USE OF A RHODAMINE TRACER STUDY TO ESTABLISH THE CAUSE OF BLUE-GREEN ALGAE BLOOMS IN THE STOCKTON WATERFRONT

The City of Stockton conducted a water quality analysis to establish the cause of bluegreen algae growth within the Stockton Channel and to develop methods for control. The project site includes a 5,000 ft long corridor along the Stockton Channel between Weber Point and Interstate 5 in Stockton, California. The Stockton Channel connects Stockton to the San Joaquin Delta and remains integral to the City's continued economic growth and success.Existing data, a Rhodamine tracer study, and nutrient analyses were used to identify the causes of blue-green algae the Stockton Channel. Based on the results of these analyses, blue-green blooms appear to be correlated to low available nitrogen to phosphorus ratios and high surface water temperatures during hot summer periods. These conditions lead to algae die-off and impair Channel aesthetics by creating offensive odors that limit the potential of the waterfront area.After evaluation, it was evident that a destratification system best met the constraints and project objectives. A pilot study will be conducted in the summer of 2002 to develop design criteria specifically for the Stockton Channel.