The Fine Print: How to remove water weeds properly

Published: March 29, 2019

Water weeds Photo by Ralu Cohn/Shutterstock

What goes through your mind when you jump in the lake and feel stringy plants tickling your toes? Like the line from the Ghostbusters song, there’s something weird and it don’t look good. If only you could fetch Bill Murray and his gang. Take invasive Eurasian water-milfoil. There’s a reason they call it the zombie weed; an underwater plant that regenerates even when severed from its roots conjures up the living dead. Who you gonna call? Well, that depends on where you are in Canada.

Before you start: Two caveats
First, people shouldn’t be afraid of plants licking their legs. “The danger is more from panic,” says James Littley of the Okanagan Basin Water Board. Nobody, to his knowledge, has ever been sucked to the bottom by aquatic vegetation, though excessive growth can choke a boat propeller. The stuff also stinks when it decays, and the process of decomposition uses up precious oxygen needed by fish. Still, if you don’t know what the plant is, leave it alone or consult experts, Littley says. “It could be sensitive or endangered.” Native water plants can also keep the water clean; provide habitat for wildlife such as fish, turtles, frogs, and small mammals; and protect against erosion.

Second, reduce excessive plant growth by minimizing nutrient-loaded runoff: don’t use fertilizers; don’t hardscape; leave at least a three-metre-wide buffer zone of plants at the shoreline; and keep your septic system operating properly.

Step 1: You may need a permit
Sometimes, though, there’s no option but to selectively harvest vegetation to make a boat channel to your dock or an open swimming area. Check with whoever manages the water bed in front of your cabin (surprise! it’s not you) to ensure that you’re not interfering with, say, fish habitat, endangered mussels, or sensitive and protected plants.

In Ontario, for example, multiple governments meet at the water’s edge: Fisheries and Oceans Canada (DFO), Parks Canada, the Ministry of Natural Resources and Forestry, and conservation authorities (CAs). In addition, First Nations consultation may be required. The MNRF has jurisdiction over most of the province’s waterways, and you won’t need a ministry permit to take out invasive aquatic plants, as long as you follow the rules. (More on these below.) The same applies for native aquatic plants, but only if you are south of a boundary stretching roughly from Ottawa north of the Trent-Severn Waterway to Georgian Bay. Search “remove native aquatic plants” on ontario.ca for a helpful map. Cottagers on the Trent-Severn or the Rideau Canal systems, which are administered by Parks Canada, will always need a permit; search online for the “in-water and shoreline work permit.” Lastly, you might need a separate permit if you are in a wetland in a CA. If you think this all sounds complicated, you’re not wrong. Your best bet is to call your local building department, which will get you started.

Is your cabin in B.C., but not in DFO territory? Go to the FrontCounter BC website and search for an application for “changes in and about a stream.”

On DFO-managed waters throughout Canada, such as coastal waterfront, cottagers don’t require a permit, again if you follow the rules. However, guidelines and the application process for provincial waters vary slightly across the country. An example is Alberta’s rigorous program through Alberta Environment and Parks. The restrictions on cutting aquatic plants are similar to the DFO’s, but all work requires approval through the new OneStop online application portal. On the other side of the country, in Nova Scotia, you should contact your local Environment office for advice.

Step 2: Do it the right way
Whatever your jurisdiction, follow basic guidelines: work only directly in front of your property, and stay within the maximum harvest area; minimize the removal of native aquatic vegetation; dispose of the invasive plants you remove well up on dry land (they’re zombies, remember!); use only a rake, a cutter bar, or your hands to remove plants; and avoid dredging the bottom or carrying out work during critical fish life stages. (Search online for “timing windows to conduct projects in or around water” to get info for each province, and start your zombie-zapping research early. It can take weeks for a permit application to be processed, and the work window is small, usually July and August.)

Wondering about applying herbicides? Check with your local environment authority, such as Ontario’s Ministry of the Environment, Conservation and Parks, to see what’s allowed.

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