MWD approves algae control storage facilities at Lake Mathews and Lake Skinner

The Metropolitan Water District of Southern California board approved the final design of copper sulfate storage facilities to control algae blooms at Lake Mathews and Lake Skinner.

The MWD board’s May 13 action also appropriated $140,000 for those two projects and found the projects to be categorically exempt from California Environmental Quality Act review.

MWD is responding to the current drought by utilizing available storage, including drafting and re-filling district reservoirs. As water levels fluctuate algae blooms can increase in both frequency and severity, especially at lower levels during warm summer months, and in recent years an increasing number of algae events have occurred at MWD reservoirs.  

Factors which influence the severity of algae blooms include hydrology, available nutrients, sunlight, and temperature. The water treatment process might not be able to correct the taste and odor problems caused by the algae blooms. The timing of specific algae blooms cannot be predicted.

Copper sulfate treatment can control the rapid growth of algae, and MWD applies copper sulfate to canals and reservoirs to control algae blooms. The rapid growth rate of algae often requires a treatment response within a matter of hours. MWD currently stores copper sulfate in limited quantities at Lake Mathews and there is no copper sulfate storage at Lake Skinner. The Lake Mathews facility, which is used to store all copper sulfate slated to be applied to MWD’s canals and reservoirs, is 40 years old and must be upgraded to meet current fire codes for storage of hazardous chemicals.

The new storage facilities will minimize delays in applying copper sulfate treatment. The distance from Lake Mathews to Lake Skinner, along with the limited quantities of copper sulfate available at Lake Mathews, make timely application a current challenge. Quicker treatment will reduce the quantity of chemicals needed for treatment.

The storage facilities will be prefabricated metal structures approximately 50 feet long, six feet wide, and nine feet high. The structures will have an integrated fire suppression system, spill control, and ventilation. The site improvements will also include water line connections, electrical tie-ins, minor grading, and paving.

All final design activities will be performed by MWD staff. The design activities include preparing drawings and specifications, refining the construction cost estimate and receiving bids, and obtaining permits from the Riverside County Fire Department.

The $140,000 appropriated covers $12,000 for field surveys, $81,000 for final design, and $33,000 for permitting, environmental documentation, and project management along with a $14,000 budgeted contingency amount. The estimated construction cost for the both facilities is between $600,000 and $700,000.

The final design is expected to be complete by November.

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