Moody Lake Alum Treatment

Project Description & Outcomes

This whole-lake alum treatment project, completed in 2019, drastically improved the water quality of Moody Lake by addressing the internal phosphorus loading.

Phosphorous is one of the main nutrients that promote algae growth in lakes and streams. It occurs naturally in the environment and comes from a variety of sources such as plants and soil. However, these nutrients become problematic when they exceed the natural threshold as one pound of phosphorous can promote up to 500 pounds of algae growth!

In 2012, Moody Lake’s summer average phosphorus concentration exceeded 150 µg/L, and the lake saw excessive algae growth on an annual basis. In 2021, one year after the alum treatment was completed, the lake’s summer average phosphorus concentration was down to 33 µg/L. This significant drop in phosphorus concentrations has resulted in cleaner water and fewer algae blooms.

The alum treatment project followed implementation of the Moody Lake Wetland Rehabilitation Project, which addressed the majority of external phosphorus loading. 

This treatment also benefits Bone Lake, which is located downstream.