Like all plants, they require sunlight, carbon dioxide, and nutrients. Fish and other aquatic animals also respire and discharge carbon dioxide into the water where it can be taken up by the algae cells. A. Nutrients can enter a lake from wind blown soil, storm water runoff, and the source water. It can also be recycled from the sediment at the bottom of the lake. At Ocotillo, most of the nutrients come from the reclaimed wastewater that is used to fill the lakes.
Treated wastewater is usually very high in nitrogen and phosphorus, the major plant nutrients.
This causes algae to flourish during the summer. During the winter, when plant growth is slowed by cold temperatures and reduced periods of sunlight, algae growth is often reduced and improved water clarity is observed. A. Yes, but the treatment plant was not designed to remove nutrients, and it is extremely expensive to convert the equipment. Facilities and operations to remove only a portion of the nutrients would cost hundreds of thousands of dollars per year. Removing nutrients to a level that would inhibit algae growth could cost millions per year.