In the summer of 2018, the Freeway Lakes near Albany were still a great place for messing about in small boats. By 2021, boating was much more restricted by the spread of ludwigia hexapetala or water primrose. Things have gotten no better since.
Last week, the east and middle of the three lakes were largely covered with the thick mats of green ludwigia. A channel of open water led from the gravel ramp to the tunnel under Three Lakes Road, and across the middle lake under the freeway to the largest of the three.
Can anything be done to win the war against this invasive pest and preserve the little county park and recreation area on Oak Creek?
Volunteers organized on Facebook (“Let’s Restore Freeway Lakes”) have been working on a trail and picnic tables on the banks, but they can’t do anything about the primrose.
For the past few years, a sign near the gravel boat ramp has said Linn County is “partnering” with the state Agriculture Department and the local watershed council to reduce the size of the infestation.
I asked the county about specifics, and I heard from Stacey Whaley, director of Linn County Parks and Recreation.
“This question is very timely” she replied by email Monday. “We actually have the spray company coming to the park on Wednesday and either Thursday or Friday this week for the annual application of the spray that controls the ludwigia, or more commonly known as water primrose.”
The weed is infesting many waterways in Linn County this year, she said.
Online publications say spraying with an herbicide approved for water use is the only effective way to fight water primrose. Pulling it by hand or machine (as was done on Albany’s Waverly Lake with a different type of growth) could break off pieces of the plants, and this causes new infestations.
“If we consistently apply the spray annually,” Whaley said, “it can take five years or more for the plant to be controlled, and this is only if it isn’t continually washing in again from upstream.”
She added: “Linn County Parks is interested in partnering with other groups (water conservation groups, etc.) to develop a plan to control the spread of this plant across the entire drainage, so we can more effectively fight this together. This might involve developing a time table for spraying each location, coordinating efforts to reduce downstream spread, and securing grants to help offset the cost, among other things. We are just starting these conversations now.”
“In the meantime, you should notice a die-back of the plants in coming weeks as this week’s spray takes effect.”
Water primrose starts in shallow water, from which the mats of plants expand and send roots down into the mud. So how about this for an aproach with a more lasting effect:
The lakes were dug out for the construction of Interstate 5 some 60 years ago. Let’s have them dredged so they are once again too deep for water primrose to take root. (hh)