An Exploration of the Past, Present and Future of Swan Lake
Christina Schulz
Summary
Swan Lake is a nature reserve located in the city of Saanich. The Lake’s history consists of uses such as for the site of a hotel, as a dairy farm, as a dumping ground for raw sewage and as a dumping ground for chemicals and pulp for two wineries. This massive intake of nutrients led the lake to become extremely eutrophic making it almost impossible for cold water fish species such as cutthroat trout to survive in the lake. In the 1970’s the municipality of Saanich began to acquire the land around Swan Lake and in 1975 the Swan Lake Christmas Hill Nature Sanctuary Society was formed. Species known to inhabit Swan Lake include insects, mammals, amphibians, reptiles, fish, and over 200 bird species. Swan Lake is home to a variety of endangered/threatened species such as the Western Painted Turtle, as well as many invasive species. Reed canarygrass is one of the most extensive invasive species in the area taking up 13.6 hectares of the 48 hectare sanctuary. The sanctuary is visited by approximately 70,000 people every year for activities such as bird watching, children’s educational programs, exercise (walking/jogging), volunteer restoration work, and fundraising. Volunteers play a crucial role in the management of the nature sanctuary, specifically helping with projects such as stream restoration, invasive plant removal, trail building as well as working in the native plant garden. Future management for Swan Lake should focus on protecting existing wetland habitat. The vegetation of a watershed is critical to its health, therefore it will be important to plant native wetland species and remove the invasive species. |
Swan Lake. (Photo by Christina Schulz)
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Genealogy
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Swan Lake was formed around 12,000 years ago when the last glacier receded (Swan Lake Christmas Hill Nature Sanctuary, n.d.). The basin of Swan Lake is comprised of marine clay and a surface layer of peat (Morrison, 2015). The first human presence recoded on Vancouver Island was around 4000 years ago by the First Nations people (Townsend & Hebda, 2013). The large volume of spear and arrow heads found in the Swan Lake area suggest that it was an important hunting and gathering area for the Songhees First Nation people (Morrison, 2015).
The first major development to happen around Swan Lake was in 1858 when William Steinberg started the Victoria Brewing Company beside Swan Lake (Swan lake: Oasis in middle suburbia, 2005; Rogers & Checkley, n.d.). However, this business was moved into town a year later due to poor water quality in the lake (2005; Rogers & Checkley, n.d.). Then, in 1864 the Swan Lake Hotel (also known as Swan Lake House) was built on the south side of the lake (BACK TO NATURE, 1995; 2005). The hotel was known for having |
Figure 1. 1928 air photo of Swan Lake (source, University of Victoria air photo archive).
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great fishing in the spring and summer and excellent skating in the winter (Morrison, 2015). This hotel is thought to have been Saanich’s first year-round resort (2015). However, in 1894 the hotel was destroyed by a fire and after being quickly rebuilt was destroyed again by another fire in 1897 (1995; 2005). The hotel was not rebuilt after the second fire (2015). In addition to the commercial business developments, Swan Lake has had a long history of farming. For instance in 1917, Joel Pendray began operating a dairy farm on the east side of the lake (Figure 1) (2015). Fertilizer runoff from this farm contaminated the lake resulting in decreased water quality (2015). This farm was operated until 1978 when the Nature Sanctuary acquired the land (2015).
Additionally, Swan Lake was inadvertently used as a dumping ground for sewage and chemicals. In the 1960s, sewage treatment facilities discharged their “treated” water into Blenkinsop Creek, which drains into Swan Lake (Townsend, 2009). These systems were insufficient in treating the volume of waste water, which led to high volumes of water bypassing the system and entering the Swan Lake watershed (2009). In addition, there were two wineries that were operated for 40 years near Swan Lake. Similar to the sewage treatment facilities, the wineries polluted the lake by discharging fruit pulp and chemicals into the Blenkinsop Creek (2009). The dumping of these sulphide and yeast compounds resulted in foul smells, which discouraged many people walking near the lake (BACK TO NATURE, 1995).
The major overloading of nutrients into the lake also caused problems for the species within it. This resulted in mass plankton growths, which in turn lead to large amounts of algae growing in the summer months (Morrison, 2015). When bacteria broke down this material, it consumed a large portion of the oxygen in Swan Lake, leaving the bottom of the lake oxygen deficient (2015). This lack of oxygen made it almost impossible for cold water fish (cutthroat trout) to survive in the lake, resulting in large die offs of fish starting in 1952 (2015). After the entire area was connected to the sewer system in 1975, the water conditions of the lake began to improve (2015). Even though the deep parts of the lake are still oxygen deprived, the overall improvement in water quality has enabled many of the cutthroat trout to survive most of the year in the lake (2015).
Another initiative to improve the water quality and ecosystem function was conducted by the municipality of Saanich in 1962, as they acquired the land around Swan Lake (Figure 2) (Morrison, 2015). Acquiring this land would allow them to take the necessary steps needed to rehabilitate the site back to its natural state (2015). The Swan Lake Christmas Hill Sanctuary was then established on June 16, 1975 (BACK TO NATURE, 1995; 2015).
Additionally, Swan Lake was inadvertently used as a dumping ground for sewage and chemicals. In the 1960s, sewage treatment facilities discharged their “treated” water into Blenkinsop Creek, which drains into Swan Lake (Townsend, 2009). These systems were insufficient in treating the volume of waste water, which led to high volumes of water bypassing the system and entering the Swan Lake watershed (2009). In addition, there were two wineries that were operated for 40 years near Swan Lake. Similar to the sewage treatment facilities, the wineries polluted the lake by discharging fruit pulp and chemicals into the Blenkinsop Creek (2009). The dumping of these sulphide and yeast compounds resulted in foul smells, which discouraged many people walking near the lake (BACK TO NATURE, 1995).
The major overloading of nutrients into the lake also caused problems for the species within it. This resulted in mass plankton growths, which in turn lead to large amounts of algae growing in the summer months (Morrison, 2015). When bacteria broke down this material, it consumed a large portion of the oxygen in Swan Lake, leaving the bottom of the lake oxygen deficient (2015). This lack of oxygen made it almost impossible for cold water fish (cutthroat trout) to survive in the lake, resulting in large die offs of fish starting in 1952 (2015). After the entire area was connected to the sewer system in 1975, the water conditions of the lake began to improve (2015). Even though the deep parts of the lake are still oxygen deprived, the overall improvement in water quality has enabled many of the cutthroat trout to survive most of the year in the lake (2015).
Another initiative to improve the water quality and ecosystem function was conducted by the municipality of Saanich in 1962, as they acquired the land around Swan Lake (Figure 2) (Morrison, 2015). Acquiring this land would allow them to take the necessary steps needed to rehabilitate the site back to its natural state (2015). The Swan Lake Christmas Hill Sanctuary was then established on June 16, 1975 (BACK TO NATURE, 1995; 2015).
Figure 2. Comparison of 1928 air photo (on left) and 1966 air photo (on right). Notice the massive clearing of forest can be seen when comparing each image (source, University of Victoria air photo archive).
Socio-ecological characterization
In the 1970’s the Municipality of Saanich began to acquire the land around Swan Lake with the aim of returning the area to its natural state (Morrison, 2015). After much land acquisition in 1975 the Swan Lake Christmas Hill Nature Sanctuary Society was formed (Figure 3) (2015). The nature sanctuary operates through a land management agreement with the city of Saanich and the land and facilities are owned by the Corporation of the District of Saanich (Swan Lake Christmas Hill Nature Sanctuary, n.d.).
Figure 3. Google Earth photo of Swan Lake Nature Sanctuary (source, Google Earth pro).
Species known to inhabit Swan Lake include insects, mammals, amphibians, reptiles, fish, and over 200 bird species (Townsend, 2010). Examples of avian species found at Swan Lake are: Golden-crowned sparrows (Zonotrichia atricapilla), Anna’s Hummingbirds (Calypte anna), Barred Owls (Strix varia), a variety of waterfowl, and many more (Figures 5 & 6). Another species found at Swan Lake is the endangered Western Painted Turtle (Chrysemys picta), which is a federally red-listed species, indicating how valuable to land at Swan Lake is (2010). The terrestrial vegetation at Swan Lake is comprised of three distinct ecosystems: mixed Douglas-fir (Pseudotsuga menziesii) and Garry Oak forests (Quercus garryana), old agricultural fields with remnant Garry oak trees and sparse understory vegetation and mixed Garry Oak, Bigleaf Maple (Acer macrophyllum) and Red Alder forests (Alnus rubra) (Townsend, 2010). Invasive species are very prevalent at Swan Lake and includes species such as English Ivy, Laurel-leafed Daphne and grasses such as reed canary grass
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Swan Lake Nature Sanctuary is 48 hectares in size (Townsend, 2009). The lake is classified as a eutrophic lake covers 9.2 hectares with a maximum depth of 5 meters (2009). The lake is surrounded by 37 hectares of grasses and shrubs comprised of 14 hectares of reed canary grass an extremely invasive species (Townsend, 2009; Townsend, & Hebda, 2013). Swan Lake is fed by watersheds such as Blenkinsop Lake, and the water is then drains into Colquitz river (Swan Lake Christmas Hill Nature Sanctuary, n.d.). The Swan Lake watershed is roughly 25% impervious, which causes large quantities of storm water to flow into Blenkinsop Creek. This increased volume of water has led to extremely unnatural changes in the water level of the lake (Townsend, 2010; Morrison, 2015). The increase in water flow can lead to flat areas of Swan Lake regularly flooding in the winter when rainfall is high (Figure 4).
Figure 4. 1977 air photo of Swan Lake, showing flooding around the lake. (source, University of Victoria air photo archive).
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(Phalaris arundinacea) (2010). Canaryreed grass is the most widespread invasive plant at Swan Lake, occupying about 13.6 hectares of land (2010). Invasive animals are also commonly found at Swan Lake. The most high risk invasive species include Black Bullhead Catfish (Ameiurus melas), Pumpkinseed Sunfish (Lepomis gibbosus), and American Bullfrogs (Lithobates catesbeianus) (2010).
Figures 5 & 6. Two avian species found at Swan Lake.
Left: Figure 5. Anna’s Hummingbird (Photo by Christina Schulz).
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Figure 6. Barred Owl (Photo by Christina Schulz).
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Roughly 70,000 people visit Swan Lake Nature Sanctuary every year (Townsend, 2010). The nature sanctuary is used for activities such as: bird watching, children’s educational programs, exercise (walking/jogging), volunteer restoration work, and fundraising (2010). Programs at the sanctuary focus on the natural history and ecology of Vancouver Island, promoting the proper use and maintenance of the lands around Victoria (2015). Furthermore, Swan Lake provides people a place to immerse themselves in nature (2015). This is accomplished through the nature house which provides information about the area and is located at Swan Lake. As well there are boardwalks, trails and a bridge that goes across the lake that help immerse people in the environment of Swan Lake.
Volunteers play a crucial role in the management of the nature sanctuary, specifically helping with projects such as stream restoration, invasive plant removal, trail building as well as working in the native plant garden (Figure 7) (Morrison, 2015). Currently, restoration at Swan Lake has been done without a long-term management plan and is carried out on a more opportunistic basis, which has been ineffective at addressing the magnitude of issues Swan Lake faces (Townsend & Hebda, 2013; Morison, 2015).
Volunteers play a crucial role in the management of the nature sanctuary, specifically helping with projects such as stream restoration, invasive plant removal, trail building as well as working in the native plant garden (Figure 7) (Morrison, 2015). Currently, restoration at Swan Lake has been done without a long-term management plan and is carried out on a more opportunistic basis, which has been ineffective at addressing the magnitude of issues Swan Lake faces (Townsend & Hebda, 2013; Morison, 2015).
Figure 7. Comparison of Swan Lake in 1966 when the Municipality of Saanich was acquiring the land (left image) and a current Google Earth Pro image of Swan Lake (right image). Restoration of the area can be seen in the current google earth image (source, University of Victoria air photo archive).
Future trajectory
When considering the future of Swan Lake an important factor to consider will be climate change. Climates are currently changing and the future predictions anticipate a change in temperature ranging from 1.1 – 6.4°C warmer (Townsend, 2010). This will lead to changes in the hydrology of the streams and lake as well as loss of forested areas with an increase in the amount of grasslands at Swan Lake (2010). This could lead to increases in invasive species such as orchard grass and reed canary grass. Impacts on the lake from climate change may include an increase in the eutrophication of the lake due to warmer summer temperatures and less rainfall (2010). Conversely, climate change could lead to increases in rainfall in the winter months which may cause major erosion to the streams that lead into Swan Lake (2010). Furthermore, climate change may cause shifts in species ranges leading to the loss of certain species such as Garry Oak trees (2010).
Ecologically, there are two main trajectories that the ecosystems within the Swan Lake Christmas Hill Nature Sanctuary could head towards. First, with the large volunteer effort that the sanctuary has, a management plan could be implemented (Townsend, 2010) which would greatly improve the ecosystem function of the area. This would lead to a decline in the proportion of invasive species in the area allowing native species to rebound. This would be a best case scenario for the Sanctuary. However an alternative trajectory that the sanctuary could move towards is that restoration efforts decline and the invasive/non-native species in the area take over. This would lead to Swan Lake turning into a novel ecosystem. One of the most dangerous species on the site is reed canary grass. If left unchecked it would take over large areas of the sanctuary decreasing native biodiversity (2010). However, this scenario is unlikely due regular management efforts by the Swan Lake Nature House (Figure 8).
Ecologically, there are two main trajectories that the ecosystems within the Swan Lake Christmas Hill Nature Sanctuary could head towards. First, with the large volunteer effort that the sanctuary has, a management plan could be implemented (Townsend, 2010) which would greatly improve the ecosystem function of the area. This would lead to a decline in the proportion of invasive species in the area allowing native species to rebound. This would be a best case scenario for the Sanctuary. However an alternative trajectory that the sanctuary could move towards is that restoration efforts decline and the invasive/non-native species in the area take over. This would lead to Swan Lake turning into a novel ecosystem. One of the most dangerous species on the site is reed canary grass. If left unchecked it would take over large areas of the sanctuary decreasing native biodiversity (2010). However, this scenario is unlikely due regular management efforts by the Swan Lake Nature House (Figure 8).
Figure 8. Progression of Swan Lake from 1928 to current day Google Earth Pro photo. Progress of restoration at Swan Lake can be seen when comparing the center and right photo (source, University of Victoria air photo archive; Google Earth Pro).
Figure 9. An area at Swan Lake that has extensive reed canary grass.
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Future Management for Swan Lake should focus on protecting existing wetland habitat. The vegetation of a watershed is critical to its health, therefore it will be important to plant native wetland species and remove invasive species (reed canary grass) (Townsend, 2010). Management of the Lake’s health will be important, including monitoring what nutrients and pollutants are entering the lake (2010). Dealing with the reed canary grass on site will be an important operation to continue in the future. Planting quick growing deciduous trees such as willow (which form a shade canopy) have proven a good tactic for controlling the reed canary grass at Swan Lake and this method should be applied to other areas in the sanctuary where this grass is taking over (Figure 9) (2010). The use of pollen analysis may help to get a sense of what this area looked like before the infestation of reed canary grass and allow workers to restore the native vegetation back to its historic state for future generations (Townsend & Hebda, 2013).
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Urban development around Swan Lake is expected to expand in the future along with population growth in the area. One concern with expansion in the Swan Lake region is that new development may further degrade downstream areas leading to more erosion (Townsend, 2010). Conversely, new development could lead to increases in the watershed and ecosystem health (2010). The increase in health may include tactics such as reducing the amount of impervious area with rainwater management such as rain gardens, or restoring ecosystems that have been degraded as a condition to development in the area around Swan Lake (2010).
References
BACK TO NATURE - over the last 20 years, swan lake has been. (1995 ). Times – Colonist.
Morrison, T. (2015). Swan Lake Christmas Hill Nature Sanctuary from the Ground Up: A Brief Guide and History. Saanich, BC.
Rogers, J., & Checkley, S. (n.d.). Capital Regional District (CRD) Community Green Map. Retrieved from http://crdcommunitygreenmap.ca/story/victorias-microbrewery-culture
Swan Lake Christmas Hill Nature Sanctuary. (n.d.). Retrieved from http://www.swanlake.bc.ca/the-ecosystems.php
Swan Lake Christmas Hill Nature Sanctuary. (n.d.). Retrieved October 11, 2016, from http://www.swanlake.bc.ca/the-sanctuary.php
Swan lake: Oasis in middle suburbia. (2005). Saanich News.
Townsend, L. (2010). Swan Lake Adaptive Ecosystem Management Plan. Saanich, BC.
Townsend, L. (2009). Urban watershed health and resilience, evaluated through land use history and eco-hydrology in Swan Lake watershed (Saanich, B. C.). In Masters Abstracts International, 48(5).
Townsend, L., & Hebda, R. J. (2013). Pollen and Macro‐Fossil Assemblages in Disturbed Urban Wetlands on South Vancouver Island Reveal Recent Invasion of Reed Canarygrass (Phalaris arundinacea) and Guide Restoration. Restoration Ecology, 21(1), 114-123.
Morrison, T. (2015). Swan Lake Christmas Hill Nature Sanctuary from the Ground Up: A Brief Guide and History. Saanich, BC.
Rogers, J., & Checkley, S. (n.d.). Capital Regional District (CRD) Community Green Map. Retrieved from http://crdcommunitygreenmap.ca/story/victorias-microbrewery-culture
Swan Lake Christmas Hill Nature Sanctuary. (n.d.). Retrieved from http://www.swanlake.bc.ca/the-ecosystems.php
Swan Lake Christmas Hill Nature Sanctuary. (n.d.). Retrieved October 11, 2016, from http://www.swanlake.bc.ca/the-sanctuary.php
Swan lake: Oasis in middle suburbia. (2005). Saanich News.
Townsend, L. (2010). Swan Lake Adaptive Ecosystem Management Plan. Saanich, BC.
Townsend, L. (2009). Urban watershed health and resilience, evaluated through land use history and eco-hydrology in Swan Lake watershed (Saanich, B. C.). In Masters Abstracts International, 48(5).
Townsend, L., & Hebda, R. J. (2013). Pollen and Macro‐Fossil Assemblages in Disturbed Urban Wetlands on South Vancouver Island Reveal Recent Invasion of Reed Canarygrass (Phalaris arundinacea) and Guide Restoration. Restoration Ecology, 21(1), 114-123.
