Current Lake Conditions

We had our first alum application of the season on June 14 to reduce phosphorus that was promoting cyanobacteria growth in Lakewood Bay. The rest of the lake is in good condition, with the Main Lake showing very low phosphorus and phytoplankton activity.

Lake Temperature

Our cool May and early June weather has slowed the increase in lake temperature over the past month, but the five days of near 90 degree weather from June 19-22 warmed the lake to just below what it was last year at this time. We are coming out of an El Niño weather which means we should be in La Niña this fall and winter, which may give us some wild weather this winter. For the moment it has been good weather for the lake and not too hot so we have not had to use river water to keep the lake full.

Secchi

We are past the spring clear water phase, but we did get over 19 feet of visibility on May 13. As our phytoplankton population shifts from diatoms to cyanobacteria and other species the lake visibility will decrease a bit more, but typically stays above five feet during summer.

Phytoplankton

Speaking of phytoplankton, the following charts shows our population so far this year. The charts show biovolume, which indicates what you see in the lake because it accounts for the size of the algal cells. When looking at the phytoplankton trend from last year Lakewood Bay and West Bay are cut off early due to the drawdown. We could still access Main Lake so sampling continued there.

Lakewood Bay

Lakewood Bay had high phosphorus concentrations and cyanobacteria was becoming dominant. The alum treatment dramatically reduced the cyanobacteria population and led to a near 50% reduction in phosphorus. This should set the bay up for a nice July 4 celebration.

Main Lake

Diatoms were very active in February and March, but by the end of March the population had declined dramatically. This is typical this time of year when zooplankton become active and consume most algae in the lake. This is the start of our “clear water phase” and the reason for the high Secchi readings you saw in the second graph.

West Bay

West Bay is always full of diatoms year around. While this impedes water clarity it also limits plant and cyanobacteria growth. If this shallow bay were maintained for clear water we would be constantly treating aquatic plants and may have to contend with cyanobacteria. The bay does occasionally see cyanobacteria, but that is primarily due to it blowing in from the Main Lake.