on small interior lakes and Rivers. BCLSS. Retrieved March 18, 2022, from https://www.bclss.org/news/wake-boats-on-small-interior-lakes-and-rivers
DFO. (2021, March 26). Government of Canada. Government of Canada, Fisheries and Oceans Canada, Communications Branch. Retrieved May 19, 2022, from https://www.dfo-mpo.gc.ca/species-especes/profiles-profils/zebramussel-moulezebree-eng.html
Ecoscape Environmental Consultants LTD. (2017, March). Kalamalka and Wood Lake Boat Impact Study on Source Waters. Okanagan Basin Water Board. Retrieved March 18, 2022, from https://www.obwb.ca/newsite/wp-content/uploads/16-1796-BoatCapacityReport-FINAL-Mar14_2017_1532113887761_2113729986.pdf
Ecoscape Environmental Consultants Ltd., & Lotic Environmental. (2021). Windermere Lake Foreshore Integrated Management Planning. Lake Windermere Ambassadors. Retrieved July 22, 2022, from https://www.lakeambassadors.ca/lwawp/wp-content/uploads/2021/06/FIM-Windermere_Final.pdf
Hildebrand, M. 2022. Lake Windermere and Columbia Lake Shoreline Fisheries Assessment, August 2021. Report prepared by Lotic Environmental Ltd. for the Lake Windermere Ambassadors. 12 pp. + 2 app.
Neufeld, A., Swain, L., and Reiberger, K. (2010). Water quality assessment and objectives for Windermere Lake. Technical Report. First Update. November 2010. Water Protection & Sustainability, Environmental Sustainability Division, Ministry of Environment.
Orrick, D. (2019, January 23). Zebra mussels’ best friend: Wakeboard boats, New U study finds. Livewells also tested. Twin Cities. Retrieved May 19, 2022, from https://www.twincities.com/2019/01/22/zebra-mussels-wakeboard-boats-umn-study-livewells-mn/
Our Living Waters. (2019, December). Harmful algae blooms: Measures the number of provinces/territories with water-quality monitoring programs with the potential to estimate the number of water bodies impacted by algal blooms. Our Living Waters – English. Retrieved May 17, 2022, from https://www.ourlivingwaters.ca/harmful_algae_blooms
Selkirk College. (2022). Population – What does this measure and why is it important. State of the basin. Retrieved May 17, 2022, from https://stateofthebasin.ca/society/demographics/population
Terra Vigilis Environmental Services. (2022, June). Wave Propagation and Water Quality Impacts on Fresh Water Lakes – Phase 2. Northwest Wisconsin Lakes Conference. Retrieved July 19, 2022, from https://nwwislakesconference.org/2022-nwlc-breakout-2a/