Since the discovery of European Water Chestnut (EWC) near Kingston, Ontario in 2013, multi-partner collaborative efforts have contributed to the control and eradication of EWC along the Rideau Canal, aiming to protect native ecosystems from this aquatic invasive plant. In partnership with Ducks Unlimited Canada (DUC), Rideau Valley Conservation Authority, and Cataraqui Region Conservation, Parks Canada has helped to coordinate extensive monitoring and control measures to address six known EWC populations across the waterway.
Early Efforts and Key Discoveries
In 2015, a substantial population of EWC was discovered by Scouts Canada/ Rideau Valley Conservation Authority outside of DUC’s surveillance area. This population is located in Ottawa, south of Black Rapids lock station and was initially managed by hand-pulling through a Water Chestnut Steering Committee. That same year, DUC discovered another significant population, this time on the opposite end of the Rideau Canal, situated along the northern shoreline of Belle Park in Kingston. Given its size and the risk of spreading contaminated sediment, this area was chosen instead for targeted herbicide applications in 2018 with hand-pulling being introduced later to supplement eradication efforts.
Funding and Expanded Control Measures
In 2019, Parks Canada funded Ducks Unlimited Canada to expand control measures on the Rideau Canal, which included additional herbicide applications to a smaller EWC population on Belle Park’s southern shoreline. By 2023, significant declines allowed for a temporary two-year trial that ceased herbicide use in favor of hand-pulling as the primary control method.
Recent Successes and Newly Discovered Populations
Thanks to continuous monitoring efforts at the Black Rapids population, over the past decade EWC has nearly been eradicated with only one rosette found and removed in 2024. This marks a significant improvement since 2015 when over 2,700 kg of plant material was removed along a 1 km stretch of the Rideau River.
In Kingston, several other smaller populations were also successfully managed through Parks Canada staff efforts resulting in previously infested areas, like in Green Bay, achieving EWC-free status in 2022.
EWC populations continue to emerge, such as one found at Port Elmsley in 2022. Based on the successful eradication at other sites, Parks Canada and its partners remain confident that these new populations can also be controlled.
Looking Forward
Thanks to partner support and effective control techniques like hand-pulling, EWC populations along the Rideau Canal continue to decline. Parks Canada remains committed to working toward complete eradication and invites community members to get involved.
If you encounter EWC, you can help by pulling it carefully by the roots, collecting any loose nuts, and disposing of the plant on land in black garbage bags for municipal waste. Sightings can be reported through iNaturalist, EDDMapS, the Invading Species Hotline (1-800-563-7711), or directly to Parks Canada at rideau@pc.gc.ca.
If you see it, pull it! Together, we can protect the Rideau Canal from invasive species.
Image: Rideau Canal Environmental Services students pulling European Water Chestnut (EWC) from Port Elmsley.
Photo credit: Parks Canada/ Kelly Cudney, June 18, 2024.
Image: Canoe full of European Water Chestnut (EWC) pulled from Port Elmsley.
Photo credit: Parks Canada/ Katherine Bain, June 18, 2024.
Image: Rideau Canal Environmental Services student, Emily Airhart, with a large European Water Chestnut (EWC) plant pulled from Belle Park North in Kingston.
Photo credit: Parks Canada/ Katherine Bain, 2024.
Image: Full European Water Chestnut (EWC) plant with a single rosette, intact roots, and nut.
Photo credit: Parks Canada / Kelly Cudney, 2023.