The Lake Health Committee charged with managing Willow and Mirror Lakes high in the Rocky Mountains above Denver Colorado had identified blue green algae as one of the major threats to water quality and their trout fishery. These blooms have degraded the lakes each year since the early 2000’s. The committee reviewed technologies to control or minimize algae growth and settled on the use of phosphorus precipitation as the solution to their problems.
Only one problem, the State of Colorado had never permitted the use of these technologies in State waters. Over the course of the past five years, the Committee worked with State officials to educate them on the process and to develop a permit for these key lake management tools. This spring Colorado approved the permit to perform this work and the first receipient of the permits were for Willow and Mirror Lakes.
As the permit process was coming together, they began their search for a company experienced in the use of these technologies and selected Aquatechnex. Our biologists have used this technology for a number of years. Algae are single celled organism and as such need to obtain the nutrients they need from the water column. Phosphorus is the limiting nutrient for algae in most cases. When phosphorus levels are reduced, the carrying capacity of the lake or pond also goes down. In addition these tools can limit or stop phosphorus release from the lake sediments.
As these lakes are high in the Rockies, the buffering capacity of these lakes was very limited. In addition, they have a trophy trout fishery that had to be protected. Alum was selected as the tool for phosphorus stripping, and as this application can drop pH rapidly in lakes with limited buffering capacity, calcium carbonate was also required to buffer and mitigate this issue.
Aquatechnex developed a unique application system that can make dual applications of a liquid Alum and a powdered buffer from one vessel to limit mobilization costs for the community. This application was performed on July 5th to both lakes and they are now a beautiful turquoiz blue. They hope to enjoy years of algae free conditions in these two lakes. The community will also be looking at the use of Phoslock, a new treatment tool our team will be bringing to the US market in August of this year.