by Susan Draper, LLMD Weed Subcommittee Chair
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In preparation for writing this weed and water quality report a group of volunteers met to do a morning lake tour on August 17, 2023. Participants included Linda Wolfe, the outgoing Weed Sub- Chair, Susan Draper, incoming Sub-Chair, Cole Webster, Aquatic Resources Specialist, and Doug Karman our 2023 Steering Committee Chair and volunteer tour boat operator. We met at 9:00 am at the Karman dock for the purpose of:
1. August weed tour of Long Lake.
2. Categorize weed densities and species.
3. Determine actionable options to present to LLMD.
4. Visually assess water quality and turbidity.
5. Formulate weed treatment recommendations for 2024.
6. Formulate phosphorus recommendations for 2024.
Our tour began and terminated in zone 8, at Doug Karman’s home due to our use of his boat.
Weed Locations, Species Identification and Densities:
A few rake pulls were used to confirm our visual evaluation of the mix of weeds in the floating mats as we navigated the perimeter of the lake. The floaters are a result of a combination of factors. These include cutting by boats, jet skis, general recreation, the escape of some weeds during the diligent waterfront owners clearing their frontage, and natural growth that can result in topping out on the water surface. Excessive heat is again a major contributor to growth this year.
While the rake pulls and visual evaluation results were inconsistent. Overall we were presented a mix of weeds including the following:
1. Elodea (native bottom growing perennial)
2. Curly Pondweed (invasive nuisance)
3. Narrow leaf pondweed (native nuisance)
4. Surface Algae (naturally occurring and visible in most areas)
5. Sago Pondweed (native found sporadically: 16, 5, 4, 1, 18)
6. Coontail (native found sporadically: 11, 18)
When touring the lake, we found a preponderance of Curly Pondweed and Narrow Leaf Pondweed in most zones. In Kirby Cove the narrow pondweed was a solid mat extending well beyond the outside area of individual docks and into the channel between lake basins. This led the committee to consider the following end-of-season action.
Weed Actionable Item #1 - Harvesting 2023:
The density of weeds in Kirby Cove and the channel between basins, zones 5 and 16, in August was extreme. The committee feels that it would be of benefit to the lakes’ health to remove this mass of weeds to prevent their decay and contribution to the phosphorus and sediment pool in this shallow area. In addition, we should get better flow between the basins which will improve water quality.
At the August 24, 2023, LMD meeting, the weed committee recommended that the steering committee consider harvesting in zones 5 and 16 as soon as possible. A motion was made to do so, and seconded. Conversation followed relative to the total acres and a limit of $10,000 that could be expensed without an RFP (request for proposal) from multiple harvest contractors. With a revision to the motion Cole Webster was directed to arrange the immediate scheduling of the sole harvester available in Washington and to look into any option for a waiver of our restriction to use LMD funds via a request to Thurston County called a "sole source justification".
An LMD member spotted the harvester on September 1st, 2023, working in both zone 5 and 16. Over a 3-4 day period they appeared to have covered the full scope of the initial target areas, about 6 acres.
A common cry is "what about us... our area is bad too"... Yep... this writer is right there with you. Time and money play a huge part. While there are other areas of concern, the recreation season is almost over and the other areas are smaller in size and would not provide the same overall end of season benefit as in the 6 acres recommended. The cost of harvesting is $2,500 per acre. Your neighborhood representatives voted in favor of limiting harvest to zones 5 and 16, with the goal to increase water flow between the basins and remove the mass of weeds to prevent their decay in those shallow areas. (see Long Lake zone map for area references)
Weed Actionable Item #2 - Weed Treatment 2024:
There will be one more weed tour in the early fall of 2023 and again in early spring 2024, before the suggested recommendations are put into play. Once defined and costs are calculated the treatment suggestions will go before the LMD Steering Committee for vote.
The weed committee recommended the following zones be treated next spring as soon as growth is starting to happen with a systemic herbicide. Zones 1, 2, 3, 4, 5, 8, 9, 13, 14, 16 & 18
Our conversation of which herbicide to use was supported by a newly obtained chart by Environmental Health Division which reviews nineteen aquatic herbicides and rates them as PASSED, CONDITIONAL OR FAILED.
There are 9 herbicides rated as PASSED. From that group the weed committee cross-referenced which products were NOT subject to the Fish Timing Window and WERE effective at the controls we need for the nuisance and invasive weeds in Long Lake. We found that Galleon SC (penoxsulam) is approved by the County, is a systemic like Sonar, and can be used during the fish timing window.
Galleon SC is a selective systemic aquatic herbicide for management of freshwater aquatic vegetation in ponds, lakes, reservoirs, marshes, wetlands, .… and slow moving or still bodies of water, including shoreline and riparian areas within or adjacent to these and other aquatic sites. It may be applied directly into water or sprayed onto emergent foliage or exposed sediment after drawdown. The product is taken up by targeted plants through emergent or floating leaves, from water through submersed plan shoots, or from hydrosoil by roots. See table1.
Most of the lake had a film of algae particles on the surface. When the wind comes up this will be blown to the shoreline. The three basins display 3 different levels of turbidity/algae particles. The Mill Pond has clear water and displays little if any algae except for filamentous in a few places. As you proceed from the Mill Pond into the North basin and then through the channel to the South basin the water becomes more turbid and is at its worst in the most southerly end of the South basin. Our strategy in the last year was to see if turbidity would reduce the sunlight on the weeds and thereby reduce weed growth. While the weeds didn’t start growing until almost mid-July, they grew prolifically after that and are very dense at the current time.
We discussed whether turbidity had a personal impact in the following areas:
1. Recreation – would you swim in the water? (Please note: respondents all over 60)
a. South Basin – No
b. North Basin – Yes
c. Mill Pond – Yes
2. Inspection – does the turbidity make it difficult to impossible to do weed tours?
a. South Basin – Yes
b. North Basin – Yes
c. Mill Pond – No
In review of the phosphorus management protocol for 2023 the committee came to the following conclusions and recommendations for 2024:
EutroSORB is superior to Phoslock.
EutroSORB is the same as Phoslock except at a higher active ingredient concentration.
EutroSORB permanently locks up the phosphorus.
Pre-treatment core sampling parameters can be improved.
Water Quality Recommendations - Algae Controls 2024
The following items are part of the draft 2024 work plan created by the LLMD Water Quality Committee members. County review and approval will be sought on plan completion.
Treat the entire lake with Alum in 2024 at the lowest dosage to strip the water column of algae particles and some phosphorus. This will assist with reducing turbidity and clearing up the water.
Treat the lake from the 6 foot depth and deeper with EutroSORB at a concentration that binds up the phosphorus to a specified depth in the settlement. This depth is in direct proportion to the pounds of EutroSORB required.
When we say the entire lake, we do not include the Mill Pond as that area showed no evidence of needing phosphorus management.
Core samples obtained by contractor will be completed with more specific detail on diameter of the sample tube and the depth of sediment to pull to decrease the margin of error in defining product poundage requirements
The entire 2024 work plan is roughed out yet unfinished. We will continue to research and fine-tune options and target dates to be considered by the LLMD Steering Committee members at monthly meetings. Our goal is always to present a plan with the greatest likelihood of approval.
We hope you enjoy this new format.
Send comments, questions, or concerns to WhatsUpLongLake@gmail.com, or call/text me and leave a message for Susan Draper at, 360-402-2343. Together we can create a BLOG that is fun, informative and that benefits all. Article ideas and contributions are welcome.
The BLOG format is aimed at increasing communication beyond the old twice-yearly newsletter. We expect to broadcast new information at least monthly to keep our neighbors informed.
CLICK HERE to SUBSCRIBE and receive new articles as they are published. You will want to get the next treatment plan update in October 2023, to learn what steps have been taken to revise our evaluation methods from subjective to scientific.