By Tim Newton
In mid-March, the City of Ottawa will start to eradicate yellow floating heart from the upper pond of Brown’s Inlet. Yellow floating heart is an invasive aquatic plant. Efforts to remove it will involve excavation and lining of affected areas. The purpose of this project is to prevent the plant’s further spread, not only within the upper pond but also to the wider ecosystem, including the lower pond of Brown’s Inlet, the Rideau Canal and the Rideau River.
Yellow floating heart is native to Europe and Asia. According to Ontario’s Invading Species Awareness Program (invadingspecies.com/), it came to North America in the late 19th century as an ornamental plant in water gardens. Since its introduction, accidental or intentional releases and flooding have contributed to its spread.
Yellow floating heart poses a threat to aquatic ecosystems. Like a carpet on the surface, the dense mats shade out native species, modify fish and wildlife habitat, and contribute to stagnation. Stagnant water offers ideal conditions for algae growth and mosquitoes. Yellow floating heart is most commonly found in slow-moving waters, in rivers, lakes and ponds. It can spread by seed or from broken stems, making it an easily dispersed species. It ranges throughout several states in the U.S., as well as a number of provinces in Canada. In Ontario, it is found in the upper pond of Brown’s Inlet, as well as in Burlington, and in areas near Georgetown and Erin.
In Brown’s Inlet, yellow floating heart is found in two areas, one at the west (upstream) end of the upper pond and the other at the east (downstream) end of the pond. Scheduled for mid-March, these areas will be excavated to a depth of 200 millimetres to remove all roots, shoots and rhizomes of the plant. (Rhizomes are horizontal underground plant stems capable of producing the shoot and root systems of a new plant. The excavated material will be hauled to the city’s Trail Road landfill. The excavated areas will then be lined with a geotextile fabric and backfilled with sand to stop the plant from growing back.
In preparing for this project, the city has consulted with regulatory agencies and other stakeholders including the Ontario Ministry of Natural Resources and Forestry, the Rideau Valley Conservation Authority, Parks Canada and the National Capital Commission. A presentation was also made to the Glebe Community Association on October 23, 2018.
Environmental impacts of this work will be minimal. The pond has been drawn down, so no fish or amphibia will be affected. Erosion and sediment control measures will be in place during construction, and trees near the work areas will be protected. Afterwards, all disturbed areas will be restored.
This project must be completed before the Rideau Canal begins refilling in mid-April. The work is expected to take three to four weeks. Tim.Newton@ottawa.ca During construction, all work areas will be fenced off. Most of the park will remain open to the public.
From this summer on, the city will monitor the pond for any remaining plants and remove them manually. These spots will be marked so that residual roots, shoots and rhizomes can be dug out during the following winter drawdown. It is expected that this procedure will have to be repeated over a period of about three years to ensure the plant does not re-grow.
If you have any questions, or need more information, please contact the City of Ottawa’s Project Manager, Tim Newton, by phone at 613-580-2424 (ext. 16023) or email at Tim.Newton@ottawa.ca.
For more information about yellow floating heart, please visit: invadingspecies.com/yellow-floating-heart/
Tim Newton is Project Specialist, Stormwater in the City of Ottawa Parks, Forestry and Stormwater Services