Austin sprays clay substance to tamp down algae

• City officials recommend that people and pets avoid the algae and not drink water directly from the lake. Do not allow dogs to lick their fur prior to rinsing.

How it works: Workers spray lanthanum-modified clay near Red Bud Isle and along the north shore of the lake between I-35 and the lagoon near the Festival Beach boat ramp.

• The clay binds to phosphorus, a key source of nutrients for algae.
• Once bound into a mineral form, the phosphorus becomes unavailable to the algae and robs the algae of one of its primary food sources.

The cost: The project costs $300,000 per year, from the Drainage Utility Fund, which comes from the drainage charge on your Austin utility bill.

Of note: The clay substance is safe for humans, the environment and wildlife, and settles to the bottom in a few hours.

• Boaters should keep plenty of distance from the barge that workers will use to spray the clay material.

What's next: More spraying is scheduled east of I-35 on Tuesday.

• Additional applications are planned for July and August.