- OES students tackle schoolyard dog poop problemPosted 4 days ago
- GMO foods dangerous, pervasive, former federal scientists tell forumPosted 4 days ago
- Former Stockwell Day assistant Neufeld will seek federal Conservative nominationPosted 4 days ago
- Christmas Lite-Up events feature Santa Parade and entertainmentPosted 4 days ago
- Vancouver pharmaceutical company applies for license to operate commercial medical pot facility in OsoyoosPosted 4 days ago
- School support staff prepared to walk picket lines starting Tuesday morningPosted 1 week ago
- Osoyoos stores open, close, move, change handsPosted 2 weeks ago
- Travel writer names Okanagan as world’s top wine destinationPosted 2 weeks ago
- Local leaders respond with caution to possible changes to modernize Agricultural Land CommissionPosted 2 weeks ago
Winter milfoil control program gets underway on Osoyoos Lake
The winter phase of the milfoil control program on Osoyoos Lake got underway last week as water temperatures continued to cool.
Unlike during the summer, when a machine cuts and harvests the tops of the invasive weed, between October and April a rototiller is used to pull the plant up by its roots.
Dave Caswell, of the Okanagan Basin Water Board (OBWB), who operates a machine used exclusively on Osoyoos Lake, was trying it out close to shore last week to make sure there were no mechanical difficulties.
As it was, the winter program was delayed a little more than a week because of mechanical issues.
“When we’re working in the water it’s really important that we don’t ever have any oil leaks, any fuel leaks or any mechanical problems out on the water,” said Caswell. “There’s always more risk to the environment if we have any mechanical problems on the water and it’s also more time-consuming to repair them, so we always take our time and try to make sure that the machines are in good working order every day so that we usually avoid those breakdowns out on the water.”
There are two main reasons why the roots are only pulled up during the winter season and not in the summer, explained James Littley, office and projects manager with the OBWB.
One is environmental. Because pulling up milfoil roots actually disturbs the lake bottom, there are only certain times of the year when it can be done. In some areas, it is not permitted at all.
The second reason is that the plant is only dormant in cooler water temperatures. When it’s cold, the roots float ashore and die, but when it’s warmer, cutting them would only spread viable plants.
Eurasian milfoil is an invasive aquatic species that first spread into the Okanagan lakes in the 1970s.
The OBWB took over the control program from the province in the early 1980s.
The OBWB prioritizes the areas where it will work each year based on surveys of the lake that determine where the highest densities are, said Littley.
They’ve also learned over the 40 years of the program where the milfoil grows and where it doesn’t – its growth is determined by a number of factors ranging from currents, water temperatures and nutrient loading.
Priority is given to areas around public beaches, although some adjacent areas fronting private property are also done as time permits, he said.
There are three rototillers for the entire Okanagan and one is dedicated to Osoyoos Lake, said Littley. Osoyoos Lake has the worst milfoil problem because of a combination of nutrient runoff, higher temperature and shallow lake bottom.
“It’s a perfect habitat for it,” he said.
When an area of milfoil is thoroughly uprooted, something that can take two to three years of treatment, it usually takes another two to three years before the plant re-establishes itself, Littley said.
The winter program runs from the beginning of October to the beginning of April, however, it often shuts down for a while in midwinter when the ice becomes too thick.
“We try to get as much done as we can before Christmas and we reassess it at that point,” said Caswell.
Freezing on the lake varies from year to year and sometimes it’s frozen for several months, while other years it never really freezes over completely, he said.
When the ice isn’t too thick, the rototiller can break right through it.
“It’s a pretty good Coast Guard icebreaker,” Caswell jokes. “When the ice is up to about three inches thick, the machine can handle breaking through ice and clearing a work area, but it gets very dangerous at that point. When we start getting that level of ice building up, the machine can get stuck. Once we get to the point where we’re breaking ice to go to work in the morning, it’s time to get the machine out of the lake.”
Aside from keeping the machinery running and pulling up weeds, the job has other challenges, Caswell said.
These include working alone in sometimes rough weather, but there are also unexpected hazards on the lake bottom that can’t always be seen.
“We routinely pick up debris and anchors, so one of the biggest hazards is just dealing with trying to keep the rototiller clear of debris and anchors and chains and things that we pick up on the bottom,” said Caswell.
This often requires bringing the machine into shore to untangle it and free it of debris, he said, adding this can be quite time-consuming.
For Caswell, who also runs an organic farm near Keremeos, there’s a lot of similarity between his work pulling weeds on Osoyoos Lake and his work on the farm.
“It’s very similar work in that it seems impossible at first blush when you look at the scale of the project,” he said. “But if you keep your nose to the grindstone and put in the time you can create something really beautiful. And you see that with public beaches here in the Okanagan particularly in Osoyoos.
“These beaches draw hundreds and thousands of people to come and play here and the reason they’re so nice, the reason that people are so attracted come and spend their time at our lakes and communities is because we put this work in. We meticulously garden these beaches and make them perfect for everybody to use in the summer.”