Removing invasive plants in Bridge-Seton River Watershed

Project Year: 2017-2018

View Provincial Database Record


Project Lead

Lillooet Regional Invasive Species Society


Coastal Region


Project Type

Research & Information Acquisition

FWCP Contribution


Action Plan Alignment

Bridge-Seton Riparian Wetlands Action Plan

Project ID


Update: Community helps remove 7,000 kgs of invasive plants

People power gets results. That’s one of the take-aways the Lillooet Regional Invasive Species Society (LRISS) discovered when evaluating its project to remove invasive plants – particularly Yellow Flag Iris – in select tributaries of the Bridge-Seton watershed. The contribution by the community, in addition to FWCP funding, has resulted in a reduction of the plant by an impressive 80 per cent in the project area.

The LRISS recently completed the three-year project that aligns with priority actions set out in the FWCP’s Bridge-Seton Riparian and Wetlands Action Plan. The work took place in riparian areas around Tyaughton Lake and Portage Creek, near Goldbridge. Years one and two focused on inventory and plant removal, with evaluation and monitoring occurring in year three.

“Year one was a slow start,” said LRISS’s Jacquie Rasmussen. “Yellow Flag Iris are extremely difficult to remove by hand. The plants are typically in water, cover more than a square metre, and weigh up to 100 lbs each. It would take more than an hour to dig one plant up.”

Then, in year two, there was much more community involvement. In Seton Portage, Tsal’alh First Nation members were trained and hired to remove plants, and on Tyaughten Lake, the local residence association got involved. The association was able to supply significant resources, much of it in-kind, including an excavator and a dump truck, that fast-tracked the work. Eleven Yellow Flag Iris sites were treated, and over 7,000 kilograms of invasive plant matter were taken to the Lillooet landfill.

The majority of the Yellow Flag Iris has been successfully removed and most importantly, one year later, there were no signs of it growing back in treated areas. In the future, LRISS plans to work with T’it’q’et and Tsal’alh partners to treat the Himalayan Blackberry and Japanese Knotweed sites, where removal will require multiple treatments over multiple years.

LRISS Aquatic Invasives Project

Aquatic invasive species threaten to take over riparian and wetland areas in the Bridge-Seton Watersheds. Over the last two years, the Lillooet Regional Invasive Species Society (LRISS) has found invasives in several lakes, namely Yellow Flag Iris, Knotweed, and Himalayan Blackberry. Manual removal of Yellow Flag Iris is very labour intensive, but eradication is an attainable goal. This project will continue to remove invasives to protect shoreline and monitor sites that have been treated. LRISS is in partnership with local stakeholders and First Nations to complete this work. The project activities fall within the priority goals as set out in the LRISS  Aquatics Action Plan for this region.


Final Report: Executive Summary

The Lillooet Regional Invasive Species Society (LRISS) with the BC Hydro Fish and Wildlife Compensation Program grant has completed the third year of an Aquatic Invasives Project. The study area includes the Bridge-Seton Watersheds. Aquatic invasive species have been detected in the LRISS region and they have the potential to take over shorelines of lakes and creeks. Invasives, like Yellow Flag Iris, can create monocultures along riparian areas that displace native plants and degrade fish and wildlife habitat. This project targeted Yellow Flag Iris (Iris pseudacorus), Himalayan Blackberry (Rubus armeniacus) and Japanese Knotweed (Fallopia japonica).

The goals of this project included:
1. Monitor the sites found and removed on Anderson Lake.
2. Targeted survey for invasives on Tyaughton Creek and Portage Creek and remove invasives found in 2016 survey.
3. Monitor the Yellow Flag Iris and Knotweed sites on Seton and Tyaughton Lakes including the channels of Portage Creek flowing into Seton Lake. Removal of any sites that have returned.
4. Partner with local stakeholders and the Seton Lake First Nations to educate and train them on how to identify aquatic invasives and remove them.
5. Participate in local community events to education the general public about the impacts of invasives and how they can stop their spread.

Benefits to fish and wildlife include the following:
• Conservation of habitat: removal of invasive sites will restore and protect riparian habitat for fish and wildlife.
• Improve science & knowledge: the surveying of shoreline will create a baseline of data that will allow future monitoring of invasives in the region. If invasive sites are found, data about the species, area covered and location are collected for treatment and monitoring purposes.

Click the provincial database link below to read the full final report for this project.

View more about this project on the provincial database