4th of July Weekend Update

Tom and I were out on Wednesday the 29th of June and I was out Friday July 1st to assess the success of the June 22nd and 23rd general herbicide treatment. In herbicide treatment zones on the smaller lakes, like Sunset and Fawn, the treated vegetation (primarily Sago, Broad Leaf, and Illinois Pondweed) was dying off but yet to fall out of the water column and down to the bottom due to lack of wind and boat turbulence on the small “no wake” lakes. We were pleased to see water clarity was still quite high and no significant filamentous algal blooms were witnessed. We will have to keep a close eye on these smaller lakes as the warm calm sunny weather can change conditions in just a day or two! But, for now, nutrients being released by the decaying plants were not sufficient to stimulate filamentous algae blooms.

We visited the untreated water bodies like Golden Pond and Lost Canyon Lake to find them in excellent condition. These water bodies are experiencing no nuisance levels of native vegetation, no exotics and no algal imbalances and as such will not be treated for the foreseeable future.

By the time we got out on the Main Lakes, the heat had us feeling like sunscreen coated desert nomads, but the dead calm and sunny weather made for very favorable aquatic vegetation assessing. Treated plants were noticeably impacted (See photo). They were dying out and some were falling out of the water column. Certain species such as the wild celery were loosing entire leaves. The thin points were the leaf blades attach to the main plants were singed to the point were they break away from the main plant. These blades are now floating to the surface and will be noticeable until the wind blows them ashore. We observed a lot of Illinois pondweed segments on the water surface for similar reasons. This surface debris is an unfortunate side effect to the wide scale use of this type of herbicide treatment.

In the days following an herbicide treatment, not only are treated aquatic plants no longer taking in and locking up nutrients out of the water column, they are now re releasing it back into the water column as the decay. Lower growing tertiary vegetation will be able to take up much of these nutrients if they are given the chance. The ability for lower growing native vegetation to take up these released nutrients is a critical component of maintaining high water clarity and minimizing negative side effects of an herbicide treatment. The major factor influencing the ability of the lower growing aquatic plants to take in available nutrients is the weather. Mild, slightly overcast and lightly breezy conditions are best. Last year, these were the conditions experienced. This year we were not so fortunate. The very hot, calm and sunny conditions stimulated the organism most able to exploit nutrients released by decaying treated vegetation in the lakes, filamentous algae. Algae thrive in hot, calm, and sunny weather and can bloom quickly. Algae can take advantage of the available nutrients released following an herbicide treatment before the lower growing plants have a chance to lock them up. We were frustrated to see how quickly filamentous was blooming in shallow low mixing bays and pockets of the Main Lakes. (See photo). This type of response is the reason we limit herbicide use as much as possible. To decrease the potential for these types of side effects in the future, mechanical harvesting is being explored and will be integrated if a cost effective scheme can be contrived.

Norm Zion of Aquatic Nuisance Control was contacted and was able to us in for spot treatments of Cutrine chelated copper sulfate algaecide in hot spot areas (See map). This algaecide carries no swimming or consumption restrictions but is a systemic that requires sunny conditions to be affective (algae must take it in during photosynthetic activities). If the sunny calm and warm weather continues algae will be a chronic problem until we can get the nutrients into the lower growing non nuisance plants and plants in “no spray” zones. But for the fourth weekend, the lakes should be in great shape, open to your recreational expectations, waiting to be explored.

Enjoy a glorious weekend.
Your Lake Mangers,
Joel Steenstra and Tom Krueger