Shade Balls in LA Reservoir

Jul 11, 2024

Shade Balls in LA Reservoir

Introduction

  • Shade balls: Used in LA Reservoir.
  • Purpose misconception: Not primarily for reducing evaporation.

Context and Overview

  • The largest collection of shade balls is at LA Reservoir.
  • Total number: 96 million.

Key Questions

  1. Why are they black?
  2. Are they safe to have in drinking water?
  3. How much do they cost?
  4. Do they reduce evaporation?
  5. What is their actual purpose?

Characteristics of Shade Balls

  • Partially filled with water to keep them stable in high winds.
  • Difficult to move due to closely packed structures they form.
  • Main purpose: Reduce Bromate formation.

Bromate and Bromide Crisis

  • Bromide: Naturally occurs, harmless.
  • Bromate: Carcinogenic, formed when Bromide is exposed to sunlight in the presence of Chlorine.
  • Regulations: Limit on Bromate levels.
  • Discovery: High Bromate levels observed by a beverage company, traced to the reservoir.

Solution Search

  • Initial ideas: Floating tarps, HDPE pipe structures, debris fields etc.
  • Dr. Bryan White's discovery: Shade balls, originally called bird balls.

Safety and Testing

  • Testing: Kiddie pool experiment showed shade balls reduced Bromate formation effectively.
  • Material: High-density polyethylene, food-grade, carbon black for UV stability.
  • Health safety: Balls are inert, non-toxic, and safe for water use.

Additional Benefits

  • Algae control: Reduced sunlight prevents algae growth, reducing the need for Chlorine.
  • Evaporation reduction: Shade balls decrease evaporation by 80-90% due to reduced surface area and airflow.

Cost and Economics

  • Cost per shade ball: Approximately 33-34 cents.
  • Economic benefits: Savings from reduced chlorination and evaporation partially offset the cost.
  • Recyclability: Shade balls are recyclable.

Environmental Management

  • Bird deterrence: Effective in keeping birds away from the reservoir.
  • Shape advantage: Spherical shape prevents stacking, ensuring better surface coverage.

Fun Facts

  • Fun comparison: Resemblance to 'boba' (bubble tea).

Summary

  • Shade balls provide multiple benefits including Bromate reduction, algae control, evaporation reduction, and maintaining water quality, all for a cost-effective price.