Lone Lake Management Plan

This small lake on Whidbey Island once supported a trophy fishery, was the site of a triathlon swim event, and provided lake recreation opportunities. However, in recent years the lake is better known for its frequent toxic algae blooms, apparently caused by the loss of all aquatic plants from grass carp planted to control a Brazilian elodea invasion. A trained volunteer and Island County staff conducted year-long monitoring of the lake and its inlet and outlet streams. Herrera’s responsibility was to help design the monitoring program, train stream monitors, analyze the data, prepare water and phosphorus budgets to evaluate nutrient sources, and evaluate effectiveness and costs of feasible watershed management and in-lake methods for controlling algae blooms. Although the inlet streams had high phosphorus concentrations, they were small, seasonal streams that accounted for only a small portion of the phosphorus input. While ongoing watershed management methods were recommended, the focus of the plan was on feasible in-lake algae control alternatives. The in-lake alternatives evaluated included alum and Phoslock treatments, aeration and mechanical mixing, nanobubble oxygenation, ultrasonic algae control, and algicide applications.