What is the primary method used to control algae growth in reservoirs?

The primary method used to control algae growth in reservoirs is chemical treatment, such as chlorine or copper sulfate. These chemicals are effective in managing algae populations by either directly killing the algae or inhibiting their growth. Chlorine can disrupt the cellular functions of algae, leading to their death, while copper sulfate affects their ability to photosynthesize, causing them to die off.

Chemical treatments are especially useful because they can be applied across large areas of water, providing a rapid response to algal blooms that can compromise water quality and safety. While other methods like mechanical removal and natural filtration can have some effectiveness, they are often more labor-intensive and may not be as efficient in quickly controlling large algal outbreaks. Reducing sunlight exposure can help limit conditions conducive to algal growth, but it is not a practical method for managing established blooms in reservoir environments. Hence, chemical treatment is generally viewed as the most effective and widely used approach for controlling algae in water bodies.