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Floating Gardens Project

Floating gardens help clean the lake with biofilm.

Floating gardens help clean the lake with biofilm.

Garden rafts clean the water while growing food.

Floating gardens are an ancient method of aquaculture, practiced in Central America since Aztec times. Rafts covered with soil and plants are anchored in the water to create floating “wetlands” that clean the water while growing food.

The plant roots grow through the raft bottom into the lake, where they absorb nitrogen and phosphorous. Bacteria create a biofilm on the raft and roots that consumes nitrogen and phosphorous, converting them to less harmful substances. Pollutants such as metals and particulates are also filtered out, since suspended solids bond to the biofilm. This makes the water clearer, which lets light penetrate deeper, thereby letting plants grow deeper, bringing oxygen deeper.

The organic matter that attaches to the underside of the floating islands also provides food for fish, and the islands provide habitat for birds. Planting floating gardens with commercially valuable plants can increase the impact of this project.

LAEIG is creating a floating garden demonstration project.

Lake Atitlán Environmental Interests group is gearing up to implement a floating garden demonstration project in the lake, with more floating gardens the following year.

These large rafts, covered with soil and plants are anchored in the lake to create floating wetlands, will serve as a continuous method of removing excess nutrients from the lake, while providing a source of food and income for the farmers who maintain them. They will also provide habitat for fish and invertebrates, as well as the microbial colonies that are the base of any healthy ecosystem.

Floating gardens will be set up in Santiago Bay and San Lucas Bay, where wind-driven wave action is minimized by protective bay entrances. Both bays are dangerously contaminated by sewage from local towns and waste from tilapia farms, and we have agreed on locations near public docks so that the floating gardens are visible.