See the end of this post for handouts and links from Ben Peterson.

Haller Lake General Meeting, November 3, 2016

Vice President Sarah Benki-Nugent called the meeting to order at 7:29.

She thanked Suzi Zook and Sheryl Grater for organizing and running the Halloween party. We had a great turnout.

She thanked Ethan Bradford for maintaining the web site and Shawn Macpherson for taking great notes at the last couple of meetings. The Candidate’s Night was quite informative. Check out the web site for meeting notes; it’s a mini election guide.

There will be a crafts fair to benefit Mary’s Place December 11, and a Christmas potluck Dec. 3. The Christmas potluck will replace the December monthly meeting.

She’d like ideas for a topic for the January meeting.

The February meeting will have Deborah Juarez, our city council representative.

On Nov. 18, there will be a story-telling event at the club called “Telebration”.

Next January 14, we’ll have a Silent Movie Night, with live organ music and dinner.

Sarah introduced Ben Peterson. He’s an aquatic-weed specialist with the King County noxious weed program. They coordinate with land owners and the state.

The main focus of their program is the control of regulated weeds. Some, like tansy ragwort, must by law be controlled by land owners.

They’re funded by $3.20 fee per parcel annually. There are 15 people on staff.

He’ll cover mostly aquatic weed control, but also cover other lake health issues.

Note: Ben has graciously sent me a copy of his slides, attached at the end. You should follow along in the slides for most of the details, but these notes have some question answers and other information he added (he was an excellent speaker!).

Image from 1936: no water lilies. 2007: lots of water lilies. He uses the 2007 image because it’s from the time of the year which shows the lilies fully (they die back in the winter).

The invasive species “Fragrant Water Lily”, Nymphaea odorata, can be distinguished from the native spaterdock in that water lilies adjust to the water level with flexible stems.

His tables on water quality come from volunteer measurments that stopped in 2008; anybody want to volunteer again? You can Google “King County Haller Lake” to get see these tables.

Native plants of the lake: coontail, American waterweed, Slender water-nymph, Small pondweed, muskgrass, probably duckweed
Invasive: Fragrant water lily, Eurasian water milfoil (contrary to his slide, neighbors have seen milfoil)
Shawn: Sees another plant which is red, below the water surface, with no rhizomes; Ben didn’t identify it.

Along the shore:
Yellow-flag iris (noxious)
Purple loosestrife (noxious, regulated)
Marsh cinquefoil

Q: Should we cut the iris? A: It’s not regulated, so it’s not required. It’s already so common, you won’t make a big impact.
Q: Do homeowners need to deal with aquatic weeds? He’ll get to it later, but no.
Audience: Our parcels do go into the lake a little ways.
Ben: The way the noxious weed act works, the plants that aren’t widespread are required to be controlled so they don’t take over. Plants like blackberry or yellow-flag iris that are widespread don’t have to be controlled. They are noxious and have a huge impact, so it would be nice to try.

Showed a map of purple loosestrife. They pretty much ring the lake. Not a big priority because the lake doesn’t connect to uninvaded ecosystems, but King County comes and cuts flower heads every year.

On controlling water lilies, you need a permit to even to pull the plants, but it’s free and downloadable from their web site.

You can starve the root/rhizome (by repeatedly cutting the leaves off before they get to the surface; that’s “carbohydrate depletion” in his notes). Sometimes they come up when they die, but sometimes they stay in the mud and decay.

The city has a harvesting machine which is used on swimming beaches.

His dept. has an “underwater hedge trimmer” he can arrange to loan out.
Q: Will it hurt the turtles? No, they’ll get out of the way.

Can cut anywhere from just below the water surface to a couple of feet deep. Machine w/ all the attachments is ~$4,000. They’ve loaned it out to 6 people so far and they’ve had great experiences. Contact Ben in the summer to borrow it.

Herbicide would require ~3 years for complete extraction. Herbicide goes directly on the lily pads, so it has low environmental impact.

Our state is conservative about permitting herbicide use.

Lake Desire took 2 years to get pretty good control. Down to 10% after 1st year (two sprayings), then 2% 2nd year (1 spraying), then just a few plants.

Q: How do we deal w/ mud islands? No idea.

Could control half the lake at a time. They spread slowly. But big costs are permit and mobilization, so more efficient to do a lot at once. Probably ~$3,000 (per application) plus permits (once). Spray in June. Spray again in August. The blue dye is the messy part (it’s just added to show where the herbicide was sprayed).

Q: Does herbicide affect insects? No. There’s surfactant mixed in to over-the-counter herbicides that’s sticky, so it’s not allowed in aquatic applications. The state studies impacts on non-target plants and animals.

Audience comment: Herbicide has a high failure rate. A: They will come back, but repeated spraying twice a year for a few years will probably eradicate them; other methods won’t.

Q: Would aerating the lake help with any of these problems? Don’t think so. That’s done more for algae issues. Algae growth happens naturally every year.

Q: Do plants develop a tolerance to particular herbicides over time? He’s heard that some do. It happens more with annuals because they produce so much seed that there’s space for selection to work. Often on land you cycle between herbicides, but for water lilies, glyphosphate is the only one used because it’s low toxicity.

Q: What are our neon green blobs? Probably blue-green algae. There are two kinds of algae: filamentous and blue-green. Filamentous is blobby and non-toxic, you can pick it up; it’s native, usually growing on plants and other surfaces. Blue-green algae you can’t pick up; some of it brown-green; some of it bright green.
Q: Can a sample of the algae be tested? Ask King County Science (contact info attached).
Audience remark: Somebody is sending in algae samples to K. C.: you can see it on their web site.
Q: Will control of the water level control other obnoxious stuff? Don’t know. Die back contributes to algae.
Audience remark: The algae problem is new, so maybe so. A: Maybe there’s runoff from lawns giving phosphorus.
Q: Could people hanging in the lake for hours contribute to algae? Ask K. C. Science. Start testing water quality to get a baseline.
Audience remark: The Dowidars control the outlet pipe, and thus the level of the lake when lots of rain is coming in (in the summer, evaporation brings the level below that anyhow).

King County has a topographic map of the catchment area of the lake. Lots come in from the north, i.e. from Shoreline.

Most the the lake is “hydroparcels” owned by the state Department of Natural Resources.

Q: Are the water lilies all we need to worry about for swimmers? There isn’t dense milfoil, which is all that interferes with swimming.
Q: Is the street-end parcel the city’s responsibility? There aren’t lily pads on the public access because it’s well used.
Suzy: It was improved as a fishing area many years ago. Parks and Rec. was supposed to turn over management to local control.
Ben: It could be dept. of transportation pays for it since it’s a street-end park.
Q: How many lakes do you work on? 20 or 30 to varying degrees. Lake Desire had a grant. There’s a management plan for Shadow Lake.
Q: Does Lake Ballanger (Snohomish County) have issues? Don’t know.
Q: Echo lake? Don’t know.
Q: Is Haller Lake unique in being mostly privately owned? Some are totally private, like Lake Burien. Lake Desire is ~20% public. 95% of Lake Samamish is private. Lots of lakes were developed early on and are mostly private.
Q: Do people swim in Bitter Lake? Jessica (a guest who lives on Bitter Lake) does every day. Not many from public park. Public park has lily pad issue. Most of the access is owned by the school district. Lily pads and Canada goose poop keeps people away from swimming from the public access.
Jessica: There are signs warning about dangers of getting into the water: lily pads, swimmers itch. For some reason (maybe that), they have fewer swimmers.

Q: What to do about knot weed? It’s non-regulated because it’s widespread. It can be controlled by land owners. Looks like bamboo, but the leaves are wide. Can only be killed by systemic herbicide because it has a huge root system. We can borrow an injection tool that injects herbicide directly into stems. You don’t need a special permit to use it. There is a limit of 2,000 stems (or so) per acre.


Ben Peterson kindly shared with me the slides from his excellent talk, as well his list of contacts for further questions.  As a bonus, he gave us this pamphlet on the control of fragrant water lilies, and this 2007 City of Seattle report on Bitter Lake, Green Lake, and Haller Lake.

He also sent us these helpful links:

  • Here is a link to the Aquatic Plants and Fish Booklet permit that I said was necessary for any pulling of weeds from the water.  It is free and as long as it is printed up, read, and followed, no other permit is needed for hand pulling of lily pads and several other types of weed control activities.  The permit does not allow any herbicide use, that is the jurisdiction of the WA Dept. of Ecology and WA Dept. of Agriculture.
  • Here is a link to a description of the small Lake weed cutter machine that our program has available for folks to borrow. We have both the weed cutter and the rake attachment.  To borrow it (or reserve it for a week or so at a time) just email me: . Whoever borrows it will need to be able to meet me at our storage facility in Issaquah during week day business hours.  Also, transport of the machine will require a pick-up truck, larger SUV, or minivan.
  • Here is the WA Dept. of Ecology’s Risk Assessment for Glyphosate (the herbicide that would be most appropriate to be used for control of fragrant water lily, assuming a herbicide is used).
  • Another herbicide that could be use would be Imazamox, here is Ecology’s Risk Assessment for that herbicide (imazamox, trade name Clearcast); it is potentially even lower toxicity, and it does have fragrant water lily control listed on the label, however I don’t know how well it works on the plant.